The 50th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians – Poster Session (P001-P755) (2024)

Table of Contents
P001 AUTOLOGOUS VERSUS HAPLOIDENTICAL DONOR STEM CELL TRANSPLANTATION FOR FAVORABLE-AND INTERMEDIATE-RISK ACUTE MYELOID LEUKEMIA IN FIRST REMISSION AND UNDETECTABLE MINIMAL RESIDUAL DISEASE: A MULTI-CENTER, PROSPECTIVE STUDY Yiyang Ding1, Yuhua Ru1, Jinjin Zhu1, Xi Zhang2, Lin Liu3, Erlie Jiang4, He Huang5, Jishi Wang6, Jiong Hu7, Yanming Zhang8, Yajing Xu9, Mingzhen Yang10, Jia Chen 1, Depei Wu1 P002 OUTCOME OF ALLOGRAFTED ACUTE LYMPHOBLASTIC LEUKEMIA PATIENTS TREATED WITH THE PEDIATRIC-INSPIRED, MRD-ORIENTED GIMEMA LAL 1913 PROTOCOL IN THE REAL-LIFE: A CAMPUS ALL STUDY Gianluca Cavallaro 1, Davide Lazzarotto2, Chiara Pavoni1, Francesca Valsecchi1, Cristina Papayannidis3, Marco Cerrano4, Sabina Chiaretti5, Nicola Fracchiolla6, Fabio Giglio7, Michelina Dargenio8, Monia Lunghi9, Silvia Imbergamo10, Maria Ilaria Del Principe11, Silvia Trappolini12, Monica Fumagalli13, Patrizia Zappasodi14, Prassede Salutari15, Mario Delia16, Crescenza Pasciolla17, Federico Mosna18, Barbara Scappini19, Fabio Forghieri20, Patrizia Chiusolo21, Cristina Skert22, Benedetta Cambò23, Marzia Defina24, Giuseppe Lanzarone25, Mauro Endri26, Massimiliano Bonifacio27, Carla Mazzone28, Lidia Santoro29, Antonino Mulè30, Valentina Mancini31, Paola Minetto32, Giorgia Battipaglia33, Alessandro Cignetti34, Lara Aprile35, Robin Foà5, Anna Candoni2,20, Federico Lussana1,36 P003 FREQUENCY AND IMPACT OF SOMATIC MUTATIONS ON OUTCOMES OF ACUTE MYELOID LEUKEMIA PATIENTS RECEIVING ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION: FROM THE EBMT ACUTE LEUKEMIA WORKING PARTY Ali Bazarbachi 1, Jacques-Emmanuel Galimard2, Myriam Labopin2, Iman Abou Dalle1, Jaime Sanz3, Huang He4, Jiri Mayer5, Carlos Solano6, Celestine Simand7, Laimonas Griskevicius8, Johan Maertens9, Maija Itäla-Remes10, Ain Kaare11, Maria-Pilar Gallego-Hernanz12, Gesine Bug13, Josep-Maria Ribera14, Alain Gadisseur15, Christoph Schmid16, Mi Kwon17, Xavier Poiré18, Paola Coccia19, Manuel Jurado Chacón20, Frédéric Baron21, Eolia Brissot22, Arnon Nagler23, Fabio Ciceri24, Mohamad Mohty25 P004 ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR ELDERLY ACUTE LYMPHOBLASTIC LEUKEMIA PATIENTS: A STUDY FROM THE SOCIÉTÉ FRANCOPHONE DE GREFFE DE MOELLE ET THÉRAPIE CELLULAIRE (SFGM-TC) Yves Chalandon 1, Raynier Devillier2, Ariane Boumendil3, Stephanie Nguyen4, Claude-Eric Bulabois5, Patrice Ceballos6, Eolia Brissot7, Marie-Thérèse Rubio8, Hélène Labussière-Wallet9, Johan Maertens10, Patrice Chevallier11, Natacha Maillard12, Xavier Poiré13, Cristina Castilla-Llorente14, Yves Beguin15, Jérôme Cornillon16, Sébastien Maury17, Tony Marchand18, Etienne Daguindau19, Jacques-Olivier Bay20, Pascal Turlure21, Amandine Charbonnier22, Anne-Lise Menard23, Karin Bilger24, Gaelle Guillerm25, Sylvie François26, Ali Bazarbachi27, Sylvain Chantepie28, Philippe Lewalle29, Ambroise Marçais30, Michael Loschi31, Malek Benakli32, Paul Chauvet33, Edouard Forcade34, Anne Huynh35, Marie Robin36, Stavroula Masouridi-Levrat1 P005 ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION FOR OLDER PATIENTS WITH PHILADELPHIA-POSITIVE ACUTE LYMPHOBLASTIC LEUKEMIA. A SURVEY BY THE ACUTE LEUKEMIA WORKING PARTY OF THE EBMT Sebastian Giebel 1, Myriam Labopin2, Ryszard Swoboda1, Didier Blaise3, Ibrahim Yakoub-Agha4, Stephanie Nguyen5, Eva Maria Wagner-Drouet6, Cristina Castilla-Llorente7, Panagiotis Kottaridis8, Thomas Schroeder9, Renato Fanin10, Jakob Passweg11, Jurjen Versluis12, Charles Crawley13, Ludovic Gabellier14, Stephan Mielke15, Xavier Poiré16, Erfan Nur17, Carlos Pinho Vaz18, Matthias Eder19, Riccardo Saccardi20, Peter Dreger21, Zinaida Peric22, Mohamad Mohty2, Fabio Ciceri23 P006 OUTCOME OF PATIENTS WITH IDH-MUTATED AML FOLLOWING ALLOGENEIC STEM CELL TRANSPLANTATION Thomas Schroeder 1, Sarah Flossdorf1, Caroline Pabst2, Michael Stadler3, Johannes Schetelig4, Claudia Wehr5, Claudia Schuh6, Matthias Stelljes7, Elisa Sala8, Andreas Burchert9, Jennifer Kaivers1, Christian Reinhardt1, Nicolaus Kroeger10, Katharina Fleischhauer1, Christina Rautenberg1 P007 CD22-TARGETED IMMUNOTHERAPY FOR ADULT PATIENTS WITH RELAPSED OR REFRACTORY B-ALL WHO PREVIOUSLY EXPOSED TO CD19-TARGETED IMMUNOTHERAPY Mingming Zhang1,2, Yongxian Hu1,2, Peihua Lu3,4, Liang Huang5, Shan Fu1,2, Jingjing Feng1,2, Ruimin Hong1,2, Alex H. Chang6, He Huang 1,2 P008 COMPARISON OF THE PROGNOSTIC IMPACT BETWEEN ELN2022 AND ELN2017 RISK CLASSIFICATION IN ALLOGENIC HEMATOPOIETIC STEM CELL TRANSPLANT RECIPIENTS WITH AML Weihao Chen1, Yeqian Zhao1,2,3,4, Jimin Shi1,2,3,4, Yi Luo1,2,3,4, Jian Yu1,2,3,4, Yamin Tan5,6, Xiaoyu Lai1,2,3,4, Lizhen Liu1,2,3,4, Huarui Fu1,2,3,4, Yishan Ye1,2,3,4, Luxin Yang1,2,3,4, Congxiao Zhang1,2,3,4, He Huang1,2,3,4, Yanmin Zhao 1,2,3,4 P009 EFFICACY AND SAFETY OF THE THIRD-GENERATION TKI OLVEREMBATINIB IN ADULT PH + ACUTE LYMPHOBLASTIC LEUKEMIA WITH RELAPSED DISEASE OR PERSISTENT MRD BRIDGING TO ALLO-HSCT XiaoYu Zhang 1, Yanhong Zhao1, Rongli Zhang1, Erlie Jiang1 P010 INTRACELLULAR CYTOKINE ASSAYS IN COMBINATION WITH DEGRANULATION ASSAY CONTRIBUTE SIGNIFICANTLY TO DETECT AND QUANTIFY LEUKEMIA SPECIFIC IMMUNE CELLS IN AML PATIENTS’ BLOOD OR CULTURE SETTINGS Olga Schutti1, Lara Klauer2,1, Tobias Baudrexler2,1, Christoph Schmid3, Andreas Rank3, Joerg Schmohl4, Markus Hentrich5, Doris Kraemer6, Helga Schmetzer 1 P011 TOTAL MARROW AND LYMPHOID IRRADIATION IN COMBINATION WITH POST-TRANSPLANT CYCLOPHOSPHAMIDE-BASED GRAFT VERSUS HOST DISEASE PROPHYLAXIS CONFERS FAVORABLE GVHD-FREE/RELAPSE-FREE SURVIVAL IN PATIENTS WITH ACUTE MYELOID LEUKEMIA Anthony Stein 1, Monzr Al Malki1, Dongyun Yang1, Joycelynne Palmer1, Ni-Chun Tsai1, Ibrahim Aldoss1, Haris Ali1, Ahmed Aribi1, Andrew Artz1, Savita Dandapani1, Len Farol1,2, Susanta Hui1, An Liu1, Ryotaro Nakamura1, Vinod Pullarkat1, Eric Radany1, Amandeep Salhotra1, James Sanchez1, Ricardo Spielberger1,2, Guido Marcucci1, Stephen Forman1, Jeffrey Wong1 P012 INCREASED MESENCHYMAL STROMAL CELLS SENESCENCE AND HIGH CXCL14 LEVELS IN BONE MARROW ARE LINKED WITH THE OCCURRENCE OF GVHD AFTER HEMATOPOIETIC STEM CELLS TRANSPLANTATION Alexandra Guelton 1, Meriem El Ouafy1, Romain Perouf1, Naceur Charif1, Simona Pagliuca1, Marie-Thérèse Rubio1, Natalia de Isla1 P013 CORRELATION OF THE OVERALL SURVIVAL IN MIXED-PHENOTYPE ACUTE LEUKAEMIA AND ACUTE LYMPHOBLASTIC LYMPHOMA WITH THE REFINED DISEASE RISK INDEX APPLIED IN AN UPPER-MIDDLE INCOME COUNTRY Naty López-Córdova 1, Jessica Meza-Liviapoma1, Jule Vasquez-Chavez1, Claudio Flores-Flores2, Shirley Quintana-Truyenque1 P014 SIGNIFICANT IMPROVEMENT OF SURVIVAL AFTER ALLOGENEIC STEM CELL TRANSPLANTATION IN ACUTE LYMPHOBLASTIC LEUKEMIA OVER TWO DECADES – A SINGLE CENTER RETROSPECTIVE ANALYSIS Ben-Niklas Baermann1, Paula Kessler 1, Astrid Tautges2, Paul Sebastian Jäger1, Mustafa Kondakci3, Kathrin Nachtkamp1, Sascha Dietrich1, Guido Kobbe1 P015 OUTCOMES OF ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION FOLLOWING BLINATUMOMAB IN CHILDREN AND YOUNG ADULTS WITH B-CELL ACUTE LYMPHOBLASTIC LEUKEMIA Mattia Algeri 1, Michele Massa2, Federica Galaverna2, Daria Pagliara2, Ilaria Pili2, Francesca Del Bufalo2, Marco Becilli2, Emilia Boccieri2, Roberto Carta2, Francesco Quagliarella2, Chiara Rosignoli2, Carmen Dolores De Luca2, Barbarella Lucarelli2, Pietro Merli2, Franco Locatelli3 P016 THE ROLE OF ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION IN CONSOLIDATION OF MINIMAL RESIDUAL DISEASE-NEGATIVE REMISSION IN RELAPSED/REFRACTORY B-CELL ACUTE LYMPHOBLASTIC LEUKEMIA IN ADULTS AFTER PHARMACOLOGIC IMMUNOTHERAPY Kseniia Afanaseva1, Ivan Moiseev 1, Bella Ayubova1, Elena Babenko1, Ildar Barkhatov1, Tatiana Gindina1, Anna Smirnova1, Olesya Smykova1, Yulia Vlasova1, Sergey Bondarenko1, Alexander Kulagin1 P017 FLAG-IDA/VENETOCLAX IS ASSOCIATED WITH HIGHER REMISSION RATES AND IMPROVED POST-TRANSPLANT SURVIVAL COMPARED TO VENETOCLAX/AZACITIDINE IN RELAPSED/REFRACTORY AML PATIENTS Evgeny Klyuchnikov1, Anita Badbaran1, Radwan Massoud 1, Normann Steiner1, Petra Freiberger1, Franziska Modemann1, Martin Schönrock1, Sophia Cichutek1, Walter Fiedler1, Micha Peeck2, Nico Gagelmann1, Christine Wolschke1, Francis Ayuk1, Ulrike Bacher3, Nicolaus Kröger1 P018 COMPARISON OF OUTCOMES OF HAPLOIDENTICAL HEMATOPOIETIC STEM CELL TRANSPLANTATION USING POST-TRANSPLANTATION CYCLOPHOSPHAMIDE AND EX-VIVO TCRΑΒ + CD19 DOUBLE-NEGATIVE SELECTED GRAFT IN ACUTE MYELOID LEUKEMIA László Gopcsa 1, Hajnalka Andrikovics1, Alexandra Balogh1, Anikó Barta1, Judit Bogyó2, Zoltán Csukly1, Katalin Dobos1, János Dolgos1, Apor Hardi1, János Fábián1, Laura Giba-Kiss1, József Harasztdombi1, Kinga Kerner1, Ágnes Király1, Gergely Lakatos1, Viktor Lakatos1, Lilla Lengyel1, Nóra Meggyesi1, Noémi Németh1, Melinda Paksi1, Laura Regáli1, Marienn Réti1, János Sinkó1, Bálint Szabó1, Anikó Szilvási2, Éva Torbágyi1, Andrea Várkonyi1, Nikolett Wohner1, István Vályi-Nagy1, Péter Reményi1 P019 AZACITIDINE AND VENETOCLAX WITH OR WITHOUT DLI IN RELAPSED MYELOID MALIGNANCIES AFTER ALLOGENIC HEMATOPOIETIC STEM CELL TRANSPLANTATION – A RETROSPECTIVE MULTICENTER STUDY OF THE SFGM-TC Turot Mélanie 1, Loschi Michael2, Chantepie Sylvain3, Arnautou Pierre4, Poire Xavier5, Maillard Natacha6, Chalandon Yves7, El-Cheikh Jean8, Ceballos Patrice9, Devillier Raynier10, Alani Mustafa11, Fatrara Thomas12, Rubio Thérèse13, Daguindau Etienne14, Klemencie Marion15, Beauvais David16, Huynh Anne17, Marchand Tony18, Volpari Victoria19, Barette Lauren19, Pivert Cécile20, Maury Sébastien21, Suarez Felipe22, Fuseau Charline23, Lauron Sandrine24, Uzunov Madalina25, Castilla Cristina26, Forcade Edouard27, Bay Jacques-Olivier1, Ravinet Aurélie1 P020 EFFICACY AND SAFETY ANALYSIS OF PROPHYLACTIC BRENTUXIMAB VEDOTIN ADMINISTRATION AFTER PEDIATRIC ACUTE LEUKEMIA HAPLOIDENTICAL HEMATOPOIETIC STEM CELL TRANSPLANTATION Zhu Huili 1, Cao Xingyu1, Lu Yue1, Zhang Jianping1, Zhao Yanli1, Liu Deyan1, Xiong Min1, Sun Ruijuan1, Liu Hongxing1, Wei Zhijie1 P021 OUTCOMES AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR ACUTE LEUKEMIA IN YOUNG ADULTS COMPARED WITH CHILDREN, ADOLESCENTS AND ELDERLY PATIENTS IN GERMANY Jochen J. Frietsch 1,2, Sarah Flossdorf3,4, Ashrafossadat Ahmadian3,4, Claudia Schuh3, Thomas Schroeder5, Igor-Wolfgang Blau6, Matthias Stelljes7, Nicolaus Kröger3,8, Katharina Egger-Heidrich9, Matthias Eder10, Peter Dreger11, Johanna Tischer12, Eva Wagner-Drouet13, Rita Beier14,15, Peter Bader16, Martin Sauer15, Barbara Meissner14,15, Katharina Fleischhauer3,17, Inken Hilgendorf2 P022 PHASE I/II STUDY OF CYCLOPHOSPHAMIDE AND BENDAMUSTINE AS POST-TRANSPLANTATION GRAFT-VERSUS-HOST DISEASE PROPHYLAXIS IN REFRACTORY MYELOID NEOPLASMS Ivan Moiseev 1, Olga Epifanovskaya1, Ksenia Afanasyeva1, Anastasia Beynarovich1, Dmitrii Zhogolev1, Mikhail Kanunnikov1, Yulia Rogacheva1, Tatyana Rudakova1, Nikita Volkov1, Zhamshidbek Khudaiberdiev1, Azamjon Meliboev1, Yulia Vlasova1, Elena Morozova1, Sergei Bondarenko1, Alexander Kulagin1 P023 REAL-WORLD OUTCOME OF ACUTE MYELOID LEUKEMIA PATIENTS TREATED WITH ALLOGENEIC STEM CELL TRANSPLANTATION WITHOUT STANDARD INDUCTION CHEMOTHERAPY Francesca Biavasco 1, Kristina Maas-Bauer1, Jesus Duque-Afonso1, Ralph Waesch1, Michael Luebbert1, Justus Duyster1, Robert Zeiser1, Juergen Finke1, Claudia Wehr1 P024 DURING CB TRANSPLANT IN MRD-POSITIVE AML, RELAPSE IS USUALLY EARLY, IS REDUCED BY ACUTE GVHD AND IS INFLUENCED BY CICLOSPORIN EXPOSURE: A MULTICENTER NATIONAL EXPERIENCE Srividhya Senthil 1, Abdul Moothedath1, Archana Rauthan2, Ioannis Peppas3, Sandeep Potluri4, Pamela Evans5, Valerie Broderick5, Sarah Lawson4, Emma Barrett6, Caroline Furness7, Kanchan Rao2, Robert Wynn1 P025 IMPACT OF RESPONSE TO THE FIRST INDUCTION COURSE IN AML PATIENTS ON ALLOHSCT OUTCOMES WITH PTCY Dmitrii Zhogolev1, Bella Aybova1, Anna Smirnova1, Yulia Vlasova1, Daria Chernyshova1, Elena Babenko1, Tatyana Gindina1, Ildar Barkhatov1, Elena Morozova1, Ivan Moiseev 1, Sergey Bondarenko1, Alexander Kulagin1 P026 POST-TRANSPLANT TYROSINE KINASE INHIBITOR MAINTENANCE IN PH-POSITIVE ACUTE LYMPHOBLASTIC LEUKEMIA DELIVERS BENEFIT TOWARD IMPROVED OVERALL, RELAPSE-FREE, GVHD/RELAPSE-FREE SURVIVAL AND DECREASED NON-RELAPSE MORTALITY WITHOUT REDUCED RELAPSE Eshrak Al-Shaibani 1, Carol Chen1, Igor Novitzky-Basso1,2, Ivan Pasic1,2, Auro Viswabandya1,2, Rajat Kumar1,2, Wilson Lam1,2, Arjun Law1,2, Armin Gerbitz1,2, Jonas Mattson1,2, Fotios V. Michelis1,2, José-Mario Capo-chichi3, Dennis D. Kim1,2 P027 IMPACT OF DONOR AND STEM-CELL SOURCE IN ADULTS WITH HIGH-RISK PHILADELPHIA-NEGATIVE ACUTE LYMPHOBLASTIC LEUKEMIA TRANSPLANTED IN FIRST COMPLETE REMISSION: A STUDY FROM GRAALL AND SFGM-TC Matthieu Jestin1, Sébastien Maury2, Anne Huynh3, Edouard Forcade4, Ibrahim Yakoubagha5, Cristina Castilla-Llorente6, Jean-Baptiste Mear7, Urs Schanz8, Sylvain Chantepie9, Jakob Passweg10, Nathalie Contentin11, Yves Chalandon12, Nicole Raus13, Véronique Lheritier13, Natacha Maillard14, Marie-Thérèse Rubio15, Raynier Devillier16, Patrice Ceballos17, Sylvie François18, Stéphanie Nguyen-Quoc19, Patrice Chevallier20, Hélène Labussière-Wallet13, Hervé Dombret1, Nicolas Boissel1, Nathalie Dhédin 1 P028 HOW DISEASE STATUS IMPACTS ON LONG-TERM SURVIVAL AFTER ALLOGENEIC TRANSPLANT IN ACUTE MYELOID LEUKEMIA: ANALYSIS ON 456 PATIENTS Alessandro Bruno1, Matteo Giovanni Carrabba1, Simona Piemontese1, Raffaella Greco1, Sarah Marktel1, Sara Mastaglio1, Daniela Clerici1, Francesca Farina1, Elisa Diral1, Luca Vago1, Lorenzo Lazzari1, Edoardo Campodonico1, Giulia Furnari1, Alessandro Criscimanna1, Chiara Secco1, Magda Marcatti1, Consuelo Corti1, Massimo Bernardi1, Jacopo Peccatori1, Fabio Ciceri1,2, Maria Teresa Lupo-Stanghellini 1 P029 TLS::ERG FUSION GENE PREDICTS A POOR PROGNOSIS AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION IN ACUTE MYELOID LEUKEMIA: A SINGLE CENTER STUDY Gele Tong 1, Yanli Zhao1, Jianping Zhang1, Min Xiong1, Xingyu Cao1, Deyan Liu1, Ruijuan Sun1, Zhijie Wei1, Jiarui Zhou1, Yue Lu1 P030 HIGH TOLERABILITY OF PROLONGED AZACITIDINE MAINTENANCE AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION IN PATIENTS WITH AML LACKING A TARGETABLE MUTATION Cuong An Do 1, Anne-Claire Mamez1, Amandine Pradier1,2, Sarah Morin1, Chiara Bernardi1,2, Sarah Prati-Perdikis1, Yan Beauverd1, Thomas Longval1, Maria Mappoura1, Sarah Noetzlin1, Laetitia Dubouchet1, Evgenia Laspa1, Marie Maulini1, Thien-An Tran1, Carmen de Ramon Ortiz1, Stavroula Masouridi-Levrat1, Federico Simonetta1,2, Yves Chalandon1,2, Federica Giannotti1 P031 OUTCOME OF ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION IN ACUTE MYELOID LEUKAEMIA FLT3 IN THE ERA OF FLT3 INHIBITORS – STUDY OF THE POLISH ADULT LEUKAEMIA GROUP (PALG) Elzbieta Patkowska1, Anna Czyz2, Alicja Sadowska-Klasa3, Andrzej Szczepaniak4, Lukasz Bolkun5, Marta Sobas2, Michal Gorka6, Edyta Subocz7, Anna Koclega8, Renata Guzicka-Kazimierczak9, Jan Zaucha3, Lidia Gil4, Marta Libura6, Agnieszka Pluta10, Dorota Bartosinska11, Ewa Lech-Maranda1, Agnieszka Wierzbowska10, Sebastian Giebel12, Barbara Nasilowska-Adamska 1 P032 CLINICAL CHARACTERISTICS AND PROGNOSIS OF ADULT T CELL ACUTE LYMPHOBLASTIC LEUKEMIA PATIENTS WITH ACTIVATING RAS MUTATIONS Mimi Xu 1,2,3, Yuqing Tu1,2,3, Mengqi Xiang1,2,3, Yi Fan1,2,3, Xiang Zhang1,2,3, Tiemei Song1,2,3, Lian Bai4, Xiaoli Li5, Yang Xu1,2,3, Yuejun Liu1,2,3, Depei Wu1,2,3 P033 PREVENTION AND TREATMENT OF ACUTE MYELOID LEUKEMIA RELAPSE FOLLOWING ALLOGENEIC STEM CELL TRANSPLANT: A NATIONAL SURVEY BY GITMO (GRUPPO ITALIANO TRAPIANTO MIDOLLO OSSEO) Francesco Saraceni1, Eliana Degrandi2, Simona Piemontese3, Francesco Saglio4, Giorgia Battipaglia 5, Marta Lisa Battista6, Patrizia Chiusolo7, Jacopo Mariotti8, Stefania Bramanti8, Anna Grassi9, Fabio Benedetti10, Manuela Tumino11, Giorgia Saporiti12, Salvatore Leotta13, Sadia Falcioni14, Martina Chiarucci15, Gladis Bortoletto16, Elisabetta Terruzzi17, Annalisa Imovilli18, Carlo Borghero19, Eugenia Piras20, Francesco Zallio21, Vincenzo Federico22, Irene Maria Cavattoni23, Andrea Gilioli24, Alessandra Picardi25, Domenico Pastore26, Anna Paola Iori27, Valentina Giudice28, Carmen Di Grazia29, Luca Castagna30, Michele Malagola31, Attilio Olivieri1, Francesca Bonifazi32, Massimo Martino33 P034 TRENDS IN THE USE OF HEMATOPOIETIC CELL TRANSPLANTATION FOR ADULTS WITH ACUTE LYMPHOBLASTIC LEUKEMIA: A REPORT FROM THE ACUTE LEUKEMIA WORKING PARTY OF THE EBMT Sebastian Giebel 1, Myriam Labopin2, Frederic Baron3, Ali Bazarbachi4, Eolia Brissot5, Gesine Bug6, Jordi Esteve7, Norbert-Claude Gorin8, Francesco Lanza9, Arnon Nagler10, Annalisa Ruggeri11, Jaime Sanz12, Bipin Savani13, Christoph Schmid14, Roni Shouval15, Alexandros Spyridonidis16, Jurjen Versluis17, Zinaida Peric18, Mohamad Mohty5, Fabio Ciceri19 P035 ALLOGENEIC STEM CELL TRANSPLANTATION FOR ADULT ACUTE LYMPHOBLASTIC LEUKEMIA - A SINGLE CENTER 25-YEARS EXPERIENCE Veronika Válková 1,2, Cyril Šálek1,2, Antonín Vítek1, Markéta Marková1,2, Ludmila Nováková1, Mariana Koubová1, Michal Kolář1, Barbora Čemusová1, Hana Bartáková1, Petr Cetkovský1,2, Jan Vydra1,2 P036 STRUCTURAL ANALYSIS OF LEUKEMIA-ASSOCIATED PROTEIN PTPN21 REVEALS A DOMINANT-NEGATIVE EFFECT OF THE FERM DOMAIN ON ITS PHOSPHATASE ACTIVITY Zijun Qian 1,2, Lu Chen1,2, Jie Zhang2, Yuyuan Zheng1, Chun Zhou1,2, Haowen Xiao1,2 P037 EARLY DETECTION OF RELAPSE AND PROMPT TREATMENT WITH DLI FACILITATED BY PROPHYLACTIC LYMPHOCYTE STORAGE PERI-TRANSPLANT RESULTS IN EFFECTIVE DISEASE CONTROL IN ACUTE LEUKAEMIA AND MDS Daire Quinn 1, Anne Parker1, Grant McQuaker1, Anne-Louise Latif1, David Irvine1, Ailsa Holroyd1, Dimitris Galopoulos1, Andrew Clark1 P038 THIOTEPA, BUSULFAN, AND FLUDARABINE CONDITIONING REGIMEN IN T-CELL REPLETE HLA-HAPLOIDENTICAL BONE MARROW TRANSPLANTATION FOR ADULTS WITH ACUTE MYELOBLASTIC LEUKEMIA IN SECOND COMPLETE REMISSION Ahmad Ibrahim 1, Ahmad Khalil2, Kamal Al Zahran3, Mohamad Hachem4, Pamela Sfeir5, Amin Abyad6, Jad Ibrahim7, Hussein Abou Abbas8, Ali Youssef8, Charbel Khalil2, Tamima Jisr9 P039 REDUCED INTENSITY CHEMOTHERAPY WITH TYROSINE KINASE INHIBITOR FOLLOWED BY ALLOGENEIC STEM CELL TRANSPLANTATION WAS EFFECTIVE IN PATIENTS WITH PHILADELPHIA CHROMOSOME POSITIVE ACUTE LYMPHOBLASTIC LEUKEMIA Dong Won Baek 1, Jung Min Lee1, Hyukjin Choi1, Joon Ho Moon1, Sang Kyun Sohn1 P040 IMPACT OF CO-MUTATIONS ON THE TRANSPLANT OUTCOMES IN AML PATIENTS WITH DNMT3A MUTATION Feng-ming Tien1, Xavier Cheng-Hong Tsai 1, Min-Yen Lo1, Hsin-An Hou1, Hwei-Fang Tien1 P041 SALVAGE TREATMENTS HAVE EXTREMELY POOR OUTCOMES FOR PATIENTS WITH RELAPSED T-ACUTE LYMPHOBLASTIC LEUKAEMIA POST TRANSPLANT Alexandros Rampotas 1, Fotios Panitsas2, Maximillian Brodermann1, Sridhar Chaganti3, Styliani Bouziana4, Emma Nicholson5, Samantha Drummond6, Sharon Allen7, Andrew King7, Henry Crosland3, Anne-Louise Latif6, Daniele Avenoso4, Claire Roddie1 P042 FEASIBILITY OF ALLOGENEIC STEM CELL TRANSPLANTATION (HSCT) IN PATIENTS WITH ACUTE MYELOID LEUKEMIA PREVIOUSLY TREATED WITH CPX-351: REPORT FROM A SINGLE CENTER Sabrina Giammarco 1, Elisabetta Metafuni1, Maria Assunta Limongiello1, Federica Sorá2, Eugenio Galli1, Filippo Frioni2, John Marra2, Patrizia Chiusolo2, Simona Sica2 P043 COMPARISON OF VENETOCLAX-BASED NON-ANTHRACYCLINE INDUCTION THERAPY VERSUS 3 + 7 FOLLOWED BY HEMATOPOIETIC STEM CELL TRANSPLANTATION IN NEWLY DIAGNOSED ACUTE MYELOID LEUKEMIA PATIENTS Tran-Der Tan 1, Lun-Wei Chiou1 P044 MYELOFIBROSIS GRADE II-III IS AN INDEPENDENT RISK FACTOR FOR RELAPSE OF ACUTE MYELOID LEUKEMIA AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION Haixiao Zhang1, Erlie Jiang 2 P045 INCIDENCE AND MANAGEMENT OF ADULT ACUTE LYMPHOBLASTIC LEUKAEMIA RELAPSE AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION IN LIMITED RESOURCE COUNTRIES Rihab Ouerghi1, Nour Ben Abdeljelil 1, Sabrine Mekni1, Insaf Ben Yaiche1, Ines Turki1, Rim Dachraoui1, Dorra Belloumi1, Lamia Torjemane1, Rimmel Kanoun1, Saloua Ladeb1, Tarek Ben Othman1 P046 IMPACT OF BODY MASS INDEX ON OUTCOME IN ADULT PATIENTS WITH ACUTE MYELOID AND ACUTE LYMPHOBLASTIC LEUKEMIA UNDERGOING ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION Iveta Oravcova1,2, Zuzana Rusinakova1, Eva Mikuskova1, Miriam Ladicka1, Ludmila Demitrovicova1, Alica Slobodova1, Vanda Mikudova1, Jana Spanikova1, Radka Vasickova1, Denis Urban1, Kristina Bandurova1, Lubos Drgona1,2, Silvia Cingelova 1 P047 VENETOCLAX COMBINED WITH HMAS-BASED THERAPY AS PRE-EMPTIVE TREATMENT FOR ACUTE MYELOID LEUKEMIA PATIENTS AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION Mimi Xu 1,2,3, Yuqing Tu1,2,3, Mengqi Xiang1,2,3, Yi Fan1,2,3, Xiang Zhang1,2,3, Tiemei Song1,2,3, Lian Bai4, Xiaoli Li5, Yang Xu1,2,3, Yuejun Liu1,2,3, Jia Chen1,2,3, Depei Wu1,2,3 P048 VENETOCLAX, AZACITIDINE, COMBINED WITH LOW-DOSE CYTARABINE IMPROVE THE REMISSION RATE IN OLDER OR UNFIT PATIENTS WITH NEWLY DIAGNOSED ACUTE MYELOID LEUKEMIA Xiao Han1, Qingxiao Song 1, Kai Wan1, Mengyun Zhang1, Xue Liu1, Hongju Yan1, Cheng Zhang1, Qin Wen1, Xi Zhang1 P049 TARGET THERAPY IN ACUTE LEUKAEMIA RELAPSES AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION Riccardo Boncompagni 1, Chiara Camerini1, Ilaria Cutini1, Mirella Giordano1, Antonella Gozzini1, Chiara Nozzoli1, Edoardo Simonetti1, Riccardo Saccardi1 P050 ALLOGENEIC STEM CELL TRANSPLANTATION IN THE MANAGEMENT OF ADULT ACUTE LYMPHOBLASTIC LEUKAEMIA: A TEN YEAR EXPERIENCE IN IRELAND’S NATIONAL ADULT ALLOGENEIC TRANSPLANT CENTRE Conor Browne 1, Micheal Brennan1, Mairead Ni Chonghaile1, Sarah Maher1, Greg Lee1, Deirdre Waldron1, Nicola Gardiner1, Michelle Regan1, Lorraine Brennan1, Carmel Waldron1, Catherine M. Flynn1, Eibhlin Conneally1, Patrick J. Hayden1, Robert Henderson1, Elisabeth Vandenberghe1, Christopher L. Bacon1 P051 FLT3-MUTATED AML: MANAGEMENT AND LONG-TERM OUTCOME OVER 24 YEARS AT A SINGLE CENTER Saveria Capria 1, Silvia Maria Trisolini1, Lorenzo Torrieri2, Elena Amabile2, Giovanni Marsili3, Alfonso Piciocchi3, Walter Barberi1, Daniela Diverio1, Daniela Carmini1, Massimo Breccia2, Maurizio Martelli2, Clara Minotti1 P052 THE ROLE OF TOLEROGENIC DENDRITIC CELLS IN SUPPRESSING AND DCLEU IN INCREASING ANTILEUKEMIC CYTOTOXICITY A.S. Hartz1, L. Li1, H. Aslan1, E. Pepeldjiyska1, E. Rackl1, T. Baudrexler1, P. Bojko2, J. Schmohl3, A. Rank4, C. Schmid4, H.M. Schmetzer 1 P053 TREATMENT EFFICACY OF BLINATUMOMAB FOR MAINTENANCE THERAPY OF PATIENTS WITH B-LINEAGE ACUTE LYMPHOBLASTIC LEUKEMIA RECEIVING ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION Jiayu Huang1, Luxiang Wang1, Chuanhe Jiang1, Zilu Zhang1, Zengkai Pan1, Ling Wang2, Jieling Jiang2, Jiong Hu2, Jun Zhu3, Lijing Shen4, Suning Chen5, Yang Cao6, Xiaoxia Hu 1 P054 EFFICACY, SAFETY AND TOLERABILITY OF MITOXANTRONE HYDROCHLORIDE LIPOSOME CONTAINING REGIMEN IN TREATING RELAPSED ACUTE MYELOID LEUKEMIA AFTER ALLOGENIC STEM CELL TRANSPLANTATION Li Liu 1, Yigeng Cao1, Ni Lu1, Erlie Jiang1 P055 STUDY ON THE EFFICACY AND SAFETY OF BLINATUMOMAB MAINTENANCE THERAPY OF HIGH RISK PH NEGATIVE ALL AFTER ALLO-HSCT Zhang Jianping1, Li Nannan1 P056 THE IMPACT OF PRE-TRANSPLANT MDS-ASSOCIATED SOMATIC MUTATIONS AND CO-MUTATIONS IN PATIENTS WITH AML ON POST-TRANSPLANT OUTCOMES Khalid Halahleh 1, Ayat Taqash1, Isra Muradi2, Farah Alul1, Osama Alsmadi1, Mohamad Ma’koseh1 P057 TRIALS IN PROGRESS: A PHASE 1B SINGLE-ARM, OPEN-LABEL STUDY OF EMAVUSERTIB IN COMBINATION WITH AZACITIDINE AND VENETOCLAX IN AML PATIENTS IN COMPLETE RESPONSE WITH MRd Adolfo de la Fuente 1, Claudio Cerchione2, Sebastian Scholl3, Jan Moritz Middeke4, Gaurav S. Choudhary5, Dora Ferrari5, Reinhard von Roemeling5, Uwe Platzbecker6 P058 PREVALENCE OF ELIGIBILITY FOR GERMLINE MUTATION TESTING IN PATIENTS WITH MDS/AML UNDERGOING ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANT IN A US ACADEMIC MEDICAL CENTER Tyler Fugere 1, Samuil Ivanovsky1, Gomathy Nageswaran1, Brad Fugere1, Urooj Hudda1, Sravani Gundarlapalli1, Lakshmi Yarlagadda1, Zhongning “Jim” Chen1, Cesar Gentille1 P059 REFINED DISEASE RISK INDEX APPLIED IN AN UPPER-MIDDLE INCOME COUNTRY AS A TOOL TO ESTIMATE OVERALL SURVIVAL AFTER ALLOGENEIC STEM CELL TRANSPLANTATION IN HAEMATOLOGICAL MALIGNANCIES Shirley Quintana-Truyenque1, Naty López-Córdova 1, Jessica Meza-Liviapoma1, Lourdes López-Chavez1, Cindy Alcarraz-Molina1, Victor Mallma-Soto1, Claudio Flores-Flores2, Jule Vasquez-Chavez1 P060 PREEMPTIVE DONOR LYMPHOCYTE INFUSION AFTER ALLOGENEIC STEM CELL TRANSPLANTATION IN PATIENTS WITH ACUTE MYELOID LEUKEMIA – SINGLE CENTRE ANALYSIS OF EFFECTIVENESS AND SAFETY Anna Łojko Dankowska 1, Ewa Bembnista1, Paula Matuszak1, Magdalena Matuszak1, Bartosz Małecki1, Andrzej Szczepaniak1, Anna Wache1, Dominik Dytfeld1, Lidia Gil1 P061 IN CHILDREN WITH RELAPSED/REFRACTORY ACUTE LYMPHOBLASTIC LEUKEMIA GIVEN ALLOGENEIC-HSCT EMPLOYING REDUCED-INTENSITY CONDITIONING, GVHD IS LESS FREQUENT IF THE PROCEDURE IS CONDUCTED ON AN OUTPATIENT BASIS Edgar Jared Hernández-Flores1, Moisés Manuel Gallardo-Pérez2, Max Robles-Nasta2, Daniela Sánchez-Bonilla2, Merittzel Abigail Montes-Robles3, Guillermo Ocaña-Ramm1, Olivia Lira-Lara4, Juan Carlos Olivares-Gazca2, David Gómez-Almaguer5, Óscar González Llano5, Yajaira Valentine Jiménez-Antolinez5, Guillermo José Ruiz-Delgado 2,1, Guillermo José Ruiz-Arguelles2,1 P062 IMPLEMENTATION OF NON-TBI CONDITIONING AND POST-TRANSPLANT CYCLOPHOSPHAMIDE FOR PEDIATRIC ACUTE LYMPHOBLASTIC LEUKEMIA IN RESOURCE-LIMITED SETTINGS Lusine Krmoyan 1,2, Inga Khalatiani1,2, Mane Gizhlaryan1, Karen Meliksetyan1 P063 RELAPSE AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION IN PATIENT WITH ACUTE MYELOBLASTIC LEUKEMIA Insaf Ben Yaiche1, Nour Ben Abdejelil 1, Rihab Ouerghi1, Ines Turki1, Sabrine Mekni1, Lamia Torjemane1, Dorra Belloumi1, Rimmel Kanoun1, Saloua Ladab1, Tarek Ben Othman1 P064 IAMP21 ACUTE LYMPHOBLASTIC LEUKEMIA WITH DELETION AROUND SUBTELOMERIC REGION OF CHROMOSOME 21: REPORT OF ONE CASE AND REVIEW OF LITERATURE Jiantuo Liu 1, Hongrui Li1, Xiangjun Chen2, Yanli He2 P065 RESULTS OF HSCT WITH TCRΑΒ AND CD19-DEPLETION FROM MATCHED RELATED DONORS AND INFUSIONS OF CD45RA DEPLETED DONOR LYMPHOCYTES IN PEDIATRIC SEVERE APLASTIC ANEMIA Daria Shasheleva1, Larisa Shelikhova1, Anna Bogoyavlenskaya1, Rimma Khismatullina1, Svetlana Radygina1, Dmitriy Balashov1, Yakov Muzalevsky1, Tatiana Salimova1, Dina Baidildina1, Elena Kurnikova1, Dmitriy Pershin 1, Pavel Trakhtman1, Galina Novichkova1, Alexei Maschan1, Michael Maschan1 P066 MITOCHONDRIAL METABOLISM IN FANCONI ANEMIA PATIENTS POST HEMATOPOIETIC STEM CELL TRANSPLANTATION Filomena Pierri1, Enrico Cappelli1, Stefano Regis1, Silvia Ravera2, Federica Grilli1, Gianluca Dell’Orso1, Stefano Giardino1, Maura Faraci 1 P067 ATLG HAS BETTER SAFETY THAN RATG IN THE TREATMENT OF ADULT AA WITH ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION Zhang Jianping 1, Lu Yue1, Zhao Yanli1, Xiong Min1, Liu Deyan1, Cao Xingyu1, Wei Zhijie1, Sun Ruijuan1, Zhou Jiarui1 P068 TREATMENT WITH DARATUMUMAB IN 4 PATIENTS WITH IMMUNE ANEMIA AFTER HSCT WITH ABO INCOMPATIBILITY OR OTHER IMMUNE-ERYTHROCYTE DISCREPANCIES Marina Aranguren Ostolaza1, Candela Ceballos Bolaños 1, Itziar Oiartzabal Ormategui1, Nerea Arratibel Zalacain1, Pamela Millacoy Austenrritt1, Mónica Fernández Pérez1, Maria Cruz Viguria Alegria1, Carlos Manuel Panizo Santos1, Irene Sánchez Prieto1, Monserrat Lozano Lobato1 P069 UPFRONT T-REPLETE HAPLO-IDENTICAL HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR CHILDREN WITH SEVERE APLASTIC ANEMIA: A SINGLE CENTER EXPERIENCE FROM JORDAN Ayad Ahmed Hussein 1, Nour Awni Ghanem1, Bayan Majed Alaaraj1, Tariq Ahmed Abdelghani1, Dina Mohammad Abu Assab1, Hadeel Hassan Al-Zoubi1 P070 PERIPHERAL BLOOD AS GRAFT SOURCE FOR APLASTIC ANEMIA TRANSPLANT: OUTCOMES OF YOUNG ADULTS AND ADULTS IN A MEXICAN PUBLIC HOSPITAL Guillermo Sotomayor Duque 1, Severiano Baltazar Arellano1, Roxana Saldaña Vazquez1, Humberto Guerra Ramos1, Raul Ramos1, Alma Fabiola Alvarado Charles1, Karen Machuca Adame1, Luis Omar Gudiño Cobos1, Victor Valerio Bugarin1, Rosa Elva De leon Cantú1, Roberto Hernandez Valdez1, Jose Marcelino Chavez Garcia1 P071 UPFRONT HEMATOPOIETIC STEM CELL TRANSPLANTATION (HSCT) IN CLASSICAL PAROXYSMAL NOCTURNAL HEMOGLOBINURIA (PNH) Lorie Gandhi 1, Col (Dr) Rajiv Kumar1, Brig(Dr) Rajan Kapoor1 P072 A REAL-WORLD ANALYSIS OF TREATMENT ADHERENCE AND CLINICAL OUTCOMES FOR PATIENTS WITH PAROXYSMAL NOCTURNAL HAEMOGLOBINURIA (PNH) RECEIVING PEGCETACOPLAN Koo Wilson 1, Carly Rich1, Zalmai Hakimi1, Regina Horneff1, Jesse Fishman2, Jennifer Mellor3, Lucy Earl3, Yasmin Taylor3, Alice Simons3 P073 EXPERIENCE OF SALVAGE HAPLO-HSCT WITH PTCY FOR ACQUIRED SEVERE APLASTIC ANEMIA Yuliya Mareika1, Nina Minakovskaya1, Natalia Kirsanava 1, Dmitriy Prudnikov1, Mariya Naumovich1, Lubov Zherko1, Aliaksei Kakunin1, Aliaksei Lipnitski1, Volha Mishkova1, Katsiaryna Vashkevich1, Anzhalika Solntsava1 P074 THYMIC SIZE LONGITUDINAL CHANGES ON CHEST HIGH-RESOLUTION COMPUTED TOMOGRAPHY AFTER AUTOLOGOUS HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR DIFFUSE CUTANEOUS SYSTEMIC SCLEROSIS Gregory Pugnet 1, Samia Collot1, Antoine Petermann1, Pauline Lansiaux2, Gwenaëlle Lorillon3, Nassim Ait Abdallah2, Mathieu Resche-Rigon4, Cécile Borel1, Zora Marjanovic5, Dominique Farge2 P075 LONG TERM PERSISTENCE OF T MEMORY STEM CELLS FOLLOWING AUTOLOGOUS HAEMATOPOIETIC STEM CELL TRANSPLANTATION FOR MULTIPLE SCLEROSIS Melissa Khoo1,2, Carole Ford1, Jennifer Massey1,2,3, Kevin Hendrawan4, Malini Visweswaran1,2, John Zaunders1,2, Ian Sutton3, Barbara Withers3, David Ma1,2,3, John Moore 1,2,3 P076 EFFECTS OF HIGH DOSE IMMUNOSUPPRESSIVE THERAPY WITH AUTOLOGOUS HEMATOPOIETIC STEM CELL TRANSPLANTATION IN MULTIPLE SCLEROSIS FROM PATIENT’S PERSPCTIVE: LONG-TERM QUALITY OF LIFE OUTCOMES Denis Fedorenko 1, Vladimir Melnichenko1, Anatoly Rukavitsin1, Nikolai Vasilev1, Tatiana Nikitina2, Natalia Porfirieva3, Tatiana Ionova2 P077 THE MATHEC-SFGM-TC REGISTRY FOR CELL THERAPY IN AUTOIMMUNE DISEASES: A DEDICATED TOOL FOR REAL-WORLD DATA COLLECTION Pauline Lansiaux1, Manuela Badoglio2, Grégory Pugnet3, Mathieu Puyade4, Emmanuel Chatelus5, Thierry Martin5, Louis Terriou6, Alexandre Maria7, Marc Ruivard8, Jacques-Olivier Bay8, Bertrand Dunogué9, Matthieu Allez1, Hélène Zéphir10, Arsène Mékinian11, Eric Deconinck12, Sabine Berthier13, Françoise Sarrot-Reynaud14, Frédéric Garban14, Nicolas Maubeuge4, Guillaume Mathey15, Cristina Castilla-Llorente16, Céline Labeyrie17, Régis Peffault de la Tour18, Marie Robin19, Zora Marjanovic11, Dominique Farge 1 P078 ATG AND OTHER SEROTHERAPY IN CONDITIONING REGIMENS FOR ASCT IN AUTOIMMUNE DISEASES: A SURVEY OF THE EBMT AUTOIMMUNE DISEASES WORKING PARTY (ADWP) Azza Ismail1, Rosamaria Nitti 2, Basil Sharrack1, Manuela Badoglio3, Pascale Ambron3, Myriam Labopin3, Tobias Alexander4, John Snowden5, Greco Raffaella2 P079 ADOPTING A STANDARD OF CARE: AUTOLOGOUS HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR SCLERODERMA Ernesto Ayala 1, Madiha Iqbal1, Hemant Murthy1, James Foran1, Vivek Roy1, Mohamed Kharfan-Dabaja1 P080 FLUDARABINE AND CYCLOPHOSPHAMIDE AS A SAFE AND EFFECTIVE LYMPHOABLATIVE CONDITIONING REGIMEN FOR MULTIPLE SCLEROSIS (MS) Denis Fedorenko 1, Anatoly Rukavitsin1, Nikolai Vasilev1, Vladimir Melnichenko1, Tatiana Ionova2 P081 IMMUNE RESET AND GRAFT COMPOSITION IN AUTOLOGOUS TRANSPLANTATION FOR MULTIPLE SCLEROSIS: EARLY RECOVERY OF NATURAL KILLER CELLS MAY BE IMPORTANT IN EFFECTING DURABLE RESPONSES Latoya Reid 1, Oliver Gittner2, Malia Begley3, Rowayda Peters3, Andy Drake3, Matthias Klammer3 P082 REDUCED PRO-INFLAMMATORY INTERLEUKINS IL-6 AND IL-8 SECRETED BY SKIN FIBROBLASTS IN SYSTEMIC SCLEROSIS PATIENTS AFTER HEMATOPOIETIC STEM CELL TRANSPLANTATION Gunter Assmann 1,2, Jan Weghorn1, Michael Schmidt1, Joerg Henes3, Claudia Pfoehler4, Frank Neumann2 P083 THE QUALITY OF LIFE OF PERSONS WITH MULTIPLE SCLEROSIS IMPROVES AFTER AUTOLOGOUS HEMATOPOIETIC STEM CELL TRANSPLANTATION Olivia Lira-Lara1, Moisés Manuel Gallardo-Pérez2, Miranda Melgar-de-la-Paz3, Paola Negrete-Rodríguez4, Luis Enrique Hamilton-Avilés5, Guillermo Ocaña-Ramm5, Max Robles-Nasta2, Daniela Sánchez-Bonilla2, Juan Carlos Olivares-Gazca2, Guillermo José Ruiz-Delgado 2,5, Guillermo José Ruiz-Arguelles2,5 P084 AUTOLOGOUS HEMATOPOIETIC STEM CELL TRANSPLANTATION IN THE TREATMENT OF MULTI-REFRACTORY STIFF PERSON SYNDROME: A CASE STUDY Tamim Alsuliman 1, Dimitri Psimaras2, Nicolas Stocker1, Simona Sestili1, Anne Banet1, Zoé Van de Wyngaert1, Agnès Bonnin1, Manuela Badoglio3, Mathieu Puyade4,5, Dominique Farge6,5, Mohamad Mohty1, Zora Marjanovic1,5 P085 BRIDGING THERAPY PRIOR TO TREATMENT WITH ANTI-CD19 CAR T CELLS FOR RELAPSED/REFRACTORY ACUTE LYMPHOBLASTIC LEUKEMIA IN CHILDREN AND YOUNG ADULTS - A MULTINATIONAL RETROSPECTIVE ANALYSIS Maike Breidenbach1, Peter Bader2, Andishe Attarbaschi3, Claudia Rossig4, Roland Meisel5, Markus Metzler6, Marion Subklewe1, Fabian Mueller7, Paul-Gerhard Schlegel8, Irene Teichert von Lüttichau9, Jean-Pierre Bourquin10, Gabriele Escherich11, Gunnar Cario12, Peter Lang13, Ramona Krauss1, Arend von Stackelberg14, Semjon Willier15, Christina Peters3, Tobias Feuchtinger 16,1 P086 SAFETY AND EFFICACY COMPARISON OF HUMANIZED CD19 CAR-T VERSUS BLINATUMOMAB THERAPY FOR RELAPSED/REFRACTORY B-ALL PATIENTS Kexin Wang 1,2,3,4, Songfu Jiang5, Yongxian Hu1,2,3,4, He Huang1,2,3,4 P087 PREDICTIVE VALUE OF PRE-TREATMENT CIRCULATING TUMOR DNA GENOMIC LANDSCAPE IN PATIENTS WITH R/RMM UNDERGOING ANTI-BCMA CAR-T THERAPY: INSIGHTS FROM TUMOR CELLS AND T CELLS Rongrong Chen 1, Chunxiang Jin1, Tingting Yang1, Kai Liu1, Mengyu Zhao1, Mingming Zhang1, Pingnan Xiao1, Jingjing Feng1, Ruimin Hong1, Shan Fu1, Jiazhen Cui1, Simao Huang1, Guoqing Wei1, He Huang1, Yongxian Hu1 P088 FINAL RESULTS OF PROSPECTIVE CLINICAL TRIAL EVALUATING OUTPATIENT ADMINISTRATION OF AXICABTAGENE CILOLEUCEL IN HIGH-GRADE B CELL LYMPHOMA Bhagirathbhai Dholaria1, Shakthi Bhaskar1, Vivek Patel1, Eden Biltibo1, Salyka Sengsayadeth1, Andrew Jallouk1, James Jerkins1, Brittney Baer1, Nur Ali1, David Morgan1, Muhamed Baljevic1, Bipin Savani1, Adetola Kassim1, Olalekan Oluwole 1 P089 EUPLAGIA-1: SEVEN-DAY VEIN-TO-VEIN POINT-OF-CARE MANUFACTURED GLPG5201 ANTI-CD19 CAR-T CELLS DISPLAY EARLY PHENOTYPES IN RELAPSED/REFRACTORY CLL INCLUDING RT Esmée P. Hoefsmit 1, Sandra Blum2, Claire Vennin1, Kirsten Van Hoorde3, Sergi Betriu4, Leticia Alserawan4, Julio Delgado4, Nadia Verbruggen5, Anna D.D. van Muyden1, Henriëtte Rozema1, Ruiz Astigarraga1, Margot J. Pont1 P090 INCIDENCES AND FACTORS ASSOCIATED WITH EARLY HEMATOTOXICITY AFTER CAR T-CELL THERAPY ASSESSED BY EHA/EBMT ICAHT CRITERIA Emily Liang 1,2, Aya Albittar1, Andrew Portuguese1,2, Jennifer Huang1,2, Natalie Wuliji1,2, Qian Wu1, Joseph De Los Reyes1,2, Nikki Pin1, Aiko Torkelson1, Delaney Kirchmeier1, Abigail Chutnik1, Barbara Pender1, Joshua Hill1,2, Noam Kopmar1,2, Rahul Banerjee1,2, Andrew Cowan1,2, Damian Green1,2, Ajay Gopal1,2, Christina Poh1,2, Mazyar Shadman1,2, Alexandre Hirayama1,2, Brian Till1,2, Erik Kimble1,2, Lorenzo Iovino1,2, Aude Chapuis1,2, Folashade Otegbeye1,2, Ryan Cassaday1,2, Filippo Milano1,2, Cameron Turtle3, David Maloney1,2, Jordan Gauthier1,2 P091 COMPARISON OF IMMUNOPHENOTYPIC AND FUNCTIONAL PROPERTIES OF ANTI-CD19 CAR-T CELL PRODUCTS MANUFACTURED USING CLINIMACS PRODIGY AND G-REX PLATFORMS Ekaterina Malakhova1, Dmitriy Pershin 1, Viktoria Vedmedskaia1, Mariia Fadeeva1, Elena Kulakovskaya1, Oyuna Lodoeva1, Tatiana Sozonova1, Elvira Musaeva1, Yakov Muzalevskii1, Alexei Kazachenok1, Vladislav Belchikov1, Anastasia Melkova1, Larisa Shelikhova1, Olga Molostova1, Michael Maschan1 P092 ALLOGENEIC HSCT AFTER CAR T-CELL THERAPY HAD DELAYED PLATELET ENGRAFTMENT, HIGHER RISK OF CYTOMEGALOVIRUS VIRUS VIREMIA AND THROMBOTIC MICROANGIOPATHY COMPARED TO CHEMOTHERAPY Luxin Yang 1, Xiaoyu Lai1, Lizhen Liu1, Jimin Shi1, Yanmin Zhao1, Jian Yu1, Huarui Fu1, Yongxian Hu1, Mingming Zhang1, He Huang1, Yi Luo1 P093 AUTOMATED GRADING OF IMMUNE EFFECTOR CELL-ASSOCIATED HEMATOTOXICITY Emily Liang 1,2, Kai Rejeski3, Sandeep Raj3, Aya Albittar1, Jennifer Huang1,2, Andrew Portuguese1,2, Natalie Wuliji1,2, Qian Wu1, Aiko Torkelson1,2, Delaney Kirchmeier1,2, Abigail Chutnik1, Barbara Pender1, Joshua Hill1,2,2, Noam Kopmar1,2, Rahul Banerjee1,2, Andrew Cowan1,2, Christina Poh1,2, Mazyar Shadman1,2, Alexandre Hirayama1,2, Erik Kimble1,2, Lorenzo Iovino1,2, Roni Shouval3, Jordan Gauthier1,2 P094 RELEVANT STUDIES ON CYTOKINES LEVEL AND CAR-T EXPANSION ASSOCIATED TO CD7 CAR-T THERAPY Dongchu Wang1, Hui Wang1, Man Chen 1 P095 AUTOLOGOUS HEMATOPOIETIC STEM CELL TRANSPLANTATION COMBINED WITH CAR-T CELL THERAPY SIGNIFICANTLY IMPROVES PROGRESSION-FREE SURVIVAL IN RELAPSED REFRACTORY CENTRAL NERVOUS SYSTEM LYMPHOMA Rui Liu 1, Fan Yang1, Fei Xue1, Zhonghua Fu1, Yuelu Guo1, Shaomei Feng1, Peihao Zheng1, Lixia Ma1, Hui Shi1, Biping Deng1, Xiaoyan Ke1, Kai Hu1 P096 SAFETY AND EFFICACY OF BENDAMUSTINE VERSUS FLUDARABINE-CYCLOPHOSPHAMIDE LYMPHODEPLETION PRIOR TO CAR-T CELL THERAPY WITH AXICABTAGENE CILOLEUCEL FOR NON-HODGKIN LYMPHOMA: A SINGLE-INSTITUTION STUDY Anthony Stack 1, Yuliya Shestovska1, Rachel Thomas2, Matthew Hamby1, Asya Varshavsky-Yanovsky1, Peter Abdelmessieh1, Michael Styler1, Henry Fung1, Rashmi Khanal1 P097 PSEUDOPROGRESSION: A FREQUENT AND CLINICALLY RELEVANT ADVERSE EVENT OF CHIMERIC ANTIGEN RECEPTOR T CELL THERAPY Torsten Schroeder 1, Tjark Martens1, Guranda Chitadze1, Fatih Yalcin1, Heiko Trautmann1, Britta Kehden1, Monika Brüggemann1, Christine Heinen1, Philipp Nakov,1, Nicolas Spath1, Lukas Sprenger1, Anca-Maria Albici1, Laura-Jane Kramp1, Matthias Ritgen1, Dominique Wellnitz1, Sebastian Lippross1, Maciej Simon1, Ingram Iaccarino Idelson1, Nico Gagelmann2, Wolfram Klapper1, Lars Fransecky1, Thomas Valerius1, Natalie Schub1, Christiane Pott1, Katja Weisel2, Winfried Alsdorf2, Fabian Müller3, Claudia Baldus1, Friedrich Stölzel1 P098 CAR-T CELL TREATMENT OF LARGE B-CELL LYMPHOMA (LBCL): DO PROGRAM DURATION AND TREATMENT LINE MATTER? Maria-Luisa Schubert 1, Michael Schmitt1, Andrea Bondong1, Mandy Wegner1, Simon Renders1, Isabelle Krämer1, Carsten Müller-Tidow1, Peter Dreger1 P099 REAL-WORLD EXPERIENCE OF CAR T-CELL THERAPY: A SINGLE CENTRE EXPERIENCE Francys Lopez Llanos1, Inês Rocha2, Gilda Teixeira1, Isabelina Ferreira1, Pedro Sousa1, Maria João Gutierrez1, Susana Pereira 1, Ana Carolina Freitas1, Carla Espadinha1, Nuno Miranda1 P100 IMPACT OF ACUTE KIDNEY INJURY IN LYMPHOMA PATIENTS TREATED WITH AXICABTAGENE CILOLEUCEL Cristina Soler1, Rafael Hernani 1, Ariadna Pérez1, Jose Luis Piñana1, Juan Carlos Hernández-Boluda1, Ana Benzaquen1, Rosa Goterris1, Montse Gómez1, Paula Amat1, Blanca Ferrer1, Francesc Moncho1, Isidro Torregrosa1, Jose Luis Górriz1, María José Terol1, Carlos Solano1 P101 CHARACTERISTICS OF CENTRAL NERVOUS SYSTEM RELAPSE AFTER CD19 CAR-T CELL THERAPY IN R/R NHL Mengyu Zhao 1, Tingting Yang1, YeTian Dong1, Jiazhen Cui1, Delin Kong1, Wenfa Huang2, Lei Wang2, Lixin Wang2, He Huang1, Yongxian Hu1 P102 DAY7-CART COUNT ENHANCES PREDICTIVE POWER OF PET30 AND POSSIBLY ANTICIPATES CD19 LOSS IN RELAPSE AFTER CART Fabian Müller 1,2, Viktoria Blumenberg3,2, Veit L. Bücklein3,2, Ralph A. Bundschuh4,2, Dennis Harrer5,2, Klaus Hirschbühl4,2, Johannes Jung6,2, Wolfgang Kunz3,2, Igor Yakushev7,2, Anna Lena Illert6,2, Simon Völkl1,2, Rainer Claus4,2, Leo Hansmann5,2, Judith Hecker6,2, Dirk Hellwig8,2, Andreas Mackensen1,2, Marion Subklewe3,2, Michael Beck1,2 P103 EXCELLENT OUTCOME OF CAR-T CELL THERAPY IN CHILDREN WITH PB-ALL RELAPSING POST HSCT, WHO HAD VERY LOW MRD AT LYMPHODEPLETING CHEMOTHERAPY – POLISH CENTRES’ EXPERIENCE Karolina Liszka 1, Paweł Marschollek1, Iwona Dachowska - Kałwak1, Monika Mielcarek-Siedziuk1, Jowita Frączkiewicz1, Anna Panasiuk1, Igor Olejnik1, Natalia Haze1, Monika Richert-Przygońska2, Krzysztof Czyżewski2, Robert Dębski2, Jan Styczyński2, Krzysztof Kalwak1 P104 THE DARK SIDE OF CORTICOSTEROIDS IN CD19. CAR-T CELL THERAPY Marcello Roberto 1,2, Francesco Iannotta1, Francesco De Felice1,2, Beatrice Casadei1, Gianluca Storci1, Serena De Matteis1, Noemi Laprovitera1, Francesca Vaglio1, Barbara Sinigaglia1, Enrica Tomassini1, Enrico Maffini1, Mario Arpinati1, Francesco Barbato1,2, Margherita Ursi1,2, Salvatore Nicola Bertuccio1, Daria Messelodi1, Irene Salamon1, Maria Naddeo1, Elisa Dan1, Luca Zazzeroni1, Cinzia Pellegrini1, Matteo Carella1,2, Marianna Gentilini2,1, Pier Luigi Zinzani1,2, Massimiliano Bonafè1,2, Francesca Bonifazi1 P105 MATCHING-ADJUSTED INDIRECT COMPARISON OF EFFECTIVE CHARACTERISTICS AMONG DIFFERENT BCMA TARGETING CAR-T IN TREATMENT OF RELAPSED OR REFRACTORY MULTIPLE MYELOMAS Chunrui Li 1, Lu-Gui Qiu2, Di Wang1, Yongping Song3, He Huang4, Jianyong Li5, Bing Chen6, Jing Liu7, Xi Zhang8, Yu-Jun Dong9, Kai Hu10, Peng Liu11, Jian-Qing Mi12, Kaiyang Ding13, Zhenyu Li14, Qi’e Dong15, Fuyuan Zhang15, Guang Hu15, Wen Wang15 P106 IMPACT OF EARLY CAR– CD4+ T-LYMPHOCYTES RECOVERY FOLLOWING CAR-T CELL INFUSION FOR RELAPSED OR REFRACTORY B CELL LYMPHOMAS Massimiliano Gambella 1,2, Simona Carlomagno2, Rosa Mangerini1, Nicoletta Colombo1, Alessia Parodi1, Chiara Ghiggi1, Livia Giannoni1, Elisa Coviello1, Chiara Setti2, Silvia Luchetti1, Alberto Serio1, Antonella Laudisi1, Monica Passannante1, Alessandra Bo1, Elisabetta Tedone1, Simona Sivori2, Emanuele Angelucci1, Anna Maria Raiola1 P107 ACUTE INFECTION AND BASELINE C-REACTIVE PROTEIN – KEY MARKERS OF PROGRESSION IN RELAPSED REFRACTORY DLBCL PATIENTS RECEIVING CAR-T CELL THERAPY Jayachandran Perumal Kalaiyarasi 1, Khalil Begg1, Luminita Keating1, Louise Corbett1, Paul Boraks1, Brendan O’Sullivan1, Andrew King1, Charles Crawley1, Benjamin Uttenthal1, Ram Malladi1 P108 THIRD-LINE CAR-T IN PATIENTS WITH EARLY RELAPSE FOLLOWING FIRST-LINE TREATMENT FOR AGGRESSIVE B-CELL LYMPHOMA: STILL A VALUABLE OPTION Massimiliano Gambella 1, Anna Maria Raiola1, Livia Giannoni1, Elisa Coviello1, Chiara Ghiggi1, Anna Ghiso1, Riccardo Varaldo1, Stefania Bregante1, Carmen Di Grazia1, Alida Dominietto1, Antonella Laudisi1, Monica Passannante1, Silvia Luchetti1, Alberto Serio1, Alessandra Bo1, Emanuele Angelucci1 P109 EASIX SCORE AS A PROGNOSTIC FACTOR OF CYTOKINE RELEASE SYNDROME IN CAR-T PATIENTS - A RETROSPECTIVE ANALYSIS OF MM AND LBCL COHORTS Jaromir Tomasik 1, Batia Avni2, Sigal Grisariu3, Shlomo Elias3, Eran Zimran3, Polina Stepensky3, Grzegorz Basak1 P110 HEMATOTOXICITY POST CAR-T CELL THERAPY: REAL-WORLD DATA ON RISK FACTORS AND OUTCOMES Zoi Bousiou 1, Ioannis Kyriakou1, Anna Vardi1, Despoina Mallouri1, Eleni Gavriilaki1, Christos Demosthenous1, Nikolaos Spyridis1, Alkistis-Kyra Panteliadou1, Eleni Papchianou1, Georgios Karavalakis1, Evangelia Yannaki1, Ioannis Batsis1, Ioanna Sakellari1 P111 DONOR-DERIVED CLL-1 CHIMERIC ANTIGEN RECEPTOR T-CELLS FOR RELAPSED/REFRACTORY ACUTE MYELOID LEUKEMIA BRIDGING TO ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION: A CASE REPORT UPDATE Xiaojuan Miao1, Yanrong Shuai1, Ying Han1, Yilan Liu1, Nan Zhang1, Hao Yao1, Xiao Wang1, Guangcui He 1, Dan Chen1, Fangyi Fan1, Alex H. Chang2, Yi Su1, Hai Yi1 P112 A RETROSPECTIVE REVIEW TO IDENTIFY OPTIMAL LYMPHODEPLETION PRIOR TO TISAGENLECLEUCIL IN PATIENTS WITH REFRACTORY OR RELAPSED LARGE B-CELL LYMPHOMA IN SCOTLAND’S NATIONAL CAR-T CENTRE Daire Quinn 1, Jennifer McLellan1, Sinead Connolly1, Grant McQuaker1, Anne Parker1, Dimitris Galopoulos1, Ailsa Holroyd1, Anne-Louise Latif1, David Irvine1 P113 METAGENOMIC NEXT-GENERATION SEQUENCING VISUALLY DISPLAYS A FALSE-POSITIVE DETECTION OF HIV NUCLEIC ACID RELATED TO CART TREATMENT: A CASE STUDY IN A CHILD M. I. Zhou 1, Lili Huang1, Zhenjiang Bai1, Shuiyan Wu1, Jun Lu1, Shaoyan Hu1 P114 IMPACT OF SERUM INTERLEUKIN 1-BETA LEVELS DURING CAR-T CELLS THERAPY ON CLINICAL OUTCOME: A SINGLE-CENTER EXPERIENCE Ilaria Cutini 1, Riccardo Boncompagni1, Chiara Camerini1, Mirella Giordano1, Antonella Gozzini1, Alessio Mazzoni1, Gaia Mirabella1, Chiara Nozzoli1, Edoardo Simonetti1, Riccardo Saccardi1 P115 THE SCOTTISH EXPERIENCE WITH CAR-T CELL THERAPY: A FOCUS ON DLBCL David Hopkins 1, Anne Parker1, Dimitris Galopoulos1, Grant McQuaker1, Andrew Clark1, Ailsa Holroyd1, Anne-Louise Latif1, David Irvine1 P116 DONOR-DERIVED LYMPHOID ANTIGEN-DIRECTED CAR-T CELLS FOR RELAPSED/REFRACTORY ACUTE LYMPHOBLASTIC LEUKEMIA IN CHILDREN AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION: REPORT OF 17 CASES Olga Molostova1, Larisa Shelikhova1, Rimma Khismatullina1, Evelina Lyudovskikh1, Yuliya Abugova1, Dmitriy Pershin 1, Maria Klimentova1, Irina Shipitsina1, Ekaterina Malakhova1, Maria Fadeeva1, Alena Kulakovskaya1, Lili Khachatryan1, Viktoria Vedmedskaya1, Galina Novichkova1, Alexei Maschan1, Michael Maschan1 P117 CARDIOVASCULAR COMPLICATIONS OF CHIMERIC ANTIGEN RECEPTOR (CAR)-T CELL THERAPY Giorgia Mancini 1, Alice Frangione1, Edlira Rrapaj1, Ilaria Scortechini1, Francesco Saraceni1, Roberta Domizi1, Simona Pantanetti1, Abele Donati1, Antonio Dello Russo1, Federico Guerra1, Attilio Olivieri1 P118 CORRELATION OF IL-6 LEVELS WITH THE EXPANSION OF LYMPHOCYTIC POPULATIONS, SEVERITY OF CYTOKINE RELEASE SYNDROME AND NEUROTOXICITY FOLLOWING CAR-T CELL THERAPY Maria Liga 1, Dimitris Tsokanas1, Memnon Lysandrou1, Dionysia Kefala1, Evangelia Triantafyllou1, Angeliki Georgopoulou1, Eleftheria Sagiadinou1, Nikolaos Savvopoulos1, Vassiliki Zacharioudaki1, Alexandros Spyridonidis1 P119 EFFICACY OF ANTI-CD19 C AR-T CELL TREATMENT IN MANTLE-CELL LYMPHOMA HARBORING P53 ALTERATION: A MONOCENTRIC RETROSPECTIVE STUDY Daniele Mannina1, Chiara De Philippis1, Jacopo Mariotti 1, Barbara Sarina1, Daniela Taurino1, Stefania Bramanti1, Armando Santoro1 P120 OUTCOMES OF COMMERCIAL AND IN-HOUSE ANTI CD19 CAR T-CELL THERAPY FOR RELAPSED/REFRACTORY B-CELL LYMPHOMA IN SINGAPORE Shin Yeu Ong1, Cindy Krisnadi 1, Samuel Sherng Young Wang1, Yun Xin Chen1, Michaela Su-fern Seng2, Shui Yen Soh2, Esther Hian Li Chan3, William Ying Khee Hwang1, Aloysius Yew Leng Ho1, Francesca Lorraine Wei Inng Lim1 P121 CHOICE OF COMMERCIALLY AVAILABLE CAR T-CELLS PRODUCT FOR AGGRESSIVE LYMPHOMA: A SURVEY OF BEHALF OF THE CELLULAR THERAPY & IMMUNOBIOLOGY WORKING PARTY (CTIWP) OF THE EBMT Urban Novak1, Jarl E. Mooyaart2, Michael Daskalakis1, Christof Scheid3, Anne Sirvent4, Ibrahim Yakoub-Agha5, Ron Ram6, Edouard Forcade7, Lucía López Corral8, Emma Nicholson9, Eugenio Galli10, Friedrich Stölzel11, Wolfgang Bethge12, Eva Maria Wagner-Drouet13, Jorinde D. Hoogenboom14, Stephan Mielke15, Caroline Arber Barth16, Federico Simonetta17, Christian Chabannon18, Jürgen Kuball19, Annalisa Ruggeri20, Florent Malard 21 P122 ASSESSMENT OF MALNUTRITION DURING PREHABILITATION FOR PATIENTS UNDERGOING CAR-BASED CELLULAR THERAPY Juliet Morgan 1, Helen Long2 P123 LEUKAPHERESIS FOR AUTOLOGOUS CHIMERIC ANTIGEN RECEPTOR T CELL THERAPY IN CHILDREN: REPORT FROM A SINGLE PEDIATRIC CENTER June Iriondo 1,2, Josune Zubicaray1,2, Guzmán López de Hontanar3,1,2, Elena Sebastián1,2, Josefa Navarrete1, Ana Torre1, Rocio Rico1, Ana Castillo1, Blanca Herrero1,2, Alba Rubio1,2, Susana Buendía1,2, Alejandro Sanz1,2, Ana de la Cruz1,2, Almudena Galán1,2, Jesus Gonzalez de Pablo2, Manuel Ramirez1,2, Julián Sevilla1,2 P124 SEVERE HHV-6 RELATED ENCEPHALITIS FOLLOWING ANTI-CD19 CAR-T TREATMENT: A CASE STORY FROM A POINT OF CARE PRODUCTION FACILITY Nina Marie Birk1, Katrine Kielsen 1,2, Özcan Met3, Inge Marie Svane3, Eva Haastrup4, Lisbeth Pernille Andersen4, Kristian Schønning5, Jonas Nielsen6, Søren Lykke Petersen7, Marianne Ifversen1 P125 UNLOCKING POSSIBILITIES: THE IMPACT OF CYTOGENETIC ANALYSIS ON PATIENTS UNDERGOING CAR-T CELL THERAPY Christos Varelas 1, Ioannis Kyriakou1, Eleni Gavriilaki2, Zoi Bousiou1, Ioannis Batsis1, Nikolaos Spyridis1, Evangelia Yannaki1, Giorgos Papaioannou1, Maria Gkaitatzi1, Michail Iskas1, Ioanna Sakellari1, Anastasia Athanasiadou1 P126 T-CELL LARGE GRANULAR LYMPHOCYTE POPULATION INVOLVING CHIMERIC ANTIGEN RECEPTOR-MODIFIED T (CAR T) CELLS IN PATIENTS WITH CYTOPENIA AFTER CD19-TARGETED CAR T-CELL THERAPY: CASE SERIES Aya Albittar 1, Alireza Torabi2, Emily Liang1,2, Andrew Portuguese1,2, Jennifer Huang1,2, Cecilia Yeung1,2, Erik Kimble1,2, Delaney Kirchmeier1, Aiko Torkelson1, Abigail Chutnik1, Ryan Cassaday1,2, Aude Chapuis1,2, Hans-Peter Kiem1,2, Filippo Milano1,2, Folashade Otegbeye1,2, Mazyar Shadman1,2, Brian Till1,2, David Maloney1,2, Cameron Turtle1,2,3, Jordan Gauthier1,2, Alexandre Hirayama1,2 P127 TREATMENT WITH TISAGENLECLEUCEL OF RELAPSE REFRACTORY DIFFUSE LARGE B CELL LYMPHOMA – SINGLE CENTER EXPERIENCE UHC ZAGREB Barbara Dreta 1, Sandra Bašić-Kinda1, Dino Dujmović1, Neno Živković1, Josip Batinić1,2, Ida Hude Dragičević1, Klara Dubravčić1, Margareta Dobrenić1, Ivana Ilić1, Snježana Dotlić2,1, Lea Galunić-Bilić1, Ivana Franić-Šimić1, Igor Aurer1,2 P128 SERUM AMYLOID-A IN CAR-T CELL THERAPY: A NEW ACUTE PHASE REACTANT Eugenio Galli 1, Ilaria Pansini2, Patrizia Chiusolo1,2, Stefan Hohaus1,2, Anna Modoni1, Luca Montini1, Nicola Piccirillo1,2, Federica Sorà1,2, Simona Sica1,2 P129 CHALLENGES IN CHIMERIC ANTIGEN RECEPTOR-T CELL PRODUCT ADMINISTRATION IN A HIGH TUMOR-BURDEN ELDERLY PATIENT WITH MANTLE-CELL LYMPHOMA Umberto Pizzano1,2, Francesca Patriarca1,2, Marta Lisa Battista 1, Giuseppe Petruzzellis1,2, Gabriele Facchin1, Giuseppe Di Renzo1,2, Renato Fanin1,2 P130 REGIONAL REPRESENTATION OF THE OUTCOMES OF A COHORT OF PATIENTS WITH B-CELL ALL TREATED WITH TISAGENLECLEUCEL FROM A CENTRE IN THE MIDDLE EAST Fahad Bahkali MD 1, Ali Alahmari MD1, Riad El Fakih1, Amr Hanbali1, Rashed Al Bakr1, Abdulwahab Albabtain1, Naeem Chaudhri1, Walid Rasheed1, Ayman Saad1, Saud Alhayli1, Ahmed Abdrabou1, Samar Alfaqaawi1, Yazeed Bajuaifer1, Ahmed Bin Salman1, Alfadil Haroon1, Amal Hejab1, Taimoor Hussain1, Heba Madien1, Mostafa Saleh1, Momen Nassani1, Marwa Nassar1, Sara Samarkandi1, Mohamed Sharif1, Reem Alasbali1, Emad Ghabashi1, Majed Altareb1, Shaykhah Alotaibi1, Shihab Ahmed1, Reena Ulahannan1, Alfadel Alshaibani1, Hanan Alkhaldi1, Abdullah Alamer1, Mansour Alfayez1, Feras Alfraih1, Ahmad Alotaibi1, Fahad Alsharif1, Marwan Shaheen1, Fahad Almohareb1, Hazza Alzahrani1, Mahmoud Aljurf1, Syed Ahmed1 P131 DELAYED ICANS IN POST BCMA CAR-T CELL THERAPY CHALLENGES Mohamed Abuhaleeqa 1, Yara Afifi1, Sheima Mahmoud Ali1, Fatema Al Kaabi1, Inas El-Najjar1, Jayakumar David Dennison1, Mansi Sachdev1, Nameer Al Saadawi1, Ruqqia Mir1, Lev Brylev1, Mohamed Mostafa1, Yendry Ventura1, Krina Patel2 P132 CAR T CELLS TARGETING CD28 SHOW PRECLINICAL ACTIVITY AGAINST T-ALl Semjon Willier1, Julian Fäber1, Theodora Ispyrlidou2, Sophia Nikolaides2, Jonas Wilhelm2, Paulina Ferrada-Ernst2, Franziska Blaeschke2, Fiona Becker-Dettling2, Maike Breidenbach2, Theresa Käuferle2, Annika Peters2, Dana Stenger2, Christoph Klein2, Tobias Feuchtinger 1 P133 HAMBURG REAL-WORLD EXPERIENCE WITH AXICABTAGENE CILOLEUCEL IN AGGRESSIVE B-CELL LYMPHOMA: IN-VIVO EXPANSION CORRELATES WITH TREATMENT OUTCOME Susanna Carolina Berger1, Anita Badbaran1, Evgeny Klyuchnikov1, Kristin Rathje1, Nico Gagelmann1, Maria Geffken1, Dominic Wichmann1, Christian Frenzel1, Dietlinde Janson1, Christine Wolschke1, Nicolaus Kröger1, Boris Fehse1, Francis Ayuk 1 P134 CD45-DIRECTED CAR-T CELLS WITH CD45 KNOCKOUT EFFICIENTLY KILL MYELOID LEUKEMIA AND LYMPHOMA CELLS IN-VITRO EVEN AFTER EXTENDED CULTURE Maraike Harfmann 1, Tanja Schröder1, Dawid Glow1, Maximilian Jung1, Almut Uhde1, Nicolaus Kröger1, Stefan Horn1, Kristoffer Riecken1, Boris Fehse1, Francis Ayuk1 P135 COMPARISON OF CD123- AND CD33-CAR-NK CELL PREPARATIONS IN A XENOGRAFT MOUSE MODEL FOR TREATMENT OF ACUTE MYELOID LEUKEMIA Fenja Gierschek 1,2, Sabine Müller3, Julia Kostyra3, Jan Kuska3, Tobias Bexte1,2,4,5, Katja Stein1,2, Lisa Marie Reindl1,2, Sophia Thul1,2, Alina Moter1,2, Philipp Wendel1,2,6,7, Hadeer Mohamed Rasheed8,9, Ningyu Li8, Juliane Schlüter1, Sabine Hünecke1, Claudia Cappel1, Olaf Penack8,10, Thomas Oellerich2,4,6, Jan-Henning Klusmann1,2, Nina Möker3, Congcong Zang3, Evelyn Ullrich1,2,4,6 P136 HELP FOR UKRAINIAN HEMATOLOGY PATIENTS (HUP) – A GLOBAL INITIATIVE SUPPORTING THE ESTABLISHMENT OF HEMATOLOGY CENTERS AND HEMATOPOIETIC CELL TRANSPLANTATION PROGRAMS IN DIFFICULT SITUATIONS Irina Korenkova 1, Sergiy Klymenko2, Oleksandr Lysytsia3, Menachem Bitan4, Olena Lukianets5, Jan M. Zaucha6, Joannis Mytilineos7, Andreas Hochhaus8, Mats Heyman9, Francois Guilhot10, Natacha Bolanos11, Roman Kuts12, Hildegard T. Greinix13, Isabel Sanchez-Ortega14, Mickey Boon Chai Koh15, Bohdan Medvediev1, Susan Landgraf16, Rüdiger Hehlmann17, Mahmoud Aljurf18, Katherina Filonenko19, Reguia Belkhedim18, Torsten Haferlach*20, Arnold Ganser*21, Anna Sureda Balari*22, Damiano Rondelli*23, Dietger Niederwieser*24,25,26 P137 A RETROSPECTIVE ANALYSIS COMPARING ORCA-T TO POST-TRANSPLANT CYCLOPHOSPHAMIDE BASED ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANT IN PATIENTS WITH MATCHED UNRELATED DONORS RECEIVING MYELOABLATIVE CONDITIONING Amandeep Salhotra 1, Alexandra Gomez Arteaga2, Caspian Oliai3, Sagar S. Patel4, Jeremy Pantin5, Arpita Gandhi6, Bhagirathbhai Dholaria7, Edmund K. Waller8, Samer A. Srour9, Anna Pavlova10, Irene Agodoa10, J. Scott McClellan10, Nathaniel B. Fernhoff10, Mehrdad Abedi11, Everett H. Meyer12 P138 PHASE I/II STUDY ON INFUSION OF ALLOREACTIVE OR EX VIVO IL-15 STIMULATED NK CELLS AFTER HAPLOIDENTICAL STEM CELL TRANSPLANTATION IN PEDIATRIC PATIENTS WITH ACUTE LEUKEMIA Carmen Mestre1,2, Odelaisy León Triana1,2,3, Alfonso Navarro Zapata1,2, David Bueno4, Luisa Sisinni4, Isabel Badell Serra5, Marta González Vicent6, Cristina Beléndez7, Laura Clares Villa1,2, Yasmina Mozo6, Karima Al-Akioui1,2, Victor Galán4, Pilar Guerra1,4, Carlos Echecopar4, Halin Bareke1,2, Cristina Aguirre1,2, Antonio Pérez Martínez 1,2,4,8 P139 HARNESSING CIK CELL INTERVENTION FOR ACUTE LEUKEMIA OR MDS RELAPSE POST ALLO-HSCT Eva Rettinger 1, Marie Luedtke1, Emilia Salzmann-Manrique1, Sabine Huenecke1, Melanie Bremm1, Claudia Cappel1, Gesine Bug1, Johann Greil2, Roland Meisel3, Eva Maria Wagner-Drouet4, Jan-Henning Klusmann1, Halvard Bonig5, Peter Bader1 P140 RISK FACTORS FOR THE DEVELOPMENT OF GRAFT-VERSUS-HOST-DISEASE FOLLOWING DONOR LYMPHOCYTE INFUSION AFTER ALLOGENEIC STEM CELL TRANSPLANTATION Eva Koster1, Peter von dem Borne1, Peter van Balen1, Erik Marijt1, Jennifer Tjon1, Tjeerd Snijders2, Daniëlle van Lammeren3, Hendrik Veelken1, Frederik Falkenburg1, Liesbeth de Wreede1, Constantijn Halkes 1 P141 RELAPSE AFTER HSCT: MAY DLI/CIK CELLS STILL PLAY A ROLE IN THE CELLULAR THERAPY ERA? DLI/CIK AS A RESCUE STRATEGY FOR CHILDREN WITH POST-TRANSPLANT MRD-POSITIVITY Francesca Limido1,2, Alex Moretti2,3, Riccardo Carnevale1,2, Sara Napolitano2, Francesca Vendemini2, Sonia Bonanomi2, Andrea Biondi1,2,3, Giuseppe Gaipa3, Adriana Balduzzi 1,2 P142 PHASE I/II PRELIMINARY RESULTS OF HUMAN PRO-T-CELLS MANUFACTURING IN VITRO TO ACCELERATE IMMUNE RECONSTITUTION AFTER UMBILICAL CORD BLOOD TRANSPLANTATION IN ADULT PATIENT WITH HEMATOLOGIC MALIGNANCIES Elisa Magrin1, Jean-Sébastien Diana 1, Clotilde Aussel1, Eden Schwartz1, Jinmi Baek1, Naim Bouazza2, Aurélie Gabrion1, Alice Girardot1, Axelle Maulet1, Brigitte Ternaux1, Aurore Touzart1, Caroline Tuchmann-Durand3, Ludovic Lhermitte1, Vahid Asnafi1, Edouard Forcade4, Huynh Anne5, Jean-Marc Treluyer1,2, Olivier Hermine1,6,3, Marina Cavazzana1,6,3 P143 INNATE DONOR EFFECTOR ALLOGENEIC LYMPHOCYTES AFTER ALLOGENEIC STEM CELL TRANSPLANTATION - THE IDEAL TRIAL Lia Minculescu 1, Lone Smidstrup Friis1, Soeren Lykke Petersen1, Brian Thomas Kornblit1, Niels Smedegaard Andersen1, Ida Schjoedt1, Helle Lesley Andersen1, Eva Haastrup1, Lisbeth Pernille Andersen1, Henrik Sengeloev1 P144 CD45RA DEPLETION PRESERVES PROPORTIONS AND CLONAL BREATH OF VIRUS-SPECIFIC T CELLS Amandine Pradier 1,2, Astrid Melotti1, Chiara Bernardi1,2, Simona Pagliuca3, Sisi Wang1, Sarah Morin2, Federica Giannotti2, Stavroula Marouridi-Levrat2, Yves Chalandon1,2, Federico Simonetta1,2, Anne-Claire Mamez2 P145 LAYING THE FOUNDATIONS FOR AN IMMUNOPOTENCY TEST FOR ALLOGENEIC MESENCHYMAL STROMAL CELLS María Esther Martínez-Muñoz 1,2, Trinidad Martín-Donaire2, Rocío Sánchez2, Elvira Ramil2, Rosalía Alonso-Trillo2, Nuria Panadero1, Rocío Zafra2, Enrique Andreu3, Gloria Carmona4, Ana María García-Hernández5, Miriam López-Parra6, Gustavo Melen7, Luciano Rodríguez-Gómez8, Rosa Yáñez9, Cristina Avendaño-Solá1,2, Jose María Moraleda5, María Eugenia Fernández10, Rafael Francisco Duarte1,2 P146 CHARACTERIZATION OF CYTOKINE RELEASE SYNDROME AND NEUROTOXICITY IN COMMERCIALLY AVAILABLE BISPECIFIC ANTIBODIES AND CHIMERIC ANTIGEN RECEPTOR T-CELLS IN MULTIPLE MYELOMA Eden Biltibo1 P147 TRIAL IN PROGRESS: OBSERVATIONAL, POST-AUTHORISATION SAFETY STUDY TO DESCRIBE SAFETY AND EFFECTIVENESS OF TABELECLEUCEL IN PATIENTS WITH EBV + PTLD IN A REAL-WORLD SETTING IN EUROPE François Denjean1, Asmaa Zkik1, Constance Battin1, Sophie Blanchet1, Florence Carrere1, Mathias Domostoj1, Valérie Cassan2, Pavan Randhawa 3, Roberta Valenti1 P148 CD45RO CELLS ADDBACK IN TCR ΑΒ/CD45RA DEPLETED HAPLOIDENTICAL HSCT LEADS TO SUPERIOR OUTCOMES IN INFANTS WITH INBORN ERRORS OF IMMUNITY: EXPERIENCE FROM A DEVELOPING COUNTRY! Vimal Kumar Gunasekaran 1, Rishab Bharadwaj1, Meena Sivasankaran2, Niranjan Hegde2, Deepti Sachan1, Deenadayalan Munirathnam1 P149 IMPACT OF MYELOFIBROSIS ON PATIENTS WITH MYELODYSPLASTIC SYNDROMES FOLLOWING ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION Panpan Zhu 1,2,3,4, Xiaoyu Lai4,2,3,4, Lizhen Liu1,2,3,4, Jimin Shi1,2,3,4, Jian Yu1,2,3,4, Yanmin Zhao1,2,3,4, Luxin Yang1,2,3,4, Weiyan Zheng1,2,3,4, Jie Sun1,2,3,4, Wenjun Wu1,2,3,4, He Huang1,2,3,4, Yi Luo1,2,3,4 P150 MANAGEMENT AND TOXICITY OF DONOR LYMPHOCYTE INFUSIONS IN PEDIATRIC PATIENTS WITH ONCOLOGICAL DISEASES AFTER ALLOGENIC STEM CELL TRANSPLANTATION IN A SINGLE INSTITUTION Luisa Paschke 1, Marie Sophie Knape1, Katrin Vollmer1, Katja Gall1, Angela Wawer1, Jan-Henning Klusmann2, Dirk Reinhardt3, Hans-Jochem Kolb4, Belinda Simoes5, Stefan EG Burdach1, Irene Teichert von Luettichau1, Julia Hauer1, Uwe Thiel1 P151 IMPROVING OUTCOMES IN MDS/MPN: TREOSULFAN-BASED CONDITIONING FOR ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION Alessandro Bruno1, Lorenzo Lazzari 1, Elisa Diral1, Sara Mastaglio1, Daniela Clerici1, Sarah Marktel1, Francesca Lunghi1, Simona Piemontese1, Daniele Sannipoli1, Camilla Gariazzo1, Gianluca Scorpio1, Gregorio Bergonzi1, Consuelo Corti1, Matteo Giovanni Carrabba1, Massimo Bernardi1, Luca Vago1, Maria Teresa Lupo-Stanghellini1, Fabio Ciceri1,2, Jacopo Peccatori1, Raffaella Greco1 P152 PREVIOUS RESPONSE TO TKIS AS A FAVORABLE PROGNOSTIC FACTOR FOR SURVIVAL IN HSCT FOR CML: LONG TERM RESULTS OF A SINGLE CENTER IN BRAZIL Vaneuza Funke 1, Giuliana Rosendo1, Daniela Setubal1, Caroline Bonamin Sola1, Samir Nabhan1, Rafael Marchesine1, Glaucia Tagliari1, Isabela Menezes1, Ana Lucia Mion1, Ricardo Pasquini1 P153 ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANT FOR MYELOFIBROSIS: UPDATED RESULTS FROM BRAZILIAN REGISTRY Vaneuza Funke 1, Alberto Cardoso Martins Lima1, Nelson Hamersclak2, Vergilio Colturato3, Afonso Vigorito4, Gustavo Machado Teixeira5, Vanderson Rocha6, Livia Mariano6, Decio Lerner7, George Mauricio Navarro Barros8, Alessandra Paz9, Celso Arrais10, Claudia Astigarra11, Fabio Pires12, Fernando Barroso Duarte13, Ricardo Pasquini1, Mary Flowers14 P154 RESULTS OF ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION IN PATIENTS WITH CHRONIC MYELOID LEUKEMIA AFTER THERAPY WITH TYROSINE KINASE INHIBITORS Larisa Kuzmina1, Vera Vasilyeva 1, Zoya Konova1, Marya Dovydenko1, Olga Koroleva1, Olga Pokrovskaya1, Darya Mironova1, Elena Parovichnikova1 P155 ALLOGENEIC STEM CELL TRANSPLANTATION IN CHRONIC MYELOID LEUKEMIA IN ERA OF TYROSINE KINASE INHIBITORS: A 13-YEAR SINGLE CENTRE EXPERIENCE FROM INDIA Mehak Trikha1, Lingaraj Nayak 1, Sachin Punatar1, Anant Gokarn1, Akanksha Chichra1, Sumeet Mirgh1, Nishant Jindal1, P.G. Subramaniam1, Nikhil Patkar1, Prashant Tembhare1, Gourav Chatterjee1, Sweta Rajpal1, Navin Khattry1 P156 ATG-TARGETED DOSING STRATEGY REDUCED CMV/EBV REACTIVATION AND IMPROVED SURVIVAL WITHOUT INCREASING GVHD AFTER URD-PBSCT: A SINGLE-CENTER, PROSPECTIVE, SINGLE-ARM, CLINICAL TRIAL Sheng Chen 1, Jishan Du1, Haitao Wang2, Nan Wang1, Liping Dou2, Daihong Liu2 P157 IMPACT OF FLUDARABINE DOSE ON OUTCOME AFTER ALLO-HCT WITH REDUCED INTENSITY CONDITIONING FOR OLDER PATIENTS WITH AML: A STUDY FROM THE ALWP OF THE EBMT Guillaume Dachy 1, Myriam Labopin2, Gerard Socié3, Cristina Castilla-Llorente4, Edouard Forcade5, Igor Wolfgang Blau6, Patrice Ceballos7, Eric Deconinck8, David Burns9, Claude Eric Bulabois10, Radovan Vrhovac11, Anne Huynh12, Didier Blaise13, Johan Maertens14, Thomas Schroeder15, Jacques-Olivier Bay16, Bipin Savani17, Alexandros Spyridonidis18, Fabio Ciceri19, Mohamad Mohty20 P158 TOXICITY COMPARISON OF TWO REDUCED INTENSITY CONDITIONING (RIC) TRANSPLANT REGIMENS FOR ADULT ALL IN CR1/2: RESULTS FROM THE RANDOMISED PHASE 2 MULTICENTRE ALL-RIC TRIAL Anna Castleton 1, Rebekah Weston2, Aimee Jackson2, Matthew Beasley3, Rebecca Bishop2, Scott Chapman2, Patricia Diez4, Mohamed Elhaneid2, Adele Fielding5, Andrea Hodgkinson2, Stephanie Lane2, George Mikhaeel6, Nick Morley7, Eduardo Olavarria8, Eleni Tholouli9, Bela Patel10, Ronjon Chakraverty11, David Marks12 P159 CXCR4 DIRECTED ENDORADIOTHERAPY WITH [177LU] PENTIXATHER ADDED TO TBI IS FEASIBLE AND SPARES THE HEMATOPOIETIC NICHE IN PATIENTS WITH RELAPSED/REFRACTORY ACUTE MYELOID LEUKEMIA Krischan Braitsch 1, Martina Rudelius2, Maike Hefter1, Katrin Koch1, Katharina Nickel1, Katharina S. Götze1, Wolfgang Weber1, Florian Bassermann1, Matthias Eiber1, Mareike Verbeek1, Peter Herhaus1 P160 EVALUATION OF THE TRANSPLANT CONDITIONING INTENSITY (TCI) SCORE FOR SECOND ALLOGENEIC STEM CELL TRANSPLANTATION (ALLO-SCT2) - A STUDY OF THE ALWP OF THE EBMT Giuliano Filippini Velázquez 1, Jacques-Emmanuel Galimard2, Alexandros Spyridonidis3, Jakob Passweg4, Didier Blaise5, Nikolaus Kröger6, Igor Wolfgang Blau7, Patrice Chevallier8, Tobias Gedde-Dahl9, Panagiotis Kottaridis10, Johan Maertens11, Emma Nicholson12, Arancha Bermudez Rodriguez13, Peter Dreger14, Gerald G. Wulf15, Mareike Verbeek16, Emanuele Angelucci17, Mathias Eder18, Uwe Platzbecker19, Bipin Savani20, Christoph Schmid1, Fabio Ciceri21, Mohamad Mohty2 P161 VENETOCLAX COMBINED WITH FLUDARABINE AND MELPHALAN CONDITIONING REGIMEN IN PATIENTS > 50 YEARS WITH MYELOID MALIGNANCIES: INTERIM ANALYSIS OF A PROSPECTIVE, MULTICENTER, PHASE II TRIAL Panpan Zhu 1,2,3,4, Xiaoyu Lai1,2,3,4, Lizhen Liu1,2,3,4, Yibo Wu1,2,3,4, Jimin Shi1,2,3,4, Jian Yu1,2,3,4, Yanmin Zhao1,2,3,4, Yishan Ye1,2,3,4, Guifang Ouyang5, Yi Chen6, Weiyan Zheng1,2,3,4, Jie Sun1,2,3,4, He Huang1,2,3,4, Yi Luo1,2,3,4 P162 FLUDARABINE/TREOSULFAN VS. FLUDARABINE/TBI CONDITIONING FOR ALLOSCT FOR AML AND MDS: COMPARABLE SURVIVAL RATES BUT DIVERGENT IMMUNE RECONSTITUTION Lina Kolloch1, Philipp Berning1, Christian Reicherts1, Julian Ronnacker1, Simon Call1, Julia Marx1, Matthias Floeth1, Eva Esseling1, Jan-Henrik Mikesch1, Christoph Schliemann1, Georg Lenz1, Matthias Stelljes 1 P163 CONDITIONING FOR ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION IN PATIENTS WITH PERIPHERAL T-CELL LYMPHOMA (PTCL): INTERMEDIATE-DOSE TBI DOES THE JOB Isabelle Krämer1, Thomas Luft 1, Ute Hegenbart1, Stefan Schönland1, Peter Stadtherr1, Linda Selberg1, Laila König1, Carsten Müller-Tidow1, Peter Dreger1 P164 5-YEAR TRANSPLANT SUCCESS AFTER TREOSULFAN CONDITIONING Rohtesh S. Mehta 1, Joachim Deeg1, Ted Gooley1, Stephanie J. Lee1, Laurel Thur1, Filippo Milano1 P165 EFFICACY ANALYSIS OF HAPLOIDENTICAL TRANSPLANTATION USING BUSULFAN/CYCLOPHOSPHAMIDE AND MELPHALAN AS CONDITIONING REGIMEN FOR RELAPSED AND REFRACTORY ACUTE MYELOID LEUKEMIA Fei Pan1, Guanlan Yue1, Kang Gao1, Kun Wang1, Huili Zhu1, Yujie Wang1, Zheren Wang1, Zhijie Wei 1 P166 POST-TRANSPLANT CYCLOPHOSPHAMIDE RESULTS IN LOW INCIDENCE OF CHRONIC GRAFT-VERSUS-HOST DISEASE IN UNRELATED OR MATCHED-SIBLING DONOR STEM CELL TRANSPLANTATION WITHOUT COMPROMISING IMMUNE RECONSTITUTION AND GRAFT-VERSUS-LEUKEMIA EFFECT Ioannis Tsonis 1, Ifigeneia Tzannou1, Tatiana Tzenou1, Natali El Gkotmi1, Maria Katsareli1, Ismini Darmani1, Vasiliki Bampali1, Evridiki Theodorou1, Maria-Eleni Karatza1, Maria Garofalaki1, Zoi Poulopoulou1, Marina Papageorgiou1, Soultana Tryfonidou1, Panagiotis Siamatas1, Eirini Tziotziou1, Eirini Grispou1, Stavros Gigantes1, Ioannis Baltadakis1, Aikaterini Souravla1 P167 CONDITIONING INTENSITY IN STEM CELL TRANSPLANTATION WITH POST-TRANSPLANT CYCLOPHOSPHAMIDE FOR ACUTE MYELOID LEUKEMIA: A STUDY FROM THE ACUTE LEUKEMIA WORKING PARTY OF THE EBMT Jaime Sanz 1, Myriam Labopin2, Jurjen Versluis3, Didier Blaise4, Jacoppo Peccatori5, Juan Montoro1, Gwendolyn Van Gorkom6, Peter von dem Borne7, Hélène Labussière-Wallet8, Montserrat Rovira9, Péter Reményi10, Patrice Chevallier11, Mi Kwon12, Matthias Eder13, Jan Vydra14, Eolia Brissot15, Alexandros Spyridonidis16, Simona Piemontese5, Mohamad Mohty15, Fabio Ciceri5 P168 EVALUATION OF A BALTIMORE MODIFIED NON-TBI CONDITIONING BEFORE ALLOGENEIC TRANSPLANT FROM HAPLOIDENTICAL OR MISMATCHED UNRELATED DONORS, RESULTS FROM A MONOCENTRIC RETROSPECTIVE STUDY Victoria Volpari 1, Claude Eric Bulabois1, Anne Thiebaut-Bertrand1, Sophie Park1, Martin Carre1, Mathieu Meunier1 P169 EXPLORING THE IMPACT OF CONDITIONING REGIMEN INTENSITY ON ALLOGENEIC STEM CELL TRANSPLANT OUTCOMES: INSIGHTS FROM A SINGLE-CENTER STUDY Vera Radici 1, Riccardo Marnoni1, Mirko Farina1, Eugenia Accorsi Buttini1, Sofia Terlizzi1, Lorenzo Masina1, Enrico Morello1, Gabriele Magliano1, Alessandro Leoni2, Federica Re2, Katia Bosio2, Simona Bernardi2, Domenico Russo1, Michele Malagola1 P170 IMPACT OF PRETRANSPLANT MRD IN PATIENTS ALLOGRAFTED FOR AML AFTER TREOSULFAN-BASED CONDITIONING Jacob Pyka 1, Nils Leimkühler1, Artur Schneider1, Jennifer Kaivers1, Rudolf Trenschel1, Annemarie Mohring1, Christian Reinhardt1, Thomas Schroeder1, Christina Rautenberg1 P171 FLUDARABINE TREOSULFAN REDUCED-INTENSITY CONDITIONING REGIMEN PRIOR HAPLOIDENTICAL HEMATOPOIETIC CELL TRANSPLANTATION WITH POST TRANSPLANTATION CYCLOPHOSPHAMIDE IN FRAIL/OLDER AML PATIENTS: PRELIMINARY RESULTS OF A SINGLE CENTER EXPERIENCE Benjamin Bouchacourt1, Anne-Charlotte Le Floch1, Sabine Fürst1, Sylvain Garciaz1, Samia Harbi1, Yosr Hicheri1, Thomas Pagliardini1, Boris Calmels1, Faezeh Legrand1, Claude Lemarie1, Federico Pagnussat1, Christian Chabannon1, Pierre-Jean Weiller1, Marie-Anne Hospital1, Norbert Vey1, Didier Blaise1, Raynier Devillier 1 P172 PHARMACOKINETIC ANALYSIS OF TARGETED DOSING OF ANTITHYMOCYTE GLOBULIN IN ADULTS: A PROSPECTIVE ANALYSIS Jishan Du 1, Haitao Wang1, Nan Wang1, Chao Ma1, Fei Li1, Lu Wang1, Liping Dou1, Daihong Liu1 P173 THE COMBINATION OF FLUDARABINE, BUSULFAN AND ANTI-T LYMPHOCYTE GLOBULIN IS WELL TOLERATED AND OFFERS EFFECTIVE REDUCED INTENSITY CONDITIONING THERAPY FOR PATIENTS WITH MYELOID DISEASE Chris Armstrong 1, Hayley Foy-Stones1, Nicola Gardiner1, Catherine Flynn1, Eibhlin Conneally1, Nina Orfali1 P174 COMPARING PTCY AND GIAC IN HAPLOIDENTICAL SETTINGS: UPDATED ANALYSIS FROM A NATIONWIDE TRANSPLANTATION REGISTRY Yi-Wei Lee 1,2, Xavier Cheng-Hong Tsai2,3, Tzu-Ting Chen4, Tung-Liang Lin5, Yi-Chang Liu6, Chi-Cheng Li7, Ming Yao2,3, Bor-Sheng Ko2,3,8 P175 THE RESULTS OF ALLOGENEIC HSCT AFTER TREOSULFAN–BASED CONDITIONING REGIMEN IN CHILDREN WITH AML: MULTICENTER RETROSPECTIVE STUDY OF THE POLISH PEDIATRIC STUDY GROUP FOR HSCT Agnieszka Sobkowiak-Sobierajska 1, Olga Zając-Spychała1, Maksymilian Deręgowski1, Monika Mielcarek-Siedziuk2, Krzysztof Kałwak2, Agnieszka Zaucha-Prażmo3, Katarzyna Drabko3, Robert Dębski4, Jan Styczyński4, Jolanta Goździk5, Jacek Wachowiak1 P176 OUTCOME OF ALLOGENEIC STEM CELL TRANSPLANTATION IN AML PATIENTS AFTER CONDITIONING WITH FLUDARABINE/TOTAL BODY IRRADIATION(2GY) WITH OR WITHOUT ANTI-THYMOCYTE GLOBULINE OR POST-TRANSPLANT CYCLOPHOSPHAMIDE Thomas Heinicke 1, Myriam Labopin2, Emmanuelle Polge3, Annoek EC Broers4, Gwendolyn van Gorkom5, Michel Schaap6, Jürgen Kuball7, Goda Choi8, Peter von dem Borne9, Gitte Olesen10, Henrik Sengeloev11, Uwe Platzbecker12, Giang Lam Vuong13, Alexandros Spyridonidis14, Bipin N. Savani15, Fabio Ciceri16, Mohamad Mohty17 P177 CONFIRMING BETTER OUTCOMES WITH TBI-BASED MYELOABLATIVE CONDITIONING FOR ACUTE LYMPHOBLASTIC LEUKEMIA PATIENTS UNDERGOING ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION EVEN IN SECOND COMPLETE REMISSION Mario Delia 1, Vito Pier Gagliardi1, Corinne Contento2, Daniela Di Gennaro2, Olga Battisti2, Camilla Presicce2, Immacolata Attolico1, Paola Carluccio1, Francesco Albano1,2, Pellegrino Musto1,2 P178 POST TRANSPLANT CYCLOPHOSPHAMIDE PLUS ABATACEPT LEADS TO DECREASED DAY + 30 CHIMERISM LEVELS Peter Abdelmessieh 1, Henry Fung1, Yuliya Shestovska1, Michael Styler1, Khanal Rashmi1, Asya Varshavsky-Yanovsky1 P179 HEMATOPOIETIC STEM CELL TRANSPLANT WITH REGULATORY AND CONVENTIONAL T CELL ADOPTIVE IMMUNOTHERAPY IN TP53-MUTATED/DELETED AML Rebecca Sembenico1, Loredana Ruggeri1, Simonetta Saldi1, Sara Tricarico2, Antonella Mancusi1, Valerio Viglione1, Francesco Zorutti1, Tiziana Zei2, Roberta Iacucci Ostini2, Eleonora Cristofani1, Roberto Limongello1, Cristina Mecucci1, Andrea Velardi1, Massimo Fabrizio Martelli1, Cynthia Aristei1, Maria Paola Martelli1, Alessandra Carotti2, Antonio Pierini 1 P180 LOMUSTINE, ETOPOSIDE, CYTARABINE, MELPHALAN (LEAM) PROTOCOL AS CONDITIONING REGIMEN BEFORE AUTOLOGOUS HEMATOPOIETIC STEM CELL TRANSPLANTATION (ASCT) IN PATIENTS WITH LYMPHOMAS: A SINGLE CENTER EXPERIENCE Željko Prka 1, Anamarija Vrkljan Vuk1, David Čičić1, Ena Sorić1, Zdravko Mitrović1,2, Marko Lucijanić1,2, Marija Ivić Čikara1, Željko Jonjić1, Mario Piršić1, Vlatko Pejša1,2, Ozren Jakšić1,2 P181 SAFETY AND EFFICACY OF BUSULFAN 9.6 BASED RIC (AUGMENTED RIC) IN OLDER PATIENTS WITH AML WHO ARE NOT SUITABLE FOR MAC Kalina Abrol 1, Ram Vasudevan Nampoothiri1, Michael Kennah1, Natasha Kekre1, David Allan1, Harold Atkins1, Lothar Huebsch1, Trang Doan1, Carolina Cieniak1, Sheryl McDiarmid1, Tim Ramsay1, Christopher Bredeson1, Ashish Narayan Masurekar1 P182 TOTAL MARROW AND LYMPHOID IRRADIATION (TMLI) IN COMBINATION WITH CYCLOPHOSPHAMIDE AND ETOPOSIDE IMPROVES THE OUTCOME OF PATIENTS WITH POOR-RISK ACUTE LEUKEMIA Anthony Stein 1, Monzr Al Malki1, Yan Wang1, Joycelynne Palmer1, Ibrahim Aldoss1, Haris Ali1, Ahmed Aribi1, Andrew Artz1, Brian Ball1, Len Farol1,2, An Liu1, Guido Marcucci1, Ryotaro Nakamura1, Vinod Pullarkat1, Eric Radany1, Firoozeh Sahebi1,2, Amandeep Salhotra1, Karamjeet Sandhu1, Eileen Smith1, Ricardo Spielberger1,2, Susanta Hui1, Stephen Forman1, Jeffrey Wong1 P183 TREOSULFAN-FLUDARABINE CONDITIONING REGIMEN WITH POST-TRANSPLANT HIGH-DOSE CYCLOPHOSPHAMIDE: A RETROSPECTIVE ANALYSIS Aura Arola 1, Lotta Tapana2, Maija Itälä-Remes1 P184 CONDITIONING WITH I.V. BUSULFAN, ONCE VERSUS FOUR TIMES DAILY IN ADULTS: IMPACT ON PHARMACOKINETICS, ORGAN TOXICITIES AND SURVIVAL AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION Claire Seydoux1, Michael Medinger1, Joerg Halter1, Dominik Heim1, Katharina M. Rentsch1, Jakob R. Passweg 1 P185 NON MYELOABLATIVE VERSUS REDUCED INTENSITY CONDITIONING IN ELDERLY PATIENTS WITH PTCY. A MULTICENTRE RETROSPECTIVE COHORT ANALYSIS FROM GATMO-TC Mariano Berro 1, Jorge Arbelbide2, Ana Lisa Basquiera3, Adriana Vitriu4, Silvina Palmer5, Martin Saslavsky6, Patricio Duarte7, Sebastian Yantorno8, Martin Castro9, Ruben Burgos10, Gabriela Sturich3, Gonzalo Bentolila11, Sol Jarchum12, Juan Real13, Gonzalo Ferini2, Georgina Bendek2, Maria M. Rivas1, Gustavo Kusminsky1 P186 IMPACT OF TRANSPLANT CONDITIONING INTENSITY ON BOTH ACUTE AND CHRONIC GVHD IN HAPLO-PTCY TRANSPLANT: TWO GITMO CENTRES’ EXPERIENCE Umberto Pizzano1,2, Simona Piemontese3, Gabriele Facchin1, Raffaella Greco3, Marta Lisa Battista1, Jacopo Peccatori3, Renato Fanin1,2, Fabio Ciceri3,4, Francesca Patriarca1,2, Maria Teresa Lupo-Stanghellini 3 P187 CHANGES IN PROGNOSTIC VARIABLES FOR ALLOGENEIC TRANSPLANTATION WITH REDUCED INTENSITY CONDITIONING IN ELDERLY PATIENTS OVER TIME Seong Kyu Park 1, Se Hyung Kim1, Jina Yun1, Chan Kyu Kim1, Jong Ho Won2 P188 COMPARISON OF FLUDARABINE-MELPHALAN AND FLUDARABINE-TREOSULFAN AS CONDITIONING REGIMENS PRIOR TO ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION Maria Liga 1, Dimitris Tsokanas1, Eleftheria Sagiadinou1, Memnon Lysandrou1, Angeliki Georgopoulou1, Evangelia Triantafyllou1, Vassiliki Zacharioudaki1, Anastasia Christopoulou1, Alexandros Spyridonidis1 P189 OUTCOMES OF PATIENTS WITH HIGH-RISK ACUTE LYMPHOBLASTIC LEUKEMIA IN CR1 UNDERGOING ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION THROUGH A FIXED TRANSPLANTATION POLICY INCLUDING A CHEMOTHERAPY-BASED CONDITIONING Enrico Santinelli1, William Arcese1, Gottardo De Angelis2, Benedetta Mariotti2, Giulia Ciangola2, Giuseppe Avvisati1, Laura Cudillo3, Paolo De Fabritiis4, Andrea Mengarelli5, Agostino Tafuri6, Antonio Bruno2, Ilaria Mangione2, Gaspare Adorno2, Adriano Venditti2, Alessandra Picardi7, Raffaella Ceretti 2 P190 DESENSITISATION TREATMENT FOR HLA-DONOR SPECIFIC ANTIBODIES IN EX-VIVO T CELL DEPLETED HAPLOIDENTICAL ALLOGENEIC HAEMATOPOIETIC STEM CELL TRANSPLANT – A MULTI-CENTRE RETROSPECTIVE STUDY IN SINGAPORE Christopher S W Tham1, Yeh Ching Linn1, Liang Piu Koh2, Jeffrey KS Quek1, Aloysius Y L. Ho1, Francesca WI Lim1, William Y.K. Hwang 1, Yeow Tee Goh1, Jing Jing Lee1, Hein Than1 P191 PROMISING OUTCOMES IN HAPLOIDENTICAL TRANSPLANTATION USING ABATACEPT IN COMBINATION WITH POST TRANSPLANT CYCLOPHOSPHAMIDE IN TREOSULFAN BASED CONDITIONING REGIMEN Mohammed Debes1, Gabe Toth1, Tom Seddon1, Shahid Iqbal1, Leah Credidio1, Hannah Williams2, Fotini Partheniou2, Sophie Hughes1, Priscilla Hetherington1, Thomas Seddon1, Muhammad Saif 1 P192 FOLLOW-UP OF TRANSPLANT-ELIGIBLE MULTIPLE MYELOMA RECEIVED BUSULFAN-BASED CONDITIONING VERSUS HIGH-DOSE MELPHALAN Sungnam Lim1, Byeong-Sok Sohn2, Seonyang Park 3 P193 SEQUENTIAL CONDITIONING REGIMEN WITH THIOTEPA, CLOFARABINE AND BUSULFAN (TEC/CLOB2A2) AND POST-TRANSPLANT CYCLOPHOSPHAMIDE IN ADULTS WITH REFRACTORY AML: A RETROSPECTIVE MONOCENTRIC STUDY Amandine Le Bourgeois1, Alice Garnier1, Pierre Peterlin1, Maxime Jullien1, Chloe Antier1, Thierry Guillaume1, Patrice Chevallier 1 P194 CLINICAL OUTCOMES OF ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION USING BUSULFAN/CYCLOPHOSPHAMIDE AND MELPHALAN OR THIOTEPA AS CONDITIONING REGIMEN IN 37 PATIENTS WITH ACUTE MEGAKARYOBLASTIC LEUKEMIA Fei Pan 1, Guanlan Yue1, Kang Gao1, Kun Wang1, Huili Zhu1, Yujie Wang1, Zheren Wang1, Zhijie Wei1 P195 RETROSPECTIVE EVALUATION OF NUTRITIONAL STATUS PRE AND POST HEMATOPOIETIC STEM CELL TRANSPLANTATION: A SINGLE CENTRE EXPERIENCE Yuva Vishalini Ravindran 1, Maria Losa Maroto2, Amrith Mathew2, Sunrit Majumder2, Lewis David Oxley2, Venkatesh Karthikeyan3, Nitin Ramanathan4, David Waldron2 P196 BEAM/LEAM VERSUS LACE CONDITIONING FOR AUTOLOGOUS HEMATOPOIETIC STEM CELL TRANSPLANTATION IN LYMPHOMAS – A RETROSPECTIVE, SINGLE-CENTRE ANALYSIS OF CLINICAL OUTCOMES AND TOXICITY PROFILE Germano Glauber de Medeiros Lima1, André Dias Américo1, Eurides Leite da Rosa2, Pedro Paulo Faust Machado1, Juliana Matos Pessoa1, Hegta Taina Rodrigues Figueiroa 1, Fauze Lutfe Ayoub1, Isabella Silva Pimentel Pittol1, José Ulysses Amigo Filho1, Phillip Scheinberg1, Fabio Rodrigues Kerbauy1 P197 REAL-WORLD, SINGLE-CENTRE OUTCOME DATA OF ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION UTILISING TREOSULFAN-BASED CONDITIONING REGIMENS Mohamed Debes1, Yeong Lim1, Thomas Seddon1, James Clarke1, Clare Hawkins1, Anna Smielewska2, Alex Howard3, Julie Grant1, Sajid Pervaiz1, Shahid Iqbal1, Arpad Toth1, Muhammad Saif 1 P198 IMPACT OF CO-ADMINISTERED ACETAMINOPHEN ON BUSULFAN PHARMACOKINETICS Rutvij Khanolkar 1, Shahbal Kangarloo1, Jan Storek1 P199 TREOSULFAN-BASED CONDITIONING REGIMEN IN PEDIATRIC ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION: A CASE SERIES OF SINGLE CENTER EXPERIENCE Ilgen Sasmaz 1,2, Ali Antmen1, Utku Ayguneş1, Barbaros Karagun1, Duygu Turksoy1 P200 IMPLEMENTATION OF MACHINE LEARNING TO MEASURE THE IMPACT OF OVER- AND UNDER-EXPOSURE, AND PREDICT BUSULFAN’S PHARMACOKINETICS, IN PATIENTS RECEIVING CONDITIONING PRIOR TO HSCT Dorian Protzenko1, Laurent Bourguignon2, Benjamin Bouchacourt 3, Raynier Devillier3, Joseph Ciccolini1 P201 MITOCHONDRIAL COPY NUMBER VARIATION AS A SURROGATE MARKER OF ACQUIRED RESISTANCE TO THE BIFUNCTIONAL ELECTROPHILIC CHEMOTHERAPEUTIC DRUG BUSULFAN Vid Mlakar1, Simona Jurkovic Mlakar1, Yvonne Gloor1, Isabelle Dupanloup 1, Yoann Sarmiento1, Denis Marino1, Mary Boudal-Khosbheen1, Chakradhara Rao Satyanarayana Uppugunduri1, Marc Ansari2,1 P202 CLOFARABINE, MELPHALAN AND THIOTEPA REDUCED-INTENSITY CONDITIONING CHEMOTHERAPY ALONG WITH POST-TRANSPLANT CYCLOPHOSPHAMIDE-BASED GRAFT VERSUS HOST DISEASE PROPHYLAXIS FOR ALLOGENEIC STEM CELL TRANSPLANT Alejandro Del Rio Verduzco1, Aileen Go1, Murali Kodali1, Matthew Ulrickson1, Nicolas De Padova1, Eric Smith1, Ivan Komerdelj1, Hayley Heers1, Jennifer Brookes1, Haley Pebler1, Rachael Yasuda1, Rajneesh Nath 1 P203 THE EFFICACY OF MODIFIED MELPHALAN AND BUSULFAN-BASED CONDITIONING REGIMEN FOR ASCT IN LOW-RISK AND INTERMEDIATE-RISK AML PATIENTS Shulian Chen1, Xiaoyu Zhang1, Yi He1, Sizhou Feng1, Mingzhe Han1, Xingli Zhao2, Jie Bai3, Lijuan Li4, Zhihua Zhang5, Ying Wang1, Jianxiang Wang1, Weihua Zhai 1, Erlie Jiang1 P204 SECOND ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION WITH REDUCED-INTENSITY CONDITIONING AND DONOR CHANGES IN HEMATOLOGICAL NON-MALIGNANCIES AFTER THE FIRST TΑΒ + CELL DEPLETED HAPLO-HSCT Jianyun Liao 1, Chaoke Bu1, Lan He1, Jujian He1, Weiwei Zhang1, Zongxin Feng1, Yanfeng Zhou1, Bo Lyu1, Wenqian Shi1, Jing Wang1, Yuelin He1, Chunfu Li1 P205 FIRST ALLOGENIC STEM CELL TRANSPLANTATION IN A PATIENT WITH ROIFMAN SYNDROME AND EBV-ASSOCIATED PLASMABLASTIC LYMPHOMA RELAPSE USING AUC CONTROLLED BUSULFAN BASED MYELOABLATIVE CONDITIONING Marie Sophie Knape1, Katja Gall1, Katrin Vollmer1, Florian Ressle1, Felicitas Ferrari von Klot1, Angela Wawer1, Michael H. Albert2, Chaim M. Roifman3, Britta Eiz-Vesper4, Birgit Burkhardt5, Wilhelm Woessmann6, Irene Teichert von Lüttichau1, Julia Hauer1, Uwe Thiel 1 P206 HIGH GRAFT FAILURE WITH FLUDARABINE, TREOSULPHAN CONDITIONING REGIMEN IN MYELOID MALIGNANCIES Taner Tan1, Sinem Civriz Bozdağ 1, Ümit Barbaros Üre1, Elif Birtaş Ateşoğlu2, Emre Osmanbaşoğlu1, Ahmet Burhan Ferhanoğlu1, Hakan Kalyon1, Meltem Olga Akay1 P207 ALLOGENEIC TRANSPLANTATION USING MYELOABLATIVE CONDITIONING REGIMES IS SAFE AND EFFECTIVE IN ELDERLY PATIENTS OVER 60 YEARS WITH AML AND MDS Yan-Li Zhao 1, Yue Lu1, Xing-Yu Cao1, Jian-Ping Zhang1, Jia-Rui Zhou1, Zhi-Jie Wei1, Min Xiong1, De-Yan Liu1, Rui-Juan Sun1 P208 COMPARISON BETWEEN DIFFERENT REDUCED INTENSITY CONDITIONING REGIMENS IN AML OR MDS José Emilio Salinas 1, Yorman Flores1, Patricio Rojas1, Catherine Gutierrez1, Marcela Vidal1, Verónica Jara1, Elizabeth Rivera1, James Campbell1, María José Garcia1, Vicente Sandoval1, Maximiliano Vergara1, Mauricio Ocqueteau1, Felipe Palacios1, Pablo Sandoval1, Mauricio Sarmiento1 P209 PHASE 1 TRIAL RESULTS FOR PATIENTS WITH ADVANCED HEMATOLOGIC MALIGNANCIES TREATED WITH ORCA-T CELL THERAPY WITH REDUCED INTENSITY CONDITIONING AND SINGLE AGENT TACROLIMUS Alejandro Villar-Prados 1, Katherine Sutherland1, Robert Negrin1, Sally Arai1, Matthew Frank1, Laura Johnston1, Robert Lowsky1, David Miklos1, Lori Muffly1, Saurabh Dahiya1, Andrew Rezvani1, Surbhi Sidana1, Parveen Shiraz1, Judith Shizuru1, Wen-Kai Weng1, Melody Smith1, Sushma Bharadwaj1, John Tamaresis1, Anna Pavlova2, Scott McClellan2, Everett Meyer1 P210 ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION WITH CONDITIONING INCLUDING DONOR CAR-T CELLS FOR R/R B-CELL LYMPHOMA AND R/R MULTIPLE MYELOMA FAILING CAR T-CELL THERAPY Fan Yang1, Rui Liu 1, Zhonghua Fu1, Teng Xu1, Hui Shi1, Lixia Ma1, Guoai Su1, Biping Deng2, Tong Wu1, Xiaoyan Ke1, Kai Hu1 P211 SMADCAM-1 IS DECREASED AFTER ALLOHCT, ALONG WITH GUT MICROBIOTA DYSBIOSIS, AND IS ASSOCIATED WITH HEMATOPOIETIC RECOVERY Karen Fadel 1, Lama Siblany1, Razan Mohty1, Nicolas Stocker1, Eolia Brissot1, Rémy Dulery1, Anne Banet1, Simona Sestili1, Zoe van de Wyngaert1, Agnes Bonnin1, Ramdane Belhocine1, Tounes Ledraa1, Antoine Capes1, Mohamad Mohty1, Béatrice Gaugler1, Florent Malard1 P212 PENTOSTATIN AND CYCLOPHOSPHAMIDE DECREASE GRAFT REJECTION BUT INCREASE TRANSPLANT-RELATED COMPLICATIONS IN HAPLOIDENTICAL HCT FOR SICKLE CELL DISEASES Emily Limerick1, Matthew Hsieh 1, Julia Varga1, Mary Lacy Grecco1, Jennifer Brooks1, Wynona Coles1, Jackie Queen1, Neal Jeffries1, Courtney Fitzhugh1 P213 GRANULOCYTES TO INDUCE DONOR-DERIVED T CELL EXPANSION AFTER T REPLETE, MISMATCHED CB IN POST-TRANSPLANT RELAPSED AND REFRACTORY PAEDIATRIC ACUTE LEUKAEMIA: RESULTS OF GRANS TRIAL Srividhya Senthil 1, Roisin Borrill1, Denise Bonney1, Ramya Hanasoge-Nataraj1, Madeleine Powys1, Omima Mustafa1, Robert Wynn1 P214 GENOME EDITING OF LONG-TERM REPOPULATING HEMATOPOIETIC STEM CELLS USING CCR5-UCO-HETTALEN Valeriia Laushkina1, Alena Shakirova1, Olga Epifanovskaya1, Vladislav Sergeev1, Kirill Lepik1, Marina Popova1, Alexander Kulagin 1 P215 ALLOGENEIC HAEMATOPOIETIC STEM CELL TRANSPLANTATION IMPROVES PROGNOSIS IN AML PATIENTS WITH CSF3R MUTATION AND CEBPA DOUBLE MUTATION Jiaxin Cao1, Yawei Zheng 1, Aiming Pang1, Erlie Jiang1 P216 CAST REGIMEN FOR GVHD PROPHYLAXIS YIELDS LOWER RELAPSE RATE AND IMPROVED DISEASE-FREE SURVIVAL: A CIBMTR PROPENSITY SCORE MATCHED CASE-CONTROL ANALYSIS Samer Al-Homsi1, Todd DeFor2, Kelli Cole1, Frank Cirrone1, Maher Abdul-Hay1, Stephanie Wo1, Andres Suarez-Londono1, Sharon Gardner1, Jingmei Hsu1, George Yaghmour3, Caitrin Bupp2, Stephen Spellman 2 P217 SEQUENTIAL INTRAVENOUS UMBILICAL CORD DERIVED MESENCHYMAL STROMAL CELLS (MSCS) FOR SALVAGE TREATMENT OF STEROID-REFRACTORY ACUTE GVHD (RS-AGVHD): A PHASE IB/II STUDY Yanmin Zhao 1,2,3,4, Yi Luo1,2,3, Jimin Shi1,2,3,4, Jian Yu1,2,3,4, Lizhen Liu1,2,3,4, Xiaoyu Lai1,2,3,4, Huarui Fu1,2,3,4, Yishan Ye1,2,3,4, Nainong Li5,6,7, Erlie Jiang8, Qiong Xie9, Jundong Gu9, Zhibo Han9, Zhongchao Han9, He Huang1,2,3,4 P218 NOVEL GVHD PROPHYLAXIS WITH POST-TRANSPLANT INTERMEDIATE DOSE CYTOXAN AND ABATACEPT – LOW RATES OF ACUTE GVHD AND TRANSPLANT-RELATED TOXICITY Asya Varshavsky Yanovsky1, Yuliya Shestovska 1, Shalina Joshi1, Dzhirgala Mandzhieva1, Peter Abdelmessieh1, Rashmi Khanal1, Michael Styler1, Henry Fung1 P219 REDUCING PTCY DOSE IN PATIENTS RECEIVING CAST FOR GVHD PREVENTION RESULTS IN ACCELERATED ENGRAFTMENT AT THE COST OF HIGHER INCIDENCE OF GVHD J. Andres Suarez-Londono 1, Kelli Cole1, Frank Cirrone1, Stephanie Wo1, Maher Abdul-Hay1, Jingmei Hsu1, Sharon Gardner1, Mohammad Abu-Zaid1, Gloria Contreras Yametti1, Benjamin Levinson1, Judith Goldberg1, A. Samer Al-Homsi1 P220 RUXOLITINIB IN ACUTE AND CHRONIC GRAFT-VERSUS-RECEPTOR DISEASE: LONG-TERM REAL-LIFE EXPERIENCE IN A MULTI-CENTRE STUDY Virginia Escamilla Gómez 1, Lucía López Corral2, Beatriz Astibia Mahillo3, Patricia Alcalde Mellado1, Francisco Manuel Martín Domínguez1, Marina Acera Gómez2, Pedro Asensi Cantó4, Juan Montoro Gómez4, Melissa Torres Ochando5, Asunción Borrego Borrego5, Leslie González Pinedo5, María Teresa Zudaire Ripa6, Marta González Vicent7, Ana Benzaquén Vallejos8, Isabel Izquierdo9, Irene García Cadenas10, Sara Redondo Velao10, Alberto Musseti11, Eloi Cañamero Giro12, Pilar Palomo Moraleda13, Guillermo Orti Pascual14, Pedro Antonio González Sierra15, Lucía García16, Valentín García Gutiérrez3, José Antonio Pérez-Simón1 P221 PHASE 1 TRIAL INVESTIGATING THE SAFETY AND TOLERABILITY OF LEFLUNOMIDE IN PATIENTS WITH STEROID-DEPENDENT CHRONIC GRAFT-VERSUS-HOST DISEASE (CGVHD) AFTER ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANT (ALLOHCT) Amandeep Salhotra 1, Dongyun Yang1, Sally Mokhtari1, Badri Modi1, Monzr Al-Malki1, Haris Ali1, Idoroenyi Amannam1, Nicole Karras1, Karamjeet Sandhu1, Ahmed Aribi1, Salman Otoukesh1, Andrew Artz1, Guido Marcucci1, Stephen Forman1, Eileen Smith1, De-Fu Zhang1, Steven Rosen1, Ryotaro Nakamura1 P222 COMPARISON OF EFFICACY AND TOLERABILITY OF RUXOLITINIB ALONE OR RUXOLITINIB WITH EXTRACORPOREAL PHOTOPHERESIS OR EXTRACORPOREAL PHOTOPHERESIS MONOTHERAPY FOR STEROID REFRACTORY AGVHD: A GITMO RETROSPECTIVE STUDY Marta Lisa Battista 1, Francesca Patriarca1,2, Miriam Isola2, Gabriele Facchin1, Patrizia Chiusolo3,4, Domenico Russo5, Attilio Olivieri6, Bruna Puglisi7, Ilaria Scortechini7, Alessandro Rambaldi8, Irene Maria Cavattoni9, Albana Lico10, Riccardo Saccardi11, Angela Cuoghi12, Marco Ladetto13, Vincenzo Federico14, Maria Caterina Micò15, Antonella Geromin1, Anna Maria Gallina16, Elena Oldani8, Eliana Degrandi17, Renato Fanin1,2, Fabio Ciceri18, Massimo Martino15 P223 MINI-DOSE METHOTREXATE COMBINED WITH METHYLPREDNISOLONE FOR INITIAL TREATMENT OF MILD ACUTE GVHD: A MULTI-CENTER, RANDOMIZED TRIAL Yu Wang 1, Qi-Fa Liu2, De-Pei Wu3, Zheng-Li Xu1, Ting-Ting Han1, Yu-Qian Sun1,4, Fen Huang2, Zhi-Ping Fan2, Na Xu2, Feng Chen3, Ye Zhao3, Yuan Kong1, Xiao-Dong Mo1, Lan-Ping Xu1, Xiao-Hui Zhang1, Kai-Yan Liu1, Xiao-Jun Huang1,5 P224 IMPROVED LONG-TERM OUTCOME OF RUXOLITINIB PLUS ECP VS RUXOLITINIB ALONE IN STEROID-REFRACTORY ACUTE GRAFT-VERSUS-HOST DISEASE (SR-AGVHD) Iryna Lastovytska1, Evgeny Klyuchnikov1, Silke Heidenreich1, Normann Steiner1, Radwan Massoud1, Niko Gagelmann1, Johanna Richter1, Christian Niederwieser1, Kristin Rathje1, Tatiana Urbanowicz1, Ameya Kunte1, Janik Engelmann1, Christina Ihne1, Cecilia Lindhauer1, Franziska Elisabeth Marquard1, Mirjam Reichard1, Alla Ryzhkova1, Rusudan Sabauri1, Mathias Schäfersküpper1, Niloufar Seyedi1, Georgios Kalogeropoulos1, Ina Rudolph1, Gabriele Zeck1, Rolf Krause1, Dietlinde Janson1, Christine Wolschke1, Francis Ayuk1, Nicolaus Kröger 1 P225 COMPARISON BETWEEN POSTTRANSPLANT CYCLOPHOSPAMIDE AND ATG BASED REGIMENS AS GVHD PROPYLAXIS IN ONE-ANTIGEN MISMATCH UNRELATED DONOR TRANSPLANTATION Gabriele Facchin1, Marta Lisa Battista 1, Maria De Martino2, Miriam Isola2, Antonella Geromin1, Chiara Savignano3, Valentina Simeon1,2, Alessandra Soravia1,2, Giuseppe Di Renzo1,2, Umberto Pizzano1,2, Martina Pucillo1,2, Renato Fanin1,2, Francesca Patriarca1,2 P226 PROSPECTIVE EVALUATION OF PLASMA INFLAMMATORY PROTEINS FOR PREDICTION OF SEVER GRAFT-VERSUS-HOST DISEASE AFTER TRANSPLANT Mingyang Wang1, Erlie Jiang 1 P227 LYMPHOPENIA BUT NOT ABSOLUTE LYMPHOCYTE COUNT BEFORE ANTI-T-LYMPHOCYTE GLOBULIN (ATLG) ADMINISTRATION IMPACTS TRANSPLANT OUTCOMES IN MATCHED UNRELATED PERIPHERAL BLOOD STEM CELL ALLOGENEIC STEM CELL TRANSPLANTATION Radwan Massoud 1, Evgeny Klyuchnikov1, Normann Steiner1, Christian Niederwieser1, Ameya Shirinian Kunte1, Silke Heidenreich1, Kristin Rathje1, Nico Gagelmann1, Tetiana Perekhrestenko1, Gaby Zeck1, Rolf Krause1, Christine Wolschke1, Dietlinde Janson1, Francis Ayuk1, Nicolaus Kröger1 P228 A PROSPECTIVE, MULTI-CENTER, RANDOMIZED, CONTROLLED CLINICAL TRIAL TO EXPLORE THE ROLE OF MESENCHYMAL STEM CELLS IN PREVENTING GRAFT VERSUS HOST DISEASE Han Yao 1, Xiaoqi Wang1, Ruihao Huang1, Haixia Fu2, Ren Lin3, Yimei Feng1, Xiaojuan Deng1, Ting Chen1, Lidan Zhu1, Jia Liu1, Yuqing Liu1, Lu Zhao1, Lu Wang1, Shichun Gao1, Huanfeng Liu1, Cheng Zhang1, Peiyan Kong1, Li Gao1, Qifa Liu3, Xiaohui Zhang2, Xi Zhang1,4,5 P229 RUXOLITINIB AS SECOND-LINE TREATMENT FOR BOS AFTER HEMATOPOIETIC CELL TRANSPLANTATION Feng Chen 1, Yuqing Tu1,2,3, Jia Chen1,2,3, Shushu Xu1,2,3, Yi Fan1,2,3, Mimi Xu1,2,3, Mengqi Xiang1,2,3, Tiemei Song1,2,3, Xiang Zhang1,2,3, Xiaoli Li4, Lian Bai5, Depei Wu1,2,3 P230 POST-TRANSPLANTATION CYCLOPHOSPHAMIDE WITH OR WITHOUT PROPHYLACTIC DONOR LYMPHOCYTE INFUSION AFTER HLA-MATCHED ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION IN MDS/AMl Joost van der Hem 1, Jurjen Versluis2, Iris Erpelinck2, Chantal Mouws2, Peter Von dem Borne1, Annoek Broers2, Stijn Halkes1 P231 IMPROVED GRFS WHEN ATG/ATLG IS USED IN ALLO-PBSCT FROM MATCHED SIBLING DONORS - AN EBMT REGISTRY STUDY BY THE TRANSPLANT COMPLICATIONS WORKING PARTY Agnieszka Piekarska 1, Mouad Abouqateb2, William Boreland2, Christophe Peczynski2, Jan Maciej Zaucha1, Nicolaus Kröger3, Robert Zeiser4, Fabio Ciceri5, Thomas Schroeder6, Thomas Luft7, Jakob Passweg8, Desiree Kunadt9, Matthias Stelljes10, Igor Wolfgang Blau11, Uwe Platzbecker12, Ibrahim Yakoub-Agha13, Didier Blaise14, Anna Maria Raiola15, Johanna Tischer16, Eva Maria Wagner-Drouet17, Julia Winkler18, Christoph Schmid19, Gerald Wulf20, Matthias Edinger21, Johan Maertens22, Friedrich Stölzel23, Jan Vydra24, Pavel Zak25, Ivan Moiseev26, Hélène Schoemans22, Olaf Penack11, Zinaida Perić27 P232 NAVIGATING GRAFT-VERSUS-HOST DISEASE PROPHYLAXIS IN MATCHED SIBLING DONOR ALLOGENEIC TRANSPLANTS: A COMPARATIVE ANALYSIS OF POST-TRANSPLANT CYCLOPHOSPHAMIDE VERSUS DIVERSE REGIMENS – INSIGHTS FROM A SINGLE-CENTER EXPERIENCE Majed Altareb1, Carol Chen1, Mats Remberger2, Armin Gerbitz1,3, Dennis Kim 1,3, Rajat Kumar1,3, Wilson Lam1,3, Ivan Pasic1,3, Fotios Michelis1,3, Igor Novitzky-Basso1,3, Auro Viswabandya1,3, Jonas Mattsson1,3, Arjun Datt Law1,3 P233 POST TRANSPLANT CYCLOPHOSPHAMIDE AS GVHD PROPHYLAXIS IN PATIENTS RECEIVING HLA MISMATCHED (7/8) UNRELATED DONOR FOR MYELOID MALIGNANCIES: RESULTS OF THE GITMO PROSPECTIVE PHYLOS TRIAL Anna Maria Raiola 1, Benedetto Bruno2, Antonio Maria Risitano3, Federico Mosna4, Irene Maria Cavattoni4, Francesco Onida5, Giorgia Saporiti5, Francesca Patriarca6, Marta Lisa Battista6, Vincenzo Pavone7, Anna Mele7, Patrizia Chiusolo8, Simona Sica8, Barbara Loteta9, Carmen Di Grazia1, Angelo Michele Carella10, Dalila Salvatore10, Enrico Morello11, Alessandro Leoni11, Luisa Giaccone2, Paolo Bernasconi12, Elisabetta Terruzzi13, Nicola Mordini14, Carlo Borghero15, Francesco Zallio16, Franco Narni17, Anna Grassi18, Attilio Olivieri19, Adriana Vacca20, Nicoletta Sacchi21, Giovannino Ciccone22, Anna Castiglione22, Emanuele Angelucci1, Francesca Bonifazi23, Fabio Ciceri24, Eliana Degrandi25, Massimo Martino9 P234 EXTRACORPOREAL PHOTOPHERESIS AS SALVAGE TREATMENT IN PEDIATRIC PATIENTS WITH STEROID-REFRACTORY ACUTE GVHD: A MULTICENTER, RETROSPECTIVE STUDY Daria Pagliara1, Valentina Sofia1, Claudia Del Fante2, Manuela Tumino3, Francesco Saglio4, Giovanna Leone1, Gianluca Viarengo2, Mattia Algeri 1, Giovanna Giorgiani2, Giovanna Del Principe1, Barbarella Lucarelli1, Pietro Merli1, Anna Colpo3, Cesare Perotti2, Marco Zecca2, Alessandra Biffi3, Franca Fagioli4, Franco Locatelli1,5 P235 BELUMOSUDIL PHASE 1 DOSE-ESCALATION STUDY IN HEALTHY VOLUNTEERS AND PHASE 2 STUDY IN PATIENTS WITH CGVHD WHO FAILED ≥1 LINE OF SYSTEMIC THERAPY IN CHINA Ying Wang 1, Depei Wu1, Xiang Zhang1, Yuhua Li2, Yanjie He2, Qifa Liu3, Li Xuan3, Zhenyu Li4, Kunming Qi4, Yuqian Sun5, Shunqing Wang6, Wenjian Mo6, Lei Gao7, Ye Hua8, Yu Wang8, Ying Zhang8, Nico Fu9 P236 IMPACT OF RESPIRATORY FUNCTION TESTS IN PATIENTS UNDERGOING ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION Francisco Manuel Martin Dominguez 1, Rocío Parody-Porras1, Virginia Escamilla-Gómez1, Nancy Rodríguez-Torres1, Cristina Blázquez-Goñi1, Javier Delgado-Serrano1, Juan Luis Reguera-Ortega1, Ildefonso Espigado-Tocino1, José Antonio Rodríguez-Portal2, José Antonio Pérez-Simón1 P237 MANAGEMENT OF CORTICOSTEROIDS IN PATIENTS RECEIVING RUXOLITINIB TREATMENT FOR CHRONIC GRAFT-VERSUS-HOST DISEASE: A POST HOC ANALYSIS FROM THE RANDOMIZED PHASE 3 REACH3 STUDY Emily Kintsch1, Zhenyi Xue1, John Galvin1, Franco Locatelli2,3, Robert Zeiser4, Valkal Bhatt 1 P238 A PROGNOSTIC MODEL FOR NON-RELAPSE MORTALITY RISK BASED ON MACHINE LEARNING IN PATIENTS UNDERGOING ALLOGENEIC HEMATOPOIETIC STEM-CELL TRANSPLANTATION Jingjing Yang1, Xiawei Zhang 1, Liping Dou1, Daihong Liu1 P239 A HIGH FREQUENCY OF TYPE 3 DENDRITIC CELLS IN CD1C + DC ON DAY + 28 AFTER HSCT COULD BE AN EFFECTIVE INDICATOR OF SEVERE GVHD IN PEDIATRIC PATIENTS Xin Liu 1, Bohan Li1, Di Yao1, Minyuan Liu1, Peifang Xiao1, Jun Lu1, Jie Li1, Yuanyuan Tian1, Shaoyan Hu1 P240 HAPLOIDENTICAL HEMATOPOIETIC CELL TRANSPLANTATION WITH UNRELATED CORD BLOOD ENHANCES SURVIVAL AND REDUCES THE INCIDENCE OF AGVHD FOR PEDIATRIC ACUTE MYELOID LEUKEMIA Fei Pan1, Jing Long2, Guanlan Yue1, Kang Gao1, Kun Wang1, Huili Zhu1, Yujie Wang1, Zheren Wang1, Yuan Feng1, Lili Shi1, Zhijie Wei 1, Kaiyan Liu2 P241 RUXOLITINIB AND ANTI-TNF-ALPHA THERAPY SUBSTANTIALLY IMPROVE SURVIVAL IN PEDIATRIC PATIENTS WITH SEVERE STEROID REFRACTORY GVHD Jaspar Kloehn1, Manon Queudeville1, Johanna Schrum1, Ysabel Alessa Schwietzer1, Ingo Müller 1 P242 IMMUNOPHENOTYPE OF EXTRACELLULAR VESICLES AS A BIOMARKER OF CHRONIC GRAFT-VERSUS-HOST-DISEASE: A PILOT STUDY Giuseppe Lia1,2, Federica Ferrando1,1, Michele Dicataldo1,2, Andrea Evangelista3, Alessia Cargnino1,2, Irene Dogliotti1,2, Stefania Bruno4, Maria Chiara Deregibus4, Aurora Martin1,2, Jessica Gill1,2, Chiara Maria Dellacasa5, Alessandro Busca5, Giovanni Camussi4, Benedetto Bruno1,2, Luisa Giaccone 1,2 P243 T-CELL DEPLETED ALLOGENEIC STEM CELL TRANSPLANTATION WITH ALEMTUZUMAB IS A VIABLE ALTERNATIVE TO POST-TRANSPLANT CYCLOPHOSPHAMIDE FOR PATIENTS WITH ACUTE MYELOID LEUKEMIA AND MYELODYSPLASTIC SYNDROME Alexandra Rojek 1, Mylove Mortel1, Andrew Artz2, Richard Larson1, Hongtao Liu3, Mariam Nawas1, Adam Duvall1, Toyosi Odenike1, Gregory Roloff1, Wendy Stock1, Michael Bishop1, Satyajit Kosuri1 P244 EXTENDED ABATACEPT USE WITH SEROTHERAPY TO REDUCE ACUTE GVHD INCIDENCE IN PEDIATRIC PATIENTS TRANSPLANTED FROM HLA-MISMATCHED UNRELATED DONORS Francesco Quagliarella1, Jochen Buechner2, Mattia Algeri1, Ingvild Heier2, Francesca Del Bufalo1, Phoi Phoi Diep2, Daria Pagliara1, Marco Becilli1, Barbarella Lucarelli1, Emilia Boccieri1, Federica Galaverna1, Ilaria Pili1, Roberto Carta1, Chiara Rosignoli1, Tiziana Corsetti1, Pietro Merli 1, Franco Locatelli1,3 P245 ENDOTHELIAL DYSFUNCTION AND RISK OF ACUTE GRAFT-VERSUS-HOST DISEASE AFTER ALLOGENEIC STEM CELL TRANSPLANTATION: A PRELIMINARY ANALYSIS OF A SINGLE CENTRE STUDY Francesco Romano1, Antonio Bianchessi1, Irene Defrancesco1, Giulia Losi 1, Beatrice Ferrari2, Virginia Ferretti2, Cristina Picone2, Erica Consensi2, Mara De Amici2, Giorgia Testa2, Daniela Caldera2, Caterina Zerbi2, Valentina Zoboli2, Luca Arcaini1,2, Nicola Polverelli2 P246 EXTENDED ABATACEPT DOSING MAY REDUCE RATES OF CHRONIC GRAFT VS HOST DISEASE IN PEDIATRIC PATIENTS UNDERGOING BONE MARROW TRANSPLANT FOR UNDERLYING HEMATOLOGICAL DISEASES Eleanor Cook1, Pooja Khandelwal1, Ashley Teusink-Cross1, Michael Grimley 1 P247 COMPARISON OF THE EFFICACY OF MYCOPHENOLATE MOFETIL AFTER ORAL OR INTRAVENOUS ADMINISTRATION IN THE PREVENTION OF ACUTE GRAFT-VERSUS-HOST DISEASE Xinhui Zheng1, AiMing Pang1, Erlie Jiang 1 P248 NEAR ELIMINATION OF GVHD WITH AN ABBREVIATED CALCINEURON AND M-TOR INHIBITOR-FREE GVHD PREVENTION REGIMEN A. Samer Al-Homsi 1, Kelli Cole1, Frank Cirrone1, Stephanie Wo1, J. Andres Suarez-Londono1, Jingmei Hsu1, Mohammad Abu-Zaid1, Maher Abdul-Hay1 P249 EFFICACY AND SAFETY OF REDUCED-DOSES OF POST-TRANSPLANT CYCLOPHOSPHAMIDE IN PERIPHERAL BLOOD STEM CELL TRANSPLANTATION OUTSIDE THE HAPLOIDENTICAL SETTING Sara Redondo 1, Anna Arrufat1, Albert Esquirol1, Silvana Saavedra1, Miguel Arguello-Tomas1, Ana Carolina Caballero1, Guadalupe Oñate1, Ana Garrido1, Jordi Lopez1, Sara Miqueleiz1, J.M. Portos1, Eva Iranzo1, M.E. Moreno-Martinez2, Mireia Riba2, Jorge Sierra1, Javier Briones1, Irene García-Cadenas1, Rodrigo Martino1 P250 A LOW TRAJECTORY OF PLATELETS IN THE EARLY STAGES AFTER TRANSPLANTATION IS LINKED TO THE DEVELOPMENT OF SEVERE ACUTE GRAFT-VERSUS-HOST DISEASE (AGVHD) Dan Feng1, Erlie Jiang 1 P251 GVHD PROPHYLAXIS WITH THREE VERSUS FIVE DRUGS COMBINATION IN AML PATIENTS UNDERGOING ALLOGENEIC TRANSPLANT FROM HLA MISMATCHED UNRELATED OR HAPLOIDENTICAL RELATED DONOR Alessandra Picardi 1,2, Stella Santarone3, Massimo Martino4, Gottardo De Angelis2, Mariangela Pedata1, Stefania Leone1, Annalisa Natale3, Benedetta Mariotti2, Barbara Loteta4, Serena Marotta1, Doriana Vaddinelli3, Maria Celentano1, Giulia Ciangola2, Maria Caterina Micò4, William Arcese5,2, Raffaella Cerretti2 P252 CYTOKINE SECRETION DURING REDUCED INTENSITY CONDITIONING HAEMATOPOIETIC STEM CELL TRANSPLANT FOR MYELOID DISEASE, AN OPPORTUNITY FOR OUTCOME PREDICTION Chris Armstrong 1, Hayley Foy-Stones1, Gardiner Nicola1, Doherty Derek2, Anthony McElligott2, Fiona O’Connell2, Eibhlin Conneally1, Catherine Flynn1, Nina Orfali1 P253 INTERFERON GAMMA ACTIVITY IN IMPAIRED HAEMATOPOIETIC STEM CELL (HSC) PROLIFERATION AND GRAFT-VERSUS-HOST DISEASE Régis Peffault de Latour 1,2, Pietro Merli3, Emmanuel Monnet4, Malin Löfqvist4, Franco Locatelli3 P254 DELETIONS OF COMPLEMENT FACTOR H-RELATED GENES CFHR-1 AND CFHR-3 AND ACUTE GRAFT-VERSUS-HOST DISEASE AFTER ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION Lars Klingen Gjærde 1, Maja Milojevic1, Niels Smedegaard Andersen1, Lone Smidstrup Friis1, Brian Kornblit1, Marietta Nygaard1, Søren Lykke Petersen1, Ida Schjødt1, Jens D. Lundgren1,2, Daniel D. Murray1, Henrik Sengeløv1,2 P255 EXTERNAL VALIDATION OF SAINT LOUIS SCORE TO PREDICT ACUTE GRAFT-VERSUS-HOST DISEASE SEVERITY Alessandro Criscimanna 1,2, Annalisa Ruggeri1, Elisa Diral1, Raffaella Greco1, Alessandro Bruno1, Luca Canziani1,2, Sarah Marktel1, Francesca Farina1, Sara Mastaglio1, Daniela Clerici1, Simona Piemontese1, Andrea Acerbis1,2, Chiara Secco1, Magda Marcatti1, Matteo Giovanni Carrabba1, Massimo Bernardi1, Consuelo Corti1, Jacopo Peccatori1, Fabio Ciceri1,2, Maria Teresa Lupo-Stanghellini1 P256 EVALUATION OF RISK FOR BRONCHIOLITIS OBLITERANS SYNDROME AFTER ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION WITH MYELOABLATIVE CONDITIONING REGIMENS Kristina Maas-Bauer 1, Paraschiva Rassner1, Kristin Walther1, Claudia Wehr1, Reinhard Marks1, Ralph Wäsch1, Robert Zeiser1, Jürgen Finke1, Jesus Duque Afonso1 P257 THE MACROPHAGE ACTIVATION MARKER SCD163 AND ACUTE AND CHRONIC GRAFT-VERSUS-HOST DISEASE IN ALLOGENEIC HSCT Maja Munk Kristoffersen 1, Elisa Peen1, Henning Grønbæk2, Holger Jon Møller2, Henrik Sengeløv1, Klaus Müller1, Lars Klingen Gjærde1, Katrine Kielsen1 P258 ETIOLOGY OF DIARRHEA IN PATIENTS UNDERGOING COLONOSCOPIC BIOPSIES POST ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANT FOR SUSPECTED ACUTE GUT GRAFT VERSUS HOST DISEASE Niket Mantri 1, Sachin Punatar1, Mukta Ramadwar1, Prachi Patil1, Shaesta Mehta1, Aditya Kale1, Shridhar Epari1, Sridhar Sundaram1, Koustubh Shekar1, Anant Gokarn1, Sumeet Mirgh1, Akanksha Chichra1, Nishant Jindal1, Lingaraj Nayak1, Libin Mathew1, Shesheer Kumar2, Rachana Tripathi2, Bhausaheb Bagal1, Navin Khattry1 P259 ABATACEPT ADDED TO POST TRANSPLANT CYCLOPHOSPHAMIDE-BASED GVHD PROPHYLAXYS IN ALLOGENEIC HEMATOPOYETIC STEM CELL TRANSPLANTATION: ONE SINGLE CENTER EXPERIENCE Paula Fernández- Caldas González 1,2, Rebeca Bailén1,2, Pilar Lancho1, Ignacio Gómez-Centurión1,2, Lucía Castilla1, Cristina Muñoz1, Santiago Sabell1, Javier Anguita1,2,3, Mi Kwon1,2,3 P260 SAFETY AND EFFICACY OF THE ROCK2-INHIBITOR BELUMOSUDIL IN CGVHD TREATMENT – A RETROSPECTIVE, MULTICENTER REAL-WORLD DATA ANALYSIS Silke Heidenreich 1, Katharina Egger-Heidrich2, Jörg P. Halter3, Friedrich Stölzel4, Matthias Edinger5, Wolfgang Herr5, Nicolaus Kröger1, Daniel Wolff5, Francis Ayuk1, Matthias A. Fante5 P261 EFFICACY AND SAFETY OF IBRUTINIB FOR CHRONIC GRAFT-VERSUS-HOST DISEASE: A SYSTEMATIC REVIEW Damai Santosa1, Daniel Rizky 1, Kevin Tandarto1, Ika Kartiyani1, Vina Yunarvika1, Desta Nur Ewika Ardini1, Budi Setiawan1, Eko Adhi Pangarsa1, Catharina Suharti1 P262 WHEN SHOULD RUXOLITINIB BE CEASED? A SINGLE CENTRE, RETROSPECTIVE, REAL-WORLD ANALYSIS OF RUXOLITINIB IN GRAFT VS HOST DISEASE POST ALLOGENEIC STEM CELL TRANSPLANT Harshita Rajasekariah 1,2, Barbara Withers1,2, Keith Fay1,3, Sam Milliken1,2, Nada Hamad1,2, John Moore1,2, Jacinta Perram1,2 P263 CLINICAL RESPONSE AND IMMUNOLOGICAL RECOVERY IN PATIENTS WITH STEROID-REFRACTORY ACUTE GRAFT-VERSUS-HOST DISEASE (AGVHD) TREATED WITH THE ASSOCIATION OF EXTRACORPOREAL PHOTOPHERESIS (ECP) AND RUXOLITINIB Chiara Marcon1,2, Chiara Savignano1, Eleonora Toffoletti 1,2, Angela Michelutti1, Margherita Cavallin1, Giovanni Barillari1, Renato Fanin1,2, Francesca Patriarca2,1 P264 GVHD PROPHYLAXIS WITH POST-TRANSPLANT HIGH DOSE CYTOXAN OVERCOMING THE BARRIER OF ALLOGENEIC HCT IN FUNCTIONAL HIGH-RISK PATIENTS Asya Varshavsky Yanovsky1, Yuliya Shestovska 1, Matthew Hamby1, Dzhirgala Mandzhieva1, Shalina Joshi1, Peter Abdelmessieh1, Rashmi Khanal1, Michael Styler1, Henry Fung1 P265 MESENCHYMAL STROMAL CELLS IN PATIENTS WITH III-IV GRADE STEROID-REFRACTORY ACUTE GRAFT-VERSUS-HOST-DISEASE: DAY 14 RESPONSE IS PREDICTIVE OF SURVIVAL Adomas Bukauskas 1, Renata Jucaitienė1, Artūras Slobinas1,2, Inga Šlepikienė1, Andrius Žučenka1,2, Linas Davainis1, Valdas Pečeliūnas2, Igoris Trociukas1, Laimonas Griškevičius1,2 P266 JAK-2 INHIBITOR RUXOLITINIB FOR THERAPY OF ACUTE STEROID-REFRACTORY GRAFT-VERSUS-HOST DISEASE AFTER ALLOGENIC HEMATOPOIETIC STEM CELL TRANSPLANTATION IN CHILDREN WITH HEMATOLOGICAL MALIGNANT DISEASES Nikita Levkovsky1, Olesya Paina1, Anna Zvyagintseva1, Anna Osipova1, Alexandra Laberko1, Ivan Moiseev1, Tatyana Bykova 1, Elena Semenova1, Alexander Kulagin1, Ludmila Zubarovskaya1 P267 THE IMPACT OF MEASURED RENAL FUNCTION BY IOTHALAMATE CLEARANCE ON ALLOGENEIC STEM CELL TRANSPLANT OUTCOMES IN PATIENTS RECEIVING POST-TRANSPLANT CYCLOPHOSPHAMIDE FOR GVHD PROPHYLAXIS Jade Kutzke 1, Christopher Cahoon2, Kristin Mara1, Jodi Taraba1, Anmol Baranwal1, Mark Litzow1, William Hogan1, Abhishek Mangaonkar1, Mehrdad Hefazi Torghabeh1, Aasiya Matin1, Mithun Shah1, Urshila Durani1, Saad Kenderian1, Robert Wolf1, Gabriel Bartoo1, Hassan Alkhateeb1 P268 RUXOLITINIB TREATMENT OUTCOMES IN ACUTE GRAFT-VERSUS-HOST DISEASE (AGVHD) IN REAL-WORLD SETTING IN FINLAND Eeva Martelin 1, Arttu Kuikka2, Hanna Rajala1, Tuomas Ruohonen2, Hannu Mönkkönen3, Johanna Vikkula4, Kristiina Uusi-Rauva4, Urpu Salmennniemi1, Maija Itälä-Remes2 P269 VON WILLEBRAND FACTOR AS A DIAGNOSTIC AND ACTIVITY INDICATOR OF CHRONIC GRAFT-VERSUS-HOST DISEASE Antonela Lelas1, Lana Desnica 1, Ivan Sabol2, Desiree Coen Herak1,3, Marija Milos1,4, Ana Zelic Kerep1, Ante Vulic1, Nadira Durakovic1,3, Ranka Serventi Seiwerth1, Zinaida Peric5,6, Radovan Vrhovac1,3, Steven Zivko Pavletic7, Drazen Pulanic1,3 P270 A PROSPECTIVE PILOT STUDY OF GRAFT-VERSUS-HOST DISEASE PROPHYLAXIS WITH POSTBIOTICS IN ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION Jong-Ho Won 1, Seug Yun Yoon1, Sun Young Jeong1, Min-Young Lee1, Kyoung Ha Kim1, Namsu Lee1 P271 POST-TRANSPLANT CYCLOPHOSPHAMIDE WITH ANTI-THYMOCYTE GLOBULIN LOWERED SERUM IL-6 LEVEL COMPARED TO POST-TRANSPLANT CYCLOPHOSPHAMIDE ALONE AFTER HAPLOIDENTICAL HEMATOPOIETIC STEM CELL TRANSPLANTATION Jeong Suk Koh1, Wonhyoung Seo1, Sora Kang1, Chul Hee Kim1, Myung-Won Lee1, Hyewon Ryu1, Hyo-Jin Lee1, Hwan-Jung Yun1, Deog-Yeon Jo1, Ik-Chan Song 1 P272 USE OF RUXOLITINIB IN STEROID DEPENDENT/REFRACTORY ACUTE AND CHRONIC GRAFT VERSUS HOST DISEASE: A SINGLE CENTRE EXPERIENCE Dimitris Galopoulos 1, David Irvine1, Anne Parker1, Grant McQuaker1, Anne-Louise Latif1, Ailsa Holroyd1, Lorna Welsh1, Andrew Clark1 P273 ALPHA-1-ANTITRYPSIN TREATMENT OF STEROID-RESISTANT ACUTE AND CHRONIC GRAFT-VERSUS-HOST DISEASE, SINGLE CENTER EXPERIENCE Şebnem İzmir Güner1 P274 EFFICACY AND SAFETY OF INFLIXIMAB THERAPY IN THE SETTING OF STEROID-REFRACTORY ACUTE GRAFT-VERSUS-HOST DISEASE Khalid Halahleh 1, Jana Al Shurman2, Ayat Taqash1, Mohammad Ma’koseh1, Ahmad Abu Khader1, Isra Muradi3, Waleed Da’na1, Rawad Rihani1 P275 THE EFFICACY AND SAFETY OF EXTRACORPOREAL PHOTOPHERESIS IN STEROID-DEPENDENT-REFRACTORY/ GVHD: COHORT STUDY FROM COMPREHENSIVE ADULT BONE MARROW TRANSPLANTATION PROGRAM IN JORDAN Khalid Halahleh 1, Raneem Al zubi1, Mohammad Bssol1, Husam Abu-Jazar1, Mohammad Ma’koseh1, Ehab Omari1, Isra Muradi2, Rawad Rihani1 P276 COMPARING THE OUTCOMES OF MATCHED AND MISMATCHED UNRELATED ALLOHCT WITH DIFFERENT ANTI-THYMOCYTE GLOBULIN FORMULATIONS. A RETROSPECTIVE ANALYSIS ON BEHALF OF POLISH ADULT LEUKEMIA GROUP Ugo Giordano1, Monika Mordak2, Małgorzata Sobczyk-Kruszelnicka3, Sebastian Giebel3, Lidia Gil4, Justyna Pilch1, Jarosław Dybko 5 P277 RITUXIMAB FOR THE TREATMENT OF STEROID-REFRACTORY ORAL CHRONIC GRAFT-VERSUS-HOST DISEASE AFTER ALLO-HEMATOPOIETIC STEM CELL TRANSPLANTATION Wei Ma 1, Xing-Yu Cao1, Song Xue2, Lei Dong1 P278 EXTRACORPOREAL PHOTOPHERESIS FOR THE TREATMENT OF GVHD IN CHILDREN IN THE ERA OF TRANSPLANT FROM PARTIALLY MATCHED DONORS Marianna Maffeis 1, Elena Soncini1, Giulia Baresi1, Stefano Rossi1, Chiara Gorio1, Emilio Ferrari2, Arnalda Lanfranchi3, Fulvio Porta1 P279 POST-TRANSPLANTATION CYCLOPHOSPHAMIDE IN HAPLOIDENTICAL TRANSPLANT: A REPORT IN LOW AND MIDDLE INCOME COUNTRY Araceli Leal-Alanis1, Juan Luis Ontiveros-Austria1, Maria Alejandra Nuñez-Atahualpa1, Anghela Milenka Mendoza-Sanchez1, Bogar Pineda-Terreros1, Rubén Solis Armenta 1, Brenda Lizeth Acosta-Maldonado1, Manuel Valero Saldaña1 P280 EFFICACY AND SAFETY OF RUXOLITINIB FOR PEDIATRIC ACUTE AND CHRONIC GRAFT-VERSUS-HOST DISEASE - A SINGLE CENTER EXPERIENCE Shu-Wei Chou 1, Meng-Yao Lu1, Hsiu-Hao Chang1, Yung-Li Yang1, Shiann-Tarng Jou1 P281 SYSTEMATIC LITERATURE REVIEW ON THE SAFETY, EFFICACY, AND EFFECTIVENESS OF EATG VERSUS COMPARATORS FOR GVHD Erin Sheffels1, Kevin Kallmes1, Keith Kallmes1, John Pederson1, Barbara Możejko-Pastewka 2, Raj Gokani2, Judith Hey-Hadavi2, Andres Quintero2 P282 A SERIES OF STEROID-REFRACTORY, SEVERE CHRONIC GRAFT- VERSUS- HOST DISEASE CASES, TREATED WITH RUXOLITINIB- A SINGLE-CENTER EXPERIENCES Ewa Karakulska-Prystupiuk 1, Agnieszka Tomaszewska1, Piotr Boguradzki1, Piotr Kacprzyk1, Grzegorz Władysław Basak1 P283 BELUMOSUDIL FOR SEVERE, REFRACTORY CHRONIC GVHD IN PEDIATRIC PATIENT: CASE REPORT Agnieszka Sobkowiak-Sobierajska 1, Maksymilian Deręgowski1, Sandra Rutkowska1, Jacek Wachowiak1 P284 CLINICAL EVOLUTION OF PATIENTS WITH GRAFT-VERSUS-HOST DISEASE - THE EXPERIENCE OF A SINGLE CENTER Ana Salselas 1, Pedro Leite-Silva2,1, Sara Lopes1, Lucia Vieira1, Susana Roncon1 P285 USE OF MYCOPHENOLATE MOFETIL FOR GRAFT VERSUS HOST DISEASE PROPHYLAXIS IN PATIENTS UNDERGOING HEMATOPOIETIC STEM CELLS TRANSPLANTATION FROM UNRELATED DONORS Davide Pio Abagnale1, Andrea Cacace1, Giuseppe Gaeta1, Maria Luisa Giannattasio1, Linda Piccolo1, Francesco Grimaldi1, Simona Avilia1, Mara Memoli1, Lucia Ammirati2, Valentina Maglione2, Alessandro Severino1, Catello Califano2, Fabrizio Pane1, Giorgia Battipaglia 1 P286 RETROSPECTIVE ANALYSIS OF RUXOLITINIB TREATMENT FOR THE MANAGEMENT OF STEROID REFRACTORY GRAFT VERSUS HOST DISEASE IN ADULTS WITH HEMATOLOGIC MALIGNANCIES Bogar Pineda Terreros1, Araceli Leal Alanis1, Brenda Lizeth Acosta Maldonado1, Luis Manuel Valero Saldaña1, Rubén Solís Armenta 1, María Alejandra Núñez Atahualpa1, Anghela Milenka Mendoza Sánchez1, Liliana Mey Len Rivera Fong1 P287 DR3 AND GITR AGONISTS BOOST ENDOGENOUS TREG POOL TO PREVENT ACUTE GVHD Juan Fernando Gamboa Vargas 1, Isabell Lang2, Svetlana Stepanzow2, Olena Zaitseva2, Estibaliz Arellano Viera1, Carolin Graf1, Haroon Shaikh1, Muhammad Daud1, Hermann Einsele3, Harald Wajant2, Andreas Beilhack1 P288 ROLE OF BCL2 IN GRAFT VERSUS HOST DISEASE José Antonio Bejarano García1,2, Melanie Nuffer1,2, Mª José Palacios Barea1,2, Luzalba Sanoja Flores1,2, Mª Reyes Jiménez León1,2, Javier Delgado Serrano2, Teresa Caballero Velázquez2,1,3, Alfonso Rodríguez Gil1,2,3, José Antonio Pérez Simón 2,1,3 P289 DIMETHYL FUMARATE INHIBITS TFH DIFFERENTIATION AND CGVHD VIA NRF2 Huanle Gong 1, Fulian Lv1, Yang Xu1, Depei Wu1 P290 SPECIFIC INHIBITION OF PATHOLOGICAL ANGIOGENESIS TO DECREASE ACUTE GVHD Katarina Riesner 1, Lydia Verlaat1, Sarah Mertlitz1, Angela Jacobi2, Hadeer Mohamed Rasheed1,3, Pedro Vallecillo Garcia1, Beate Anahita Jung1, Ningyu Li1, Martina Kalupa1, Claudine Fricke1, Bertina Mandzimba-Maloko1, Laura Barrero1, Lars Bullinger1, Olaf Penack1 P291 ENDOTHELIAL-TO-MESENCHYMAL TRANSITION IN CHRONIC GVHD Katarina Riesner 1, Lydia Verlaat1, Sarah Mertlitz1, Hadeer Mohamed Rasheed1,2, Pedro Vallecillo Garcia1, Beate Anahita Jung1, Ningyu Li1, Martina Kalupa1, Claudine Fricke1, Bertina Mandzimba-Maloko1, Lars Bullinger1, Bruce Blazar3, Olaf Penack1 P292 RAPID ADAPTATION OF DONOR REGULATORY T CELLS (TREG) TO RECIPIENT TISSUES FOR THE CONTROL OF ACUTE GRAFT-VERSUS-HOST DISEASE (GVHD) Franziska Pielmeier 1, David J. Dittmar1, Nicholas Strieder2, Alexander Fischer1, Michael Herbst1, Hanna Stanewsky1, Niklas Wenzl2, Eveline Röseler2, Rüdiger Eder1, Claudia Gebhard2, Lucia Schwarzfischer-Pfeilschifter1, Christin Albrecht1, Wolfgang Herr1, Michael Rehli1,2, Petra Hoffmann1,2, Matthias Edinger1,2 P293 INHIBITION OF MYELOPEROXIDASE AMELIORATES MURINE ACUTE GRAFT-VERSUS-HOST DISEASE Michelle Klesse 1, Sebastian Schlaweck1, Oliver Schanz1, Peter Brossart1, Annkristin Heine1 P294 IFN-GAMMA INDUCES ACUTE GRAFT-VERSUS-HOST DISEASE BY PROMOTING HMGB1-MEDIATED NUCLEAR-TO-CYTOPLASM TRANSLOCATION AND AUTOPHAGIC DEGRADATION OF P53 Xu Yajing 1, Wang Shiyu1, Cheng Tingting1, Chen Xu1, Zeng Cong1, Qin Wei1 P295 DEFINING THE TRANSCRIPTOMIC LANDSCAPE OF ACUTE SKIN GVHD AT SINGLE CELL RESOLUTION Callum Wright 1, Jason Lam1, Lucas Cortes1, Paul Milne1, Jamie Macdonald1, Laura Jardine1, Rafiqul Hussain1, Jonathan Coxhead1, Rachel Queen1, Megan Hasoon1, Adrienne Unsworth1, Michael McCorkindale1, Erin Hurst2, Amy Publicover2, Venetia Bigley1, Matthew Collin1 P296 IMPROVING THE THERAPEUTIC EFFECT OF HUMAN UMBILICAL CORD MESENCHYMAL STEM CELLS ON ACUTE GRAFT-VERSUS-HOST DISEASE BY CRISPLD2-OVEREXPRESSION Qing Xu1,2, Ya Zhou1, Yuxi Xu1, Rui Wang1, Xiaoqi Wang1, Shijie Yang1, Qingxiao Song 1,2, Xi Zhang1,2 P297 RUXOLITINIB USE DURING DONOR STEM CELL MOBILIZATION RESULTS IN RECIPIENTS IMMUNOMODULATION POST BONE MARROW TRANSPLANT IN MURINE MODEL AND MIGHT REDUCE GRAFT VERSUS HOST DISEASE Vamsi Kota 1, Ahmet Alptekin1, Hasanul Chowdhury1, Mahrima Parvin1, Evila Sales2, Amanda Barrett3, Babak Baban2, Ali Arbab1, Ravindra Kolhe3 P298 ROS DEFICIENCY OF RECEIPT DERIVED MDSCS EXACERBATES ALLO-REACTIVE T CELLS RESPONSES DURING HYPERACUTE GVHD Yigeng Cao1, Jiali Wang1, Zihan Zhao1, Erlie Jiang 1, Yuanfu Xu1 P299 DIAGNOSIS OF CUTANEOUS ACUTE GRAFT-VERSUS-HOST THROUGH CIRCULATING PLASMA MIR-638, MIR-6511B-5P, MIR-3613-5P, MIR-455-3P, MIR-5787, AND MIR-548A-3P AS PROSPECTIVE NONINVASIVE BIOLOGICAL INDICATORS IN ACUTE MYELOID LEUKEMIA Marjan Yaghmaie 1, Marzieh Izadifard1, Mohammad Ahmadvand1, Hossein Pashaiefar1, Kamran Alimoghadam1, Amir Kasaeian1, Maryam Barkhordar1, Ghazal Seghatoleslami1, Mohammad Vaezi1, Ardeshir Ghavamzadeh2 P300 THE IMPORTANCE OF CYTOGENETIC BONE MARROW TESTS IN POST-TRANSPLANT CARE OF PATIENTS AFTER ALLO-HSCT DUE TO ACUTE MYELOID LEUKEMIA OR MYELODYSPLASTIC SYNDROME- A SINGLE-CENTER ANALYSIS Ewa Karakulska-Prystupiuk 1, Agnieszka Stefaniak1, Anna Kulikowska1, Krzysztof Madry1, Agnieszka Tomaszewska1, Piotr Boguradzki1, Tomasz Stokłosa1, Grzegorz Władysław Basak1 P301 INFECTION BY HUMAN HERPES VIRUS 6 IN ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION IN THE POST-TRANSPLANT CYCLOPHOSPHAMIDE ERA Paola Charry1, Virginia Rodríguez1, Ares Guardia1, Teresa Solano1, Jordi Arcarons1, Joan Cid1, Miquel Lozano1, Laura Rosiñol1, Carmen Martínez1, María Queralt Salas1, Francesc Fernandez-Avilés1, Mª Ángeles Marcos1, Montserrat Rovira1, María Suárez-Lledó 1 P302 SECOND HAPLOIDENTICAL HAEMATOPOIETIC STEM CELL TRANSPLANTATION WITH POST-TRANSPLANT CYCLOPHOSPHAMIDE AS RESCUE STRATEGY FOR HIGH RISK CHILDREN WITH LEUKEMIA Giorgio Ottaviano1, Maria Barazzoni2, Federica Acone2, Francesca Vendemini1, Giulia Prunotto1, Alex Moretti2, Pietro Casartelli1, Sara Napolitano1, Marta Verna1, Sonia Bonanomi1, Adriana Balduzzi 1,2 P303 DISTINCT CLINICO-BIOLOGICAL FEATURES IN NPM1-MUTATED ACUTE MYELOID LEUKEMIA PATIENTS FOLLOWING ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION Xiaolin Yuan 1,2,3,4, Yibo W1,2,3,4, Xiaoyu Lai1,2,3,4, Lizhen Liu1,2,3,4, Jimin Shi1,2,3,4, Weiyan Zheng1,2,3,4, Jian Yu1,2,3,4, Yanmin Zhao1,2,3,4, Jie Sun1,2,3,4, Zhen Cai1,2,3,4, He Haung1,2,3,4, Yi Luo1,2,3,4 P304 DIFFERENT SOURCES OF HEMATOPOIETIC STEM CELL TRANSPLANTATION IN PATIENTS WITH THALASSEMIA MAJOR: RELATIONSHIP BETWEEN IMMUNE RECONSTITUTION, GRAFT-VERSUS-HOST DISEASE, AND VIRAL INFECTIONS Jianyun Liao 1, Chaoke Bu1, Lan He1, Huaying Liu1, Zhiyong Peng1, Jujian He1, Weiwei Zhang1, Yuqian Xia1, Yuelin He1, Chunfu Li1 P305 COMBINATION OF POST-TRANSPLANT CYCLOPHOSPHAMIDE WITH ANTITHYMOCYTE GLOBULIN AFTER HAPLOIDENTICAL ALLOGENEIC HEMATOPOIETIC STEM-CELL TRANSPLANTATION: A SINGLE CENTER ANALYSIS Chiara Bernardi 1,2, Amandine Pradier1,2, Anne-Claire Mamez1, Federica Giannotti1, Sarah Morin1, Sisi Wang1,2, Astrid Melotti1,2, Yves Chalandon1, Federico Simonetta1,2, Starvoula Masouridi-Levrat1 P306 TRIPLE STEM CELL INFUSION ALLEVIATE GRAFT VERSUS HOST DISEASE AND IMPROVE OUTCOME IN UNMANIPULATED HAPLOIDENTICAL HEMATOPOIETIC STEM CELL TRANSPLANTATION Fang Hua1,2, Shan Zhang1, Xiao-Mei Zhang1, Yan Deng1, Ying Han1, Si-Han Lai1, Ying He1, Lei Ma1, Xu-Pai Zhang1, Dan Chen1, Yi Su1, Ling Zhang1, Hui Yang1, Rong Huang1, Guang-Cui He 1, Hao Yao1, Hai Yi1 P307 HIGH-DOSE CHEMOTHERAPY WITH AUTOLOGOUS BONE MARROW TRANSPLANTATION IN MULTI-REFRACTORY TESTICULAR GERM CELL CANCER: A RETROSPECTIVE SINGLE INSTITUTIONAL ANALYSIS Andrea Tamayo1, Adolfo Sáez1, Reyes Mas1, Lucia Medina1, Guillermo Ramos1, Esther Parra1, Alberto Blanco1, Clara Cuellar1, Paula Lázaro1, Ana Jimenez1, Rafael Alonso1, Tycho Baumann1, Jose Sanchez Pina 1, Pilar Martinez1, Enrique Gonzalez1, Joaquin Martinez1, Maria Calbacho1 P308 KIR-MISMATCH IMPACTS THE OUTCOMES AFTER HLA-HAPLOIDENTICAL STEM-CELL TRANSPLANTATION WITH POST-TRANSPLANT CYCLOPHOSPHAMIDE Jairo Eduardo Niño-Ramirez1, Francisco Javier Gil-Etayo1, Marta Fonseca Santos1, Isabel Jiménez-Hernaz1, Ariadna Vicente-Parra1, Pilar Terradillos-Sánchez1, Ana Balanzategui1, Francisco Boix1, Miguel Alcoceba1, Almudena Navarro-Bailón1, Estefanía Pérez-López1, Mónica Cabrero1, Fermín Sanchez-Guijo1, Ramón García-Sanz1, Lucía López-Corral 1, Amalia Tejeda-Velarde1 P309 NOVEL AUTOMATIC APPLICATION FOR ENRICHMENT OF CD34 + CELLS FROM APHERESIS PRODUCTS USING THE CLINIMACS PRODIGY Julia Dzionek 1, Stephanie Soltenborn1, Valeriya Olevska1, Svenja Oberbörsch1, Christin Bosbach1, Felix Hebbeker1, Burgund Kauling1, Juliane Raasch1, Carina Wenzel1, Heike Lahnor2, Katharina Krämer2, René Meißner2, Eleni Papanikolaou1, Andreas Bosio1 P310 OUTCOMES OF ALLOGENEIC HAEMATOPOIETIC STEM CELL TRANSPLANTATION IN CHILDREN WITH WISKOTT-ALDRICH SYNDROME Samin Sharafian1,2, Su Han Lum1,3, Christo Tsilifis1,3, Terry Flood1, Eleri Williams1, Stephen Owens1, Sophie Hambleton1,3, Andrew Gennery1,3, Mary Slatter 1,3, Zohreh Nademi1,3 P311 STEM CELL TRANSPLANT ACTIVITY IN KYIV NATIONAL CANCER INSTITUTE IN THE CONDITIONS OF FULL-SCALE RUSSIAN AGGRESSION IN UKRAINE Nazar Shokun 1, Alevtyna Burtna1, Maryna Bushuieva1, Moiseienko Kateryna1, Irina Kryachok1, Yana Stepanishyna1 P312 HOME-BASED HEMATOPOIETIC CELL TRANSPLANTATION IS FEASIBLE AND SAFER IN TERMS OF NUTRITIONAL PARAMETERS, TOXICITY AND LENGTH OF HOSPITALIZATION STAY Javier Cornago Navascués1, Laura Pardo Gambarte 1, Juan Carlos Caballero Hernáez1, María Carolina Dassen1, Ana Rodríguez-Calvo Parra1, Alberto Sánchez Donaire1, Jesús Ignacio Merlo Luis1, José Luis López Lorenzo1, Amalia Domingo González1, Pilar Llamas Sillero1, Laura Solán Blanco1 P313 A RISK-ADAPTED STRATEGY TO SELECT AUTOLOGOUS OR ALLOGENEIC TRANSPLANT CONSOLIDATION IS EFFECTIVE IN MATURE T-CELL LYMPHOMA: A SINGLE CENTER EXPERIENCE Alessio Maria Edoardo Maraglino1, Simona Sammassimo1, Viviana Amato1, Anna Vanazzi1, Paulina Maria Nierychlewska1, Ginevra Lolli1, Simonetta Viviani1, Tommaso Radice1, Fabio Giglio 1, Federica Gigli1, Rocco Pastano1, Corrado Tarella1, Enrico Derenzini1,2 P314 EFFECTS OF THE PERIPHERAL EXPANSION OF CYTOTOXIC T LYMPHOCYTES ON OUTCOMES FOLLOWING HAPLOIDENTICAL ALLOGENEIC STEM CELL TRANSPLANTATION Lucía García Tomás1, Oriana Jimena López Godino 1, Cristina Aroca Valverde1, Inmaculada Heras Fernando1, María Luisa Lozano Almela1 P315 OUTCOME OF ALLO-HSCT IN THERAPY RELATED MYELOID NEOPLASMS WITH A HISTORY OF OVARIAN CANCER PREVIOUSLY TREATED WITH CHEMOTERAPY AND PARP INHIBITORS Alessio Maria Edoardo Maraglino1, Simona Sammassimo1, Patrizia Chiusolo2, Cristina Papayannidis3, Federica Gigli1, Filippo Frioni2, Chiara Sartor4, Viviana Amato1, Rocco Pastano1, Elisabetta Todisco5, Corrado Tarella1, Enrico Derenzini1,6, Fabio Giglio 1 P316 EFFECTS OF LOW-DOSE HYPOMETHYLATING AGENTS ON THE PREVENTION OF RELAPSE AFTER TRANSPLANTATION IN PEDIATRIC HIGH-RISK AML Qingwei Wang1, Shengqin Cheng1, Wei Gao1, Qi Ji1, Peifang Xiao1, Jun Lu1, Jie Li1, Shaoyan Hu 1 P317 OUTCOMES OF PEDIATRIC CHRONIC MYELOID LEUKEMIA IN ADVANCED PHASE AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION WITH REDUCED-INTENSITY CONDITIONING REGIMEN Polina Sheveleva1, Elena Morozova1, Anna Osipova1, Olesya Paina1, Olga Slesarchuk1, Tatyana Gindina1, Ekaterina Izmailova1, Ildar Barkhatov1, Tatyana Bykova 1, Elena Semenova1, Alexander Kulagin1, Ludmila Zubarovskaya1 P318 UPDATE ON DONOR DERIVED NK CELLS INFUSION FOLLOWING HAPLOIDENTICAL HEMATOPOIETIC STEM CELL TRANSPLANT IN PEDIATRIC HIGH-RISK AND RELAPSED/REFRACTORY LEUKEMIA Emanuela Rossitti1, Fabiana Cacace2, Flavia Antonucci1, Valeria Caprioli2, Maria Rosaria D’amico2, Giuseppina De Simone2, Maria Simona Sabbatino2, Mario Toriello2, Giovanna Maisto2, Roberta Penta de Vera d’aragona2, Francesco Paolo Tambaro 2 P319 COMPARISONS OF SAFERTY AND EFFICACY OF ALLO-HSCT AFTER CAR T-CELL OR CHEMOTHERAPY-BASED COMPLETE REMISSION IN PEDIATRIC T-ALL Ruijuan Sun 1, Jianping Zhang1, Yue Lu1, Yanli Zhao1, Deyan Liu1, Xingyu Cao1, Min Xiong1, Jiarui Zhou1, Zhijie Wei1 P320 EFFECT OF CYTOMEGALOVIRUS REACTIVATION ON RELAPSE AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION IN ACUTE LYMPHOBLASTIC LEUKEMIA Mekni Sabrine1, Ben Abdeljelil Nour 1, Rihab Ouerghi1, Turki Ines1, Khayati Malek1, Ben Yaiche Insaf1, Frigui Siwar1, Torjemane Lamia1, Belloumi Dorra1, Kanoun Rimmel Yosra1, Ladeb Saloua1, Ben Othman Tarek1 P321 LOWER INCIDENCE OF CHRONIC GVHD WITH ATLG AS GVHD PROPHYLAXIS IN ALL PATIENTS IN FIRST COMPLETE REMISSION UNDERGOING ALLOGENEIC SCT COMPARED TO POST-TRANSPLANT CYCLOPHOSPHAMIDE Normann Steiner 1, Radwan Massoud1, Evgeny Klyuchnikov1, Nico Gagelmann1, Johanna Richter1, Christian Niederwieser1, Kristin Rathje1, Ameya Kunte1, Jannik Engelmann1, Christina Ihne1, Tatiana Urbanowicz1, Iryna Lastovytska1, Cecilia Lindhauer1, Franziska Marquard1, Mirjam Reichard1, Alla Ryzhkova1, Rusudan Sabauri1, Mathias Schäfersküpper1, Niloufar Seyedi1, Georgios Kalogeropoulos1, Silke Heidenreich1, Gabriele Zeck1, Ina Rudolph1, Dietlinde Janson1, Christine Wolschke1, Francis Ayuk1, Nicolaus Kröger1 P322 LONGITUDINAL FOLLOW-UP ON HUMORAL AND T CELL IMMUNE RESPONSES AFTER COVID-19 VACCINATION IN ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTED PATIENTS Alma Wegener 1, Line Dam Heftdal1, Sebastian Rask Hamm1, Cecilie Bo Hansen1, Laura Pérez-Alós1, Andreas Runge Poulsen1, Dina Leth Møller1, Kamille Fogh2, Mia Pries-Heje1, Rasmus Bo Hasselbalch2, Sisse Rye Ostrowski1, Ruth Frikke-Schmidt1, Erik Sørensen1, Linda Hilsted1, Marietta Nygaard1, Niels Smedegaard Andersen1, Lone Smidstrup Friis1, Søren Lykke Petersen1, Ida Schjødt1, Brian Kornblit1, Henrik Sengeløv1, Henning Bundgaard1, Peter Garred1, Kasper Iversen2, Kirsten Grønbæk1, Susanne Dam Nielsen1, Lars Klingen Gjærde1 P323 HAPLOIDENTICAL DONOR PERIPHERAL BLOOD STEM CELL TRANSPLANTATION USING THIRD-PARTY CORD BLOOD COMPARED WITH MATCHED UNRELATED DONOR TRANSPLANTATION FOR PATIENTS WITH HEMATOLOGIC MALIGNANCIES Xia Ma1, Yan Chen1, Yi Liu1, Tingting Cheng1, Cong Zeng1, Xu Chen1, Shiyu Wang1, Juan Hua1, Yajing Xu 1 P324 ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION IN PATIENTS WITH PERIPHERAL T-CELL LYMPHOMAS: A RETROSPECTIVE MULTICENTER STUDY IN CHINA Hongye Gao1, Jiali Wang1, Zhuoxin Zhang1, Hao Zhang2, Xin Du3, Dehui Zou1, Xianmin Song4, Erlie Jiang 1 P325 SAFETY AND EFFICACY OF POST-TRANSPLANT CYCLOPHOSPHAMIDE FOR MUD, MMUD AND HAPLOIDENTICAL STEM CELL TRANSPLANTS IN PAEDIATRIC POPULATION Gloria Miguel 1, Julia Marsal1, Maria Trabazo1, Cristina Rivera1, Montserrat Rovira2, Laura Jimenez1, Paula Mazorra1, Julio Ropero3, Ana Maria Infante4 P326 BEYOND BORDERS: HSCT’S GLOBAL SITUATIONS AND INDONESIA’S PURSUIT OF HEALTH EQUITY Daniel Rizky 1, Ridho M. Naibaho2, Mohammed Bader Obeidat3, Mabruratussania Maherdika1, Budi Setiawan1, Eko Adhi Pangarsa1, Damai Santosa1, Catharina Suharti4, Marco A. Salvino5,6, Abel Santos Carreira7, Annalisa Paviglianiti7, Marta Peña7, Alberto Mussetti7, Anna Sureda7 P327 EFFECTIVENESS OF THE SIMPLIFIED COMORBIDITY INDEX COMPARED TO THE HCT-CI AS A PREDICTOR OF TRANSPLANT RELATED MORTALITY AND OVERALL SURVIVAL AFTER ALLOGENEIC STEM CELL TRANSPLANTATION Maria Alejandra Nunez Atahualpa 1, Ruben Solis Armenta1, Anghela Milenka Mendoza Sánchez1, Araceli Leal Alanis1, Bogar Pineda Terreros1, Liliana Rivera Fong1, Brenda Lizeth Acosta Maldonado1, Luis Manuel Velero Saldaña1 P328 8 VS 12 GRAY TBI IN ALLOGENEIC SCT FOR ALL PATIENTS RESULTS IN SIMILAR SURVIVAL, BUT IMPROVED SURVIVAL FOR MRD + PATIENTS AFTER 12 GRAY Normann Steiner 1, Radwan Massoud1, Evgeny Klyuchnikov1, Nico Gagelmann1, Johanna Richter1, Christian Niederwieser1, Kristin Rathje1, Ameya Kunte1, Tatiana Urbanowicz1, Jannik Engelmann1, Christina Ihne1, Iryna Lastovytska1, Cecilia Lindhauer1, Franziska Marquard1, Mirjam Reichard1, Gabriele Zeck1, Alla Ryzhkova1, Rusudan Sabauri1, Mathias Schäfersküpper1, Niloufar Seyedi1, Georgios Kalogeropoulos1, Silke Heidenreich1, Ina Rudolph1, Dietlinde Janson1, Christine Wolschke1, Francis Ayuk1, Nicolaus Kröger1 P329 POST-TRANSPLANT MAINTENANCE THERAPY WITH AZACITIDINE FOR HIGH-RISK MYELOID MALIGNANCIES: WHO BENEFITS THE MOST? Linli Lu1, Xin Li 1, Qian Cheng1 P330 PHYSICIAN PERSPECTIVES ON THE BURDEN AND CLINICAL MANAGEMENT OF CYTOMEGALOVIRUS (CMV) INFECTION IN TRANSPLANT RECIPIENTS IN CENTRAL AND EASTERN EUROPE Radovan Vrhovac 1, Alicja Dębska-Ślizień2, Tina Roblek3, Aleksandar Biljić Erski4, Milena Todorović Balint5 P331 THE DOSES OF POST-TRANSPLANTATION CYCLOPHOSPHAMIDE IN HAPLOIDENTICAL STEM CELL ALLOGRAFTS CAN BE REDUCED Juan Carlos Olivares-Gazca1, María de Lourdes Pastelín-Martínez2,1, Merittzel Abigail Montes-Robles2,1, Moisés Manuel Gallardo-Pérez1, Edgar Jared Hernández-Flores1,3, Max Robles-Nasta1,3, Daniela Sánchez-Bonilla1, César Homero Gutiérrez-Aguirre4, Andrés Gómez-De-León4, David Gómez-Almaguer4, Guillermo José Ruiz-Delgado 1,3, Guillermo José Ruiz-Arguelles1,3 P332 OUTCOMES WITH ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION IN THERAPY RELATED ACUTE MYELOID LEUKEMIA: A SYSTEMATIC REVIEW AND META-ANALYSIS Moazzam Shahzad 1, Muhammad Kashif Amin2, Muhammad Fareed Khalid3, Iqra Anwar2, Michael Jaglal1 P333 OUTCOME OF ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR THERAPY RELATED ACUTE MYELOID LEUKEMIA: MULTICENTER REAL-LIFE EXPERIENCE Alessandra Sperotto1, Matteo Leoncin2, Chiara Cigana3, Roberta De Marchi1, Carla Filì4, Albana Lico5, Corinna Greco5, Marco Petrella6, Endri Mauro7, Eleonora De Bellis8, Ilaria Tanasi9, Federico Mosna10, Giulia Ciotti1, Cristina Skert2, Mariagrazia Michieli3, Alberto Tosetto5, Carmela Gurrieri6, Francesco Zaja8, Mauro Krampera9, Michele Gottardi1, Costanza Fraenza 2 P334 OUTCOMES OF SECOND ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR HEMATOLOGIC DISEASES: A SINGLE-CENTER REAL-WORLD EXPERIENCE Marta Castelli 1, Anna Grassi2, Alessandra Algarotti2, Maria Caterina Micò2, Federico Lussana1, Maria Chiara Finazzi1, Chiara Pavoni2, Gianluca Cavallaro2, Federico Mazzon1, Giuliana Rizzuto2, Benedetta Rambaldi2, Alessandro Rambaldi1 P335 PERSPECTIVES OF GENERAL HEMATOLOGISTS ON A PROPOSED SHARED CARE MODEL FOR HSCT IN SAUDI ARABIA FOR SICKLE CELL DISEASE Abdulrahman Alsultan 1, Mohsen Alzahrani2, Mohammed Essa3, Abdullah Aljefri4, Hatoon Ezzat5, Wasil Jastaniah6 P336 DOES AGE MATTER? IMPACT OF DONOR AGE IN ENGRAFTMENT AND GRAFT FUNCTION AFTER HEMATOPOIETIC STEM CELL TRANSPLANTATION Oana Enache1, Lavinia Eugenia Lipan2,1, Oana Gabriela Craciun2, Andra Georgiana Stoica2, Adela Ionela Ranete2, Ileana Constantinescu2,1, Alina Daniela Tanase 2,1 P337 COMPARABLE RESULTS OF HAPLOIDENTICAL AND MATCHED RELATED HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR PATIENTS WITH BLAST PHASES CHRONIC MYELOID LEUKEMIA Darina Zammoeva1, Renat Badaev 1, Yuliya Alekseeva1, Dmitriy Motorin2, Elza Lomaia1 P338 ANALYSIS OF THE EFFICACY OF LUSPATERCEPT IN THE TREATMENT OF ANEMIA AFTER ALLOGENEIC HAEMATOPOIETIC STEM CELL TRANSPLANTATION Lei Dong 1, Wei Ma1, Liu Chan-Chan1, Zhang Fang-Fang1, Tian Yue-Feng1, Liu Ji-Cong1, Zhao Xiao-Zhen1, He Yang2, Cao Xing-Yu1 P339 THE IMPACT OF THE TRAVELED DISTANCE TO THE TRANSPLANT CENTER ON THE CLINICAL OUTCOME OF ALLOGENEIC BONE MARROW TRANSPLANT PATIENTS Jean El-Cheikh 1, Mustafa Saleh1, Khodr Terro1, Radwan Massoud2, Ghassan Bidaoui1, Layal Sharrouf1, Sara Chehayeb1, Toufik Sebai3, David Karam1, Ammar Zahreddine1, Rita Nehme1, Iman Abou Dalle1, Nour Moukalled1, Ali Bazarbachi1 P340 THE CLINICAL ANALYSIS OF ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION IN THERAPY-RELATED MYELOID NEOPLASMS Shu Yan1, Deyan Liu1, Fang Xu 1 P341 HAPLOIDENTICAL TRANSPLANTATION FOR PATIENTS WITH FANCONI ANEMIA HAPLOIDENTICAL TRANSPLANTATION FOR PATIENTS WITH FANCONI ANEMIA Eman Khattab 1, Hasan Hashem1, Mayada Abu Shanap1, Iyad Sultan1, Rawad Rihani1 P342 NK-CELL INFUSIONS TO PREVENT RELAPSE FOLLOWING HEMATOPOIETIC STEM CELL TRANSPLANTATION Maryia Navumovich1, Tatsiana Shman1, Yuliya Mareika1, Volha Mishkova1, Katsiaryna Vashkevich1, Natalia Kirsanava1, Iryna Pakhomova1, Viktoryia Belabokava1, Dmitriy Prudnikov1, Lubov Zherko1, Nina Minakovskaya 1, Anzhalika Solntsava1 P343 SURVIVAL OF PATIENTS WITH MULTIPLE MYELOMA WITH ASCT IN ONCOSALUD - AUNA BETWEEN 2015 AND 2021 Alonso Diaz1, Claudio J. Flores1, Shirley Quintana 2, Cesar Samanez2 P344 RESOLUTION OF VOD/SOS WITH DEFIBROTIDE AFTER HSCT AND PERSISTENT HEPATIC DEMAGE: MONOCENTRIC PEDIATRIC EXPERIENCE Fabiana Cacace1, Emanuela Rossitti2, Valeria Caprioli1, Flavia Antonucci2, Maria Rosaria D’amico1, Giuseppina De Simone1, Maria Simona Sabbatino1, Francesco Paolo Tambaro 1 P345 ACCURATE DIETARY EVALUATION AND ADEQUATE NUTRITIONAL THERAPY ARE INDISPENSABLE FOR BETTER OUTCOMES OF ALLO-HSCT Yuki Mori 1, Koichi Nakase1, Toshimi Noma1, Tomoya Katsuta1, Ryuichiro Hiyama1, Yuki Goto1, Ryo Ueda1, Risa Hashida1, Kyoko Itakusu1, Kyosuke Saeki1, Masakazu Mori1, Yuichiro Nawa1 P346 ALLOGENOUS BONE MARROW TRANSPLANT IN HIGH-RISK CHRONIC MYELOID LEUKEMIA IN THE ERA TKI INHIBITOR: A SYSTEMATIC REVIEW Nia Novianti Siregar 1, Resti Mulya Sari1, Andree Kurniawan2, Felix Wijovi2, Devina Adella Halim2, Patricia Angel2, Rivaldo Steven Heriyanto2 P347 LONELINESS AND RUMINATIONS IN CANCER PATIENT-CAREGIVER DYADS – ANALYSIS OF DAILY FLUCTUATIONS Małgorzata Sobczyk-Kruszelnicka1, Aleksandra Kroemeke2 P348 PATIENTS WITH FOLLICULAR LYMPHOMA AND CANDIDATES FOR AUTOLOGOUS TRANSPLANTATION: IS THE COLLECTION OF HEMATOPOIETIC PROGENITORS EFFICIENT AFTER THE FIRST LINE OF TREATMENT? María Casado Sánchez1, Sara Hormaza de Jauregui1, Juan José Mateos Mazón1, Javier Arzuaga Méndez1, Xabier Martín Martitegui1, Paula María Zoco Gallardo 1, Laura Aranguren del Castillo1, Ariadna García Ascacibar1, Gorka Pinedo Martín1, María Elena Amutio Díez1, Juan Carlos García Ruiz1 P349 HAPLOIDENTICAL BONE MARROW TRANSPLANTATION IN A COLOMBIAN BMT UNIT: CLINICAL DESCRIPTION AND OUTCOMES Jorge Cuervo sierra 1, Germán A. Velasquez-Quintero1, Juan Felipe Jaramillo-Alvarez1, Wang Nataly Montoya-Arbelaez1, Sandra Gisella Martinez-Jimenez1, Luz Maridier Tobon-Tobon1, Jurany Andrea Marin-Montoya1, Deisy Johana Giraldo-Gomez1, Luisa Fernanda Castro-Quintero1, Maira Alejandra Mesa-Giraldo1, Maribel Londoño-Buitrago1 P350 HAPLOIDENTICAL STEM CELL TRANSPLANTATION IN FANCONI ANEMIA: A SINGLE CENTER EXPERIENCE Guzmán López de Hontanar 1,2,3, June Iriondo2,3, Josune Zubicaray2,3, Elena Sebastián2,3, Blanca Molina2,3, Sara Vinagre2,3, Marta González-Vicent2,3, Julián Sevilla2,3 P351 EARLY AUTOLOGOUS AND/OR ALLOGENEIC STEM CELL TRANSPLANTATION FOR ADULT PATIENTS WITH ADVANCED STAGE T- LYMPHOBLASTIC LEUKEMIA/LYMPHOMA OR BURKITT LYMPHOMA. A RETROSPECTIVE SINGLE-CENTRE ANALYSIS Normann Steiner 1, Katherina Baier1, Denise Ritter1, Gabriele Hetzenauer1, Jakob Rudzki1, Stefan Köck1, Eberhard Gunsilius1, Brigitte Kircher1, Dominik Wolf1, David Nachbaur1 P352 MONOCYTES IN ALLO-HSCT WITH AGED DONORS SECRET IL-1/IL-6/TNF TO INCREASE THE RISK OF GVHD AND DAMAGE THE AGED HSCS Xia Li 1, Wanying Zhang2, Yanan Wang2, Chentao Li2, Yibo Wu1, Xiaoyu Lai1, Yi Luo1, Pengxu Qian1, He Huang1 P353 SETTING UP THE FIRST PEDIATRIC BONE MARROW TRANSPLANTATION UNIT IN THE UAE AND THE EXPERIENCE OF COMPLETING THE FIRST 30 PEDIATRIC BMTS WITHOUT ANY MORTALITY Zainul Aabideen 1, Sagar Mohan Nivargi1, Abdullah Odat1, Mohammed Alfar1, Charbel Khalil1, Rakeshkumar Shah1, Kesava Ramakrishnan1, Rajesh Phatak2, Ahmed Elsheikh1, Mohamed Abdelsamad1, Krishnappa Venkatesh1, Ghulam Mujtaba1, Dr. Georgey Koshy1, Amro El Saddik3, Humaid Alshamsi4, Fulvio Porta5, Lawrence Faulkner6, Mohammed Hamid1 P354 POST-TRANSPLANT CYCLOPHOSPHAMIDE ± ANTI-THYMOCYTE GLOBULIN IN PATIENTS WITH AML/MDN UNDERGOING ALLOGENEIC HCT WITH PBSC FROM HAPLOIDENTICAL DONOR: A SINGLE-CENTER EXPERIENCE Francesca Cavallaro 1, Marta Canzi1,2, Fabio Serpenti1, Maria Cecilia Goldaniga1, Kordelia Barbullushi1, Giulia Galassi3, Francesco Onida4,2, Francesco Passamonti1,2, Giorgia Natascia Saporiti1 P355 DESCRIPTION OF PATIENTS WITH RELAPSED/REFRACTORY HODGKIN LYMPHOMA WHO UNDERWENT TO ALLOGENEIC STEM CELL TRANSPLANTATION IN A REFERENCE CENTER IN BOGOTA, COLOMBIA Carlos Fernando Gómez Calcetero 1, Angie Paola Guarin Castañeda1, Oscar Javier Peña Ardila1, Gloria Elena Mora Figueroa1, Cesar Lamadrid Sastre1, Enrique Pedraza Mesa1, Gerson Menoyo Caballero1, Gustavo Adolfo Martinez Salazar1, Licet Villamizar Gómez1 P356 TREOSULFAN-BASED HAPLOIDENTICAL T CELL DEPLETED HSCT FOR ADOLESCENTS AND YOUNG ADULTS (AYA) WITH ADVANCED STAGE SICKLE CELL DISEASE AND THALASSEMIA Anja Troeger 1, Juergen Foell1, Katharina Kleinschmidt1, Gina Penkivech1, Tarek Hanafee-Alali1, Andreas Brosig1, Robert Offner1, Daniel Wolff1, Selim Corbacioglu1 P357 COMPARISON OF THE UNRELATED TRANSPLANTATION RESULTS OF AN HLA FULLY MATCHED DONOR AND A HOMOZYGOUS MM DONOR AT ONE LOCUS IN PATIENTS WITH BETA THALASSEMIA Koray Yalçın 1,2, Safiye Suna Çelen1, Seda Öztürkmen3, Hayriye Daloğlu4, Suleimen Zhumatayev5, Vedat Uygun6, Gülsün Karasu5, Akif Yeşilipek3 P358 CLINICAL OUTCOMES AND HEALTHCARE RESOURCE USE IN PATIENTS WITH SICKLE CELL DISEASE WITH RECURRENT VASO-OCCLUSIVE CRISES WHO RECEIVED HEMATOPOIETIC STEM CELL TRANSPLANTS IN FRANCE Jessica Baldwin 1, Chuka Udeze1, Naxin Li1, Lyes Boulmerka1, Lila Dahal1, Giancarlo Pesce2, Nadia Quignot2, Heng Jiang2, Frederic Galactéros3 P359 SINGLE-CENTER EXPERIENCE OF STEM CELL TRANSPLANTATION IN PATIENTS WITH SEVERE SICKLE CELL DISEASE Miriam P. Klahr 1, Amer Assal1, Christian Gordillo1, Ran Reshef1, Monica Bhatia1, Diane George1, Markus Y. Mapara1 P360 HAEMATOPOIETIC STEM CELL TRANSPLANTATION IN A LOW RESOURCE COUNTRY NIGERIA. A 10 YEARS REPORT FROM A SINGLE CENTER Nosakahare Bazuaye 1, Nancy Ojiemhangbe2 P361 IMPACT OF THE FIRST ONLINE WEBINAR OF THE WBMT NURSING GROUP IN COLLABORATION WITH THE LAGOS UNIVERSITY TEACHING HOSPITAL AND SICKLE CELL FOUNDATION OF NIGERIA Adetola Kassim 1, Reggie Belkhedim2, Sebastian Galeano3, Dietger Niederwieser3, Damiano Rondelli4, Abijah Princy B5, Amala Lucas6, Ainy Azra7, Cristina Vogel8, Diana Villalobos9, Eugenia Arjona10, Felicia Michael11, Francisca Negrete12, Gloria Ceballo13, John Murray14, Jorge Morales15, Josephine Suganya6, Kishwar Sultana16, Komal Mundhe17, Latha Gracelin6, Lu Yin18, Megan Hogg11, Michelle Kenyon19, Niti Lotey20, Nouf Shwikan21, Paola Llamas22, Rita Nehme23, Sandeep Elizabeth24, Suman Kubal17, Trish Joyce25, Yvonne Panek-Hudson25, Adriana Seber26, Annette Akinsete27, Edamisan Temiye28, Oluseye Akinstete28, Mahmoud Aljurf21 P362 MATCHED-RELATED HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR INTERMEDIATE AND HIGH RISK THALASSEMIA PATIENTS USING REDUCED INTENSITY CONDITIONING REGIMEN WITH POST-TRANSPLANT CYCLOPHOSPHAMIDE AS GRAFT-VERSUS-HOST DISEASE PROPHYLAXIS. A SINGLE CENTER EXPERIENCE FROM JORDAN Ayad Ahmed Hussein 1, Bayan Majed Alaaraj1, Tariq Ahmed Abdelghani1, Nour Awni Ghanem1, Hadeel Hassan Al-Zoubi1, Dina Mohammad Abu Assab1 P363 ABO INCOMPATIBILITY DID NOT IMPACT TRANSPLANT OUTCOMES FOLLOWING REDUCED INTENSITY HAPLOIDENTICAL BONE MARROW TRANSPLANTATION FOR PATIENTS WITH SICKLE CELL DISEASE: MULTICENTER EXPERIENCE Danielle Murphy 1, Pavina Akhom1, Karina Wilkerson1, Katie Gatwood1, Lindsay Orton1, Jim Connelly1, Reena Jayani1, Olalekan Oluwole1, Bhagirathbhai Dholaria1, Nancy Clayton-Long1, Brittney Baer1, Bipin Savani1, James Jerkins1, Andrew Jallouk1, Mohsen Alzahrani2, Ali D. Alhamari3, Josu de la Fuenta4, Erfan Nur5, Heidi Chen1, Adetola Kassim1 P364 DURABLE ENGRAFTMENT AFTER PHARMACOLOGICAL PRE-TRANSPLANT IMMUNE SUPPRESSION FOLLOWED BY REDUCED-TOXICITY MYELOABLATIVE HAPLOIDENTICAL STEM CELL TRANSPLANTATION IN HIGHLY HLA-IMMUNIZED ADULTS WITH SICKLE CELL DISEASE Sabine Fürst 1, Emmanuelle Bernit2, Faezeh Legrand1, Angela Granata1, Samia Harbi1, Raynier Devillier1, Benjamin Bouchacourt1, Thomas Pagliardini1, Valerio Maisano1, Djamel Mokart1, Claude Lemarié1, Boris Calmels1, Christophe Picard3, Agnès Basire3, Borje S. Andersson4, Didier Blaise1 P365 CLINICAL OUTCOMES AND HEALTHCARE RESOURCE USE IN PATIENTS WITH TRANSFUSION-DEPENDENT Β-THALASSEMIA WHO RECEIVED HEMATOPOIETIC STEM CELL TRANSPLANTS IN FRANCE Jessica Baldwin1, Chuka Udeze 1, Nanxin Li1, Lyes Boulmerka1, Lila Dahal1, Giancarlo Pesce2, Nadia Quignot2, Heng Jiang2, Frederic Galactéros3 P366 THE IMPACT OF PANEL REACTIVE ANTIBODIES IN PEDIATRIC BETA THALASSEMIA PATIENTS UNDERGOING STEM CELL TRANSPLANTATION Gülay Sezgin1 P367 SICKLE CELL DISEASE WITH SEVERE ACUTE CHEST SYNDROME AND HEPATOPATHY: CAN ALLOGENEIC SCT BE PERFORMED IN SUCH DESPERATE CLINICAL SITUATIONS? A CASE REPORT Celia Kaffenberger 1, Eva Rettinger1, Shahrzad Bakhtiar1, André Willasch1, Roland Schrewe1, Michael Merker1, Birgit Knoppke2, Jean-Hugues Dalle3, Jan-Henning Klusmann1, Peter Bader1, Andrea Jarisch1 P368 OUTCOMES FOLLOWING HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR MONOGENIC INFLAMMATORY BOWEL DISEASE Xiaowen Zhai 1, Ping Wang1, Wenjin Jiang1, Hongsheng Wang1, Ying Huang1, Xiaowen Qian1 P369 CLINICAL CHARACTERISATION AND OUTCOME OF 125 CASES WITH GRISCELLI SYNDROME Adriel Roa-Bautista1, Mahreen Sohail2, Reem Elfeky3, Maaike Kusters 3 P370 OUTCOMES FOR ALLOGENEIC SCT FOR PATIENTS WITH INBORN ERRORS OF IMMUNITY UTILIZING REDUCED INTENSITY CONDITIONING REGIMEN WITH TARGETED BUSULFAN Hannah Lust1, Olatundun Williams2, Morris Kletzel1, Reggie Duerst1, Jennifer Schneiderman1, William Tse3, Sonali Chaudhury 1 P371 OUTCOME OF THE PATIENTS DIAGNOSED WITH SEVERE COMBINED IMMUNODEFICIENCY THROUGH NEWBORN SCREENING IN CATALONIA (2017-2023) Laura Alonso1, Andrea Martin-Nalda1, Maria Isabel Benitez Carabante 1, Ana Argudo-Ramirez2, Luz Uria-Ofialdegui1, Judit Garcia-Villoria2, Melissa Panesso1, Jacques Gabriel Riviere1, Pere Soler-Palacin1, Cristina Diaz de Heredia1 P372 HSCT AS A CURATIVE TREATMENT OPTION IN PATIENTS WITH A PRIMARY IMMUNODEFICIENCY DUE TO IL2RB-DEFECT: DESCRIPTION OF A SMALL COHORT Ommo E. Mauss 1, Christo Tsilifis2,3, Eva-Maria Jacobsen1, Manfred Hönig1, Ansgar Schulz1, Mary A. Slatter2,3, Sophie Hambleton2,3, Klaus-Michael Debatin1, Klaus Schwarz4,5, Ulrich Pannicke4,5, Andrew R. Gennery2,3, Mehtap Sirin1 P373 WHICH ALTERNATIVE TO CHOOSE? - A COMPARATIVE STUDY BETWEEN MATCHED UNRELATED AND HAPLOIDENTICAL DONOR TRANSPLANTS IN CHILDREN WITH INBORN ERRORS OF IMMUNITY IN LOW-MIDDLE-INCOME COUNTRIES Anuraag Reddy Nalla 1, Revathi Raj1, Ramya Uppuluri1, Venkateswaran Swaminathan1, Kavitha Ganesan1, Suresh R D1, Anupama Nair1, Vijayshree M1, Indira Jayakumar1, Ravindra Prasad Thokala1, Usha Suriyanarayanan1 P374 MUD-HSCT IN A RARE COMBINED IMMUNODEFICIENCY WITH ARPC1B DEFICIENCY-CASE REPORT Devyani Surange 1, Rajiv Kumar1, Rajan Kapoor1, Sanjeev Khera1 P375 ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION (HCT) IN TWO PEDIATRIC PATIENTS WITH CENTRAL NERVOUS SYSTEM-RESTRICTED FAMILIAL HEMOPHAGOCYTIC LYMPHOHISTIOCYTOSIS Alison Cusmano1, Ariane Soldatos1, Jessenia Campos1, Katherine Townsend1, Corina Gonzalez1, Allison Grimes2, Sara Makkeyah3, Maha Mohammed3, Hoda Tomoum3, Luigi Notarangelo1, Laila Selim4, Jennifer Kanakry1, Dimana Dimitrova 1 P376 SIL2-RΑ AND ST2 LEVELS BEFORE HEMATOPOIETIC STEM CELL TRANSPLANTATION ARE ASSOCIATED WITH MORTALITY IN HLH PATIENTS Anne B. Verbeek 1, Anja M. Jansen-Hoogendijk1, Erik G J. von Asmuth1, Marco W. Schilham1, Arjan C. Lankester1, Emilie P. Buddingh1 P377 HEMATOPOIETIC STEM CELL TRANSPLANTATION IN CHILDREN FOR PRIMARY IMMUNE DEFICIENCIES: THE EXPERIENCE OF SINGLE CENTER Utku Aygunes1, Ali Antmen 1, Ilgen Sasmaz1,2, Barbaros Karagun1, Duygu Turksoy1 P378 THE OUTCOMES OF UMBILICAL CORD BLOOD STEM CELL TRANSPLANTATION FOR COMBINED IMMUNODEFICIENCY DISEASE IN CHILDREN WITH CD40LG MUTATION Xiaowen Qian 1, Ping Wang1, Wenjin Jiang1, Xiaowen Zhai1 P379 BACILLE CALMETTE-GUÉRIN (BCG) VACCINE-ASSOCIATED COMPLICATIONS FOLLOWING STEM CELL TRANSPLANTATION IN PATIENTS WITH INBORN ERRORS OF IMMUNITY (IEI) – SINGLE TERTIARY CENTRE EXPERIENCE FROM SOUTH INDIA Stalin Ramprakash 1, C P. Raghuram1, P. Anoop1, Neha Singh1, Jyothi Janardhanan1, Sagar Bhattad1 P380 UNSUCCESSFUL HSCT IN 2 ADA2 DEFICIENCY PATIENTS ASSOCIATED WITH HIGH LEVELS OF ANTI-HLA ANTIBODIES Amit Dotan 1, Marganit Benish1, Hila Rosenfeld Keidar1, David Hagin1, Sabina Edelman1, Ronit Elhasid1 P381 FATAL NEUROLOGICAL COMPLICATION POST HSCT IN A PEDIATRIC PATIENT WITH IMMUNODEFICIENCY DUE TO NFKB2 MUTATION Paula Catalán 1,2, Cristián Sotomayor2, Cecilia Poli3,4, María Angélica Wietstruck1,2 P382 ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION (HSCT) TO CHILDREN WITH PRIMARY IMMUNODEFICIENCY –THE HELLENIC EXPERIENCE Eleni Ioannidou 1, Aikaterini Kaissari1, Anna Paissiou1, Christina Oikonomopoulou1, Anna Komitopoulou1, Michalis Kastamoulas1, Georgia Stavroulaki1, Ioannis Grafakos1, Vassiliki Kitra1, Ioulia Peristeri1, Stylianos Grafakos1, Georgios Vessalas1, Maria Theodosaki1, Eftychia Petrakou1, Irene Sfougataki1, Dimitra Kattemi1, Alexandra Papasarantopoulou1, Evangelia Farmaki2, Rediona Cane3, Marianna Tzanoudaki3, Evgenios Goussetis1 P383 POSTTRANSPLANT COMPLICATIONS IN A CASE OF LATE-ONSET FAMILIAL HEMOPHAGOCYTIC LYMPHOHISTIOCYTOSIS TYPE 2 Delfien Bogaert 1, Siel Daelemans2, Tessa Wassenberg2, Filomeen Haerynck1, Victoria Bordon1, Catharina Dhooge1 P384 HEMATOPOIETIC STEM CELL TRANSPLANTATION IN PRIMARY IMMUNODEFICIENCY DISEASES: SINGLE CENTRE EXPERIENCE Nayera El-Sherif 1, Heba G.A. Ali1, Sara Makkeyah1, Safa Sayed1, Nesrine Radwan2, Dalia ElGhoneimy2, Fatma S.E. Ebeid1, Sally Gouda2 P385 HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR INBORN ERRORS OF IMMUNITY (IEI): GAP BETWEEN NEED AND REALITY IN A LIMITED RESOURCE SETTING: A FIVE-YEAR SINGLE-CENTER EXPERIENCE Stalin Ramprakash 1, Neha Singh1, Jyothi Janardhanan1, Harish Kumar1, Chetan Ginegeri1, C P. Raghuram1, P. Anoop1, Sagar Bhattad1 P386 AN INNOVATIVE PLATFORM APPROACH FOR THE DEVELOPMENT OF EX-VIVO HEMATOPOIETIC STEM AND PROGENITOR CELL-GENE THERAPY FOR THE TREATMENT OF LYSOSOMAL STORAGE DISEASES WITH SKELETAL INVOLVEMENT Stefania Crippa1, Pamela Quaranta1, Margherita Berti1, Luca Basso-Ricci1, Ludovica Santi1, Giada De Ponti1, Raisa Jofra Hernandez1, Claudia Forni1, Ilaria Visigalli1, Paola Albertini1, Rossella Parini1, Serena Scala1, Alessandro Aiuti2, Maria Ester Bernardo 2 P387 HEMATOPOETIC STEM CELL TRANSPLANTATION WITH CURRENT PERSPECTIVE IS SAFE FOR MUCOPOLYSACCHARIDOSIS TYPE VI PATIENTS Vedat Uygun1, Gülsün Karasu2, Koray Yalçin 3,4, Seda Öztürkmen5, Safiye Suna Çelen3, Hayriye Daloğlu6, Suleimen Zhumatayev2, Akif Yesilipek5 P388 HEMATOPOIETIC STEM CELL TRANSPLANTATION FROM MATCHED AND MISMATCHED DONORS WITH POST-TRANSPLANT CYCLOPHOSPHAMIDE AND ANTITHYMOCYTE GLOBULIN IN CHILDREN WITH PRIMARY IMMUNODEFICIENCIES Alexandr Bazaev1, Alexandra Laberko 1,2, Yulia Skvortsova1, Elena Gutovskaya1, Svetlana Kozlovskaya1, Anna Vasilieva1, Larisa Shelikhova1, Galina Novichkova1, Alexey Maschan1, Michael Maschan1, Dmitry Balashov1 P389 CONDITIONING FOR SECOND HSCTS FROM THE SAME DONOR AFTER MYELOID AUTOLOGOUS RECONSTITUTION IN PATIENTS WITH IEI AND THALASSEMIA: IMMUNOSUPPRESSION IS NOT ALWAYS REQUIRED Sarah Bauer1, Beatrice Zwiebler1, Michael H. Albert2, Jörn-Sven Kühl3, Mehtap Sirin1, Kerstin Felgentreff1, Ingrid Furlan1, Klaus-Michael Debatin1, Eva-Maria Jacobsen1, Ansgar Schulz1, Manfred Hoenig 1 P390 SINGLE CENTER OBSERVATION ON CLINICAL PRESENTATION, TRANSPLANTATION AND OUTCOME OF SEVEN PATIENTS WITH ZAP-70 DEFICIENCY Felix Immanuel Maier 1, Philipp Friederichsen1,2, Ansgar Schulz1, Eva-Maria Jacobsen1, Klaus-Michael Debatin1, Katharina Kleinschmidt3, Selim Corbacioglu3, Jürgen Föll3, Klaus Schwarz4,5, Ulrich Pannicke4, Manfred Hönig1 P391 POLYMORPHISM OR RISK ALLELE? PRF1 A91V IN TRANS WITH A “SEVERE” PRF1 MUTATION Oliver Wegehaupt 1,2, Oleg Borisov3, Florian Oyen4, Jasmin Mann1, Despina Moshous5, Geneviève de Saint Basile5, Kimberly Gilmour6, Wenying Zhang7, Rebecca Marsh7, Eberhard Gunsilius8, Laine Hosking9, Sharon Choo9, Katharina Wustrau10, Sujal Gosh11, Kai Lehmberg4, Anna Köttgen3, Stephan Ehl1 P392 IMMUNE-MEDIATED CYTOPENIA AFTER ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION IN CHILDREN WITH INHERITATED METABOLIC DISORDERS Hirotoshi Sakaguchi 1, Tetsumin So1, Yoshihiro Gochio1, Akihiro Iguchi1, Takao Deguchi1, Daisuke Tomizawa1, Motomichi Kosuga1, Kimikazu Matsumoto1 P393 PROPHYLACTIC ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR CSF1R-RELATED LEUKOENCEPHALOPATHY- A CASE REPORT Malu Lian Hestdalen 1, Morten Andreas Horn2, Camilla Dao Vo1, Ingerid Weum Abrahamsen1, Tor Henrik Anderson Tvedt1, Tobias Gedde-Dahl1, Anders Eivind Myhre1 P394 CLINICAL PROFILE AND TRANSPLANT OUTCOMES OF 41 PATIENTS WITH INBORN ERRORS OF IMMUNITY: A SINGLE CENTER EXPERIENCE FROM SOUTH INDIA Stalin Ramprakash 1, Neha Singh1, C P. Raghuram1, P. Anoop1, Jyothi Janardhanan1, Harish Kumar1, Chetan Ginigeri1, Fulvio Porta2, Sagar Bhattad1 P395 HEMATOPOIETIC CELL TRANSPLANTATION AND SPLIT LIVER TRANSPLANTATION IN A PATIENT WITH ERYTHROPOIETIC PROTOPORPHYRIA - A CASE REPORT Lasse Jost 1, Ulrich Stölzel2, Daniel Seehofer3, Katharina Egger-Heidrich4, Kristina Hölig4, Thomas Stauch5, Desiree Kunadt4, Detlef Schuppan6, Johannes Schetelig4, Nils Wohmann2, Martin Bornhäuser4, Friedrich Stölzel1 P396 SUCCESSFUL THIRD ALLOGENEIC STEM CELL TRANSPLANTATION FOLLOWING TWO GRAFT REJECTIONS IN A PATIENT WITH CHRONIC GRANULOMATOUS DISEASE AND HEPATIC/PARAPHRENIC ABSCESSES Daniela Sperl 1, Martin Benesch1, Ursula Posch1, Konrad Rosskopf1, Volker Strenger1, Sebastian Tschauner1, Markus G. Seidel1, Wolfgang Schwinger1 P397 CHRONIC GRANULOMATOUS DISEASE DO NOT NEED MOST OF THE TIMES NGS FOR DIAGNOSIS Marianna Maffeis 1, Marta Comini2, Alessandra Beghin2, Federica Bolda2, Elena Soncini1, Giulia Baresi1, Stefano Rossi1, Fulvio Porta1, Arnalda Lanfranchi2 P398 BLINATUMOMAB IS AN EFFECTIVE AND LOW TOXICITY BRIDGE TREATMENT TO HEMATOPOIETIC STEM CELL TRANSPLANTATION IN ACUTE LYMPHOBLASTIC LEUKEMIA ASSOCIATED WITH SHWACHMAN-DIAMOND SYNDROME Fabiana Cacace1, Giovanna Giagnuolo1, Pio Stellato1, Emanuela Rossitti2, Valeria Caprioli1, Flavia Antonucci2, Maria Rosaria D’amico1, Giuseppina De Simone1, Maria Simona Sabbatino1, Rosanna Parasole1, Giuseppe Menna1, Francesco Paolo Tambaro 1 P399 BREAKTHROUGH INVASIVE FUNGAL DISEASE IN PATIENTS UNDERGOING ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION IN CHINA: A MULTICENTER EPIDEMIOLOGICAL STUDY (CAESAR 2.0) Yu-Qian Sun 1, Chuan Li1, Dan-Ping Zhu1, Jia Chen2, Xiao-Yu Zhu3, Nai-Nong Li4, Wei-Jie Cao5, Zhong-Ming Zhang6, Hai-Long Yuan7, Xiao-Xia Hu8, Xiao-Sheng Fang9, Hong-Tao Wang10, Yue Yin11, Ye-Hui Tan12, Xiao-Jun Huang1 P400 CHANGES IN THE EPIDEMIOLOGY OF INVASIVE FUNGAL DISEASES IN HSCT OVER ALMOST A QUARTER OF A CENTURY Marina Popova 1, Yuliya Rogacheva1, Valentin Zagranichnov2, Olga Pinegina3, Vladislav Markelov1, Aleksander Siniaev1, Irina Baranova1, Yulia Rodneva1, Alisa Volkova1, Ilya Nikolaev1, Alena Zaytseva1, Alexander Shvetsov1, Anna Spiridonova2, Oleg Golochtapov1, Yulia Vlasova1, Anna Smirnova1, Natalia Mikhaylova1, Maria Vladovskaya1, Sergey Bondarenko1, Alexander Kulagin1 P401 OUTCOMES FROM BRONCHOSCOPY AND BRONCHOALVEOLAR LAVAGE IN HEMATOPOIETIC CELL TRANSPLANT RECIPIENTS Colin Hayes 1, Benison Lau1, Kengo Inagaki1, Mike Triebwasser1, John Magenau1, Mary Riwes1, Mark Vander Lugt1, Ghada Abusin1, Sung Choi1, Sarah Anand1, Monalisa Ghosh1, John Maciejewski1, Attaphol Pawarode1, Gregory Yanik1 P402 LETERMOVIR PROPHYLAXIS FOR CYTOMEGALOVIRUS INFECTION IS THE POTENTIAL RISK OF EBV-POSITIVE POSTTRANSPLANT LYMPHOPROLIFERATIVE DISORDERS AFTER HAPLOIDENTICAL STEM-CELL TRANSPLANTATION Xuying Pei 1, Xiaojun Huang1 P403 DIAGNOSIS OF MUCORMYCOSIS IN ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION USING METAGENOMIC NEXT-GENERATION SEQUENCING: A SINGLE-CENTER CLINICAL STUDY Fang Xu 1, Jianping Zhang1, Min Xiong1, Yanli Zhao1, Deyan Liu1, Xingyu Cao1, Zhijie Wei1, Jiarui Zhou1, Ruijuan Sun1, Yue Lu1 P404 MARIBAVIR USE FOR REFRACTORY CMV INFECTION/DISEASE: THE RESULTS FROM THE FRENCH COMPASSIONATE PROGRAMME Catherine Cordonnier 1, Nassim Kamar2, Philippe Gatault3, Faouzi Saliba4, Fanny Vuotto5, Lionel Couzi6, Cinira Lefevre7, Michèle Maric7, Sophie Alain8 P405 COMPREHENSIVE SCREENING AND SENSITIVITY-GUIDED TREATMENT SIGNIFICANTLY REDUCES THIRTY-DAY MORTALITY OF METALLO-Β-LACTAMASES PRODUCING ENTEROBACTERALES (MBL-E) INFECTION FOLLOWING ALLOGENEIC STEM CELL TRANSPLANTATION: INSIGHTS FROM A PROSPECTIVE STUDY Yi-Han Yang1, Meng Lv1, Qi Wang1, Jing Liu1, Xiao-Lu Zhu1, Xiao-Dong Mo1, Yu-Qian Sun 1, Yu Wang1, Lan-Ping Xu1, Xiao-Hui Zhang1, Xiao-Jun Huang1,2 P406 PENTAGLOBIN® AS EARLY ADJUVANT TREATMENT FOR FEBRILE NEUTROPENIA IN HEMATOLOGICAL PATIENTS COLONIZED BY CARBAPENEM-RESISTANT ENTEROBACTERIACEAE OR PSEUDOMONAS AERUGINOSA: INTERIM ANALYSIS OF GITMO STUDY “PENTALLO” Daniela Clerici 1, Alessandra Picardi2, Patrizia Chiusolo3, Nicola Di Renzo4, Anna Paola Iori5, Mario Delia6, Ilaria Cutini7, Francesca Bonifazi8, Michele Malagola9, Raffaella Cerretti10, Maria Goldaniga11, Francesca Patriarca12, Daniele Vallisa13, Attilio Olivieri14, Roberto Sorasio15, Stefania Bregante16, Angelo Michele Carella17, Alessandro Busca18, Consuelo Corti1, Eliana Degrandi19, Fabio Ciceri1, Massimo Martino20, Corrado Girmenia5 P407 MUCOSITIS-ASSOCIATED BLOODSTREAM INFECTIONS IN HAEMATOLOGY PATIENTS WITH FEVER DURING NEUTROPENIA Nick de Jonge 1,2,3, Jeroen Janssen1,2,3, Paula Ypma4, Alexandra Herbers5, Arne de Kreuk6, Wies Vasmel6, Jody van den Ouweland7, Aart Beeker8, Otto Visser9, Sonja Zweegman1,3, Nicole Blijlevens2, Michiel van Agtmael1, Jonne Sikkens1 P408 DESCRIPTIVE ANALYSES OF PULMONARY FUNCTION CHANGES BEFORE AND AFTER COVID-19 IN ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANT RECIPIENTS. AN INFECTIOUS DISEASE WORKING PARTY STUDY Jose-Luis Piñana 1, Per Ljungman2, Stephan Mielke2, Gloria Tridello3, Helene Labussiere4, Carlos Solano1, Anna Torrent5, Regis Peffault De Latour6, Nicolaus Kroeger7, Maria Jesus Pascual Gascon8, Adriana Balduzzi9, Lutz Peter-Muller10, Jürgen Kuball11, Amjad Hayat12, Urpu Salmenniemi13, Fabio Benedetti14, Dina Averbuch15, Rafael De La Camara16 P409 EPSTEIN-BARR VIRUS-RELATED POSTTRANSPLANT LYMPHOPROLIFERATIVE DISORDERS IN THE LETERMOVIR ERA Jingtao Huang1, Luxiang Wang1, Zengkai Pan1, Zilu Zhang1, Jiayu Huang1, Chuanhe Jiang1, Xiaoxia Hu 1 P410 PATTERN OF SENSITIVITY OF STOOL SURVEILLANCE OVER 13 YEARS AND IMPACT OF STOOL SURVEILLANCE GUIDED SELECTION OF ANTIBIOTIC IN ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANT PATIENTS Keshav Garg1, Akanksha Chichra1, Davinder Paul1, Anant Gokarn1, Sachin Punatar1, Sumeet Mirgh1, Nishant Jindal1, Lingaraj Nayak1, Sujata Lall1, Vivek Bhat1, Sadhana Kannan1, Bhausaheb Bagal1, Navin Khattry1, Laxma Reddy 2 P411 CYTOMEGALOVIRUS (CMV) LOAD PREDICTS CMV DISEASE AND MORTALITY INDEPENDENT OF POSTTRANSPLANT IMMUNOSUPPRESSION AFTER HEMATOPOIETIC CELL TRANSPLANTATION (HCT) Alicja Sadowska-Klasa 1,2, Danniel Zamora1, Hu Xie1, Elizabeth R. Duke1, Margaret L. Green3, Masumi Ueda Oshima1,3, Alpana Waghmare1,3,4, Joshua A. Hill1,3, Brenda M. Sandmaier1,3, Keith R. Jerome1,3, Wendy M. Leisenring1,3, Michael Boeckh1,3 P412 ADENOVIRUS INFECTION IN ADULT ALLOGENEIC TRANSPLANT RECIPIENTS WITH POST-TRANSPLANT CYCLOPHOSPHAMIDE Maria Chiara Quattrocchi 1, Giorgio Orofino1, Edoardo Campodonico1, Alessandro Bruno1, Lorenzo Lazzari1, Daniela Clerici1, Francesca Farina1, Simona Piemontese1, Elisa Diral1, Oltolini Chiara1, Raffaele Dell’Acqua1, Sara Racca1, Raffaella Milani1, Elisabetta Xue1, Sara Mastaglio1, Consuelo Corti1, Jacopo Peccatori1, Maria Teresa Lupo-Stanghellini1, Antonella Castagna1, Fabio Ciceri1, Raffaella Greco1 P413 NON-TUBERCULOUS MYCOBACTERIAL INFECTIONS AMONG HEMATOPOIETIC STEM CELL TRANSPLANT RECIPIENTS: A MULTICENTER EUROPEAN CASE-CONTROL STUDY BY THE INFECTIOUS DISEASES WORKING PARTY OF EBMT Maria Stamouli 1, John Snowden2, Alienor Xhaard3, Awatif AlAnazi4, Antonio Perez Martinez5, Moshe Yeshurun6, Nicolaus Kröger7, Jürgen Kuball8, Fanourios Kontos1, Jakob Passweg9, Stephan Mielke10, Mohsen Al Zahrani11, Luis Miguel Juarez-Salcedo12, Joanna Drozd-Sokolowska13, Fabio Benedetti14, Lucrecia Yañez Sansegundo15, Alessandra Biffi16, Maria Teresa Lupo Stanghellini17, Pavel Jindra18, Alexander Kulagin19, Nuno Miranda20, Urpu Salmenniemi21, Petr Sedlacek22, Gloria Tridello23, Inge Verheggen23, Dina Averbuch24, Rafael de la Camara12 P414 BACTEREMIA IN THE FIRST + 100 DAYS AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION: MICROORGANISMS, RESISTANCE AND PROGNOSTIC IMPACT Merce Aren1, Rosa Pacheco2, Mireia Morgades1, Nadia Güell1, Gerard García-Cirera1, Cristina Blanco-Montes1, Vitor Botafogo1, Maria Izquierdo1, Anna Torrent1, Christelle Ferrà3, Maria Josefa Jiménez1, Josep Maria Ribera1, Juan Manuel Sancho1, Maria Dolores Quesada2, Maria Huguet 1 P415 ISAVUCONAZOLE THERAPEUTIC DRUG MONITORING-DRIVEN TREATMENT IN A COHORT OF PAEDIATRIC PATIENTS UNDERGOING HAEMATOPOIETIC STEM CELL TRANSPLANTATION: A SINGLE-CENTRE EXPERIENCE Carmen Dolores De Luca 1,2, Chiara Rossi1, Chiara Rosignoli1, Federica Galaverna1, Francesca Del Bufalo1, Marco Becilli1, Michele Massa1,2, Raffaele Simeoli1, Emilia Boccieri1, Barbarella Lucarelli1, Antonio Torelli1, Daria Pagliara1, Bianca Maria Goffredo1, Mattia Algeri1, Franco Locatelli1,3, Pietro Merli1 P416 THINK TO CHECK PREVIOUS SEROLOGIES WHEN CMV OR TOXOPLASMA SEROLOGIES ARE NEGATIVE AT TRANSPLANT Christine Robin 1, Ludovic Cabanne1, Florence Beckerich1, Anne Le Bouter1, Francoise Foulet1, Catherine Cordonnier1 P417 IMMUNE POPULATIONS PREDICT CONTROL OF CMV REACTIVATION AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION Paula Díaz-Fernández 1,2,3, Valle Gómez García de Soria1,2,3, Javier Sevilla-Montero1,2, Ana Marcos-Jiménez1,2, José María Serra López-Matencio1,2, Laura Cardeñoso1, Ángela Figuera Álvarez1,2,3, Rafael de la Cámara1,2, Cecilia Muñoz-Calleja1,2,3 P418 NEW ANTIMICROBIAL STEWARDSHIP PROGRAM TOOL TO REDUCE THE EMPIRICAL ANTIBACTERIAL THERAPY IN HAPLO-HSCT Yuliya Rogacheva1, Marina Popova 1, Alexandr Siniaev1, Yuliya Vlasova1, Ivan Moiseev1, Sergey Bondarenko1, Alexander Kulagin1 P419 LETERMOVIR IS SAFE AND EFFECTIVE FOR TREATMENT AND PREVENTION OF CMV REACTIVATION IN PAEDIATRIC ALLOGENEIC STEM CELL TRANSPLANT Nathanael Lucas 1, Abbey Forster1, Malcolm Guiver1, Ramya Nataraj1, Madeleine Powys1, Noor Barotchi1, Omima Mustafa1, Srividhya Senthil1, Robert Wynn1 P420 DUAL METAGENOMICS NEXT-GENERATION SEQUENCING FOR FIRST-LINE DIAGNOSIS OF BLOODSTREAM INFECTION IN HEMATOLOGIC PATIENTS WITH FEBRILE NEUTROPENIA: A MULTICENTER PROSPECTIVE STUDY Yuqian Sun 1, Jingrui Zhou1, Yue Yin2, Jianping Zhang3, Meixiang Zhang4, Yun He1, Wei Gai5, Xiaohui Zhang1, Yu Wang1, Lanping Xu1, Kaiyan Liu1, Xiaojun Huang1 P421 CYTOMEGALOVIRUS-SPECIFIC T CELL IMMUNITY RECONSTITUTION AFTER LETERMOVIR WITHDRAWAL IN ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION RECIPIENTS Luxiang Wang1, Jingtao Huang1, Jiayu Huang1, Zilu Zhang1, Zengkai Pan1, Chuanhe Jiang1, Sujiang Zhang1, Xiaoxia Hu 1 P422 CMV REACTIVATION AND ITS IMPACT ON SURVIVAL AFTER ALLOGENEIC STEM CELL TRANSPLANTATION IN LETERMOVIR ERA – A SINGLE CENTRE STUDY Lana Desnica 1, Nadira Durakovic1, Zinaida Peric2, Zrinka Bosnjak1, Ranka Serventi Seiwerth1, Dubravka Sertic1, Ante Vulic1, Mirta Mikulic1, Violeta Rezo Vranjes1, Pavle Roncevic1, Drazen Pulanic1, Nurka Rustan1, Zorana Grubic1, Radovan Vrhovac1 P423 IMPACT OF QUANTIFERON-CMV (QNF-CMV) ON LATE ONSET CLINICALLY SIGNIFICANT CMV INFECTION (CSCMVI) AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION (HSCT) Chiara Maria Dellacasa 1, Roberto Passera1, Carolina Secreto1, Luisa Giaccone1, Irene Dogliotti1, Jessica Gill1, Davide Stella1, Aurora Martin1, Federica Ferrando1, Sofia Zompi1, Alessandro Busca1 P424 THERAPEUTIC DRUG MONITORING (TDM) OF PIPERACILLIN IN PATIENTS WITH NEUTROPENIC FEVER AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION Sabrina Kraus1, Prisca Rauen1, Josip Zovko1, Hermann Einsele1, Güzin Surat 1, Torsten Steinbrunn1 P425 ESTABLISHING EBV LOAD THRESHOLDS FOR PREDICTING PERSISTING EBV-DNAEMIA AND ASSOCIATED DISEASE IN HAEMATOPOIETIC CELL TRANSPLANT RECIPIENTS Svenia Schmid 1, Andrea Erba1, Rainer Gosert1, Hans H. Hirsch2, Jakob Passweg1, Joerg Halter1, Nina Khanna1, Karoline Leuzinger1 P426 CLINICAL OUTCOMES OF STRONGYLOIDIASIS IN HEMATOPOIETIC CELL TRANSPLANT (HCT) RECIPIENTS Avneet Kaur 1, Deepa Nanayakkara1, Ryotaro Nakamura1, Randy Taplitz1, Jana Dickter1, Stephen Forman1, Monzr Malki1, Sanjeet Dadwal1 P427 MONITORING OF CMV-SPECIFIC CELL-MEDIATED IMMUNITY - PROGNOSTIC FACTORS AND CLINICAL VALUE Jonas Wißkirchen 1, Diana Wolff1, Isabelle Ries1, Oliver Kriege1, Pascal Wölfinger1, Beate Hauptrock1, Matthias Theobald1, Eva Wagner-Drouet1 P428 USE OF LETERMOVIR IN PEDIATRIC HEMATOPOIETIC STEM CELL TRANSPLANT RECIPIENTS UNDER AGE OF 12: A RETROSPECTIVE MULTI-CENTRE STUDY ON BEHALF OF THE IEWP AND PDWP Katharina Kleinschmidt 1, Giovanna Lucchini2, Jacques-Emmanuel Galimard3, Adriana Balduzzi4, Krzysztof Czyzewski5, Jowita Frączkiewicz6, Francesco Paolo Tambaro7, Jaroslava Adamcakova8, Andrea Urtasun9, Matthias Woelfl10, Maria Ester Bernardo11, Alessandra Biffi12, Gergely Kriván13, Iván Lopez Torija14, Petr Sedlacek15, Wolfgang Holter16, Tamara Diesch17, Michael H. Albert18, Agnieszka Sobkowiak-Sobierajska19, Marta Gonzalez Vicent20, Elif Ince21, Sarah May Johnson2, Roland Meisel22, Arnaud Dalissier3, Selim Corbacioglu1, Bénédicte Neven23, Krzysztof Kalwak6 P429 CONVENTIONAL VERSUS NGS-BASED PATHOGEN DIAGNOSTICS IN FEBRILE ALLOGENEIC STEM CELL TRANSPLANT PATIENTS: A PROSPECTIVE SINGLE-CENTRE STUDY Sophie Weil 1, Madlen Amersbach1, Jochen J. Frietsch1, Sabrina Kraus1, Christoph Schoen2, Johannes Forster2, Philipp Reuter-Weissenberger2, Philip Stevens3, Oliver Kurzai2, Hermann Einsele1, Daniel Teschner1,4 P430 MULTINATIONAL STUDY ASSESSING TREATMENT PATTERNS, OUTCOMES, AND HEALTHCARE RESOURCE UTILIZATION IN HEMATOPOIETIC STEM CELL TRANSPLANT RECIPIENTS WITH CYTOMEGALOVIRUS INFECTION AND INTOLERANCE TO ANTI-CYTOMEGALOVIRUS THERAPIES Genovefa Papanicolaou1,2, Robin Avery3, María Laura Fox 4,5, Karl S. Peggs6, Luís Veloso7, Tien Bo8, Ishan Hirji8, Kimberly Davis8 P431 EFFICACY OF LETERMOVIR IN PREVENTING CYTOMEGALOVIRUS REACTIVATION AFTER CORD BLOOD TRANSPLANTATION Naoki Okada 1, Hiroyuki Muranushi1, Kazuya Okada1, Takayuki Sato1, Takeshi Maeda1, Tatsuhito Onishi1, Yasunori Ueda1 P432 SARS-COV-2 CYCLE THRESHOLD LEVELS AND COVID-19 OUTCOME IN ALLOGENEIC STEM CELL TRANSPLANTATION. AN INFECTIOUS DISEASE WORKING PARTY STUDY Jose Luis Piñana Sanchez 1, Per Ljungman2, Alexander Kulagin3, Maria Teresa Lupo Stanghellini4, Carlos Solano5, Gloria Tridello6, Jiri Mayer7, Maria Suarez-Lledó8, Hélène Labussière-Wallet9, Robert Zeiser10, Jennifer Clay11, Anna Bergendahl Sandstedt12, Inmaculada Heras13, Krzysztof Kalwak14, Jose Luis Lopez15, Judith Schaffrath16, Adriana Balduzzi17, Fabio Benedetti18, Amjad Hayat19, David Gallardo20, Harry Koene21, Jose Rifón22, Paul Gerard Schlegel23, Nina Knelange24, Dina Averbuch25, Rafael De la Camara26 P433 SINGLE-DAY TRIMETHOPRIM-SULFAMETHOXAZOLE PROPHYLAXIS FOR PNEUMOCYSTIS PNEUMONIAE AND TOXOPLASMOSIS INFECTION IN HEMATOPOIETIC STEM CELL TRANSPLANTATION PEDIATRIC PATIENTS Maria Speranza Massei 1, Ilaria Capolsini1, Elena Mastrodicasa1, Grazia Gurdo1, Carla Cerri1, Francesco Arcioni1, Maurizio Caniglia1, Katia Perruccio1 P434 AN INTERIM ANALYSIS OF FOVOCIP: A MULTICENTER RANDOMIZED TRIAL OF FOSFOMYCIN VERSUS CIPROFLOXACIN FOR FEBRILE NEUTROPENIA PREVENTION IN HEMATOLOGIC PATIENTS Ahinoa Fernández Moreno1, Ana Julia GonzalezHuerta2, Paula López de Ugarriza1, Cristina Muñoz3, Rebeca Rodríguez Veiga4, Laura Solán Blanco5, Maria Luisa Calabuig6, Karem Humala7, Juan Manuel Bergua Burgués3, Marta Polo Zarzuela8, Maria Luz Amigo9, María Izquierdo de Miguel3, Eva González Barberá4, Marina Medel Plaza5, Guillermo Ruiz Carrascoso7, Laura López Gonzalez8, Irene Weber9, Pau Montesinos Fernández4, Ana Maria Fernández Verdugo2, Javier Fernández Dominguez2, Teresa Bernal 1 P435 IMPACT OF LETERMOVIR PRIMARY AND SECONDARY PROPHYLAXIS IN A PEDIATRIC COHORT Francesca Vendemini1, Francesca Romani1,2, Sonia Bonanomi1, Giorgio Ottaviano1, Paola de Lorenzo3, Maria Grazia Valsecchi2, Sergio Maria Ivano Malandrin4, Marta Verna 1, Giulia Prunotto1, Pietro Casartelli1, Adriana Cristina Balduzzi1,2 P436 EPSTEIN-BARR VIRUS REACTIVATION AND POST-TRANSPLANT LYMPHOPROLIFERATIVE DISORDER (PTLD) AFTER IMPLEMENTATION OF ANTITHYMOCYTE GLOBULIN AS GVHD PROPHYLAXIS. A SINGLE CENTER EXPERIENCE Tor Henrik Anderson Tvedt1, Mats Remberger1,2,3, Ingerid Weum Abrahamsen1, Camilla Dao Vo 1, Anders Eivind Leren Myhre1, Tobias Gedde-Dahl1 P437 IMPACT OF INVASIVE FUNGAL DISEASE UPDATED DEFINITIONS ON ALLOGENEIC HEMATOPOIETIC TRANSPLANTATION OUTCOME IN ADULT PATIENTS - POST-HOC ANALYSIS OF NATION-WIDE CROSS-SECTIONAL 2012-2014 Patrycja Mensah-Glanowska 1, Agnieszka Piekarska2, Monika Adamska3, Joanna Drozd-Sokolowska4, Anna Waszczuk-Gajda4, Agnieszka Tomaszewska5,4, Agnieszka Wierzbowska6, Marek Hus7, Joanna Manko5, Sylwia Bartzel-Palinska8, Lidia Gil3 P438 SURVEILLANCE BLOOD CULTURES FROM TUNNELLED CENTRAL VENOUS CATHETERS ON ADMISSION ARE OFTEN POSITIVE, GUIDE MANAGEMENT AND HELP INFORM REPORTING OF HOSPITAL ACQUIRED INFECTIONS Debbie Barrow1, Krzysztof Ciesielski1, Seamus McDermott1, Grant McQuaker1, David Irvine1, Annie Latif1, Ailsa Holroyd1, Christine Peters1, Dimitris Galopoulos1, Andrew Clark 1 P439 ROLE OF HUMAN HERPESVIRUS 6 REACTIVATION IN T-DEPLETE TREG/TCON ALLOGENEIC STEM CELL TRANSPLANTATION Valerio Viglione 1, Loredana Ruggeri2, Antonella Mancusi1, Sara Tricarico2, Alessandra Cipiciani1, Rebecca Sembenico1, Matteo Caridi1, Zorutti Francesco1, Anna Castaldo1, Tiziana Zei2, Roberta Iacucci Ostini2, Simonetta Saldi1, Roberto Castronari2, Silvia Bozza1, Cynthia Aristei1, Antonella Mencacci1, Maria Paola Martelli1, Alessandra Carotti2, Antonio Pierini1 P440 INTERLEUKIN-6 IS SIGNIFICANTLY INCREASED IN SEVERE PNEUMONIA AFTER ALLO-HSCT AND MIGHT INDUCE LUNG INJURY VIA IL-6/SIL-6R/JAK1/STAT3 PATHWAY Jingrui Zhou1, Leqing Cao1, Rui Ma1, Yun He1, Danping Zhu1, Na Li1, Xiaosu Zhao1, Xiaojun Huang1, Yuqian Sun 1 P441 ECHINOCANDIN PROPHYLAXIS IS ASSOCIATED WITH BREAKTHROUGH TRICHOSPORON AND CANDIDA INFECTIONS AND A LIMITED ROLE OF GALACTOMANNAN MONITORING AMONG ALLOGENEIC STEM CELL TRANSPLANT RECIPIENTS André Dias Américo 1, João Antônio Gonçalves Garreta Prats1, Hegta Tainá Rodrigues Figueiroa1, Juliana Matos Pessoa1, Eurides Leite da Rosa1, Fauze Lutfe Ayoub1, Moyses Antônio Porto Soares1, Isabella Silva Pimentel Pittol1, Fabio Rodrigues Kerbauy1,2, Phillip Scheinberg1, José Ulysses Amigo Filho1 P442 REAL WORLD EXPERIENCE OF EPSTEIN-BARR VIRUS(EBV) SCREENING FOR PERSISTENT VIRAEMIA POST HAEMATOPOIETIC STEM CELL TRANSPLANT (HSCT) Abigail Downing 1, David Davies1, Keith Wilson1,2, Emma Kempshall1, Sophie Bertorelli1, Serena Linley-Adams1, Damith Dhanasekara1, Rey Consolacion1, Susannah Froude3, Samantha Ray3, Wendy Ingram1 P443 EPIDEMIOLOGY OF VIRAEMIA IN CHILDREN UNDERGOING CORD BLOOD STEM CELL TRANSPLANT (CB-SCT) WITH NON-MALIGNANT DISEASES: A RETROSPECTIVE COHORT STUDY Patel Zeeshan Jameel 1, Denise Bonney1, Omima Mustafa1, Malcolm Guiver1, Madeleine Powys1, Ramya Nataraj1, Srividhya Senthil1, Robert Wynn1 P444 PREVALENCE OF VZV REACTIVATION AND EFFECTIVENESS OF VACCINATION WITH RECOMBINANT ADJUVANTED ZOSTER VACCINE IN ALLOGENEIC HEMATOPOIETIC STEM CELL RECIPIENTS: A SINGLE-CENTER ANALYSIS Ewa Karakulska-Prystupiuk 1, Magdalena Feliksbrot-Bratosiewicz1, Maria Król1, Agnieszka Tomaszewska1, Grzegorz Władysław Basak1 P445 BK VIRUS-ASSOCIATED HEMORRHAGIC CYSTITIS IN POSTTRANSPLANT CYCLOPHOSPHAMIDE-BASED ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION (HCT) FOR IMMUNE DEFICIENCY OR DYSREGULATION Dimana Dimitrova 1, Christi McKeown1, Scott Napier1, Anita Stokes1, Alison Cusmano1, Ruby Sabina1, Jennifer Sponaugle1, Elisabetta Xue1, Jeffrey Cohen1, Alexandra Freeman1, Luigi Notarangelo1, Gulbu Uzel1, Vladimir Valera Romero1, Christopher Kanakry1, Jennifer Kanakry1 P446 INFECTION PREVENTION MEASURES TAKEN FOR ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANT PATIENTS DURING THE COVID-19 PANDEMIC AND THEIR IMPACT ON CLINICAL OUTCOMES Sarah Noetzlin1, Michael Bader2, Andriyana Bankova3, Dominik Schneidawind3, Jakob Passweg2, Anne-Claire Mamez1, Federica Giannotti1, Sarah Morin 1, Federico Simonetta1, Stavroula Masouridi-Levrat1, Dionysios Neofytos1, Yves Chalandon1 P447 EFFECT OF EARLY ADMINISTRATION OF ANTI-MRSA DRUGS ON THE COURSE OF FEBRILE NEUTROPENIA IN ALLO-SCT Anna Akaogi 1, Junya Kanda1, Fumiya Wada1, Yasuyuki Arai1, Chisaki Mizumoto1, Toshio Kitawaki1, Kouhei Yamashita1, Akifumi Takaori-Kondo1 P448 VISCERAL TOXOCARIAS IN THE EARLY POST-TRANSPLANT COURSE Iacopo Bellani 1, Francesca Vendemini2, Sonia Bonanomi2, Sergio Foresti3, Guglielmo Marco Migliorino3, Gaia Kullmann3, Alex Moretti2, Sergio Maria Ivano Malandrin4, Adriana Balduzzi2,1 P449 DE-ESCALATION ANTIBIOTIC STRATEGY IN MULTIDRUG-RESISTANCE BACTERIAL COLONIZED PATIENTS AFTER ALLOGENEIC STEM CELL TRANSPLANTATION. A 3-YEAR RETROSPECTIVE STUDY Roberto Bono1, Giuseppe Sapienza 1, Stefania Tringali1, Cristina Rotolo1, Alessandra Santoro2, Laura Di Noto3, Orazia Di Quattro4, Caterina Patti5, Luca Castagna1 P450 MARIBAVIR FOR TREATMENT OF REFRACTORY/RECURRENT CYTOMEGALOVIRUS INFECTION IN ALLOGENEIC HSCT RECIPIENTS Aleksandr Siniaev1, Ivan Moiseev1, Marina Popova 1, Yulia Rogacheva1, Yulia Vlasova1, Sergey Bondarenko1, Alexander Kulagin1 P451 REAL LIFE MANAGEMENT OF ANTIBIOTIC THERAPY IN HSCT RECIPIENTS – FOCUS ON DE-ESCALATION IN PRE-ENGRAFTMENT NEUTROPENIA, THE STUDY FROM THE EBMT INFECTIOUS DISEASES WORKING PARTY (IDWP) Malgorzata Mikulska 1, Lotus Wendel2, Gloria Tridello2, Alexander Kulagin3, Anna Czyz4, Nabil Yafour5, Fabio Ciceri6, Burak Deveci7, Simona Sica8, Kristina Carlson9, Matthias Eder10, Agnieszka Tomaszewska11, Tunc Fisgin12, Michel Schaap13, Michal Karas14, Anastasia Pouli15, Elisabetta Calore16, Marta Gonzalez Vicent17, Mariagrazia Michieli18, Maria Jesús Pascual Cascon19, Alessandra Picardi20, Gergely Krivan21, Anna Torrent Catarineu22, Tessa Kerre23, Pedro Chorão24, Fabio Benedetti25, Alessandra Carotti26, Melissa Gabriel27, Rik Schots28, Amjad Hayat29, Antonio Perez Martinez30, Domenico Pastore31, Mauro Turrini32, Diana Averbuch33, Jan Styczynski34, Rafael de la Camara35 P452 INFECTIOUS COMPLICATIONS IN 549 BMTS DONE WITHOUT CENTRAL HEPA FILTRATION OR POSITIVE PRESSURE? Rajpreet Soni1,2, Lawrence Faulkner 3,4, Priya Marwah1,2, Harshita Agarwal1, Deepa Trivedi5, Vaibhav Shah5, Mohan Reddy6, Neema Bhatt6, Stalin Ramprakash4, Rajat Kumar Agarwal4,7, Rachna Narain1,2, Ganesh Narain Saxena1,2 P453 COVID-19 IN PATIENTS WITH HAEMATOLOGICAL DISEASES: THE ASSOCIATION OF RNAEMIA WITH CLINICAL OUTCOMES IN VACCINATED PATIENTS Francisco Manuel Martin Dominguez 1, Sonsoles Salto-Alejandre2, Carmen Infante-Domínguez2, Mónica Carretero-Ledesma2, Natalia Maldonado-Lizarazo3, Pedro Camacho-Martínez2, Inmaculada Tallón-Ruiz4, Zaira Palacios-Baena3, Patricia Pérez-Palacios3, Rocío Álvarez-Marín2, José Antonio Lepe-Jiménez2, José Miguel Cisneros2, María Elisa Cordero2, Jerónimo Pachón2, Javier Sánchez-Céspedes2, José Antonio Pérez-Simón1, Manuela Aguilar-Guisado2 P454 COST-EFFECTIVENESS OF MARIBAVIR FOR POST-TRANSPLANT CYTOMEGALOVIRUS INFECTION THAT IS REFRACTORY TO ALTERNATIVE TREATMENTS FROM THREE HEALTHCARE SYSTEM PERSPECTIVES: ITALY, UK AND US Stacey L. Amorosi1, Emtiyaz Chowdhury2, Riccardo Ressa2, Peter Cain3, Simone Corinti4, Bob G. Schultz5, Tien Bo 1 P455 INVASIVE FUNGAL INFECTIONS IN PEDIATRIC HEMATOPOIETIC STEM CELL TRANSPLANTATION: A 4-YEAR SINGLE INSTITUTION ANALYSIS WITH FOCUS ON PROPHYLAXIS Federica Gironi1, Benedetta Elena Di Majo2,1, Ilaria Castelli1, Sonia Bonanomi1, Francesca Vendemini1, Giorgio Ottaviano1, Annalisa Cavallero1, Sergio Maria Malandrin1, Irene Maria Sciabica1, Guglielmo Marco Migliorino1, Sergio Foresti1, Marta Verna 1, Adriana Balduzzi2,1 P456 ENHANCING SARS-COV-2 IMMUNITY EARLY AFTER HEMATOPOIETIC STEM CELL TRANSPLANTATION: A THREE-DOSE RBD–TT-CONJUGATED VACCINE APPROACH Maryam Barkhordar 1, Mohammad Vaezi1, Leyla Sharifi Aliabadi1, Mohammad Ahmadvand1, Ardeshir Ghavamzadeh2 P457 USE OF LETERMOVIR IN PEDIATRIC POPULATION POST BONE MARROW TRANSPLANT Cristina Rivera-Pérez1, Nuria Mas Malagarriga1, Silvia Simó Nebot1, Maria Trabazo del Castillo1, Gloria Miguel Llordes1, Laura Jimenez Prat1, Montserrat Rovira Tarrats1,2, Julia Marsal Ricoma 1, Cristina Rivera P458 REAL-WORLD OUTCOMES AND TREATMENT PATTERNS OF CMV INFECTIONS IN HEMATOPOIETIC STEM CELL TRANSPLANT RECIPIENTS, REFRACTORY OR INTOLERANT TO TREATMENTS IN EUROPE, CANADA, ISRAEL: INTERIM ANALYSIS Johan Maertens 1, Matthew Pellan Cheng2, Avichai Shimoni3, Andreas Braun4, Nawal Bent-Ennakhil4, Irmgard Andresen4 P459 THE RESPECT STUDY DESIGN: COMPARISON OF ONCE-WEEKLY REZAFUNGIN AGAINST STANDARD ANTIMICROBIAL PROPHYLAXIS IN ADULTS UNDERGOING ALLOGENEIC BLOOD AND MARROW TRANSPLANTATION Johan Maertens 1,2, Federica Sora3,4, Drew J. Winston5, Shariq Haider6, Lourdes Vazquez Lopez7, Christine Robin8, Alexander Schauwvlieghe9, Dominik Selleslag9, Taylor Sandison10, Kieren A. Marr11,12,13 P460 NO INFERIOR OUTCOME OF OMITTING FLUOROQUINOLONE PROPHYLAXIS IN PATIENTS UNDERGOING ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION Vanessa Nehrbaß 1, Krischan Braitsch1, Katharina Nickel1, Maike Hefter1, Katrin Koch1, Kathrin Rothe1, Florian Bassermann1, Jochen Schneider1, Katharina S. Götze1, Peter Herhaus1, Mareike Verbeek1 P461 OUTCOMES, CHOICE OF ANTIBIOTICS AND THEIR EFFECTIVENESS IN ALLOGENEIC-HSCT RECIPIENTS COLONIZED WITH MULTIRESISTANT GRAM-NEGATIVE BACTERIA: A SINGLE-CENTER RETROSPECTIVE ANALYSIS Igor Age Kos 1, Jana Speer2, Onur Cetin1, Vadim Lesan1, Angelika Bick1, Konstantinos Christofyllakis1, Manfred Ahlgrimm1, Sigrun Smola3, Andreas Link1, Torben Rixecker1, Anna K. H. Hirsch4,5, Joerg Thomas Bittenbring1, Fabian Berger3, Sören Becker6, Lorenz Thurner1, Moritz Bewarder1 P462 LETERMOVIR AS TREATMENT AND SECONDARY PROPHYLAXIS OF CMV REACTIVATION IN LOW-WEIGHT PEDIATRIC PATIENTS Chiara Mainardi 1, Cecilia Liberati1, Marica De Pieri1, Antonio Marzollo1, Manuela Tumino1, Maria Gabelli1, Marta Pillon1, Elisabetta Calore1, Alessandra Biffi1,2 P463 COMPARISON OF BLOOD STREAMING INFECTIONS BETWEEN TUNNELED CENTRAL VENOUS CATHETERS AND NON-TUNNELED CENTRAL VENOUS CATHETERS IN ACUTE LEUKEMIA REMISSION INDUCTION – A SINGLE CENTER EXPERIENCE Cheongin Yang 1, Seong Hyun Jeong1, Joon Seong Park1 P464 INCIDENCE OF INFECTIONS AND QUALITY OF IMMUNE RECONSTITUTION FOLLOWING CRYOPRESERVATION OF PERIPHERAL BLOOD STEM CELLS FROM HLA-IDENTICAL DONOR Luca Barabino1, Stefania Bregante2, Massimiliano Gambella 2, Anna Ghiso2, Livia Giannoni2, Silvia Lucchetti2, Alberto Serio2, Riccardo Varaldo2, Antonella Laudisi2, Monica Passannante2, Roberta Murru3, Andrea Galitzia1, Alessandra Bo2, Emanuele Angelucci2, Giovanni Caocci1, Anna Maria Raiola2 P465 DETECTION OF RESPIRATORY VIRUSES AMONG PAEDIATRIC HSCT RECIPIENTS – A TEN YEARS SINGLE-CENTRE EXPERIENCE Petr Hubacek 1,2, Petr Riha2, Ales Briksi2, Petra Keslova2, Renata Formankova1,2, Daniela Janeckova2, Miroslav Zajac2, Zdenek Kepka2, Petr Sedlacek1,2 P466 MUTUAL IMPACT AND CHARACTERISTICS OF VIRAL REACTIVATIONS AND IMMUNE RECONSTITUTION AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION IN CHILDREN. A SINGLE CENTER EXPERIENCE Cristian Jinca 1,2, Andrada Oprisoni1,2, Anca Isac2, Andreea Pascalau2, Loredana Balint-Gib2, Margit Serban2, Mihaela Baica2, Smaranda Arghirescu1,2 P467 CMV MONITORING AND LETERMOVIR PROPHYLAXIS IN ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION: A SINGLE CENTER EXPERIENCE Yuta Katayama 1, Yu Kochi1, Takuya Nunomura1, Riichiro Ikeda1, Kenjiro Hino1, Ryota Imanaka1, Kohei Kyo1, Takeshi Okatani1, Mitsuhiro Itagaki1, Shinya Katsutani1, Tsuyoshi Muta1 P468 LETERMOVIR COMBINED WITH GANCICLOVIR AS A PREEMPTIVE OR TREATMENT FOR CYTOMEGALOVIRUS INFECTION FOLLOWING ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION, A SINGLE-CENTER RETROSPECTIVE REVIEW Han Yao 1,2, Yimei Feng1,2, Ting Chen1,2, Lu Zhao1,2, Yuqing Liu1,2, Lidan Zhu1,2, Jia Liu1,2, Lu Wang1,2, Shichun Gao1,2, Huanfeng Liu1,2, Lei Gao1,2, Peiyan Kong1,2, Xi Zhang1,2,3 P469 THE CLINICAL MANIFESTATION, PROGNOSTIC FACTORS, AND OUTCOMES OF ADENOVIRUS PNEUMONIA AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION Yuewen Wang 1, Xiaohui Zhang1, Lanping Xu1, Yu Wang1, Chenhua Yan1, Huan Chen1, Yuhong Chen1, Fangfang Wei1, Wei Han1, Fengrong Wang1, Jingzhi Wang1, Xiaojun Huang1, Xiaodong Mo1 P470 OPTIMIZING CMV PREVENTION IN STEM CELL TRANSPLANTS: HYBRID STRATEGY DELIVERS PROMISING REDUCTION IN REACTIVATION RATES Amirabbas Rashidi1,2, Tanaz Sayar Bahri1,2, Maryam Barkhordar 1,2, Seied Asadollah Mousavi1,2, Ahmad Khajeh-Mehrizi3, Mohammad Vaezi1,2 P471 STRATIFICATION AND IMMUNOLOGIC ANALYSIS OF PATIENTS WITH SARS-COV-2 INFECTION AFTER HEMATOPOIETIC STEM CELL TRANSPLANTATION Man Chen 1, Wei Zhao1, Hui Wang1 P472KLEBSIELLA PNEUMONIAE INFECTION BEFORE AND AFTER ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION IN THE ERA OF NOVEL ANTIBIOTICS: A COMPARATIVE STUDY Eleni Gavriilaki 1, Damianos Sotiropoulos2, Ioannis Batsis2, Despina Mallouri2, Alkistis Panteliadou2, Nikolaos Spyridis2, Giorgos Karavalakis2, Paschalis Evangelidis1, Vasiliki Kanava2, Giannis Kyriakou2, Eleni Papchianou2, Christos Demosthenous2, Zoi Bousiou2, Anna Vardi2, Ioanna Sakellari2 P473 OUTCOMES OF HYPERBARIC OXYGEN THERAPY IN LATE-ONSET HEMORRRHAGIC CYSTITS AFTER ALLO-HSCT: A RETROSPECTIVE ANALYSIS Mariana Trigo Miranda 1, Joana Arana Ribeiro2, Diogo Alpuim Costa3,4,3, Carla D’Espiney Amaro4,3, Andreia Teixeira5,6, Inês Portugal Rodrigues7, Clara Gaio-Lima7, Carlos Pinho Vaz8, Óscar Camacho7 P474 INVASIVE FUNGAL DISEASES IN PATIENTS WITH CLL TREATED WITH BRUTON TYROSINE KINASE INHIBITORS, A MONO-CENTRIC RETROSPECTIVE STUDY Yuri Vanbiervliet 1, Robina Aerts1, Finn Segers1, Johan Maertens1, Ann Janssens1 P475 PREDICTORS OF INVASIVE FUNGAL INFECTION AND IMPACT OF OUTCOME AFTER ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION: SINGLE CENTER EXPERIENCE FROM THE KINGDOM OF SAUDI ARABIA Lama AlHmaly 1, Ahmad Alharbi1, Moussab Damlaj1,2,3, Ahmed Alaskar1,2,3,4, Ayman Hejazi1,2,3, Hind Salama1,2,3, Abdulrahman Al raizah1,2,3, Abdullah S. Al Saleh1,2,3, Ayman Ibrahim1,2,3, Ayel Yahya1,2,3, Mohammed Bakkar1,2,3, Inaam Shehabeddine1, Suha Alkhraisat1, Amani Alharbi1, Isam Mahasneh1, Maybelle Ballili1, Mazen Ahmed1, Husam Alsadi1,2,3, Mohsen Alzahrani1,2,3,4, Bader Alahmari1,2,3 P476 THE ROLE OF COLONIZATION WITH RESISTANT G-BACTERIA IN THE TREATMENT OF FEBRILE NEUTROPENIA AFTER STEM CELL TRANSPLANTATION Tereza Sokolova1, Pavla Paterova1, Alzbeta Zavrelova1, Benjamin Visek1, Pavel Zak1, Jakub Radocha 1 P477 OUTCOME OF THE USE OF LETERMOVIR AS PROPHYACTIC TREATMENT FOR HSCT RECIPIENTS: A SINGLE CENTER EXPERIENCE Giulia Baresi1, Marianna Maffeis 2, Elena Soncini1, Stefano Rossi1, Giulia Albrici1, Marta Comini3, Federica Bolda3, Alessandra Beghin3, Arnalda Lanfranchi3, Fulvio Porta1 P478 COMPARATIVE EVALUATION OF THE EFFECTIVENESS OF LETERMOVIR SINCE ITS USE IN PREVENTION OF CYTOMEGALOVIRUS (CMV) INFECTIONS IN ALLOGENEIC TRANSPLANT PATIENTS HEMATOLOGY DEPARTMENT OF CAEN UNIVERSITY HOSPITAL Tchuanga Djialeu Yannick Noel 1, Gandhi Damaj Laurent2, Johnson Ansah Hyacinthe Atchroue2, Dina J.2, Parienti Jean Jacques2, Chantepie Sylvain2 P479 EXPERIENCE WITH THE USE OF MARIBAVIR IN HEMATOPOIETIC STEM CELL TRANSPLANT RECIPIENTS WITH REFRACTORY OR RESISTANT CYTOMEGALOVIRUS (CMV) Mónica Fernández Pérez1, Candela Ceballos Bolaños 1, Itziar Oiartzabal Ormategui1, Nerea Arratibel Zalacain1, Pamela Millacoy Austenrritt1, Marina Aranguren Ostolaza1, Maria Cruz Viguria Alegria1, Carlos Manuel Panizo Santos1 P480 IS THERE A PLACE FOR ANTI-HCMV HUMAN IMMUNOGLOBULIN AS PRE-EMPTIVE THERAPY IN T-DEPLETE TREG/TCON ALLOGENEIC STEM CELL TRANSPLANTATION? Valerio Viglione 1, Loredana Ruggeri2, Antonella Mancusi1, Sara Tricarico2, Alessandra Cipiciani1, Rebecca Sembenico1, Matteo Caridi1, Francesco Zorutti1, Anna Castaldo1, Simonetta Saldi1, Roberto Castronari2, Silvia Bozza1, Cynthia Aristei1, Antonella Mencacci1, Maria Paola Martelli1, Antonio Pierini1, Alessandra Carotti2 P481 FREQUENCY AND OUTCOME OF CYTOMEGALOVIRUS INFECTION IN RECIPIENTS OF HAEMATOPOIETIC STEM CELL TRANSPLANTATION – AN EXPERIENCE FROM PAKISTAN Natasha Ali 1, Zurrya Khan1, Mohammad Usman Shaikh1, Zehra Fadoo1, Salman Adil1 P482 CENTRAL VENOUS ACCESS DEVICE IN AUTOLOGOUS STEM CELL TRANSPLANT PATIENTS Danah Chakfeh 1, Antonette Amao1, Baaba Bentil Tumi1, Josephine Crowe1 P483 FACTORS AFFECTING OUTCOME OF SALVAGE CHEMOTHERAPY AND AUTOLOGOUS STEM CELL TRANSPLANT IN PATIENTS WITH CLASSICAL HODGKIN LYMPHOMA RELAPSING OR PROGRESSING AFTER A FRONT-LINE PET-ADAPTED THERAPY Simonetta Viviani1, Anna Vanazzi1, Samuele Frassoni2, Chiara Rusconi3, Andrea Rossi4, Lessandra Romano5, Caterina Patti6, Corrado Schiavotto7, Roberto Sorasio8, Vincenzo Marasco3, Laura Lissandrini7, Davide Rapezzi8, Daniela Gottardi9, Federica Cocito10, Antonio Mulé11, Salvatore Leotta5, Guido Gini12, Marco Sorio13, Enrico Derenzini1, Alessandro Rambaldi 4,14, Vincenzo Bagnardi2, Corrado Tarella1,14 P484 REDUCED RELAPSE INCIDENCE AFTER CHECK-POINT INHIBITORS RELATIVE TO BRENTUXIMAB VEDOTIN AS SALVAGE THERAPY BEFORE ALLOGENEIC STEM CELL TRANSPLANTATION FOR REFRACTORY/RELAPSED HODGKIN LYMPHOMA: A RETROSPECTIVE ANALYSIS Jacopo Mariotti 1, Chiara Pinton1, Chiara de Philippis1, Daniele Mannina1, Barbara Sarina1, Daniela Taurino1, Armando Santoro1, Stefania Bramanti1 P485 LOW NON-RELAPSE MORTALITY ASSOCIATED WITH ALLOGENEIC HAEMATOPOIETIC CELL TRANSPLANTATION AFTER CAR-T FAILURE IN PATIENTS AFFECTED BY LARGE B CELL LYMPHOMA Chiara de Philippis1, Massimiliano Gambella2, Jacopo Mariotti 1, Anna Dodero3, Patrizia Chiusolo4, Alessia Castellino5, Laura Giordano6, Barbara Sarina1, Daniela Taurino1, Daniele Mannina1, Anna Maria Raiola2, Simona Sica4, Carmelo Carlo-Stella1, Emanuele Angelucci2, Armando Santoro1, Paolo Corradini3, Stefania Bramanti1 P486 TREOSULFAN-BASED CONDITIONING AND SIROLIMUS-PTCY GVHD PROPHYLAXIS IN ALLOGENEIC STEM CELL TRANSPLANTATION FOR AGGRESSIVE B-CELL NHL Lorenzo Lazzari 1, Alessandro Bruno1, Simona Piemontese1, Federico Erbella1, Piera Angelillo1, Maria Teresa Lupo Stanghellini1, Andrés Ferreri1,2, Fabio Ciceri1,2, Raffaella Greco1, Jacopo Peccatori1 P487 OUTCOME OF HIGH-DOSE CHEMOTHERAPY FOLLOWED BY AUTOLOGOUS HEMATOPOIETIC CELL TRANSPLANTATION IN PATIENTS WITH PERIPHERAL T-CELL LYMPHOMA AT A SINGLE INSTITUTION OVER 20 YEARS Joanna Romejko-Jarosińska 1, Ewa Paszkiewicz-Kozik1, Marcin Szymanski1, Lidia Poplawska1, Anna Borawska1, Anna Dabrowska-Iwanicka1, Katarzyna Domanska-Czyz1, Agnieszka Druzd-Sitek1, Robert Konecki1, Martyna Kotarska1, Ewa Mroz-Zycińska1, Wlodzimierz Osiadacz1, Beata Ostrowska1, Monika Swierkowska1, Joanna Tajer1, Lukasz Targonski1, Elzbieta Wojciechowska-Lampka1, Jan Walewski1 P488 IMPROVING RESULTS OF ALLO-HCT FOR PATIENTS WITH RELAPSED/REFRACTORY HODGKIN LYMPHOMA. A SINGLE CENTER EXPERIENCE Andrzej Frankiewicz 1, Małgorzata Ociepa-Wasilkowska1, Tomasz Czerw1, Monika Dzierżak-Mietła1, Magdalena Głowala-Kosińska1, Jerzy Hołowiecki1, Małgorzata Krawczy-Kuliś1, Włodzimierz Mendrek1, Iwona Mitrus1, Jacek Najda1, Maria Saduś-Wojciechowska1, Małgorzata Sobczyk-Kruszelnicka1, Sebastian Giebel1 P489 THE SINGLE-CELL LANDSCAPE EXPLORING ABNORMAL T CELL STATES AND DEVELOPMENTAL TRAJECTORIES IN HETEROGENEOUS NON-HODGKIN LYMPHOMA Yuqing Wang 1, Cong Wang1, Chanmin Xiao1, Zheng Wang1, Xi Zhang1 P490 BEYOND TRANSPLANTATION: BRENTUXIMAB’S IMPACT ON LONG-TERM OUTCOMES AFTER AUTOLOGOUS STEM CELL TRANSPLANT (ASCT) IN ROMANIAN TRANSPLANT CENTERS Lavinia Eugenia Lipan1,2, Andrei Colita3,2, Angela Dascalescu4, Anca Colita1,2, Zsofia Varady1, Laura Diana Stefan1, Miruna Tirnovan1, Alina Daniela Tanase 1,2 P491 ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION FOR T CELL LYMPHOMAS: A RETROSPECTIVE ANALYSIS FROM THE POLISH LYMPHOMA RESEARCH GROUP (PLRG) Malgorzata Sobczyk-Kruszelnicka 1, Tomasz Czerw1, Joanna Drozd-Sokołowska2, Patrycja Mensah-Glanowska3, Agnieszka Piekarska4, Jarosław Dybko5, Anna Łojko-Dankowska6, Anna Czyż7, Jan Maciej Zaucha4, Sebastian Giebel1 P492 OPTIMIZING OUTCOMES: THE VITAL SIGNIFICANCE OF TRANSPLANTATION IN RESCUING PATIENTS DISCONTENTED WITH INITIAL PERIPHERAL T-CELL LYMPHOMA TREATMENT Hongye Gao1, Zhuoxin Zhang1, Jiali Wang1, Yannan Jia2, Hao Zhang3, Xin Du4, Xianmin Song2, Yao Liu5, Dehui Zou1, Erlie Jiang 1 P493 LOW DOSE NIVOLUMAB IN COMBINATION WITH SALVAGE CHEMOTHERAPY BEFORE AUTO-HSCT IN PRIMARY REFRACTORY HODGKIN LYMPHOMA – A PILOT STUDY Rakesh Reddy Boya 1, Pradeep Ventrapati1, Veni Prasanna Gedala1, Chandrasekhar Bendi2 P494 PREDICTORS OF DELAYED PLATELET ENGRAFTMENT AFTER AUTOLOGOUS STEM CELL TRANSPLANTATION IN NON-HODGKIN LYMPHOMA Rita Costa e Sousa 1, Cátia Almeida1, João Gaião Santos1, Ricardo Ferreira1, Mafalda Urbano1, Maria Carolina Afonso1, Marília Gomes1, Adriana Roque1, Catarina Geraldes1 P495 NON-MYELOABLATIVE ALLOGENEIC TRANSPLANTATION AFTER TOTAL SKIN ELECTRON BEAM THERAPY (TSEBT) IN CUTANEOUS T-CELL LYMPHOMA. A SINGLE CENTER EXPERIENCE Carlos De Miguel 1, Belén Navarro1, Irma Zapata1, Mercedes Hospital1, Guiomar Bautista1, Ana Bocanegra1, José Antonio García-Vela1, María Esther Martínez-Muñoz1, Silvia Monsalvo1, José Luis Bueno1, Isabel Salcedo1, Luis Gastón Roustan1, Jesús Romero1, Rafael Duarte1 P496 ROLE OF AUTOLOGOUS STEM CELL TRANSPLANT IN PRIMARY AND SECONDARY CENTRAL NERVOUS SYSTEM LYMPHOMA – A SINGLE CENTER EXPERIENCE Meredith Tan 1,2, Tertius Tuy1,2, Melinda Tan1,2, Chieh Hwee Ang1,2, Jeffrey Quek1,2, Than Hein1,2, Yunxin Chen1,2, Francesca Lim1,2, Chandramouli Nagarajan1,2, Jordan Hwang1, Jing Jing Lee1, Lalitha Krishnan1, Lyn Lee Wong1, Zi Jing Seng1, Yeow Tee Goh1,2, Yeh Ching Linn1,2, Colin Diong1,3, Yuh Shan Lee1,3, William Hwang1,2, Aloysius Ho1,2, Lawrence Ng1,2 P497 HIGH DOSE THERAPY FOLLOWED BY AUTOLOGOUS STEM CELL TRANSPLANTATION IN 236 PATIENTS WITH HODGKIN LYMPHOMA ON 25 YEARS PERIOD (1998-2022) Sabrina Akhrouf 1, Hanane Bouarab1, Rihab Benouattas1, Farih Mehdid1, Nadia Rahmoun1, Mounira Baazizi1, Dina Ait ouali1, Nacera Ait Amer1, Farida Tensaout1, Rose Marie Hamladji1, Redhouane Ahmed Nacer1, Malek Benakli1 P498 NON-CRYOPRESERVED AUTOLOGOUS HEMATOPOIETIC STEM CELL TRANSPLANTATION IN HODGKIN LYMPHOMA. ELEVEN-YEAR SINGLE CENTRE EXPERIENCE FROM ORAN. ALGERIA Nabil Yafour 1, Kamila Amani1, Nawel Bounoua1, Fatima Aoudia1, Amel Bendimerad1, Mohamed Amine Benaissa1, Nour El Houda Hassam1, Mounir Serradj1, Manel Maarouf1, Leila Charef1, Badra Enta Soltane1, Soufi Osmani1, Rachid Bouhass1, Abdessamad Arabi1, Mohamed Brahimi1, Mohamed Amine Bekadja1 P499 AUTOLOGOUS AND ALLOGENEIC STEM CELL TRANSPLANTATION IN MATURE NK/T-CELL LYMPHOMA: A TWO-CENTER RETROSPECTIVE REAL-LIFE ANALYSIS Michele Wieczorek 1, Giorgia Bonetto1, Beatrice Bugnotto2,1, Alessia Moioli2, Albana Lico1, Francesca Elice1, Marcello Riva1, Cristina Tecchio2, Mauro Krampera2, Carlo Borghero1, Alberto Tosetto1 P500 PRETREATMENT WITH RITUXIMAB IS SUSPECTED TO INCREASE RISK FOR OCCURRENCE OF VENO-OCCLUSIVE DISEASE IN PATIENTS WITH AGGRESSIVE LYMPHOMA AFTER ALLOGENEIC TRANSPLANT Ahmet Elmaagacli 1, Mathis Samuel Bittermann1, Farouk Dahmash1, Anju Singh1, Yana Shikova1, Vitaly Varyushkin1, Mathias Vierbuchen1, Hans Salwender1, Christian Jehn1 P501 GENETIC PREDICTORS OF PROGNOSIS IN CHRONIC LYMPHOCYTIC LEUKEMIA: INSIGHTS FROM NEXT-GENERATION SEQUENCING Emilia Jaskuła1,2, Anna Sobczyńska-Konefał2,1, Iga Jendrysik2, Marzena Wojtaszewska3, Monika Mordak-Domagała2, Krzysztof Suchnicki2, Mariola Sędzimirska2, Monika Jasek1, Lidia Karabon1, Jarosław Dybko 2 P502 A REAL WORLD EXPERIENCE WITH PD1 INHIBITORS IN RELAPSED/REFRACTORY HODGKINS LYMPHOMA Disha Kakkar 1, Narendra Agarwal1, Tribikram Panda1, Aakanksha Singh1, Rohan Halder1, Roy J. Palatty1, Dinesh Bhurani1 P503 PEGFILGRASTIM AFTER CONDITIONING WITH BEAM AND AUTOLOGOUS HEMATOPOIETIC PERIPHERAL BLOOD STEM CELL TRANSPLANTATION IN LYMPHOMA PATIENTS Barbara Loteta 1, Giovanni Tripepi2, Pitino Annalisa3, Mercedes Gori3, Gaetana Porto1, Giovanna Utano1, G. Policastro1, Ludovica Santoro1, Maria Caterina Micò1, Massimo Martino1 P504 BEGEV AS SECOND-LINE SALVAGE THERAPY IN RELAPSED/REFRACTORY HODGKIN LYMPHOMA: A REAL‐LIFE EXPERIENCE Ant Uzay 1, Elif Şenocak Taşçı1, Arda Ulaş Mutlu1, Barış Koşan2, Aybüke Görkem Koç1, Bülent Küçük2, S. Sami Kartı2 P505 EVALUATION IN SARDINIAN GENETIC UNIQUENESS POPOLATION: STEREOTYPED SUBSETS# AND MOLECULAR PROGNOSTIC MARKERS, CATEGORIZATION IN U-MUTATED POOR PROGNOSTIC GROUP OF CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) Fabio Culurgioni 1, Roberta Murru2, Alba Piras2, Wedad Salem Hamdi1, Manal Yaghmour1, Abdallah Alkhoujah1, Sara Alromaihi1, Aisha Alkaseri1, Nasimeh Azadi1, Giorgio La Nasa2, Einas Al Kuwari1 P506 A NATIONWIDE STUDY OF CHRONIC LYMPHOCYTIC LEUKEMIA INCIDENCE AND MORTALITY IN THE REPUBLIC OF KOREA Min Ji Jeon1, Hoonji Oh1, Kunye Kwak1, Eun Sang Yu1, Dae Sik Kim1, Chul Won Choi1, Byung-Hyun Lee1, Se Ryeon Lee1, Hwa Jung Sung1, Yong Park1, Byung Soo Kim1, Ka-Won Kang 1 P507 AUTOLOGOUS HEMATOPOETIC STEM CELL TRANSPLANTATION IN CHILDREN WITH RELAPSED AND REFRACTORY PRIMARY MEDIASTINAL LARGE B-CELL LYMPHOMA Alexander Galimov1, Andrey Kozlov1, Ilya Kazantsev1, Tatiana Yuhta1, Polina Tolkunova1, Natalia Mihailova1, Yuri Punanov1, Vadim Baykov1, Ivan Moiseev1, Alexander Kulagin1, Lyudmila Zubarovskaya 1 P508 HAPLOIDENTICAL TRANSPLANTATION OF HEMATOPOIETIC STEM CELLS FOR PATIENT WITH POST-TRANSPLANT LYMPHOPROLIFERATIVE DISEASE Vera Vasilyeva 1, Larisa Kuzmina1, Olga Aleshina1, Mariya Dovydenko1, Mikhail Drokov1, Irina Lukyanova1, Vera Troitskaya1, Elena Parovichnikova1 P509 ALLOGENEIC HAEMATOPOIETIC STEM CELL TRANSPLANT IN LYMPHOMA: A SINGLE-CENTRE EXPERIENCE; A CASE SERIES Jan Miko Aaron Baybay 1, Francisco Vicente Lopez1 P510 THE FIRST CASE OF ALLOGENIC HEMATOPOIETIC STEM CELL TRANSPLANTATION AT DHARMAIS HOSPITAL – INDONESIAN NATIONAL CANCER CENTER Dwi Wahyunianto Hadisantoso 1, Resti Mulya Sari1, Edel Herbitya1, Lyana Setiawan1, Hubertus Hosti Hayuanta1, Muhammad Raya Kurniawan1, Yanto Ciputra1, Annisa Annisa1, I Gusti Ngurah Agastya1, Della Manik Worowerdi Cintakaweni1 P511 PRE-EMPTIVE DONOR LYMPHOCYTE INFUSION AS OPTIMAL TREATMENT FOR RELAPSED ACUTE MYELOID LEUKEMIAS AND MYELODYSPLASTIC SYNDROMES FOLLOWING ALLOGENEIC STEM CELL TRANSPLANTATION:A FRENCH-ITALIAN EXPERIENCE WITH 103 PATIENTS Eugenia Accorsi Buttini1, Cristina Doran2, Michele Malagola 1, Vera Radici1, Mirko Farina1, Marco Galli1, Gabriele Magliano1, Alessandro Leoni3, Federica Re3, Simona Bernardi3, Mohamad Mohty2, Domenico Russo1, Eolia Brissot2 P512 HLA-DR+REGULATORY T CELLS ARE ASSOCIATED WITH THE ONSET AND SEVERITY OF ACUTE GRAFT-VERSUS-HOST DISEASE AFTER HEMATOPOIETIC CELL TRANSPLANTATION Kinga Hosszu 1, Devin McAvoy1, Moises Garcia-Rosa2, Charlie White1, Matthew Thomsen1, Evangelos Ntrivalas1, Elizabeth Klein1, Abdulrahman Alsultan1, Audrey Mauguen1, Kevin J. Curran1, Maria Cancio1, Andromachi Scaradavou1, Andrew Kung1, Joseph H. Oved1, Miguel-Angel Perales1, Andrew C. Harris1, Jaap Jan Boelens1 P513 MAINTENANCE THERAPY WITH OLAPARIB AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION IN PATIENTS WITH TP53 MUTATED HEMATOLOGIC MALIGNANCIES Zhihui Li 1, Teng Xu1, Yipei Guo1, Xianxuan Wang1, Xiaopei Wen1, Lei Wang1, Jingjing Wang1, Yanzhi Song1, Yongqiang Zhao1, Tong Wu1 P514 PERSISTENCE OF MINOR HISTOCOMPATIBILITY ANTIGEN- AND VIRUS-SPECIFIC T CELLS IN LEUKEMIC REMISSION AFTER HEMATOPOIETIC ALLOGENEIC STEM CELL TRANSPLANTATION Lisa Marie Schulz 1, Debora Basilio-Queiros1, Susanne Luther-Wolf1, Elke Dammann1, Michael Stadler1, Eva Mischak-Weissinger1 P515 SERIAL LINEAGE CHIMERISM ANALYSIS IMPROVES EARLY DIAGNOSIS OF GRAFT FAILURE AFTER ALLOGENEIC HAPLOIDENTICAL HSCT Pilar Lancho Lavilla1, Ignacio Gómez Centurión1,2, Rebeca Bailén Almorox 1,2, Paula Fernández-Caldas1,2, Asunción Escudero1, Lucía Castilla1,2, Javier Anguita1,2,3, Ismael Buño1,2,4,3, Mi Kwon1,2,3, Carolina Martínez-Laperche1,2,4 P516 PREDICTING MEASURABLE RESIDUAL DISEASE FOR ACUTE LYMPHOBLASTIC LEUKEMIA PATIENTS POSTTRANSPLANTATION Yue-Wen Wang 1, Guo-Mei Fu1, Lan-Ping Xu1, Yu Wang1, Yi-Fei Cheng1, Yuan-Yuan Zhang1, Xiao-Hui Zhang1, Yan-Rong Liu1, Kai-Yan Liu1, Xiao-Jun Huang1, Ying-Jun Chang1 P517 CYTOKINE PROFILES ASSOCIATED WITH GRAFT VERSUS HOST DISEASE AND RECENT THYMIC EMIGRANT T CELL RECONSTITUTION AFTER HEMATOPOIETIC CELL TRANSPLANTATION Devin McAvoy 1, Kinga Hosszu1, Matthew Thomsen1, Evangelos Ntrivalas1, Elizabeth Klein1, Katina Singh1, Esther Vidal1, Kevin Curran1, Maria Cancio1, Andromachi Scaradavou1, Joseph Oved1, Miguel-Angel Perales1, Andrew Harris1, Andrew Kung1, Jaap Jan Boelens1 P518 FAVOURABLE IMPACT OF POST-TRANSPLANT MINIMAL DISEASE NEGATIVITY ASSESSED BY FLOW CYTOMETRY ON SURVIVAL IN PATIENTS WITH MYELODYSPLASTIC SYNDROMES Evgeny Klyuchnikov1, Anita Badbaran1, Tetiana Perekhrestenko2, Normann Steiner1, Radwan Massoud 1, Petra Freiberger1, Christine Wolschke1, Francis Ayuk1, Ulrike Bacher3, Nicolaus Kröger1 P519 FLOW-CYTOMETRIC AND TRANSCRIPTIONAL CHARACTERIZATION OF RECENT THYMIC EMIGRANTS AFTER HEMATOPOIETIC STEM CELL TRANSPLANTATION (HSCT) IN CHILDREN WITH ACUTE LYMPHOBLASTIC LEUKEMIA (ALL) Silvia Nucera1,2, Francesca Limido1,2,3, Marco Maria Sindoni 1,2, Cristina Bugarin1, Grazia Fazio1, Andrea Biondi1,2,3, Adriana Balduzzi2,3, Giuseppe Gaipa1 P520 LOW PERCENTAGES OF EARLY B-CELL PRECURSORS IN THE BONE MARROW MAY PREDICT THE DEVELOPMENT OF CGVHD FOLLOWING PEDIATRIC HSCT Elisa Christine Peen 1, Klaus Gottlob Müller1, Claus Henrik Nielsen1, Katrine Kielsen1, Hanne Vibeke Marquart1 P521 MEASURABLE RESIDUAL DISEASE (MRD) AND T-CELL CHIMERISM ARE PROGNOSTIC BIOMARKERS IN ACUTE MYELOID LEUKEMIA (AML) PATIENTS UNDERGOING ALLOGENEIC STEM CELLS TRANSPLANTATION (ASCT) Elisa Meddi 1, Raffaele Palmieri1, Giovanni Marsili2, Federico Moretti1, Flavia Mallegni1, Alfonso Piciocchi2, Luca Maurillo1, Maria Ilaria Del Principe1, Giovangiacinto Paterno1, Raffaella Cerretti1, Gottardo De Angelis1, Benedetta Mariotti1, Maria Irno Consalvo1, Mariadomenica Divona1, Tiziana Ottone1, Sara Gargiulo1, Giulia Colafranceschi1, Maria Teresa Voso1, Adriano Venditti1, Francesco Buccisano1 P522 THE NUMBER OF CENTRAL MEMORY CD8 + T CELLS INFUSED AND THEIR EARLY RECOVERY AFTER ALLOGENEIC HSCT WAS ASSOCIATED WITH A DECREASED RISK OF DISEASE RELAPSE Valle Gómez García de Soria 1,2,3, Paula Díaz-Fernández1,2,3, Ana Marcos-Jiménez1,2, Nuria Montes-Casado1,2, Javier Sevilla-Montero1,2, Itxaso Portero-Sainz1,2, Yaiza Pérez-García1,2, Ángela Figuera Álvarez1,2,3, Rafael de la Cámara1,2, Cecilia Muñoz-Calleja1,2,3 P523 CONTRASTING GENE EXPRESSION PROFILES AND SIGNALING PATHWAYS BETWEEN CIRCULATING DONOR-AND HOST-DERIVED MONOCYTES DURING TOLERANCE IN MIXED CHIMERISM FOLLOWING UNRELATED DONOR CADAVERIC BMT AND LUNG TRANSPLANT Paul Szabolcs 1, Evelyn Garchar1, Dhivyaa Rajasundaram1, Xiaohua Chen1 P524 MEASURABLE RESIDUAL DISEASE AND CHIMERISM ANALYSIS INTERPLAY: IMPACT IN PROGNOSIS OF ACUTE MYELOID LEUKEMIA PATIENTS UNDERGOING ALLOGENIC STEM CELL TRANSPLANTATION Manuel Jorge Fernandez-Villalobos1, Ignacio Gomez-Centurion1,2, Rebeca Bailen 1,2, Paula Fernandez-Caldas1,2, Lucia Castilla1, Ana Pérez-Corral1,2, Carolina Martinez-Laperche1,2, Mi Kwon1,2,3 P525 THE INFLUENCE OF GRAFT IMMUNE COMPOSITION ON IMMUNE RECOVERY AND TRANSPLANT OUTCOME: A SINGLE CENTER EXPERIENCE Stefania Leone 1, Serena Marotta1, Maria Celentano1, Mariangela Pedata1, Cristina Luise1, Angela Carobene1, Ilaria Migliaccio1, Alfonso Fiumarella2, Aldo Leone2, Mario Toriello3, Daniela Graziano1, Mirella Alberti1, Simona Maria Muggianu Muggianu1, Mafalda Caputo1, Assunta Viola1, Roberta Penta3, Claudio Falco1, Antonio Meles1, Alessandra Picardi1,4 P526 RELAPSE MONITORING BY NPM1-PCR AND ITS PROGNOSTIC VALUE BEFORE AND AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION Oliver Kriege 1, Johannes Barucha2,1, Markus Radsak3,1, Jonas Wißkirchen1, Pascal Wölfinger1, Beate Hauptrock1, Eva-Maria Wagner-Drouet1 P527 GUIDING POST-TRANSPLANT RELAPSE TREATMENT IN MYELOID MALIGNANCIES WITH QPCR MONITORING OF CHIMERISM DYNAMIC FROM PERIPHERAL WHOLE BLOOD – SINGLE CENTRE EXPERIENCE Ana Bošković1, Tadeja Dovč Drnovšek2, Primož Rožman2, Klara Šlajpah1, Njetočka Gredelj Šimec1, Matjaž Sever1, Polona Novak 1 P528 THE COMBINATION OF DISEASE BIOLOGY WITH PRE-HSCT MRD STATUS COULD BETTER STRATIFY RELAPSE RISK AFTER HSCT AMONG ADULT AML PATIENTS IN FIRST COMPLETE REMISSION Margherita Ursi1,2, Francesco Barbato1,2, Francesco De Felice1,2, Enrico Maffini2, Marcello Roberto 1,2, Gianluca Storci2, Salvatore Nicola Bertuccio2, Daria Messelodi2, Serena De Matteis2, Noemi Laprovitera2, Maria Naddeo2, Irene Salamon2, Francesco Iannotta2, Elisa Dan2, Luca Zazzeroni1, Barbara Sinigaglia2, Enrica Tomassini2, Massimiliano Bonafè1,2, Mario Arpinati2, Francesca Bonifazi2 P529 IMPACT OF ABSOLUTE LYMPHOCYTE COUNT RECOVERY AT DIFFERENT TIME-POINTS ON CLINICAL OUTCOMES AFTER THE ALLOGENIC HEMATOPOIETIC STEM CELL TRANSPLANTATION Nour Ben Abdeljelil 1, Hana Ben Hammamia1, Ines Jemaa1, Rihab Ouerghi1, Insaf Ben Yaiche1, Ines Turki1, Lamia Torjemane1, Sabrine Mekni1, Rimmel Kanoun1, Dorra Belloumi1, Saloua Ladeb1, Tarek Ben othman1 P530 PHENOTYPES OF BONE MARROW MONOCYTES IN HEMATOPOIETIC CELL TRANSPLANTATION FOR ACUTE MYELOID LEUKEMIA: A DESCRIPTIVE PILOT STUDY Gül Yavuz Ermiş1, Klara Dalva1, Ekin Kırcalı2, Şenay İpek1, Nihal Okul1, Güldane Cengiz Seval1, Pervin Topçuoğlu1, Selami Koçak Toprak1, Meltem Kurt Yüksel 1 P531 AVAILABLE METHODS FOR MONITORING AML NPM1 + PATIENTS POST ALLOGENEIC TRANSPLANTATION CANNOT PREDICT OUTCOME Apostolia Papalexandri 1, Eleni Gavriilaki2, Vassiliki Kanava1, Panayiotis Dolgyras1, Fotini Kika1, Tasoula Touloumenidou1, Aggeliki Paleta1, Georgia Konstantinidou1, Panayiota Zerva1, Lamprini Vachtsetzi1, Christos Demosthenous1, Zoi Boussiou1, Anna Vardi1, Maria Papathanasiou1, Ioannis Batsis1, Anastasia Athanasiadou1, Anastasia Marvaki1, Chrisavgi Lalayianni1, Ioanna Sakellari1 P532 DONOR LYMPHOCYTE INFUSION, A SINGLE-CENTER RETROSPECTIVE SAFETY ANALYSIS Birgitte Strand Bergland 1, Anders Eivind Myhre1, Camilla Dao Vo1, Ingerid Weum Abrahamsen1, Tobias Gedde-Dahl1,2, Tor Henrik Anderson Tvedt1 P533 WT1 MONITORING AFTER ALLOGENEIC STEM CELL TRANSPLANTATION: A NEW IDEA OF DYNAMIC ASSESSMENT THROUGH THE PARAMETER “DELTA-WT1 THRESHOLD”. A SINGLE-CENTRE RETROSPECTIVE STUDY Beatrice Manghisi 1, Paola Perfetti1, Marilena Fedele1, Elisabetta Terruzzi1, Andrea Aroldi1, Sonia Palamini2, Martina Venegoni2, Carlo Gambacorti Passerini3, Matteo Parma1 P534 CHIMERISM DYNAMICS POST ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION: A TOUGH NUT TO CRACK Fatma SE Ebeid1, Sara Makkeyah1, Safa Matbouly1, Heba G.A. Ali1, Nayera HK Elsherif 1 P535 ANALYSIS OF THE EXTENDED T-LYMPHOCYTES PHENOTYPE REVEALS DIFFERENCES IN THE EARLY IMMUNE RECONSTITUTION AMONG PEDIATRIC PATIENTS RECEIVING MATCHED-UNRELATED DONOR OR HAPLOIDENTICAL HSCT Alessandro Di Gangi 1,2, Giorgio Costagliola3, Annalisa Legitimo4, Eva Parolo3, Elisa Costa4, Chiara Lardone4, Gabriella Casazza3, Mariacristina Menconi3 P536 CLINICAL FACTORS ASSOCIATED WITH IMMUNOGLOBULINS AFTER ALLO-SCT Alberto Blanco Sánchez1, José María Sánchez Pina 1, Adolfo Sáez Marín1, Guillermo Ramos Moreno1, Esther Parra Virto1, Andrea Tamayo Soto1, Lucía Alba Medina1, Reyes Más Babio1, María Calbacho Robles1, Joaquín Martínez-López1 P537 REAL-WORLD OUTCOMES OF UPFRONT AUTOLOGOUS HEMATOPOIETIC STEM CELL TRANSPLANTATION IN NEWLY DIAGNOSED MULTIPLE MYELOMA PATIENTS WITH DEL (17P) Curtis Marcoux 1, Oren Pasvolsky2, Denái R. Milton2, Hina Khan3, Mark R. Tanner2, Amna Ahmed4, Qaiser Bashir2, Samer Srour2, Neeraj Saini2, Paul Lin2, Jeremy Ramdial2, Yago Nieto2, Guilin Tang2, Yosra Aljawai2, Hans C. Lee2, Krina K. Patel2, Partow Kebriaei2, Sheeba K. Thomas2, Donna M. Weber2, Robert Z. Orlowski2, Elizabeth J. Shpall2, Richard E. Champlin2, Muzaffar H. Qazilbash2 P538 IMPACT OF DARA-VTD INDUCTION THERAPY ON HEMATOPOIETIC STEM CELL COLLECTION AND ENGRAFTMENT IN MULTIPLE MYELOMA PATIENTS ELIGIBLE FOR ASCT: RESULTS OF THE REAL-LIFE PRIMULA STUDY Vanda Strafella1, Immacolata Attolico 2, Francesco Tarantini1,2, Paola Carluccio2, Paola Curci2, Nicola Sgherza2, Rita Rizzi1,2, Angelo Ostuni2, Gabriele Buda3, Maria Livia Del Giudice3, Viviana Beatrice Valli4, Giuseppe Mele5, Candida Rosaria Germano6, Angela Maria Quinto7, Giulia Palazzo8, Massimiliano Arangio Febbo9, Lorella Melillo10, Nicola Di Renzo11, Francesco Albano1,2, Pellegrino Musto1,2 P539 SAFETY AND EARLY EFFICACY OF TANDEM AUTOLOGOUS STEM-CELL TRANSPLANTATION AFTER DARATUMUMAB VTD INDUCTION IN NEWLY DIAGNOSED MULTIPLE MYELOMA Carmine Liberatore1, Elena Rossi2, Lara Malerba3, Francesca Fioritoni1, Francesca Di Landro2, Francesca Fazio4, Silvia Ferraro5, Giusy Antolino6, Laura De Padua7, Ugo Coppetelli8, Velia Bongarzoni9, Stefano Pulini1, Patrizia Chiusolo2, Doriana Vaddinelli1, Annalisa Natale 1, Giuseppe Visani3, Valerio De Stefano2, Mauro Di Ianni1 P540 RESPONSE AND SURVIVAL IMPROVEMENT WITH AUTOLOGOUS STEM CELL TRANSPLANTATION IN PATIENTS WITH NEWLY DIAGNOSED MULTIPLE MYELOMA: DIFFERENT INDUCTION THERAPY IMPACT OVER THE LAST 30 YEARS José Miguel Mateos Pérez 1,2, Francesc Fernández-Avilés3,2, Carlos Fernández de Larrea1,2, Maria Teresa Cibeira1,2, Natalia Tovar1,2, Carmen Martínez3,2, Luis Gerardo Rodrígez-Lobato1,2, Maria Suárez-Lledó3,2, Maria Queralt Salas3,2, Montserrat Rovira3,2, Joan Bladé1,2, Laura Rosiñol1,3,2 P541 OUTCOMES OF FRAIL PATIENTS RECEIVING HIGH-DOSE CHEMOTHERAPY/AUTOLOGOUS STEM CELL TRANSPLANTATION FOR MULTIPLE MYELOMA Stephanie Yohay 1, Temitope Oloyede2, Binod Dhakal1, Anita D’Souza1, Ayesha Aijaz3, Meera Mohan1, Ravi Narra1, Marcelo Pasquini1,2, Mehdi Hamadani1,2, Ciara Louise Freeman4, Othman Salim Akhtar1,2 P542 BASELINE INVESTIGATIONS AND AUTOLOGOUS STEM CELL TRANSPLANT OUTCOMES: A RETROSPECTIVE REVIEW OF ECHOCARDIOGRAPHY AND PULMONARY FUNCTION TESTS Yousif Badri 1, Amany Ihab Mohamed1, Gordon Cook1, Roger Owen1, Simon Bulley1, Sylvia Feyler1, Christopher Parrish1, Frances Seymour1 P543 IMPROVED SURVIVAL OF MULTIPLE MYELOMA PATIENTS IN RELAPSE AFTER AUTOLOGOUS STEM CELL FOR THOSE WHO PREVIOUSLY ACHIEVED COMPLETE REMISSION AFTER TRANSPLANT Nour Moukalled 1, Ammar Zahreddine1, Iman Abou Dalle1, Jean El Cheikh1, Ali Bazarbachi1 P544 NON-CRYOPRESERVED PERIPHERAL BLOOD STEM CELL AUTOLOGOUS TRANSPLANTATION FOR MULTIPLE MYELOMA AS A SAFE ALTERNATIVE IN COUNTRIES WITH LOW RESOURCES: A NINE-YEARS OF BICENTRIC EXPERIENCE Siham Ahchouch 1, Othman Doghmi1, Selim Jennane1, El Mehdi Mahtat1, Sara Bougar2, Saadia Zafad3, Hicham El Maaroufi1, Kamal Doghmi1 P545 UP-FRONT HIGH DOSE MELPHALAN AND AUTOLOGOUS STEM CELL TRANSPLANTATION FOR NEWLY DIAGNOSED MULTIPLE MYELOMA - SINGLE CENTER REAL-WORLD ANALYSIS OF 165 CASES Nobuhiro Tsukada 1, Taku Kikuchi1, Kodai Kunisada1, Yuki Oda1, Moe Yogo1, Tomomi Takei1, Kota Sato1, Mizuki Ogura1, Yu Abe1, Kenshi Suzuki1, Tadao Ishida1 P546 SETTING UP A HEMATOPOIETIC STEM CELL TRANSPLANT PROGRAM IN BAHRAIN -EXPERIENCE FROM BAHRAIN ONCOLOGY CENTER Shruti Prem Sudha1, Hazem Afify 1, Nabil Abdelfattah1, Volkan Kahraman1, Salih Aksu1, Aly Rashed1, Cigdem Ozturk1 P547 SALVAGE SECOND AUTOLOGOUS STEM CELL TRANSPLANTS FOR PATIENTS WITH MYELOMA: A 24-YEAR RETROSPECTIVE AUDIT IN A NATIONAL TERTIARY REFERRAL CENTRE (1999-2022) Micheal Brennan 1, Patrick Hayden1, James Fey1, Catherine Ronayne1, Orla Fallon1, Greg Lee1, Nicola Gardiner1, Ezzat El Hassadi2, Meegahage Perera3, Helen Enright4, Johnny McHugh4, Philip Murphy5, Patrick Thornton5, John Quinn5, Jeremy Sargent5, Mary McCloy6, Peter O’Gorman7, Denis O’Keeffe8, Hilary O’Leary8, Mark Gurney1 P548 NOVEL DRUGS INCLUDING MONOCLONAL ANTIBODIES AND/OR DONOR LYMPHOCYTE INFUSIONS CONFERRED LONG TERM SURVIVAL TO MULTIPLE MYELOMA PATIENTS RELAPSED AFTER ALLOGENEIC STEM CELL TRANSPLANTATION Chiara Nozzoli 1, Martina Pucillo2, Massimo Martino3, Luisa Giaccone4, Alessandro Rambaldi5, Edoardo Benedetti6, Domenico Russo7, Nicola Mordini8, Silvia Mangiacavalli9, Pietro Enrico Pioltelli10, Paola Carluccio11, Piero Galieni12, Marco Ladetto13, Simona Sica14, Miriam Isola15, Maria De Martino15, Elena Oldani5, Eliana Degrande16, Elisabetta Antonioli17, Renato Fanin2, Riccardo Saccardi1, Fabio Ciceri18, Francesca Patriarca2 P549 HAPLOIDENTICAL ALLOGENEIC CELL TRANSPLANTATION IN RELAPSED/REFRACTORY MULTIPLE MYELOMA Julia Frimmel 1, Anke Morgner2, Claudia Brogsitter3, Karolin Trautmann-Grill3, Desiree Kunadt3, Raphael Teipel3, Christoph Röllig3, Mathias Hänel2, Johannes Schetelig3,4, Friedrich Stölzel1, Martin Bornhäuser3,5,6 P550 ANTI-HLA ANTIBODIES AND INCIDENCE OF PLATELET TRANSFUSION IN PATIENTS WITH MULTIPLE MYELOMA AFTER AUTO-HSCT Elena Kuzmich1, Irina Pavlova1, Ivan Kostroma1, Sergey Gritsaev 1 P551 AUTOLOGOUS PERIPHERAL BLOOD STEM CELL HARVESTING AND UTILIZATION IN MULTIPLE MYELOMA PATIENTS IN LUHS KAUNAS CLINICS, LITHUANIA 2015-2022 Titas Tiskevicius 1,2, Domas Vaitiekus1,2, Rolandas Gerbutavicius1,2, Milda Rudzianskiene1,2, Ruta Dambrauskiene1,2, Migle Kulboke1,2, Ignas Gaidamavicius1,2, Diana Remeikiene1,2, Birute Sabaniene1, Ieva Stakaitiene1, Egidija Kukarskyte2, Jonas Surkus1,2, Ruta Leksiene1,2, Elona Juozaityte1,2, Dietger Niederwieser3 P552 AUTOLOGOUS PERIPHERAL BLOOD STEM CELL TRANSPLANTATION IN MULTIPLE MYELOMA AT DHARMAIS HOSPITAL – INDONESIAN NATIONAL CANCER CENTER Resti Mulya Sari 1, Dwi Wahyunianto Hadisantoso1, Edel Herbitya1, Lyana Setiawan1, Hubertus Hosti Hayuanta1, Muhammad Raya Kurniawan1, Yanto Ciputra1, Annisa Annisa1, I Gusti Ngurah Agastya1, Della Manik Worowerdi Cintakaweni1 P553 OUTCOMES OF HEMATOPOIETIC STEM CELL TRANSPLANTATION FROM HAPLOIDENTICAL DONORS IN PATIENTS WITH MYELODYSPLASTIC SYNDROMES – A SINGLE-CENTER RETROSPECTIVE ANALYSIS Marketa Stastna Markova 1, Ludmila Novakova1, Mariana Koubova1, Barbora Cemusova1, Veronika Valkova1, Antonin Vitek1, Petr Cetkovsky1, Jan Vydra1 P554 CHALLENGES AND REALITIES OF HEMATOPOIETIC CELL TRANSPLANTATION OF MYELODYSPLASTIC SYNDROMES PATIENTS IN LATIN AMERICA: A SURVEY Fernando Barroso Duarte 1, Rodolfo Daniel de Almeida Soares2, Abrahão Elias Hallack Neto3, Anderson João Simione4, Talyta Ellen de Jesus dos Santos Sousa5, Erika Oliveira de Miranda Coelho6, Vaneuza Araujo Moreira Funke7, Nelson Hamerschlak8, Rodolfo Froes Calixto9, Maria Claudia Rodrigues Moreira10, Alicia Enrico11, Marco Aurelio Salvino12, Eduardo José de Alencar Paton13, Mariana Stevenazzi14, Neysimelia Costa Villela15, Carmem Bonfim7, Gisele Loth16, Breno Moreno Gusmão17, Maria Cristina Martins de Almeida Macedo18, Isabella Araújo Duarte19, Vergílio Antônio Rensi Colturato4 P555 OUTCOMES OF RELAPSE POST HEMATOPOIETIC CELL TRANSPLANTATION IN MYELODYSPLASTIC SYNDROMES FROM THE LATIN AMERICAN REGISTER Fernando Duarte 1, Talyta Ellen de Jesus dos Santos Sousa1, Vaneuza Araújo Moreira Funke2, Nelson Hamerschlak3, Neysimélia Costa Villela4, Maria Cristina Martins de Almeida Macedo5, Afonso Celso Vigorito6, Rodolfo Daniel de Almeida Soares7, Alessandra Paz8, Lilian Diaz9, Mariana Stevenazzi9, Abrahão Elias Hallack Neto10, Gustavo Bettarello11, Breno Moreno Gusmão12, Marco Aurélio Salvino13, Rodolfo Froes Calixto14, Maria Cláudia Rodrigues Moreira15, Gustavo Machado Teixeira16, Cinthya Corrêa Silva3, Eduardo José de Alencar Paton17, Vanderson Rocha18, Alicia Enrico19, Carmem Bonfim20, Ricardo Chiattone21, Anderson João Simioni22, Celso Arrais23, Erika Oliveira de Miranda Coelho24, Vergílio Antônio Rensi Colturato22 P556 OUTCOME OF HEMATOPOIETIC STEM CELL TRANSPLANTATION OF IN CHILDREN WITH A NPM1 MUTATION AND MYELODYSPLASTIC SYNDROME WITH EXCESS BLASTS Ayami Yoshimi 1, Miriam Erlacher1, Peter Noellke1, Senthilkumar Ramamoorthy1, Gudrun Göhring2, Shlomit Barzilai-Birenboim3, Ivana Bodova4, Jochen Buechner5, Albert Catala6, Valérie De Haas7, Barbara De Moerloose8, Michael Dworzak9, Henrik Hasle10, Kirsi Jahnukainen11, Krisztian Kallay12, Marko Kavcic13, Paula Kjollerstrom14, Franco Locatelli15, Riccardo Masetti16, Sophia Polychronopoulou17, Markus Schmugge18, Owen Smith19, Jan Stary20, Dominik Turkiewicz21, Marek Ussowicz22, Marcin Wlodarski23, Christian Thiede24, Brigitte Strahm1, Charlotte Niemeyer1 P557 SYSTEMATIC LITERATURE REVIEW ON THE SAFETY, EFFICACY, AND EFFECTIVENESS OF EATG VERSUS COMPARATORS FOR MDS Erin Sheffels1, Kevin Kallmes1, Keith Kallmes1, Barbara Możejko-Pastewka2, Raj Gokani 2, Judith Hey-Hadavi1, Andres Quintero2 P558 TCRALPHABETA/CD19 DEPLETED ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION IN COMBINATION WITH POST-TRANSPLANT RUXOLITINIB FOR MYELOFIBROSIS Flores Weverling1, Yousra van der Leest1, Frances Verheij1, Iris Brinkman1, Anna van Rhenen1, Lotte van der Wagen1, Laura Daenen1, Kasper Westinga2, Henk-Jan Prins2, Lisette van de Corput3, Reinier Raymakers1, Anke Janssen1, Jurgen Kuball1, Moniek de Witte 1 P559 MINIMAL RESIDUAL DISEASE MONITORING OF DRIVER MUTATION BY DIGITAL DROPLET PCR IS PREDICTIVE OF RELAPSE AFTER ALLOGENEIC STEM CELL TRANSPLATION IN MYELOFIBROSIS Maria Chiara Finazzi 1,2, Roberta Stavola1, Francesca Valsecchi2, Alessia Civini2, Chiara Pavoni2, Matteo Raviglione2, Anna Grassi2, Alessandra Algarotti2, Maria Caterina Micò2, Federico Lussana1,2, Benedetta Rambaldi2, Gianluca Cavallaro2, Giuliana Rizzuto2, Orietta Spinelli2, Alessandro Rambaldi1,2, Silvia Salmoiraghi2 P560 EVALUATION AND IMPLICATIONS OF PORTAL AND PULMONARY HYPERTENSION IN MYELOFIBROSIS PRIOR TO TRANSPLANT: A PRACTICE-BASED SURVEY OF THE CHRONIC MALIGNANCIES WORKING PARTY OF THE EBMT Giorgia Battipaglia 1, Nicola Polverelli2, Joe Tuffnell3, Patrizia Chiusolo4, Marie Robin5, Massimiliano Gambella6, Annoek Broers7, Elisa Sala8, Jakob Passweg9, Sabine Furst10, Henrik Sengeloev11, Remy Dulery12, Moniek de Witte13, Ibrahim Yakoub-Agha14, Maria Chiara Finazzi15, Claudia Wehr16, Arnon Nagler17, Deborah Richardson18, Wolfgang Bethge19, Andrew Clark20, Joanna Drozd-Sokolowska21, Kavita Raj22, Tomasz Czerw23, Juan Carlos Hernández-Boluda24, Donal P. McLornan22 P561 IMPACT OF NUMBER OF CD34 + CELLS INFUSED ON OVERALL SURVIVAL IN MYELOFIBROSIS PATIENTS AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION Filippo Frioni 1, Sabrina Giammarco2, Elisabetta Metafuni2, Maria Assunta Limongiello2, Nicola Piccirillo2, John Donald Marra1, Luca Di Marino1, Luciana Teofili2, Andrea Bacigalupo1, Simona Sica2, Patrizia Chiusolo2 P562 AVAPRITINIB IN THE POST-ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANT SETTING IN PATIENTS WITH ADVANCED SYSTEMIC MASTOCYTOSIS Deborah Christen 1, Johannes Luebke2, Juliana Schwaab2, Anne Kaiser1, Svetlana Rylova3, Saša Dimitrijević3, Ilda Bidollari3, Jens Peter Panse1, Andreas Reiter2,1 P563 ASCIMINIB: A NEW TKI BEFORE AND AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION IN CHRONIC MYELOID LEUKEMIA Iuliia Vlasova 1, Elena Morozova1, Elza Lomaia2, Tamara Chitanava2, Ksenia Tsvirko1, Tatiana Rudakova1, Nikita Volkov1, Tatiana Gindina1, Dmitriy Motorin3, Yulia Alexeeva2, Valeriya Katerina1, Ivan Moiseev1, Alexander Kulagin1 P564 EXCELLENT LONG TERM SURVIVAL DESPITE LOW RATES OF GVHD IN PATIENTS WITH MYELOFIBROSIS FOLLOWING ALLOGENIC HSCT: A SINGLE CENTRE EXPERIENCE Mariam Amer 1, Michael Nathan1, Christopher Dalley1, Kim Orchard1, Sara Main1, Amy Creighton1, Jane Lamb1, Helen Snow1, Annie Major1, Sarah Holtby1, Linda Jarvis1, Mathew Lee1, Muhammad Maqbool1, Hwai Jing Hiew1, Fiona Duggan1, Deborah Richardson1 P565 VENETOCLAX PLUS AZACITIDINE VERSUS AZACITIDINE ALONE AS POST-TRANSPLANT MAINTENANCE TREATMENT IN HIGH-RISK AML AND MDS Yigeng Cao1, Wenwen Guo1, Erlie Jiang 1 P566 CURRENT PRACTICE WHEN TRANSPLANTING PATIENTS WITH MYELOFIBROSIS: A SURVEY ON BEHALF OF THE BRITISH SOCIETY OF BLOOD AND MARROW TRANSPLANTATION AND CELLULAR THERAPY (BSBMTCT) Emma Kempshall 1, Donal McLornan2, Anjum Khan3, Pramilla Krishnamurthy4, Daniele Avenoso4, Sebastian Francis5, Matthew Collin6 P567 LONG-TERM OUTCOME OF ALLOGENEIC TRANSPLANTATION IN PRIMARY AND SECONDARY MYELOFIBROSIS Alzbeta Zavrelova 1,1, Benjamin Visek1, Miriam Lanska1, Pavel Zak1, Petra Lukesova1, Jakub Radocha1 P568 FIRST-IN-HUMAN PHASE I/II CLINICAL TRIAL OF IG-TREGS FOR GVHD PREVENTION Memnon Lysandrou1, Dionysia Kefala1, Panagiota Christofi1,2, Maria Liga1, Antonis Miggos3, Charys Papagregoriou4, Elisavet Vlachonikola3, Nikolaos Savvopoulos1, Vassiliki Zacharioudaki 1, Ioanna Vallianou2, Eleutheria Sagiadinou1, Dimitris Tsokanas1, Rodanthy Theodorellou5, Anastasia Papadopoulou2, Evi Triantafyllou1, Ioanna Sakellari2, Paul Costeas4,6, Anastasia Chatzidimitriou3, Evangelia Yannaki2, Alexandros Spyridonidis1 P569 GILTERITINIB WITH VENETOCLAX, ACTINOMYCIN D, AND LOW-DOSE CYTARABINE AS BRIDGING TO ALLOGENEIC STEM CELL TRANSPLANTATION IN RELAPSED OR REFRACTORY FLT3 MUTATED ACUTE MYELOID LEUKEMIA Andrius Žučenka1,2, Guoda Daukėlaitė1,2, Vilmantė Vaitekėnaitė1,2, Regina Pileckytė1,2, Igoris Trociukas2, Adomas Bukauskas1,2, Rita Čekauskienė 1,2, Laimonas Griškevičius1,2 P570 EFFICACY OF SALVAGE THERAPY INCLUDING NOVEL AGENTS IN ADULT B-CELL ACUTE LYMPHOBLASTIC LEUKAEMIA (B-ALL) PROGRESSING AFTER ALLOGENEIC STEM CELL TRANSPLANTATION: A REAL-WORLD UK STUDY Alexandros Rampotas 1, Fotios Panitsas2, Maximillian Brodermann1, Sridhar Chaganti3, Bouziana Styliani4, Emma Nicholson5, Samanth Drummond6, Sharon Allen7, Andrew King7, Anne-Louise Latif6, Henry Crosland3, Daniele Avenoso4, Claire Roddie1 P571 TREOSULFAN PLUS FLUDARABINE “REDUCED INTENSITY CONDITIONING” WITH POSTTRANSPLANT CYCLOPHOSPHAMIDE IN PATIENTS WITH ACUTE MYELOID LEUKEMIA OLDER THAN 65 YEARS Vincenzo Federico 1,2, Rosella Matera1, Dalila Salvatore3, Filippo Antonio Canale4, Manuela Merla3, Daniela Valente3, Corine Contento1, Giulia Campagna1, Doriana Vaddinelli5, Annalisa Natale5, Davide Seripa1, Stella Santarone5, Tiziana Grassi2, Francesco Bagordo2, Nicola Di Renzo1, Massimo Martino4, Angelo Michele Carella3 P572 ORAL IPTACOPAN MONOTHERAPY MAINTAINS EFFICACY AND SAFETY OVER 48 WEEKS IN COMPLEMENT INHIBITOR-NAÏVE PATIENTS WITH PAROXYSMAL NOCTURNAL HEMOGLOBINURIA (PNH) IN THE PHASE III APPOINT-PNH TRIAL Antonio M. Risitano 1,2, Bing Han3, Yasutaka Ueda4, Jaroslaw P. Maciejewski5, Rong Fu6, Li Zhang7, Austin Kulasekararaj8,9,10, Alexander Röth11, Lee Ping Chew12, Jun Ho Jang13,14, Lily Wong Lee Lee15, Jens Panse16,17, Eng-Soo Yap18, Luana Marano1,2, Flore Sicre de Fontbrune19,20, Chen Yang3, Hui Liu6, Roochi Trikha8,9,10, Navin Mahajan21, Tomasz Lawniczek21, Zhixin Wang22, Christine Thorburn23, Shujie Li22, Marion Dahlke21, Régis Peffault de Latour19,20 P573 T CELLS DIRECTED AGAINST THE METASTATIC DRIVER CHONDROMODULIN-1 IN EWING SARCOMA: COMPARATIVE ENGINEERING WITH CRISPR/CAS9 VS. RETROVIRAL GENE TRANSFER FOR ADOPTIVE TRANSFER Uwe Thiel 1, Kristina von Heyking1, Busheng Xue1, Hendrik Gaßmann1, Melanie Thiede1, Kilian Schober2, Josef Mautner3, Julia Hauer4, Jürgen Ruland5, Dirk H. Busch6, Stefan E.G. Burdach7 P574 UTILITY OF ROMIPLOSTIM IN PAEDIATRIC ALLOGENEIC STEM CELL TRANSPLANT ASSOCIATED POOR GRAFT FUNCTION, IMMUNE MEDIATED CYTOPENIA AND IMMUNE MEDIATED GRAFT FAILURE Srividhya Senthil 1, Abdul Moothedath2, Abbey Forster1, Ramya Hanasoge-Nataraj1, Madeleine Powys1,1, Omima Mustafa1,1, Robert Wynn1,1 P575 RAG2>-/-ΓC-/- MICE HUMANIZED WITH CD34+ HEMATOPOIETIC STEM CELLS ARE A SUITABLE TOOL TO SCREEN FOR FUNCTIONAL EWING SARCOMA-SPECIFIC T CELLS IN VIVO Uwe Thiel 1, Sabine Heim1, Hendrik Gaßmann1, Kristina von Heyking1, Sebastian J. Schober1, Melanie Thiede1, Markus Niemeyer2, Dirk Busch3, Ropert Oostendorp4, Irene Esposito5, Julia Hauer1, Günther HS Richter6 P576 REAL-WORLD EFFECTIVENES OF VENETOCLAX COMBINED WITH IPOMETILATING-AGENTS AS A BRIDGE TO ALLOGENEIC TRANSPLANTATION IN ACUTE MIELOID LEUKEMIA: RETROSPECTIVE AND MULTICENTRIC STUDY OF APULIAN HEMATOLOGICAL NETWORK “REP05” Vincenzo Federico 1,2, Rosella Matera1, Domenico Pastore3, Giuseppe Tarantini4, Lorella Melillo5, Angelo Michele Carella6, Attilio Guarini7, Caterina Buquicchio4, Lucia Ciuffreda5, Mariachiara Abbenante6, Paola Carluccio8, Crescenza Pasciolla7, Mariapaolo Fina1, Alessandro Spina3, Marina Urbano3, Daniela Carlino1, Mariangela Lecciso1, Michelina Dargenio1, Davide Seripa1, Pellegrino Musto8,9, Giorgina Specchia10, Nicola Di Renzo1 P577 T CELL RECEPTOR IDENTIFICATION AGAINST EWING SARCOMA ASSOCIATED DICKKOPF 2 (DKK2) DERIVED ANTIGEN USING SINGLE-CELL RNA SEQUENCING Sophia Laube 1, Kristina von Heyking1, Melanie Thiede1, Hendrik Gassmann1, Sebastian Johannes Schober1, Jennifer Eck1, Hannah Hüls1, Carolin Prexler1, Sabrina Wagner2, Elvira D’Ippolito2, Julia Hauer1, Stefan E G. Burdach3, Dirk H. Busch2, Uwe Thiel1 P578 TARGETED CD8+ T CELL THERAPY IN ADVANCED EWING SARCOMA: EXPLORING LIPI, GPR64, PAX7, AND CHM1 AS TARGETS FOR ADOPTIVE TRANSFER APPROACHES Hannah Hüls 1, Kristina von Heyking1, Melanie Thiede1, Hendrik Gassmann1, Sebastian Johannes Schober1, Jennifer Eck1, Sophia Laube1, Carolin Prexler1, Sabrina Wagner2, Elvira D’Ippolito2, Julia Hauer1, Stefan E G. Burdach3, Dirk H. Busch2, Uwe Thiel1 P579 COMPARATIVE EFFECTIVENESS OF IPTACOPAN VERSUS C5 INHIBITORS IN COMPLEMENT INHIBITOR-NAÏVE PATIENTS WITH PAROXYSMAL NOCTURNAL HEMOGLOBINURIA FROM THE PHASE III APPOINT-PNH TRIAL AND REAL-WORLD APPEX COHORT Matthew Holt 1, Richard J. Kelly1, Jilles M. Fermont2, Georgina Bermann2, Ariel Chernofsky2, Jens Haenig2, Marion Dahlke2, Régis Peffault de Latour3,4 P580 TREATMENT WITH BLAST-MODULATORY RESPONSE MODIFIERS INDUCED SPECIFIC IMMUNE RESPONSES AND LED TO DISEASE STABILIZATION IN A PATIENT WITH REFRACTORY AML AFTER SECOND ALLOGENEIC SCT Philipp Anand1, Giuliano Fillipini Velazquez 2, Joudi Abdulmajid1, Xiaojia Feng1, Klaus Hirschbühl2, Anwesha Sinha1, Helga Schmetzer1, Christoph Schmid2 P581 REDUCED PRESENCE OF MESENCHYMAL STEM CELLS IN BONE MARROW ASPIRATES OF FEMALE PATIENTS PERSISTS AFTER ALLOGENEIC STEM CELL TRANSPLANTATION Judith Schaffrath 1, Ole Vollstädt2, Jana Lützkendorf1, Cornelia Baum1, Sabine Edemir1, Kirstin Lauer1, Lutz P. Müller1 P582 EFFICACY AND SAFETY OF A CORD BLOOD-DERIVED PLATELET CONCENTRATE FOR THE TREATMENT OF OCULAR SURFACE DISEASES: RESULTS FROM A SINGLE-CENTER PROSPECTIVE STUDY Camilla Delponte1, Laura Mazzucco2, Maria Rosa Astori3, Lucia Brunello3, Sara Butera3, Paolo Rivela3, Valeria Balbo2, Davide Dealberti4, Riccardo Dondolin5, Monia Lunghi5, Francesca Pollis2, Marco Ladetto3, Francesco Zallio 3 P583 IMPACT OF DIMENSIONALITY AND EXTRACELLULAR MATRIX ON MESENCHYMAL STEM CELL PHENOTYPE Jeong Jun Kim1, Ji Hye Lee1, Hee Hoon Yoon1, Jun Eun Park 2 P584 PROTECTING HLA-A AND HLA-B ANTIGENS THROUGH EPLETS ANALYSIS IN THE SETTING OF PLATELET TRANSFUSIONS IN HAPLOIDENTICAL HEMATOPOIETIC STEM CELL ALLOGRAFT CANDIDATES Magalie Joris1, Amandine Charbonnier1, Delphine Lebon1, Judith Desoutter1, Etienne Paubelle1, Nicolas Guillaume 1 P585 CLINICAL SIGNIFICANCE OF CYTOKINE RELEASE SYNDROME FOLLOWING HLA-MISMATCHED HEMATOPOIETIC STEM CELL TRANSPLANTATION: A RETROSPECTIVE MONOCENTRIC STUDY ON 250 TRANSPLANTS Filippo Frioni 1, Eugenio Galli2, Sabrina Giammarco2, Elisabetta Metafuni2, Federica Sorà2, Maria Assunta Limongiello2, Roberto Maggi1, John Donald Marra1, Luca Di Marino1, Andrea Mattozzi1, Andrea Bacigalupo1, Simona Sica2, Patrizia Chiusolo2 P586 INVESTIGATING VASCULAR ENDOTHELIAL DYSFUNCTION BY SYNDECAN-1 FOLLOWING PEDIATRIC HSCT Sarah Weischendorff 1, Denise Elbæk Horan1, Katrine Kielsen1, Maria Ebbesen Sørum1, Marianne Ifversen1, Pär Ingemar Johansson1, Klaus Mûller1,2 P587 ASSESSING THE IMPACT OF FLUID OVERLOAD ON OUTCOMES AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION Ana Belen Bocanegra 1, David Jaimovich2, Irene Solano1, Javier Martinez-Costa1, Jorge Verdejo1, Maria Valdenebro1, Carlos De Miguel1, Guiomar Bautista1, Sangeeta Hingorani3, Rafael Francisco Duarte1 P588 BEYOND PAIN MANAGEMENT: ASSESSING THE NEGATIVE IMPACT OF INTENSE OPIOID USE ON ALLOHCT SURVIVAL Tommy Alfaro Moya 1, Igor Novitzky Basso1, Shiyi Chen1, Mats Remberger2, Refik Saskin3, Jonas Mattsson1 P589 VENO-OCCLUSIVE DISEASE/SINUSOIDAL OBSTRUCTION SYNDROME (VOD/SOS)-ASSOCIATED MORBIDITY IN CHILDREN POST HEMATOPOIETIC STEM CELL TRANSPLANTATION - A HINT FOR AN ADEQUATE PROPHYLAXIS? Zofia Szmit 1, Zuzanna Gamrot1, Anna Król1, Jowita Frączkiewicz1, Monika Mielcarek-Siedziuk1, Karolina Liszka1, Igor Olejnik1, Tomasz Jarmoliński1, Selim Corbacioglu2, Krzysztof Kałwak1 P590 OUTCOME AND COMPLEMENT SYSTEM INVOLVEMENT IN PATIENTS WITH THROMBOTIC MICROANGIOPATHY AFTER ALLOGENEIC STEM CELL TRANSPLANTATION Jacopo Mariotti 1, Massimo Cugno2, Luigi Porcaro3, Daniela Taurino1, Barbara Sarina1, Chiara de philippis1, Daniele Mannina1, Armando Santoro1, Gianluigi Ardissino4, Stefania Bramanti1 P591 BONE REMODELLING ARE SIGNIFICANTLY IMPAIRED AFTER PEDIATRIC HSCT AND INFLUENCED BY DIAGNOSIS, CONDITIONING REGIMEN AND ACUTE GRAFT-VERSUS-HOST DISEASE Katrine Kielsen 1, Kathrine Fogelstrøm1, Anne Nissen1, Marianne Ifversen1, Bolette Hartmann2, Klaus Müller1,2 P592 IDIOPATHIC UPPER GASTROINTESTINAL BLEEDING AFTER ALLOGENEIC STEM CELL TRANSPLANTATION: AN UNPRECEDENTED COMPLICATION Juan Eirís 1, Marina Pérez-Bravo2, Nuria Rausell1, Carla Satorres1, Marta Villalba1, Pedro Chorão1, Juan Montoro1,3, Pedro Asensi1, Pablo Granados1, David Martínez-Campuzano1, Alberto Louro1, Marta Henriques4, Ana Facal5, Mª Consejo Ortí-Verdet6, Miguel Sanz1, Javier de la Rubia1,3, Jaime Sanz1, Aitana Balaguer-Roselló1 P593 ACUTE KIDNEY INJURY AND CRONIC KIDNEY DISEASE AFTER ALLOGENEIC HCT. A SINGLE-CENTER EXPERIENCE Ana Belén Bocanegra 1, Jaimovich David2, Irene Solano3, Javier Martinez-Costa3, Jorge Verdejo3, Maria Valdenebro3, Ana Muñoz Sanchez3, Carlos De Miguel3, Guiomar Bautista3, Sangeeta Hingorani4, Rafael Francisco Duarte3 P594 SINUSOIDAL OBSTRUCTION SYNDROME/VENO-OCCLUSIVE DISEASE: A RETROSPECTIVE STUDY OF THE SPANISH HEMATOLOGY ASSOCIATION-HEMATOPOIETIC STEM CELL TRANSPLANTATION GROUP (GETH) Cristina Blázquez Goñi 1, Francisco Manuel Martin Dominguez1, Silvia García Canale1, Cristina Díaz de Heredia2, Melissa Panesso Romero2, Maribel Benítez Carabante2, María Luz Uría2, David Bueno3, Annalisa Paviglianiti4, Pilar Palomo Moraleda5, Ana Isabel Gallardo Morillo6, Antonia Pascual Martínez6, Marina Acera Gómez7, Alexandra Regueiro8, Carlos Vallejo Llamas9, Gillen Oarbeascoa10, Diana Campos11, Leslie González Pinedo12, Melissa Torres12, Julia Marsal Ricomà13, Marta González Vicent14, María José Jiménez Lorenzo15, Estefanía García Torres16, Mónica López Duarte17, Andrés Sánchez Salinas18, Pedro González Sierra19, José Luis López Lorenzo20, Amaya Zabalza21, Sara Redondo Velao22, Oriana López-Godino23, Alejandro Luna de Abia24, Cristina Beléndez10, Beatriz Aguado25, María Teresa Artola Urain26, Patricia Jiménez Guerrero27, Agustín Nieto Vázquez28, Francisca Almagro Torres29, José Antonio Sanz30, Beatriz de Rueda31, Rocío Picón González32, José Antonio Pérez Simón1 P595 SAFETY AND BENEFIT OF LIVER BIOPSY AFTER ALLOGENIC STEM CELL TRANSPLANTATION: A RETROSPECTIVE SINGLE-CENTER STUDY Marie Maulini 1, Aurélie Bornand1, Federico Simonetta1, Anne-Claire Mamez1, Chiara Bernardi1, Federica Giannotti1, Yan Beauverd1, Thomas Longval1, Maria Mappoura1, Sarah Noetzlin1, Laetitia Dubouchet1, Sarah Perdikis-Prati1, Evgenia Laspa1, Cuong-An Do1, Thien-An Tran1, Carmen De Ramon Ortiz1, Amandine Pradier1, Sarah Morin1, Stavroula Masouridi-Levrat1, Simon Maulini2, Laura Rubbia-Brandt1, Laurent Spahr1, Yves Chalandon1 P596 INVESTIGATION OF LABORATORY PARAMETERS BEFORE THE ONSET OF HEPATIC SINUSOIDAL OBSTRUCTION SYNDROME IN CHILDREN AFTER HEMATOPOIETIC STEM CELL TRANSPLANTATION Bernd Gruhn 1, Lorena Johann1 P597 OUTCOME OF ALLOGENEIC HCT RECIPIENTS COMPARED TO OTHER PATIENTS WITH HEMATOLOGICAL MALIGNANCIES ADMITTED TO THE INTENSIVE CARE UNIT. A SINGLE CENTRE STUDY Ana Belen Bocanegra 1, Marta Perez Calle1, Jorge Verdejo1, Alicia Segura1, Ana María Bellón1, Rosalia Alonso1, Ana Amaro Harpigny1, Patricia Enciso1, Inmaculada Tendero1, Maria Esther Martinez-Muñoz1, Carlos De Miguel1, Guiomar Bautista1, Ines Lipperheide1, Daniel Ballesteros1, Rafael Francisco Duarte1 P598 ADVERSE PROGNOSTIC IMPACT OF PRETRANSPLANT HEPCIDIN AND FERRITIN ON OUTCOMES FOLLOWING HEMATOPOIETIC STEM CELL TRANSPLANTATION Michelle Pirotte 1, Marianne Fillet2, Laurence Seidel3, Evelyne Willems1, Sophie Servais1, Frédéric Baron1, Yves Beguin1 P599 IMPACT OF GRANULOCYTE-COLONY STIMULATING FACTOR (G-CSF) ON CLINICAL OUTCOMES IN ALLOGENEIC STEM CELL TRANSPLANTATION: INSIGHTS FROM A SINGLE-CENTER EXPERIENCE AT PRINCESS MARGARET CANCER CENTRE Ahmed Alnughmush1,2, Ayman Sayyed1,2, Mohammed Kawari 2, Mats Remberger3, Carol Chen1, Caden Chiarello1, Ivan Pasic1,2, Igor Novitzky-Basso1,2, Arjun Datt Law1,2, Wilson Lam1,2, Dennis (Dong Hwan) Kim1,2, Fotios V. Michelis1,2, Armin Gerbitz1,2, Auro Viswabandya1,2, Rajat Kumar1,2, Jonas Mattsson1,2,4 P600 VALIDATION OF EBMT 2023 VOD CRITERIA: IMPACT ON EARLY DIAGNOSIS AND SENSITIVITY/ESPECIFICITY OF PROBABLE VOD CATEGORY Monica Cabrero 1,2, Maria Cortes-Rodriguez3,2, Almudena Cabero1,2, Estefania Perez-Lopez1,2, Ana Africa Martin-Lopez1,2, Monica Baile1,2, Alejandro Avendaño1,2, Ana Garcia-Bacelar1,2, Lorena Hernandez-Medina2, Marina Acera2, Lourdes Vazquez1,2, Fermin Sanchez-Guijo1,2, Lucia Lopez-Corral1,2 P601 EFFICACY AND SAFETY OF NETUPITANT/PALONOSETRON COMBINATION (NEPA) AND LOW DOSE OF DEXAMETHASONE IN PREVENTING NAUSEA AND VOMITING IN PATIENTS UNDERGOING ALLOGENEIC STEM CELL TRANSPLANTATION Alessandro Spina 1, Marina Aurora Urbano1, Claudia Schifone1, Francesca Merchionne1, Maria Laura Di Noi1, Gianluca Guaragna1, Erminia Rinaldi1, Giovanni Quintana1, Giuseppe Mele1, Domenico Pastore1 P602 CYTOKINE RELEASE SYNDROME AFTER HAPLOIDENTICAL HEMATOPOIETIC STEM CELL TRANSPLANTATION AND ITS IMPACT ON OVERALL SURVIVAL Isabella Silva Pimentel Pittol 1, Camila Carminatti Isoppo2, André Dias Américo1, Germano Glauber de Medeiros Lima1, Eurides Leite da Rosa3, João Antônio Gonçalves Garreta Prats1, Hegta Tainá Rodrigues Figueroa1, Juliana Matos Pessoa1, Phillip Scheinberg1, Fauze Lutfe Ayoub1, Fabio Rodrigues Kerbauy1 P603 EXPLORING THE SAFETY PROFILE OF NORETHINDRONE IN POST-MENARCHAL STEM CELL TRANSPLANT PATIENTS: ADDRESSING VOD CONCERNS AND CAUTIONARY CONSIDERATIONS Mahvish Rahim1, Jodi Skiles1, Devin Dinora1, Jessica Harrison1, Ryanne Green1, Allie Carter1, April Rahrig 1 P604 POST-TRANSPLANT DE NOVO ANTI-HLA DONOR SPECIFIC ANTIBODIES MAY CONTRIBUTE TO POOR GRAFT FUNCTION AFTER HAPLOIDENTICAL HEMATOPOIETIC STEM CELL TRANSPLANTATION Xinyu Ji 1, Luxin Yang1,2, Xiaoyu Lai1,2, Yishan Ye1,2, Yibo Wu1,2, Shipei Xiang1, Yi Luo1,2, Lizhen Liu1,2 P605 IMPACT OF EARLY CYCLOSPORINE INITIATION ON CYTOKINE RELEASE SYNDROME AND TRANSPLANT OUTCOMES IN PEDIATRIC T CELL REPLETE PERIPHERAL BLOOD HAPLO-IDENTICAL HEMATOPOIETIC STEM CELL TRANSPLANT Veerendra Patil 1, Pavan Kumar Boyella1, Pallavi Ladda1, Rakesh Pinninti1, Rohan Tewani1, Senthil Rajappa1 P606 USE OF GRANULOCYTE COLONY-STIMULATING FACTORS IS FEASIBLE IN ALL DONOR SETTING WITHOUT INCREASING THE RISK OF ENGRAFTMENT SYNDROME Maria Luisa Giannattasio 1, Linda Piccolo1, Andrea Cacace1, Davide Pio Abagnale1, Giuseppe Gaeta1, Francesco Grimaldi1, Simona Avilia1, Mara Memoli1, Lucia Ammirati2, Valentina Maglione2, Catello Califano2, Claudia Andretta3, Ermanno Badi3, Pasqualino Correale3, Patrizia Ricci4, Domenica Borzacchiello4, Marco Picardi1, Antonio Feliciello4, Antonio Leonardi3, Fabrizio Pane1, Giorgia Battipaglia1 P607 THE UTILITY OF EXTRACORPOREAL ULTRASONOGRAPHY SCORE (HOKUS-10) IN PEDIATRIC SOS/VOD Atsushi Narita 1, Hideki Muramatsu1, Ryo Maemura1, Daiki Yamashita1, Daichi Sajiki1, Yusuke Tsumura1, Ayako Yamamori1, Manabu Wakamatsu1, Kotaro Narita1, Shinsuke Kataoka1, Yoshiyuki Takahashi1 P608 RETROSPECTIVE REVIEW OF TRANSPLANT AND TRANSFUSION OUTCOMES IN PATIENTS WITH PRE-TRANSPLANT RED CELL ALLOANTIBODIES Samantha Drummond 1, Jennifer Laird2, David Irvine3 P609 TWO GLOBAL PHASE 3 TRIALS OF THE EFFICACY AND SAFETY OF RAVULIZUMAB IN ADULT AND PEDIATRIC PATIENTS WITH THROMBOTIC MICROANGIOPATHY AFTER HEMATOPOIETIC STEM CELL TRANSPLANT Carolyn Hahn 1, Elsa Konig1, Jonathan Monteleone1, Edward Wang1 P610 RITUXIMAB, BORTEZOMIB, PLASMA EXCHANGE COMBINED WITH IVIG FOR DESENSITIZATION DURING HAPLOIDENTICAL STEM CELL TRANSPLANTATION IN PATIENTS WITH A POSITIVE DONOR-SPECIFIC ANTI-HLA ANTIBODY Fang Liu 1, Cunbang Wang1, Yecheng Li1, Min Chen1, Jialin Duan1, Xinyu Wei1, Yongli Li1, Jing Wu1, Xiaofei Shen1, Ying Zhou1, Jinwei Li1, Yaoling Fu1, Lingling Yu1 P611 PREDICTIVE FACTORS OF GRAFT FAILURE IN ADULT AND PAEDIATRIC PATIENTS WITH MALIGNANT AND NON-MALIGNANT DISEASE UNDERGOING HAEMATOPOIETIC STEM CELL TRANSPLANT (HSCT) Pietro Merli 1, Régis Peffault de Latour2,3, Emmanuel Monnet4, Malin Löfqvist4, Franco Locatelli1 P612 EARLY LOW DOSE CYCLOSPORINE AND MYCOPHENOLATE REDUCE THE RISK OF CYTOKINE RELEASE SYNDROME AFTER HLA-HAPLOIDENTICAL PERIPHERAL BLOOD STEM CELL TRANSPLANTATION WITH PTCY BASED GVHD PROPHYLAXIS Jan Vydra 1, Ludmila Nováková1, Veronika Válková1, Markéta Šťastná Marková1, Mariana Koubová1, Anna Dobrovolná1, Barbora Čemusová1, Antonín Vítek1, Petr Cetkovský1 P613 INCIDENCE, RISK FACTORS, AND OUTCOMES OF TRANSPLANT-ASSOCIATED THROMBOTIC MICROANGIOPATHY IN PEDIATRIC PATIENTS AFTER ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION Kyung-Nam Koh 1, Su Hyun Yun1, Eun Seok Choi1, Sung Han Kang1, Hyery Kim1, Ho Joon Im1 P614 STEM CELL MOBILIZATION EFFECTS ON HEART SIZES AND FUNCTION Domas Vaitiekus 1, Ignas Gaidamavicius1, Audrone Vaitiekiene1, Migle Kulboke1, Monika Bieseviciene1, Benas Kireilis1, Ruta Dambrauskiene1, Milda Rudzianskiene1, Antanas Jankauskas1, Elona Juozaityte1, Dietger Niederwieser1, Jolanta Justina Vaskelyte1, Gintare Sakalyte1, Rolandas Gerbutavicius1 P615 EASIX SCORE AS INDEPENDENT PREDICTOR FOR OVERALL SURVIVAL IN PATIENTS WITH ACUTE LEUKEMIA AND MDS UNDERGOING ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION Penka Ganeva1, Andriyana Bankova 1, Georgi Vasilev1, Krasen Venkov1, Kameliya Milcheva1, Victoria Yankova1, Margarita Guenova1, Georgi Mihaylov1 P616 EARLY CICLOSPORINE TO EVEROLIMUS CONVERSION POST HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR PATIENT WITH CALCINEURIN INHIBITORS INDUCED TOXICITIES Benjamin Bouchacourt 1, Raynier Devillier1,2, Didier Blaise1,2, Thomas Pagliardini1, Sabine Furst1, Samia Harbi1, Faezeh Legrand1, Charlotte Nykolyszyn1, Federico Pagnussat1, Pierre Jean Weiller1, Claude Lemarie1,3, Boris Calmels1,3, Christian Chabannon1,3,2 P617 IMMUNE-MEDIATED CYTOPENIA IN PEDIATRIC PATIENTS FOLLOWING ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION: ON BEHALF OF THE RBC DISORDER WORKING PARTY OF THE KOREAN SOCIETY OF HEMATOLOGY Hyoung Soo Choi 1, Jeong-A Park2, Hee Won Chueh3, Hee-Jo Baek4, Hoon Kook4 P618 ENGRAFTMENT SYNDROME IN PATIENTS UNDERGOING AUTOLOGOUS STEM CELL TRANSPLANTATION FOR MULTIPLE MYELOMA: A SINGLE-CENTER DATA ANALYSIS OF CLINICAL FEATURES AND RISK FACTORS Shanshan Liu 1, Luxin Yang2, Lizhen Liu2, Yan Gao1, Xianqi Feng1, He Huang2, Yi Luo2 P619 DONOR SPECIFIC ANTI-HLA ANTIBODIES IN HAPLOIDENTICAL PERIPHERAL STEM CELL TRANSPLANTATION: SINGLE CENTER EXPERIENCE Alessandro Spina 1, Marina Aurora Urbano1, Claudia Schifone1, Maria Laura Di Noi1, Francesca Merchionne1, Maria Rosaria Coppi1, Maria Patrizia D’Errico1, Maria Antonietta Miccoli2, Domenico Pastore1 P620 EARLY ONSET OF EPSTEIN-BARR VIRUS POSITIVE MULTIPLE MYELOMA TYPE OF POSTTRANSPLANT LYMPHOPROLIFERATIVE DISORDER – A CASE OF INFREQUENT COMPLICATION AFTER ALLOGENIC PERIPHERAL BLOOD STEAM CELL TRANSPLANTATION Kamila Kruczkowska-Tarantowicz1, Piotr Rzepecki1 P621 THE ROLE OF DARATUMUMAB IN POST-TRANSPLANT COMPLICATIONS: A PROSPECTIVE STUDY ON PRCA AND AIHA Sabrina Giammarco 1, Maria Assunta Limongiello1, Luca Di Marino2, Elisabetta Metafuni1, Maggi Roberto2, Federica Sorá2, Eugenio Galli1, Patrizia Chiusolo2, Simona Sica2 P622 TRANSPLANT ASSOCIATED THROMBOTIC MICROANGIOPATHY IS AN IMPORTANT CAUSE OF HIGH EARLY MORTALITY IN ALLOGENIC BONE MARROW TRANSPLANT Pawan Kumar Singh 1, Isha Gambhir1, Ravi Shanker1, Rasika Setia1, Anil Handoo1 P623 IMMUNE DYSREGULATION AFTER ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION BEYOND GVHD: A COMPREHENSIVE PEDIATRIC CASE REPORT - FROM DIAGNOSTICS TO TAILORED BTK INHIBITION BY IBRUTINIB Peter Švec 1, Maria Füssiová1, Jaroslava Adamčáková1, Ivana Boďová1, Júlia Horáková1, Dominika Dóczyová1, Miroslava Pozdechová1, Tomáš Sýkora1, Alexandra Kolenova1 P624 A RARE CASE OF MULTIPLY RELAPSED POST-ALLOGENEIC STEM CELL TRANSPLANT IMMUNE THROMBOTIC THROMBOCYTOPENIC PURPURA IN A YOUNG PATIENT WITH GATA-2 POSITIVE MYELODYSPLASTIC SYNDROME Angela Dăscălescu 1, Antohe Ion2, Elena Dolachi3, Roxana Dumitru4 P625 CENTRAL NERVOUS SYSTEM TOXICITY WITH EXCLUSIVE INVOLVEMENT OF THE BRAIN WHITE MATTER LIKELY RELATED TO TOXIC/IMMUNOLOGIC CAUSES. A PRESENTATION OF 4 SIMILAR CASES Valentina Sangiorgio1, Elena Agostani 1, Marilena Fedele2, Paola Perfetti2, Cristina Capraro2, Elisabetta Terruzzi2, Andrea Aroldi2, Carlo Gambacorti Passerini1, Matteo Parma2 P626 EVALUATING AN UPDATED ANTIEMETIC PROTOCOL IN HAEMATOPOIETIC STEM CELL TRANSPLANTATION Katie Robertson1, Muhammad Saif 1, Ann Griffiths1, Thomas Sanders1, Daniel Monnery1 P627 ECULIZUMAB TREATMENT OF HEMATOPOIETIC STEM CELL TRANSPLANTATION-ASSOCIATED THROMBOTIC MICROANGIOPATHY: SINGLE CENTER EXPERIENCE Tatiana Rudakova1, Julia Vlasova1, Olesya Paina1, Olga Slesarchuk1, Marina Gorodnova1, Tatyana Schegoleva1, Oleg Goloshchapov1, Tatyana Bykova 1, Elena Morozova1, Lyudmila Zubarovskaya1, Ivan Moiseev1, Alexander Kulagin1 P628 IMMUNE THROMBOCYTOPENIA FOLLOWING ALLOGENEIC STEM CELL TRANSPLANT : RESULTS FROM A FRENCH MULTICENTRIC RETROSPECTIVE STUDY OF 35 CASES Antoine Gondé 1,2, Aude Legal3, Flore Sicre de Fontbrune4, Mathieu Puyade5, Maud d’Aveni6, Yves Béguin7, Carmen Botella Garcia8, Éolia Brissot9, Étienne Daguindau10, Bertrand Godeau1, Marc Michel1, Thibault Comont3 P629 AT-HOME AUTOLOGOUS HEMATOPOIETIC CELL TRANSPLANT FOR ADULTS WITH HEMATOLOGICAL MALIGNANCIES. HOW FRAILTY SYNDROME IMPACTS AND EVOLVES DURING HCT PROCEDURE Juan Ortiz 1, Maria Teresa Solano2, Cristina Galleago2, Nuria Ballestar2, Anna Serrahima2, Noemi de llobet2, Raquel Salinas2, Alexandra Patricia Martinez2, María Suárez-Lledó2, Beatriz Merchán2, Paola Charry2, Joan Cid2, Miquel Lozano2, Laura Rosiñol2, Carmen Martinez2, Montserrat Rovira2, Enric Carreras2, Francesc Fernandez2 P630 FRAILTY ASSESSMENT IN ADULTS UNDERGOING ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION OUTCOMES. PROSPECTIVE STUDY ON BEHALF OF THE GRUPO ESPAÑOL DE TRASPLANTE HEMATOPOYÉTICO Y TERAPIA CELULAR (GETH-TC) Maria Queralt Salas 1,2, Maria Teresa Solano1,2, Mónica Baile-González3,2, Marina Acera-Gómez3,2, Laura Fox4,2, Maria del Mar Pérez-Artigas4,2, Ana Santamaría5,2, María del Carmen Quintela-González5,2, Andrés Sánchez-Salinas6,2, Joaquina M. Salmerón-Camacho6,2, Verónica Illana-Álvaro7,2, Zahra Abdallahi-Lefdil7,2, Javier Cornago-Navascues78,2, Laura Pardo8,2, Sara Fernández-Luis9,2, Leddy Patricia Vega-Suárez9,2, Sara Villar10,2, Patricia Beorlegui-Murillo10,2, Albert Esquirol11,2, Isabel Izquierdo-García12,2, Sonia Rodríguez González13,2, Alberto Mussetti13,2, Esperanza Lavilla14,2, Javier López-Marin15,2, Ángel Cedillo2, Leyre Bento16,2, Anna Sureda13,2 P631 LATE EFFECTS AFTER PEDIATRIC ALLOGENIC HEMATOPOIETIC STEM CELL TRANSPLANTATION Raquel García Ruiz1, Sara Fernández-Luis1, Miriam Sánchez Escamilla1, María Terán Díaz1, Juan Manuel Cerezo Martín1, Juan José Dominguéz-García1, Arancha Bermúdez Rodríguez1, Enrique M. Ocio San Miguel1, Mónica López Duarte 1 P632 OUTCOMES AND RISK FACTORS FOR SURVIVAL OF LUNG TRANSPLANTATION AFTER PRIOR ALLOGENEIC HAEMATOPOIETIC STEM CELL TRANSPLANTATION: A STUDY FROM THE EBMT TRANSPLANT COMPLICATIONS WORKING PARTY Saskia Bos1, Juan Montoro 2, Christophe Peczynski3, Pascale Ambron3, Manuela Badoglio3, Robin Vos4, Tobias Gedde-Dahl5, Mahmoud Aljurf6, Werner Rabitsch7, David Ma8, Harshita Rajasekariah8, Jaime Sanz2, Johannes Schetelig9, Anna Paola Iori10, Christian Koenecke11, Mar Bellido12, Juergen Finke13, Montserrat Rovira14, Angela Figuera15, Rabah Redjoul16, Ivan Moiseev17, Olaf Penack18, Hélène Schoemans19, Zina Peric20 P633 DEPRESSION IN SURVIVORS OF HEMATOPOIETIC STEM CELL TRANSPLANTATION COMPARED WITH A MATCHED GENERAL POPULATION COMPARISON SAMPLE: THE MOSA STUDY Bianca Wauben 1, M.W.M. van der Poel1, M. van Greevenbroek2, S. Koehler2, H.C. Schouten1, N. van Yperen2 P634 PREGNANCY OUTCOMES IN WOMEN FOLLOWING HAEMATOPOIETIC STEM CELL TRANSPLANT FOR HAEMATOLOGICAL CONDITIONS Michele Robinson1, Melanie Davies1, Anna L. David1, Panagiotis Kottaridis 1 P635 SAFETY AND EFFICACY OF IMMUNE CHECKPOINT INHIBITORS FOR SOLID ORGAN MALIGNANCIES AFTER ALLOGENEIC HSCT: A RETROSPECTIVE, MULTICENTRIC STUDY FROM THE EBMT TRANSPLANT COMPLICATIONS WORKING PARTY Jan Brijs 1, Christophe Peczynski2,3, William Boreland2,3, Angela Cuoghi4, Johan Maertens1, Mohamad Mohty5, Nicolaus Kröger6, Philipp Nakov7, Annoek E.C. Broers8, Matthias Eder9, Concepcion Herrera Arroyo10, Martin Kaufmann11, Ron Ram12, Michel Schaap13, Olaf Penack3,14, Christian Könecke3,9, Ivan Moiseev3,15, Helene Schoemans1,3,16, Zinaida Peric3,17 P636 POST-TRANSPLANT CYCLOPHOSPHAMIDE IS ASSOCIATED WITH REDUCED RATE OF SECONDARY MALIGNANCIES POST ALLOGENEIC STEM CELL TRANSPLANT Nihar Desai 1, Mariana Pinto Pereira1, Mats Remberger2, Rajat Kumar1, Dennis Kim1, Auro Viswabandya1, Arjun Law1, Wilson Lam1, Ivan Pasic1, Armin Gerbitz1, Igor Novitzky-Basso1, Jonas Mattsson1, Fotios Michelis1 P637 MOBILE HEALTH IN THE MANAGEMENT OF ALLOGENIC STEM CELL TRANSPLANT RECIPIENTS (MY-MEDULA STUDY): PRELIMINARY RESULTS OF THE CLINICAL TRIAL Sara Redondo 1, Anna De Dios1, Marina Vallve1, Jordi Real1, Merce Triquell1, Olga Aso1, Albert Esquirol1, Me Moreno-Martinez1, Mireia Riba1, Julia Ruiz1, Eva Tobajas1, Jorge Sierra1, Javier Briones1, Rodrigo Martino1, Mar Gomis-Pastor1, Irene Garcia-Cadenas1 P638 HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR PATIENTS FROM AREAS OF CONFLICT: THE KING HUSSEIN CANCER CENTER TRANSPLANTATION PROGRAM EXPERIENCE Salwa Saadeh 1,2, Haya Hamarsha1, Razan Odeh3, Mohammad Makoseh1,2, Zaid Abdel Rahamn1 P639 AUTOIMMUNE NEUTROPENIA AFTER ALLOGENIC BONE MARROW TRANSPLANTATION DUE TO ANTIBODIES SPECIFICALLY TARGETING THE HNA-1A ANTIGEN IN PEDIATRIC PATIENTS Maria Luz Uria Oficialdegui 1, Enric Casanovas2, Carme Canals2, Nuria Nogues2, Marta Rodriguez2, Cecilia Gonzalez2, Melissa Panesso1, Laura Alonso1, Lucia Garcia3, Monica Linares2, M. Isabel Benitez-Carabante1, Cristina Diaz-de-Heredia1 P640 IONA - INTERDISCIPLINARY ONCOLOGICAL FOLLOW-UP CLINIC IN VIENNA Alexandra Böhm 1, Sabine Burger1, Anna Pucher2, Sabina Ziomek2, Arno Hraschan2, Sophie Lindermann2, Barbara Schröder-Aranyosy2, Felix Keil1 P641 RAISING FOLLOW-UP AFTER CELL THERAPY TO THE NEXT LEVEL: A TRANS-REGIONAL, TRANS-SECTORAL, INTERDISCIPLINARY RESEARCH PROJECT Katharina Egger-Heidrich 1, Martin Schneider1, Gabriele Müller1, Roman Schmädig1, Franziska Schmidt1, Lynn Leppla2,3, Sabina De Geest3, Alexandra Teynor4, Markus Wolfien1,5, Martin Sedlmayr1,5, Mathias Hänel6, Anke Morgner6, Vladan Vucinic7, Jochen Schmitt1, Johannes Schetelig1, Uwe Platzbecker7, Martin Bornhäuser1, Jan Moritz Middeke1 P642 SEVERE POLYAUTOIMMUNITY AFTER ALLOGENIC HEMATOPOIETIC STEM CELL TRANSPLANTATION: POTENTIAL ROLE OF THE GENETIC BACKGROUND AND CHIMERISM LOSS Giorgio Costagliola1, Alessandro Di Gangi1, Eva Parolo 1, Chiara Lardone1, Sayla Bernasconi1, Sofia D’Elios1, Nina Tyutyusheva1, Gabriella Casazza1, Mariacristina Menconi1 P643 A CASE REPORT OF A REFRACTORY EVANS SYNDROME AFTER ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION Viktoria Yankova 1, Krasen Venkov1, Andriyana Bankova1, Kameliya Milcheva1, Penka Ganeva1, Jonka Lazarova1, Georgi Mihaylov1, Galya Kondeva1 P644 PLASMA REG3Α AND CITRULLINE LEVELS PREDICT GASTROINTESTINAL AGVHD BEFORE CLINICAL ONSET IN PEDIATRIC HSCT Nakisa Kamari-Kany1, Sarah Weischendorff 1,2, Christian Enevold1, Marianne Ifversen1, Katrine Kielsen1, Klaus Müller1,2 P645 THE OUTCOME OF HEMATOPOIETIC STEM CELL TRANSPLANTATION IN PEDIATRIC PATIENTS WITH CHEMOREFRACTORY ACUTE MYELOID LEUKEMIA Maria Ilushina1, Larisa Shelikhova1, Daria Shasheleva1, Yuliya Skvortsova1, Sergey Blagov1, Dmitriy Balashov1, Galina Novichkova1, Alexei Maschan 1, Michael Maschan1 P646 OUTCOMES AFTER HEMATOPOIETIC CELL TRANSPLANTATION FOR HURLER SYNDROME AFTER IMPLEMENTATION NEWBORN SCREENING IN US AND EUROPE Jaap Jan Boelens 1, Caroline Lindemans2, Peter van Hasselt3, Klaas Koop3, Maria I. Cancio1, Paul J. Orchard4, Troy C. Lund4 P647 ADDITION OF DINUTUXIMAB-BETA ON DAY -1 TO IMPROVE GRAFT-VERSUS-NEUROBLASTOMA EFFECTS OF HAPLOIDENTICAL STEM CELL TRANSPLANTATION IN RELAPSED HIGH-RISK NEUROBLASTOMA Christina Lämmle 1, Michaela Döring1, Johannes H. Schulte1, Tim Flaadt1, Florian Heubach1, Peter Lang1,2,3, Christian M. Seitz1,2,3 P648 HHV-6 INFECTION MAY IMPAIR IMMUNE RECONSTITUTION FOLLOWING PEDIATRIC HAPLO-HSCT Katrine Kielsen 1, Eva Kannik Haastrup1, Lisbeth Pernille Andersen1, Tania Masmas1, Marianne Ifversen1 P649 FINAL HEIGHT AND IMPACT OF GROWTH HORMONE TREATMENT IN CHILDREN RECEIVING TBI-BASED CONDITIONING REGIMEN BEFORE HSCT FOR ACUTE LYMPHOBLASTIC LEUKEMIA Charlotte Calvo1,2, Coline Mornet3, Caroline Storey3, Carine Halfon-Domenech4, Cécile Pochon5, Marie-Dominique Tabone6, Guy Leverger6, André Baruchel1, Catherine Paillard7, Charlotte Jubert8, Marilyne Poirée9, Dominique Plantaz10, Justyna Kanold11, Virginie Gandemer12, Anne Sirvent13, Sandrine Thouvenin14, Marlène Pasquet15, Julie Berbis16, Pascal Auquier17, Jean-Hugues Dalle 1,2, Gérard Michel18, Paul Saultier19 P650 ENGRAFTMENT SYNDROME AND ACUTE GVHD AFTER HAPLOIDENTICAL POST-TRANSPLANT CYCLOPHOSPHAMIDE: A PAEDIATRIC MULTICENTRIC EXPERIENCE Maura Faraci 1, Francesco Saglio2, Francesca Baudi1, Filomena Pierri1, Francesca Bagnasco1, Stefano Giardino1, Francesca Gottardi3, Davide Leardini3, Franca Fagioli2,4, Riccardo Masetti3 P651 PULMONARY COMPLICATIONS IN CHILDREN FOLLOWING HAEMATOPOIETIC STEM CELL TRANSPLANT Hannah Walker 1, Diane Hanna1, Theresa Cole1, Gabrielle Haeusler1, Shivanthan Shanthikumar1, Melanie Neeland2 P652 EXCELLENT SURVIVAL USING T-REPLETE UMBILICAL CORD BLOOD TRANSPLANT IN HIGH RISK PAEDIATRIC MYELOID LEUKAEMIA, INCLUDING IN REFRACTORY DISEASE Kate Davies 1, Rob Wynn1 P653 TCRΑΒ + /CD19 + -DEPLETION IN HEMATOPOIETIC STEM CELLS TRANSPLANTATION FROM MATCHED UNRELATED AND HAPLOIDENTICAL DONORS IN CHILDREN WITH HIGH-RISK ACUTE MYELOBLASTIC LEUKEMIA Larisa Shelikhova 1, Olga Molostova1, Maria Ilyushina1, Yuliya Skvortsova1, Irina Shipitsina1, Rimma Khismatullina1, Sergey Blagov1, Svetlana Kozlovskaya1, Irina Kalinina1, Dina Baidildina1, Elena Gytovskaya1, Dmitriy Balashov1, Alexey Kazachenok1, Alexander Popov1, Ekaterina Mikhailova1, Julia Olshanskaya1, Dmitriy Litvinov1, Galina Novichkova1, Alexey Maschan1, Michael Maschan1 P654 IMPLEMENTATION OF CYP3 A5 GENOTYPING TO INDIVIDUALISE TACROLIMUS DOSE IN PAEDIATRIC PATIENTS UNDERGOING HAEMATOPOIETIC STEM CELL TRANSPLANTATION Iván López Torija 1, Laura Gras Martín1, Pablo Escribano Sanz1, Pau Riera Armengol1, Carla Miñarro Chacón1, Sara Bernal Noguera1, Montserrat Torrent Español1, Esther Rojas Rodriguez1, Susana Boronat Guerrero1, Edurne Fernández de Gamarra Martínez1 P655 >EPIDEMIOLOGY OF GUT COLONIZATION AND INFECTION BY CARBAPENEM-RESISTANT GRAM-NEGATIVE BACILLI (CR-GNB) IN PEDIATRIC HEMATO-ONCOLOGICAL AND TRANSPLANTED PATIENTS Adriana Balduzzi 1,2, Iacopo Bellani2, Bianca Monti2, Marta Adavastro2, Francesca Limido2, Sonia Bonanomi1, Arianna De Buglio2, Marianna Rossi1, Francesca Vendemini1, Sergio Foresti1, Andrea Biondi1,2, Paolo Bonfanti1,2, Marco Guglielmo Migliorino1, Sergio Malandrin1, Francesca Iannuzzi1 P656 ALPHA/BETA-DEPLETION AND EARLY TIMING OF SEROTHERAPY PROVIDES RELIABLE ENGRAFTMENT AND LOW TRANSPLANT RELATED MORBIDITY IN CHILDREN UNDERGOING HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR MUCOPOLYSACCHARIDOSIS Annika Ewert 1, Anna Zychlinsky Scharff1, Rita Beier1, Britta Maecker-Kolhoff1, Isolde Schridde1, Kirsten Mischke1, Karl Walter Sykora1, Martin Sauer1 P657 CARDIORESPIRATORY FITNESS, PHYSICAL PERFORMANCE, AND METABOLIC SYNDROME IN ADULT SURVIVORS OF PAEDIATRIC HEMATOPOIETIC STEM CELL TRANSPLANTATION Anne Nissen 1, Tina Gerbek1, Kathrine Fogelstrøm1, Peter Schmidt-Andersen1, Kaspar Sørensen1, Abigail L. Mackey2,3, Martin Kaj Fridh1, Klaus Müller1,3,4 P658 HEMATOPOIETIC TRANSPLANTATION WITH CD45RA+ DEPLETION AND ADOPTIVE THERAPY WITH CD45RO- T-LYMPHOCYTES AND NK CELLS IN PEDIATRIC PATIENTS DIAGNOSED WITH HEMATOLOGICAL MALIGNANCIES AND NON-MALIGNANT DISEASES Mercedes Gasior Kabat 1, David Bueno1, Luisa Sisinni1, Yasmina Mozo1, Raquel De Paz1, Dolores Corral1, Mikel Fernandez Artazcoz1, Ana Belen Romero1, Antonio Marcos1, Victor Jimenez-Yuste1, Antonio Pérez-Martínez1 P659 PSYCHOLOGICAL IMPACT OF HEMATOPOIETIC STEM CELL DONATION ON PEDIATRIC SIBLING DONORS Sara Mostafa Makkeyah 1, Nihal Hussien Aly1, Eslam Elsayed Elhawary2, Sally Abdelmonsif Mohammed1, Salwa Amin Abdelhamid1 P660 AUTOLOGOUS STEM CELL TRANSPLANTATION IN HIGH-RISK NEUROBLASTOMA: A LONG-TERM FOLLOW-UP Ana Pinto1, Isabelina Ferreira 1, Gilda Teixeira1, Ana Sofia Jorge1, Pedro Sousa1, Maria João Gutierrez1, Bárbara Marques2, Ana Forjaz Lacerda1, Fernando Leal-da-Costa1, Nuno Miranda1 P661 OUTCOMES OF ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION IN CHILDREN WITH DIAMOND-BLACKFAN ANEMIA – REPORT OF THE POLISH PEDIATRIC STUDY GROUP FOR HEMATOPOIETIC STEM CELL TRANSPLANTATION Anna Pieczonka 1, Olga Zajac-Spychala1, Krzysztof Kałwak2, Marek Ussowicz2, Jolanta Goździk3, Katarzyna Drabko4, Jan Styczynski5, Agnieszka Sobkowiak-Sobierajska1, Katarzyna Derwich1, Jacek Wachowiak1 P662 OUTCOMES OF ALLO-HSCT FROM MISMATCHED DONORS WITH POST-TRANSPLANT CYCLOPHOSPHAMIDE IN CHILDREN WITH NON- MALIGNANT DISEASES Tatyana Bykova 1, Anna Osipova1, Olga Slesarchuk1, Oleg Goloshchapov1, Elena Semenova1, Alexander Kulagin1, Ludmila Zubarovskaya1 P663 CARDIOVASCULAR RISK FACTORS AND SUBCLINICAL ORGAN DAMAGE ARE COMMON AND INCREASING OVER TIME IN CHILDREN AFTER HEMATOPOIETIC STEM CELL TRANSPLANTATION Damaris Werner 1, Jeannine von der Born1, Elena Lehmann1, Nima Memaran1, Britta Maecker-Kolhoff1, Martin Sauer1, Anette Melk1, Rita Beier1 P664 POSITIVE PRE-TRANSPLANT RESPIRATORY VIRAL PCR IS ASSOCIATED WITH INCREASED DAY 100 TRANSPLANT-RELATED MORTALITY IN PEDIATRIC HSCT RECIPIENTS Jane Trainor 1, Benjamin Hanisch1, Kelly Lyons Snelling1, Robert Podolsky1, David Alex Jacobsohn1 P665 HAPLOIDENTICAL HEMATOPOIETIC STEM CELL TRANSPLANTATION IN PEDIATRIC PATIENTS WITH MYELODYSPLASTIC SYNDROME Anna Osipova1, Tatiana Bykova 1, Olga Slesarchuk1, Olesya Paina1, Oleg Goloshchapov1, Tatiana Gindina1, Elena Semenova1, Alexander Kulagin1, Ludmila Zubarovskaya1 P666 COMPARISONS OF PROGNOSIS OF ALLO-HSCT AFTER CAR-T CELL THERAPY OR CHEMOTHERAPY IN PAEDIATRIC PATIENTS OF REFRACTORY/RELAPSED B-CELL ACUTE LYMPHOBLASTIC LEUKEMIA : A MULTICENTER STUDY CCCG-ALL-2015 Bohan Li 1, Jing Chen2, Chengjuan Luo2, Shaoyan Hu1 P667 TCR-ΑΒ DEPLETED HAPLOIDENTICAL TRANSPLANT WITH CD 45 RA- DEPLETED MEMORY T CELL ADD-BACK IN PAEDIATRIC NON-MALIGNANT DISEASES IN A SINGLE PAEDIATRIC CENTER: 10-YEAR RESULTS Tan Ah Moy 1,2, Michaela Seng1,2, Pham Ngi Thoc Anh1, Vijayakumari K1, Mya Soe Nwe1, Prasad Iyer1,2, Shui Yen Soh1,2, Joyce Lam1,2, Wing Leung1,3 P668 AIEOP EXPERT BOARD RECOMMENDATIONS FOR MANAGEMENT OF POST-HCT HEMORRHAGIC CYSTITIS IN PEDIATRIC SETTING Gianluca Dell’Orso 1, Simone Cesaro2, Marcello Carlucci1, Evelina Olcese1, Adriana Balduzzi3, Francesca Vendemini3, Massimo Catti4, Francesco Saglio4, Francesca Compagno5, Natalia Maximova6, Marco Rabusin6, Maria Cristina Menconi7, Katia Perruccio8, Elena Soncini9, Francesco Paolo Tambaro10, Veronica Tintori11, Daria Pagliara12, Maura Faraci1 P669 EXCELLENT SURVIVAL AND LONG TERM OUTCOMES IN INFANTS RECEIVING TOTAL BODY IRRADIATION FOR CONDITIONING PRIOR TO ALLOGENEIC TRANSPLANT Hannah Lust1, Stephanie Powell1, Karina Danner Koptik1, Erin Kaseda1, Jennifer Schneiderman1, Sonali Chaudhury 1 P670 BCG-VACCINE COMPLICATIONS IN CHILDREN WITH INFANT ACUTE LYMPHOBLASTIC LEUKEMIA Mikhail Lemeshev1, Alexandra Laberko 1, Larisa Shelikhova1, Veronika Fominykh1, Lili Khachatryan1, Galina Solopova1, Natalia Myakova1, Dmitry Balashov1 P671 WORKFORCE CONSENSUS RECOMMENDATIONS FOR PAEDIATRIC HSCT CENTRES ON BEHALF OF THE PAEDIATRIC SUB-COMMITTEE OF THE BRITISH SOCIETY OF BLOOD, BONE MARROW TRANSPLANTATION CELLULAR THERAPY (BSBMTCT) Reem Elfeky 1, Valerie Broderick2, Anna- Marie Ewins3, Elizabeth Rivers1, Wing Roberts4, Mary Slatter4, Kanchan Rao1, Beki James5, Brenda Gibson3 P672 HAPLOIDENTICAL HEMATOPOIETIC STEM CELL TRANSPLANTATION WITH A CONTROLLED NUMBER OF CD3 + CELLS AND POST-TRANSPLANT CYCLOPHOSPHAMIDE: EXPERIENCE FROM A SINGLE PEDIATRIC CENTER Giulia Albrici1, Giulia Baresi1, Stefano Rossi1, Elena Soncini1, Elisa Bertoni1, Marta Comini2, Federica Bolda2, Alessandra Beghin2, Arnalda Lanfranchi2, Fulvio Porta1, Marianna Maffeis 1 P673 PLASMA AMINO ACIDS AND FECAL CALPROTECTIN USAGE FOR THE PREDICTION OF INTESTINAL INJURY AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION IN CHILDREN Igne Kairiene 1, Jelena Rascon1, Ramune Vaisnore1 P674 MULTIPLE MINOR PHLEBOTOMIES IN EPP INVOLVING THE LIVER: IS THERE A WAY TO AVOID NEEDING A LIVER AND HAEMATOPOIETIC STEM CELL TRANSPLANT? Rita Beier 1, Jasmin Barman-Aksözen2, Franziska van Breemen2, Hagen Ott3, Katharina Becker1, Annika Ewert1, Ulrich Baumann1, Eva Pfister1, Martin Sauer1, Elisabeth Minder2, Britta Maecker-Kolhoff1, Anna-Elisabeth Minder2 P675 COMPARISON OF BUSULFAN-BASED AND TREOSULFAN-BASED HIGH-DOSE CHEMOTHERAPY AND AUTOLOGOUS STEM CELL TRANSPLANTATION IN HIGH-RISK NEUROBLASTOMA Kyung-Nam Koh 1, Young Kwon Koh2, Aejin Kang1, Ji Young Kim1, Su Hyun Yun1, Sung Han Kang1, Hyery Kim1, Ho Joon Im1 P676 USE OF BLINATUMOMAB TO ACHIEVE REMISSION AND CONSOLIDATION WITH HAPLOIDENTICAL TRANSPLANT WITH CYCLOPHOSPHAMIDE FOR THE TREATMENT OF CHILDREN WITH REFRACTORY ACUTE LYMPHOBLASTIC LEUKEMIA Alberto Olaya Vargas 1, Haydee Salazar-Rosales2, Martin Peréz-Gárcia3, Yadira Melchor-Vidal4, Annecy Herver-Olivares5, Gerardo López- Hernández2, Nideshda Ramírez-Ortiz2, Cesar Galván-Diaz2, Alberto Olaya-Nieto2 P677 HEMORRHAGIC CYSTITIS IN CHILDREN AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION: INCIDENCE, TREATMENT, OUTCOME, AND RISK FACTORS Nur Ayca Celik 1, Talia Ileri2, Elif Ince2, Hasan Fatih Cakmaklı2, Berk Burgu1, Zeynep Ceren Karahan1, Seda Kaynak Sahap1, Ebru Dumlupınar1, Mehmet Ertem2 P678 TRANSPLANT-ASSOCIATED THROMBOTIC MICROANGIOPATHY (TA-TMA) IN CHILDREN TREATED WITH ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION (ALLO-HSCT): ONE CENTER STUDY Tomasz Jarmoliński 1, Monika Rosa1, Iwona Bil-Lula1, Joanna Korlaga1, Krzysztof Kałwak1, Marek Ussowicz1 P679 DISTANCE MAKES THE CELLS GROW FONDER- PAEDIATRIC ALLOGENIC TRANSPLANT AND CELLULAR THERAPY REFERRAL PROGRAM, THE SOUTH AUSTRALIAN EXPERIENCE Matthew O’Connor 1,2, Catherine Mitchell1, Laura Chapman2, Karen McCleary2, Adam Nelson2, Richard Mitchell2 P680 INCREASING TIM-3 + T CELLS IN PERIPHERAL BLOOD OF PEDIATRIC PATIENTS WITH RELAPSE B-ALL AFTER HAPLOIDENTICAL ALLO-HSCT Liubov Tsvetkova 1, Olga Epifanovskaya1, Elena Babenko1, Olesya Paina1, Polina Kozhokar’1, Zhemal Rakhmanova1, Olesya Yudinceva1, Anna Osipova1, Sabina Ryabenko1, Elena Dobrovolskaya1, Ivan Moiseev1, Alexandr Kulagin1, Ludmila Zubarovskaya1 P681 IMMUNE-MEDIATED CYTOPENIA AFTER PEDIATRIC HEMATOPOIETIC CELL TRANSPLANTATION – A RETROSPECTIVE ANALYSIS Mária Füssiová 1, Júlia Horáková1, Ivana Boďová1, Jaroslava Adamčáková1, Dominika Dóczyová1, Miroslava Pozdechová1, Tomáš Sýkora1, Peter Švec1, Alexandra Kolenová1 P682 SEQUENTIAL KIDNEY-STEM CELL TRANSPLANTATION IN PATIENT WITH SCHIMKE IMMUNO-OSSEOUS DYSPLASIA: CASE REPORT Alexandra Shutova1, Alexandr Bazaev1, Yulia Skvortsova1, Alexandr L. Rumyantsev2, Diana Khalikova2, Galina Novichkova1, Michael Maschan 1, Dmitry Balashov1, Alexey Maschan1 P683 CYCLOSPORINE PLUS METHOTREXATE VERSUS CYCLOSPORINE ALONE FOR GRAFT-VERSUS-HOST DISEASE PROPHYLAXIS IN PEDIATRIC PATIENTS UNDERGOING HEMATOPOIETIC STEM CELL TRANSPLANTATION FROM HLA-IDENTICAL SIBLING Vincenzo Apolito 1, Valeria Ceolin1, Manuela Spadea1,2, Marta Barone1, Marco Basiricò1, Francesco Saglio1, Franca Fagioli1,2 P684 NUTRITIONAL DYNAMICS IN PEDIATRIC HEMATOPOIETIC STEM CELL TRANSPLANTATION: A RETROSPECTIVE MONOCENTRIC STUDY ASSESSING BMI PERCENTILES AND CLINICAL OUTCOMES Timo Stetter1, Michaela Döring 1, Christian Seitz1, Nora Rieflin1, Thomas Baumgarten1, Léa Thérond1, Pia Glogowski1, Johannes Schulte1, Rupert Handgretinger1, Peter Lang1, Karin M. Cabanillas Stanchi1 P685 INTEGRATING CAR T-CELL THERAPY AND ALLOGENEIC STEM CELL TRANSPLANTATION IN CHILDREN WITH HIGH RISK ACUTE LYMPHOBLASTIC LEUKEMIA. THE EXPERIENCE OF A SINGLE CENTER Blanca Molina 1, Marta Gonzalez Vicent1, Sara Vinagre1, Blanca Herrero1, David Diaz1, Miguel Angel Diaz1 P686 ASSESSMENT OF THE ENDOTHELIAL GLYCOCALYX BY VIDEO MICROSCOPY IN CHILDREN WITH ACUTE LEUKEMIA AFTER ALLOGENEIC STEM CELL TRANSPLANTATION Zarina Khaerova1, Zhemal Rakhmanova1, Olesya Paina1, Timur Vlasov2, Elena Semenova1, Ivan Moiseev 1, Alexander Kulagin1, Ludmila Zubarovskaya1 P687 INTRODUCTION OF BODY IMPEDENCE ANAYSIS TO MEASURE BODY COMPOSITION CHANGES AND FLUID STATUS OF PAEDIATRIC PATIENTS UNDERGOING HAEMATOPOIETIC STEM CELL TRANSPLANTATION Rebecca Fisher 1, Alice Brewer1, Belinda Meares1, Sheridan Collins1, Sarah Slack1, Melissa Gabriel1 P688 TRANSPLANTATION OUTCOME OF HIGH RISK ACUTE MYELOID LEUKEMIA AND MYELODYSPLASTIC SYNDROME IN CHILDREN: SINGLE CENTER EXPERIENCE IN KOREA Young Tak Lim 1, Eu Jeen Yang1, Jun Young Oh1 P689 BUILDING A PEDIATRIC HEMATOPOIETIC STEM CELL TRANSPLANT UNIT IN PARAGUAY: LESSON LEARNT Marta Verna 1, Maria Liz Benitez2, Attilio Maria Rovelli1, Jabibi Noguera2, Marta Canesi1, Valentino Conter1, Susy Thiel Figueredo3, Andrea Biondi1,4 P690 HIGH-DOSE CHEMOTHERAPY WITH STEM CELL TRANSPLANTATION IN ADULT PRIMARY MEDIASTINAL GERM CELL TUMORS. A RETROSPECTIVE STUDY OF THE EBMT, CELLULAR THERAPY & IMMUNOBIOLOGY WORKING PARTY Paolo Pedrazzoli1, Manuela Badoglio2, Myriam Labopin2, Giovanni Rosti1, Matthieu Delaye3, Carsten Bokemeyer4, Christoph Seidel4, Jane Apperley5, Elisabetta Metafuni6, Juergen Finke7, Jean-Henri Bourhis8, Christos Kosmas9, Florent Malard10, Jurgen Kuball11, Christian Chabannon12, Annalisa Ruggeri13, Simona Secondino 1 P691 SURVIVAL OUTCOMES IN PANCREATIC CANCER: EVALUATING THE IMPACT OF WIPPLE’S SURGERY AND HAEMATOPOIETIC CELL TRANSPLANTATION Olle Ringden 1, Johan Permert2, Johan Törlen1, Stephan Mielke1, Behnam Sadeghi1 P692 SUCCESSFUL HIGH DOSE CHEMOTHERAPY WITH STEM CELL RESCUE IN DISSEMINATED OVARIAN CHORIOCARCINOMA COMPLICATED WITH CHORIOCARCINOMA SYNDROME Abdulaziz Bin Mesained 1, Abdulwahab Alharthi1, Walid Hazem1, Omar Alsharif1, Nawaf Alkhayat1, Mohammad Alshahrani1, Hasna Hamzi1, Amal Binhassan1, Yasser Elborai1 P693 DONOR-SPECIFIC ANTI-HLA ANTIBODIES (DSAS) IN PATIENTS UNDERGOING ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION FROM MISMATCHED DONORS, ON BEHALF OF GITMO AND AIBT Ursula La Rocca1,2, Roberto Ricci1, Alfonso Piciocchi3, Walter Barberi1, Elena Oldani4, Alida Dominietto5, Raffaella Cerretti6, Alessandra Picardi6, Francesca Bonifazi7, Riccardo Saccardi8, Maura Faraci9, Giovanni Grillo10, Lucia Farina11, Benedetto Bruno12,13, Anna Grassi4, Anna Proia14, Elena Tagliaferri15, Giuseppina De Simone16, Michele Malagola17, Michela Cerno18, Simone Cesaro19, Paolo Bernasconi20, Lucia Prezioso21, Paola Carluccio22, Nicola Mordini23, Matteo Pelosini24, Attilio Olivieri25, Patrizia Chiusolo26, Stella Santarone27, Michele Cimminiello28, Roberto Crocchiolo10, Franco Papola29, Gianni Rombolà30, Nicoletta Sacchi31, Valeria Miotti32,33, Lia Mele34,33, Benedetta Mazzi35,33, Fabio Ciceri36, Massimo Martino37, Anna Paola Iori 1 P694 DETERMINING THE PREDICTIVE IMPACT OF DONOR PARITY ON THE OUTCOMES OF HUMAN LEUKOCYTE ANTIGEN MATCHED HEMATOPOIETIC STEM CELL TRANSPLANTS: A RETROSPECTIVE, SINGLE-CENTER STUDY Tanaz Bahri1, Maryam Barkhordar 1, Mojtaba Azari1, Hosein Kamranzadeh1, Seied Asadollah Mousavi1, Soroush Rad1, Sahar Tavakoli Shiraji1, Mohammad Vaezi1 P695 POST-TRANSPLANTATION CYCLOPHOSPHAMIDE IMPROVES GRAFT-VERSUS-HOST DISEASE-FREE, RELAPSE-FREE SURVIVAL IN HLA-DPB1 MISMATCHED UNRELATED DONOR ALLOGENEIC TRANSPLANT Shannon R. McCurdy1, Scott R. Solomon2, Brian C. Shaffer3, Meilun He4, Yung-Tsi Bolon 4, Amanda G. Blouin3, Alla Keyzner5, Francisco A. Socola6, Uroosa Ibrahim5, Jun Zou7, Hana Safah6, Nakhle Saba6, Shahinaz Gadalla8, Miguel-Angel Perales9, Sophie Paczesny10, Steven Marsh11, Effie W. Petersdorf12, Tao Wang13, Ephraim J. Fuchs14, Stephanie J. Lee12 P696 THE RESCUE TRANSPLANTATION STRATEGY FOR GRAFT FAILURE: DONOR SELECTION AND GVHD PROPHYLAXIS IN THE CURRENT ERA Mizuki Watanabe 1,2, Junya Kanda1, Kentaro Fukushima3, Kaito Harada4, Naoyuki Uchida5, Makoto Onizuka4, Noriko Doki6, Ken-ichi Matsuoka7, Takahiro Fukuda2, Satoshi Yoshihara8, Toshiro Kawakita9, Shingo Yano10, Masatsugu Tanaka11, Yasushi Onishi12, Fumihiko Ishimaru13, Tatsuo Ichinohe14, Yoshiko Atsuta15, Kimikazu Yakushijin16, Hideki Nakasone17,18 P697 UNRELATED DONOR SELECTION FOR STEM CELL TRANSPLANT USING POST-TRANSPLANT CYCLOPHOSPHAMIDE FOR ACUTE MYELOID LEUKEMIA: A STUDY FROM THE ACUTE LEUKEMIA WORKING PARTY OF THE EBMT Jaime Sanz 1, Myriam Labopin2, Goda Choi3, Alexander Kulagin4, Jacopo Peccatori5, Jan Vydra6, Péter Reményi7, Jurjen Versluis8, Montserrat Rovira9, Didier Blaise10, Hélène Labussière-Wallet11, Juan Montoro12, Simona Sica13, Ellen Meijer14, Maija Itäla-Remes14, Nicolaas Schaap15, Claude Eric Bulabois16, Simona Piemontese5, Mohamad Mohty17, Fabio Ciceri5 P698 PATIENT HLA GENOTYPE AND REGISTRY DIVERSITY STRONGLY INFLUENCE DONOR SEARCH DURATION AND SUCCESS Stefanie V. Dorner 1, Henning Baldauf2, Carina Rave2, Christine Urban3, Thilo Mengling3, Johannes Schetelig2, Alexander H. Schmidt3,1, Julia Pingel1 P699 FEASIBILITY AND SAFETY OF GRANULOCYTE COLONY-STIMULATING FACTOR (G-CSF) PERIPHERAL BLOOD STEM CELL MOBILIZATION AND COLLECTION BY APHERESIS IN RELATED DONORS AGED 65 AND OVER Kahina Amokrane 1, Kamelia Alexandrova1, Cristina Castilla-Llorente1, Sylvain Pilorge1, Tereza Coman1, Jean-Henri Bourhis1, Valerie Lapierre1 P700 HAPLOIDENTICAL VERSUS MISMATCHED UNRELATED ALLOGENEIC STEM CELL TRANSPLANTATION FOR MYELOID MALIGNANCIES: AN ANALYSIS ON 1413 PATIENTS FROM THE GERMAN REGISTRY Andrea Gantner 1, Daniel Fürst2,3, Aysenur Arslan2,3, Svenja Labuhn4, Mark Ringhoffer5, Johannes Schetelig6,7, Thomas Schroeder8, Gesine Bug9, Elisa Amann2,3, Christine Neuchel2,3, Sandra Schmeller4, Jan Beyersmann4, Hubert Schrezenmeier2,3, Joannis Mytilineos10, Nicolaus Kröger11, Elisa Sala1 P701 THE POST-PANDEMIC HAEMATOPOIETIC STEM CELL (HSC) GRAFT CRYOPRESERVATION TRENDS AND THEIR EFFECTS ON UNRELATED DONOR REGISTRIES: THE UK EXPERIENCE Ruta Barkauskiene1, Sara Lozano Cerrada1, Angharad Pryce1, Joanne Badger1, Paul Johnson1, Ann O’Leary1, Robert Danby 1, Chloe Anthias1 P702 ALLOGENIC STEM CELL TRANSPLANTATION AND PERI TRANSPLANT STRATEGIES IN PATIENTS WITH MISMATCH DONORS – A SINGLE CENTER EXPERIENCE IN 151 PATIENTS Paul Jäger1, Benno Biermann 1, Felicitas Schulz1, Kathrin Nachtkamp1, Patrick Tressin1, Ben-Niklas Baermann1, Annika Kasprzak1, Felix Matkey1, Ulrich Germing1, Sascha Dietrich1, Guido Kobbe1 P703 SURVIVAL PROGNOSTIC FACTORS AFTER A SECOND ALLOGENEIC HEMATOPOIETIC TRANSPLANTATION Rodrigo Cantera Estefanía1, Raquel García Ruiz1, Miriam Sánchez Escamilla1, Leddy Patricia Vega Suárez1, María Terán1, Dianis Escorcio Fariab2, Sara Fernández Luis1, Juan José Domínguez García1, Tatiana Fernández Barge 1, Ana Gea Peña1, Irene Francés Alexandre1, Ana Tobalina García1, María Oviedo Madrid1, Irene Gorostidi Álvarez1, Julia Bannatyne Undabeitia1, Juan Manuel Cerezo Martín1, Mercedes Colorado Araujo1, Mónica López Duarte1, Guillermo Martín Sánchez1, Lucrecia Yáñez San Segundo1, Noemí Fernández Escalada1, Andrés Insunza Gaminde1, Monserrat Briz del Blanco1, Jose Iñigo Romón Alonso1, Gala Aglaia Méndez Navarro1, Enrique Ocio San Miguel1, Arancha Bermúdez Rodríguez1 P704 QUALITY OF ENGRAFTMENT AND INCIDENCE OF ACUTE GVHD GRADE II – IV POST PERIPHERAL HAEMOPOIETIC CELLS CRYOPRESERVATION IN PATIENTS UNDERGOING ALLOGENEIC TRANSPLANTATION FROM HLA IDENTICAL DONORS Anna Maria Raiola 1, Massimiliano Gambella1, Barabino Luca2, Stefania Bregante1, Carmen Di Grazia1, Alida Dominietto1, Anna Ghiso1, Livia Giannoni1, Alberto Serio1, Silvia Luchetti1, Riccardo Varaldo1, Monica Passannante1, Antonella Laudisi1, Alessandra Scalas2, Paola Contini3, Federico Ivaldi3, Raffaele De Palma3, Alessandra Bo1, Emanuele Angelucci1 P705 WHAT WORKS AND WHAT DOES NOT? THE IMPACT OF DONOR CHARACTERISTICS IN T REPLETE HAPLOIDENTICAL STEM CELL TRANSPLANTATION WITH POST-TRANSPLANT CYCLOPHOSPHAMIDE IN CHILDREN Anuraag Reddy Nalla 1, Revathi Raj1, Ramya Uppuluri1, Venkateswaran Vellaichamy1, Suresh Duraisamy1, Kavitha Ganesan1, Anupama Nair1, Vijayshree Muthukumar1, Indira Jayakumar1, Ravindra Prasad1, Usha Surianarayanan1 P706 OUTCOMES OF OLDER ADULTS UNDERGOING ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION WITH POST-TRANSPLANT CYCLOPHOSPHAMIDE BASED PROPHYLAXIS Victoria Murillo Cortés 1, Paola Charry2, María Suárez-Lledó3,4, María Teresa Solano4, Anna Serrahima4, Joan Cid2,4, Miquel Lozano2,4, Laura Rosiñol3,4, Jordi Esteve3,4, Álvaro Urbano-Ispizua3,4, Enric Carreras5, Francesc Fernandez-Avilés3,4, Carmen Martínez3,4, Montserrat Rovira3,4, María Queralt Salas3,4 P707 COMPARING THE CLINICAL OUTCOMES OF ALLOGENEIC STEM CELL TRANSPLANTATION FROM MATCHED-SIBLING DONORS AND ALTERNATIVE DONORS IN PATIENTS WITH SEVERE THALASSEMIA : SYSTEMATIC REVIEW AND META-ANALYSIS Sirichai Srichairatanakool 1, Wuttipat Kiratipaisarl1, Sarunsorn Krintratun1, Adisak Tantiworawit1, Chatree Chai-Adisaksopha1 P708 IMPACT OF DONOR BLOOD GROUP AND CMV MATCH ON ALLOGENEIC STEM CELL TRANSPLANTATION: A SINGLE CENTER LONG TERM FOLLOW UP STUDY Mohamed Debes1, James Clarke1, Yeong Lim1, Shahid Iqbal1, Leah Credidio1, Hannah Williams2, Jennifer Gibson1, Sajid Pervaiz1, Angela Milner1, Thomas Seddon1, Arpad Toth1, Muhammad Saif 1 P709 DIFFERENCES IN OVERALL SURVIVAL AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANT WITH IDENTICAL AND HAPLOIDENTICAL DONORS IN MEXICO Marco Alejandro Jiménez-Ochoa 1, Elsa Avila-Arreguin2, Severiano Baltazar-Arellano3, María Margarita Contreras-Serratos1, Martha Leticia González Bautista1, Alba Morales-Hernandez2, Uendy Pérez-Lozano4, María Guadalupe Rodríguez González2, Guillermo Sotomayor-Duque3, Elizabeth Urbina-Escalante1 P710 ANTI-T LYMPHOCYTE GLOBULIN (ATLG) TO PREVENT GRAFT FAILURE AFTER HAPLOIDENTICAL STEM CELL TRANSPLANTATION WITH DONOR SPECIFIC ANTIBODIES (DSA) Christian Niederwieser 1, Radwan Massoud1, Evgeny Klyuchnikov1, Gagelmann Nico1, Johanna Richter1, Kristin Rathje1, Tatiana Urbanowicz1, Ameya Kunte1, Janik Engelmann1, Christina Ihne1, Iryna Lastovytska1, Cecilia Lindhauer1, Franziska Marquard1, Mirjam Reichard1, Alla Ryzhkova1, Rusudan Sabauri1, Mathias Schaeferskuepper1, Niloufar Seyedi1, Georgios Kalogeropoulos1, Silke Heidenreich1, Ina Rudolph1, Normann Steiner1, Julia Kienast1, Maroly Bohorquezmanjarres1, Dietlinde Janson1, Christine Wolschke1, Francis Ayuk1, Nicolaus Kröger1 P711 HAPLOIDENTICAL TRANSPLANT WITH POST- CY WITHOUT T DEPLETION. PEDIATRIC EXPERIENCE IN HIGH-RISK LEUKEMIAS FROM GATMO [ARGENTINIAN GROUP OF BONE MARROW TRANSPLANT] Maria Laura Rizzi 1, Natalia Gonzalez1, Evelin Colombo1, Sol Jarchum1, Emilia Mas2, Victoria Suen2, Sandra Formisano3, Vera Milovik4, Rquel Staciuk5, Pablo Longo6, Silvina Palmer3, German Stemelin3, Silvina Wilberger4, Valeria Santidrian5 P712 DONOR SELECTION CRITERIA IN ALLOGENEIC STEM CELL TRANSPLANTATION FOR ACUTE MYELOID LEUKAEMIA: RETROSPECTIVE SINGLE-CENTER EVALUATION Ursula La Rocca1,2, Saveria Capria 1, Claudia Lucci1, Roberto Ricci1, Adele Delli Paoli1, Martina Salvatori1, Maurizio Martelli1, Anna Paola Iori1, Walter Barberi1 P713 IRANIAN DONORS SAVE LIVES: COLLABORATING WITH COMMUNITY ADVOCATES TO ADDRESS RACIAL DISPARITY IN ACCESS TO UNRELATED DONORS FOR ALLOGENEIC TRANSPLANTATION Farnaz Farahbakhsh 1,2,3, Warren Fingrut1,4,5, Bonnie Lu1 P714 INVESTIGATE THE POTENTIAL ASSOCIATION OF HLA ALLELES WITH HEMATOPOIETIC STEM CELL TRANSPLANTATION OUTCOMES Fatma Al Lawati 1,2, Murtadha Alkhbouri3, Salma Al Harrasi2, Aliya Al Ansari1 P715 SUCCESSFUL OUT-PATIENT SELF-ADMINISTRATION OF MOBILISATION AGENTS FOR HAEMATOPOIETIC STEM CELL TRANSPLANT Yona Skosana 1, Emma Smith1, Bridged Mofokeng1, Thabo Gcayiya1, Tanya Glatt1,2,3 P716 ANALYSIS OF BONE MARROW TRANSPLANTATION OUTCOMES BETWEEN JAPANESE AND NON-JAPANESE DONORS AND RECIPIENTS Ryu Yanagisawa 1, Michiho Shindo2, Akihito Shinohara2, Yachiyo Kuwatsuka3, Koichi Nakase4, Fumihiko Kimura5, Naoki Shingai6, Tetsuya Nishida7, Takahiro Fukuda8, Masatoshi Sakurai9, Mineo Kurokawa10, Takashi Koike11, Shuichi Ota12, Satoru Takada13, Makoto Onizuka11, Tatsuo Ichinohe14, Yoshiko Atsuta15,16, Junya Kanda17, Hideki Nakasone18,19, Tomomi Toubai20 P717 PSYCHOLOGICAL ASSESSMENT OF HEMATOPOIETIC STEM CELL DONORS UNDERGOING PERIPHERAL BLOOD STEM CELL MOBILISATION Alka Khadwal 1, Ritwik Lahiri1, Sandeep Grover1, Rekha Hans1, Nabhajit Mallik1, Charanpreet Singh1, Arihant Jain1, Deepesh Lad1, Gaurav Prakash1, Aditya Jandial1, Pankaj Malhotra1 P718 IMPACT AND EFFICACY OF DONOR TYPE IN ALLOGENEIC STEM CELL TRANSPLANTATION IN PATIENTS WITH ACUTE LEUKEMIA, SINGLE CENTER EXPERIENCE Lazar Chadievski 1, Irina Panovska Stavridis1, Sanja Trajkova1, Nevenka Ridova1, Milche Cvetanoski1, Simona Stojanovska1, Bozidar Kocoski1, Lidija Chevreska1, Svetlana Krstevska Balkanov1, Aleksandra Pivkova Veljanovska1 P719 THE EFFECT OF GRAFT MANIPULATION AND CRYOPRESERVATION ON DIFFERENT GRAFT COMPONENT AND ITS POTENTIAL CLINICAL APPLICATIONS Mohammed Kawari 1,2, Emily Fu1, Shiyi Chen1, Mileidys Alvarez1, Jessica McLeod1, Muhammad Badawi1, Arpita Parikh1, Rashied Kawshermolla1, Racheljihye Kim1, Bramdeo Motiram1, Lynn Jean1, Miyada Himmat1, Lydia Morrison1, Keanu Herzog1, Madhavi Gerbitz3, Megan Nelles1, Eunyoung Cho1, Ahmed Najemeldin1, Igor Novitzky-Basso1,2, Armin Gerbitz1,2,3 P720 A SIMPLE PREDICTIVE ALGORITHM FOR ESTIMATION OF THE BLOOD VOLUME TO BE PROCESSED TO YIELD TARGET CELL NUMBERS FOR MANUFACTURING OF TISA-CEL® AND AXI-CEL® Stephanie Winter 1, Andreas Tanzmann1, Manuela Branka1, Patricija Rajsp1, Philipp Wohlfarth1, Philipp Staber1, Ulrich Jaeger1, Antonia Mueller1, Nina Worel1 P721 REAL-WORLD MOBILIZATION AND HARVEST OUTCOMES IN NEWLY DIAGNOSED MULTIPLE MYELOMA PATIENTS RECEIVING D-VTD: UK EXPERIENCE Jose Aspa Cilleruelo 1, Christianne Bourlon2, Elisa Roldan Galvan1, Reuben Benjamin2, Kirsty Cuthill2, Arief Gunawan2, Majid Kazmi3, Pramila Krishnamurthy2, Victoria Potter2, Robin Sanderson2, Michelle Kenyon2, Mili Shah2, Matthew Streetly3, Fabio Serpenti2, Benjamin Robinson1, Andrew Chantry1, Stella J. Bowcock2, Lalita Banerjee4, John Robert Jones5, Sabia Rashid6, Ana Isabel Duran Maestre6, Satyajit Sahu6, Sudarshan Gurung7, Lianwea Chia8, Haili Cui2, Alison Pratt2, Maheen Ahsan2, Stella Bouziana2, John A. Snowden1, Katharine Elizabeth Bailey2 P722 FACTORS AFFECTING CD34 + CRUDE COLLECTION EFFICIENCY IN MOBILIZED DONORS UNDERGOING LEUKOCYTAPHERESIS Jesús Fernandez 1, Monica Linares1, David Gomez-Vives1, Sara Lewandowski2, Hugo Fabre3, Ana Garcia-Buendia1, Marina Rierola1, Veronica Pons1, Julia Ayats1, Juan Porras1, Carmen Montanero1, Teresa Contijoch1, Isabel Amaya1, Esperanza Ribas1, Marc Vilches1, Marta Guerrero1, Alba Acedo1, Sofia Alonso1, Nerea Castillo-Flores1, Sergi Querol1, Rafael Parra1 P723 EFFICACY OF PROPHYLACTIC ANTIBIOTICS FOR THE PREVENTION OF NEUTROPENIC FEVER IN PATIENTS WITH MULTIPLE MYELOMA RECEIVING HIGH-DOSE CYCLOPHOSPHAMIDE FOR STEM CELL MOBILIZATION Liqiong Hou1, Juan Li 1 P724 EFFICACY OF PLERIXAFOR IN CD34+ STEM CELL MOBILIZATION IN HEALTHY PEDIATRIC STEM CELL DONORS Rishab Bharadwaj1, Vimal Kumar 1, Deenadayalan Munirathnam1 P725 PEGFILGRASTIM FOR STEM CELL MOBILIZATION FOLLOWED BY FRESH STEM CELL INFUSION IN MULTIPLE MYELOMA Hegta Tainá Rodrigues FIgueiroa 1, Pedro Paulo Faust1, Phillip Scheinberg1, Juliana Matos Pessoa1, Fauze Lutfe Ayoub1, André Dias Américo1, Dimitra Delijaicov1, Breno Moreno Gusmão1, André Larrubia1, Eurides Leite da Rosa1, Ana Cynira Franco Marret1, Arlette Edna Lazar1, Germano Glauber de Medeiros Lima1, Isabella Silva Pimentel Pitol1, Fabio Rodrigues Kerbauy1,2 P726 A MID-APHERESIS CD34 COUNT UTILITY IN EARLY STOPPAGE OF APHERESIS IN PATIENTS/DONORS IN A PBSCT PROCEDURE – ANALYSIS OF EXPERIENCE IN TWO SOUTH INDIAN CANCER CENTRES Veni Prasanna Gedala 1, Rakesh Reddy Boya1, Pradeep Ventrapati1, Anuradha Dasari1, Chandrasekhar Bendi2, Praveena Voonna2 P727 PLERIXAFOR AS A MOBILIZING AGENT FOR SALVAGE HIGH-DOSE CHEMOTHERAPY IN RELAPSED/REFRACTORY TESTICULAR CANCER: AN EXPERIENCE OF 22 CASES Sara Bleve1, Maria Concetta Cursano1, Cecilia Menna1, Caterina Gianni1, Giuseppe Schepisi1, Valentina Gallà2, Chiara Casadei1, Serena Mangianti3, Stefano Baravelli4, Accursio Fabio Augello4, Francesco Lanza5, Simona Secondino6, Paolo Pedrazzoli6, Giovanni Rosti1, Ugo De Giorgi 1 P728 ASSESSING AND REFINING PREDICTIVE MODELS OF POTENTIAL POOR MOBILIZERS Nelson Chan1, Kai Wan 2, Sinju Thomas1, Sandra Loaiza1, Noora Buti1, Sophie Zemenides1, Eitan Mirvis1, Lucy Cook1,2, Edward Bataillard1, Edward Kanfer1, Maria Atta2, Aristeidis Chaidos2,1, Jane Apperley2,1, Edurado Olavarria2,1, Renuka Palanicawandar1 P729LEFT OUT IN THE COLD: STEM CELL GRAFTS ARE STILL FUNCTIONAL AFTER MORE THAN 20 YEARS IN CRYOSTORAGE Rebecca Axelsson Robertson 1,2, Lyda Osorio Fernandez1, Michael Uhlin2 P730 SAFETY AND EFFICACY OF PLERIXAFOR IN POOR MOBILIZERS: AN INTERIM ANALYSIS AND MULTICENTER PROSPECTIVE STUDY Weiping Liu1, Yao Liu2, Hui Liu3, Mingxing Zhong4, Zengjun Li5, Caixia Li6, Yuerong Shuang7, Jun Luo8, Jian Zhou9, Jie Ji 10, Sujun Gao11, Wenzheng Yu12, Xiaopei Wang1, Yuqin Song1, Jun Zhu1 P731 BONE MARROW HARVESTING IN ALLOGENEIC DONORS: HOW TO PREDICT SUCCESSFUL AND SATISFYING BM PRODUCT Tigran Torosian 1, Alicja Wozniak1, Grzegorz Hensler1, Katarzyna Szymanska1, Iwona Tomanek1 P732 COMPARISON OF MOBILIZATION REGIMENS USED IN LYMPHOMA AND FACTORS THAT INFLUENCE PERIPHERAL BLOOD STEM CELL MOBILIZATION Laxma Reddy 1,2, Anant Gokarn1,2, Akanksha Chichra1,2, Sachin Punatar1,2, Sumeet Mirgh1,2, Nishant Jindal1,2, Lingaraj Nayak1,2, Navin Khattry1,2, Sumathi Hiregoudar1,2, Minal Poojary1,2, Suryatapa Saha1,2, Shashank Ojha1,2, Bhausaheb Bagal1,2 P733 THIRTEEN-YEAR EXPERIENCE WITH PLERIXAFOR IN CHILDREN FROM A SINGLE CENTRE: TOLERABILITY, GRAFT QUALITY AND ENGRAFTMENT Lucy Metayer1, Charlotte Rigaud1, Valerie Lapierre1, Sylvie Psyche1, Angelique Benoit-Tricoire1, Claudia Pasqualini1, Christelle Dufour1, Kamélia Alexandrova 1 P734 AN ALTERNATIVE USE OF A COLLOIDAL SUBSTITUTE (SUCCINYLATED GELATINE) FOR QUALITY CONTROLS IN PERIPHERAL BLOOD STEM TRANSPLANTATION Claudia Del Fante 1, Eugenio Barone1, Simona De Vitis1, Rosalia Cacciatore1, Daniela Troletti1, Cesare Perotti1 P735 ANTI-CD38 TREATMENT AS A PREDICTIVE FACTOR FOR STEM CELL MOBILIZATION FAILURE AND DELAYED GRAFT RECOVERY IN MULTIPLE MYELOMA: A TERTIARY HOSPITAL EXPERIENCE Paula Zoco Gallardo 1, Ariadna García Ascacibar1, Juan Mateos Mazón1, Laura Posada Alcón1, Javier Arzuaga Méndez1, Julia Arrieta Aguilar1, Amaia Uresandi Iruin1, Amaia Balerdi Malcorra1, Maria Elena Amutio Díez1, María Casado Sánchez1, Sara Hormaza De Jauregui1, Gorka Pinedo Martín1, Laura Aranguren Del Castillo1, Ana Lobo Olmedo1, Maria Elena Amutio Díez1, Juan Carlos García Ruiz1 P736 INCREASED DOSE OF G-CSF OVERCOMES AGE AS A RISK FACTOR FOR POOR MOBILIZATION Yuliya Shestovska 1, Shalina Joshi1, Dzhirgala Mandzhieva1, Regina Mullaney1, Ey Luu1, Rashmi Khanal1, Asya Varshavsky Yanovsky1, Michael Styler1, Henry Fung1, Peter Abdelmessieh1 P737 THE IMPACT OF TRANSPORTATION TIME ON STEM HEMATOPOIETIC CELL VIABILITY AFTER CRYOPRESERVATION Iwona Mitrus 1, Marcin Wilkiewicz1, Agata Kawulok1, Wojciech Fidyk1, Małgorzata Sobczyk-Kruszelnicka1, Sebastian Giebel1 P738 LENOGRASTIM AND FILGRASTIM: REAL-LIFE COMPARISON IN MOBILIZATION OF ALLOGENEIC HEMATOPOIETIC STEM CELL DONORS Rosamaria Nitti 1, Filippo Magri1, Alessia Orsini1, Michela Giulia Tassara1, Raffaella Milani1, Salvatore Gattillo2, Milena Coppola1, Luca Santoleri1, Fabio Ciceri3 P739 NIVOLUMAB-IFOSFAMIDE-CARBOPLATIN-ETOPOSIDE (NICE) AS MOBILIZING REGIMEN FOR RELAPSED/REFRACTORY HODGKIN LYMPHOMA (R/R HL) Maria K. Angelopoulou1, Eleni Lalou1, Athanasios Liaskas 1, Aikaterini Benekou1, Maria-Aikaterini Lefaki1, Ioannis Vasilopoulos1, Angeliki Georgopoulou1, Chrysovalantou Chatzidimitriou1, Alexandros Machairas1, Alexia Piperidou1, Kalliopi Zerzi1, Konstantinos Keramaris1, Marina P. Siakantaris1, Panayiotis Panayiotidis1, Theodoros P. Vassilakopoulos1 P740 IMPACT OF DARATUMUMAB, BORTEZOMIB, THALIDOMIDE DEXAMETHASONE INDUCTION THERAPY ON STEM CELL MOBILIZATION: A REAL WORLD EXPERIENCE Giuseppe Sapienza 1, Marika Porrazzo1, Fabrizio Accardi1, Roberto Bono1, Stefania Tringali1, Cristina Rotolo1, Cirino Botta2, Caterina Patti1, Alessandra Santoro1, Laura Di Noto1, Lucia Sbriglio1, Luca Castagna1 P741 INSTITUTIONAL THRESHOLD OF PREAPHERESIS PERIPHERAL BLOOD CD34+ CELL COUNT: A SINGLE-CENTER EXPERIENCE Yandy Marx Castillo Aleman 1,2, Carlos Agustin Villegas Valverde1, Antonio Alfonso Bencomo Hernandez1, Yendry Ventura Carmenate1,2, Fatema Mohammed Al Kaabi1,2, Shinnette Lumame2, Charisma Castelo2, Nameer Abdul Al-Saadawi1,2, Inas El-Najjar2, Mohamed Ibrahim Abu Haleeqa1,2, Jayakumar David Dennison2, Mansi Sachdev2, Fatma Abdou1, Shadi Shamat1, Anil Kumar Sarode1, Dina El Mouzain1,2, Hiba Mohamad Abdelrahman2, Rene Antonio Rivero Jimenez1 P742 APPLICATION OF GRANULOCYTE COLONY STIMULATING FACTOR DURING CYTAPHERESIS LEADS TO BETTER STEM CELL YIELDS Ivan Tonev 1, Stanislav Simeonov1, Milcho Mincheff1 P743 ADAPTATION OF THE VOLUMETRIC METHOD ON THE FACSLYRIC CYTOMETER FOR THE ENUMERATION OF CD34 + STEM CELLS Mohamed Brahimi 1, Amel Mihoubi2, Kamilia Amani2, Nawel Bounoua2, Aoudia Fatima2, Benaissa Mohamed Amine2, Amel Bendimerad2, Nabil Yafour1 P744 COMPARISON OF CE CHEMOTHERAPY PLUS G-CSF VS. G-CSF ALONE FOR AUTOLOGOUS HEMATOPOIETIC STEM CELL MOBILIZATION IN PATIENTS WITH MULTIPLE MYELOMA: A SINGLE CENTER RETROSPECTIVE ANALYSIS Martin Hildebrandt1, Veronika Dill 1, Philipp Blüm2, Anja Lindemann1, Alexander Biederstädt3, Marion Högner1, Katharina Götze1, Florian Basssermann1 P745 BLOOD TRANSFUSION NEEDS DURING PERIPHERAL BLOOD STEM CELL COLLECTION: A SINGLE-CENTER RETROSPECTIVE STUDY Liliana Fonseca1, Catarina Almeida2, Pedro Leite-Silva3, Ana Salselas 3, Susana Roncon3 P746 ENHANCING PRECISION IN PERIPHERAL BLOOD HAEMATOPOIETIC PROGENITOR CELL APHERESIS: A NOVEL APPROACH TO INTEGRATE COLLECTION EFFICIENCY VARIANCE FOR PRECISE CD34 + YIELD PREDICTION Nelson Chan1, Kai Wan 1, Sinju Thomas1, Sandra Loaiza1, Shab Uddin1, Edward Aina1, Emma Bray1, Kaivalya Kulkarni1, Romeo Valeza1, Ruth Emhazion1, Jane Apperley2,1, Edurado Olavarria2,1, Renuka Palanicawandar1 P747 STEM CELL MOBILIZATION IN MULTIPLE MYELOMA: DESCRIPTIVE ANALYSIS AND PREDICTIVE FACTORS FOR STEM CELL MOBILIZATION FAILURE Laura Pardo Gambarte 1, Isabel Iturrate Basarán1, Begoña Pérez de Camino Gaisse1, Soledad Sánchez Fernández1, Javier Cornago Navascués1, Laura Solán Blanco1, Jose Luis López Lorenzo1, Elham Askari1, Amalia Domingo González1, Elena Prieto Pareja1, Alberto Velasco Valdazo2, Rafael Martos Martínez3, Daniel Naya Errea4, Pilar Llamas Sillero1 P748 MOBILIZATION AND HEMATOPOIETIC STEM CELL TRANSPLANTATION IN PATIENTS WITH MULTIPLE MYELOMA WITH DARATUMUMAB-BASED INDUCTION TREATMENS Isabel Izquierdo 1, Ana Gomez2, Ana Godoy1, Juan Gimeno1, Beatriz Martinez3, Vicente Carrasco4 P749 STEM CELL MOBILIZATION IN MULTIPLE MYELOMA PATIENTS: A SINGLE CENTER STUDY IN TUNISIA Imen Bellalah1, Karima Kacem 1, Malek Sayadi1, Dorra Jabeur1, Raoudha Mansouri1, Raihane Banlakhal1 P750 CHALLENGES OF HEMATOPOIETIC STEM CELL COLLECTION IN BIG PEDIATRIC TRANSPLANT CENTER: SINGLE CENTER EXPERIENCE Nara Stepanyan 1, Kirill Kirgizov1, Elena Machneva2, Ramil Fatkhullin1, Timur Aliev1, Irina Kostareva1, Nune Matinyan1, Vladimir Zhogov1, Marina Rubanskaya1, Olga Romantsova1, Natalia Batmanova1, Timur Valiev1, Tatiyana Gorbunova1, Vladimir Polyakov1, Svatlana Varfolomeeva1 P751 IMMUNOPHENOTYPING OF PERIPHERAL BLOOD MONONUCLEAR CELLS COLLECTED BY APHERESIS Carlos Agustin Villegas-Valverde 1, Antonio Bencomo-Hernandez1, Yandy Max Castillo-Aleman1, Fatrma Abdou1, Shadi Shamat1, Anil Kumar1, Yendry Ventura-Carmenate2, Fatema Al Kaabi3, Inas El-Najjar3, Shinnette Lumame3, Charisma Castelo3, Nameer Abdul Al Saadawi3, Dina El Mouzain3, Hiba Abdelrahman3, Jayakumar Dennison3, Mansi Sachdev3, Rene Antonio Rivero-Jimenez1 P752 REAPPRAISING CORD BLOOD AS A PRIORITY CELL SOURCE IN ALTERNATE DONOR TRANSPLANT AND IN DIFFICULT-TO-CURE PAEDIATRIC HEMATOLOGIC MALIGNANCY Abdul Wajid Moothedath 1, Denise Bonney1, Madeleine Powys1, Ramya Nataraj1, Omima Mustafa1, Srividhya Senthil1, Robert Wynn1 P753 CORTICOSTEROIDS IMPAIR HEMATOPOIETIC MICROENVIRONMENT VIA INDUCING SENESCENCE OF THE MESENCHYMAL STROMAL NICHE Yuqing Wang 1, Cong Wang1, Zheng Wang1, Xi Zhang1 P754 THE CORD BLOOD POST THAW CLINIC – HELPING YOU WORK OUT “WHAT GOOD LOOKS LIKE” Roger Horton 1, Ben Cash2, Kennedy Davies2, Irina Evseeva3, Phoebe Groves3, Sophie Macleod3, Alex Ross2, Claire Simpson1, Daniel Gibson1 P755 USE ON NON-CRYOPRESERVED HEMATOPOIETIC STEM CELLS FOR AUTOLOGOUS HSCT IN ADULTS - MULTICENTER STUDY, FROM THE IDWP AND TCWP EBMT – PRELIMINARY RESULTS Emilian Snarski 1, Gloria Tridello2, Lotus Wendel2, Zinaida Peric3, William Boreland4, Dina Averbuch5, Rafael de la Camara6 References

14 – 17 April, 2024 Hybrid Meeting

Copyright: Modified and published with permission from https://www.ebmt.org/annual-meeting

Sponsorship Statement: Publication of this supplement is sponsored by the European Society for Blood and Marrow Transplantation. All content was reviewed and approved by the EBMT Committee, which held full responsibility for the abstract selections.

19: Acute Leukaemia

P001 AUTOLOGOUS VERSUS HAPLOIDENTICAL DONOR STEM CELL TRANSPLANTATION FOR FAVORABLE-AND INTERMEDIATE-RISK ACUTE MYELOID LEUKEMIA IN FIRST REMISSION AND UNDETECTABLE MINIMAL RESIDUAL DISEASE: A MULTI-CENTER, PROSPECTIVE STUDY

Yiyang Ding1, Yuhua Ru1, Jinjin Zhu1, Xi Zhang2, Lin Liu3, Erlie Jiang4, He Huang5, Jishi Wang6, Jiong Hu7, Yanming Zhang8, Yajing Xu9, Mingzhen Yang10, Jia Chen 1, Depei Wu1

1National Clinical Research Center for Hematologic Diseases, Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University, Suzhou, China, 2Xinqiao Hospital, Third Military Medical University, Chongqing, China, 3The First Affiliated Hospital of Chongqing Medical University, Chongqing, China, 4Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China, 5Bone Marrow Transplantation Center, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China, 6Affiliated Hospital of Guizhou Medical University, Guiyang, China, 7Shanghai Institute of Hematology, State Key Laboratory of Medical Genomics, National Research Center for Translational Medicine at Shanghai, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China, 8Huai’an Hospital Affiliated to Xuzhou Medical College and Huai’an Second People’s Hospital, Huai’an, China, 9XiangYa Hospital, Central South University, Changsha, China, 10the First Affiliated Hospital of Anhui Medical University, Hefei, China

Background: In the absence of HLA-matched donor, HLA-haploidentical donor stem cell transplantation (haplo-SCT) and autologous SCT (ASCT) are both valid postremission therapy with well-documented effects in patients with favorable-and intermediate-risk acute myeloid leukemia (AML). Our previous retrospective study has suggested similar survival following ASCT compared to haplo-SCT for favorable- and intermediate-risk AML patients in the first complete remission (CR1). Hence, we designed a prospective, multi-center study to further confirm this conclusion.

Methods: A prospective study was conducted in 10 Chinese centers. The main inclusion criteria were: 1) adult patients >=18 years old; 2) diagnosis as AML with intermediate-risk according to ELN 2010 or 2017; 3) ASCT or haplo-SCT underwent between 2014-2019; 4) in CR1 and MRD negative before transplant. The Primary endpoint was overall survival (OS). Secondary endpoints were progression-free survival (PFS), cumulative incidence of relapse (CIR), treatment-related mortality (TRM), and graft-versus-host disease-free and relapse-free survival (GRFS).

Results: A total of 368 patients diagnosed with favorable-and intermediate-risk AML were included from 10 institutions between January 2014 and December 2019, in accordance with the European Leukemia Net criteria (Table 1). Of these, 184 patients underwent ASCT, and 184 underwent haplo-SCT. In the overall cohort analysis, the CIR in the ASCT group was offset by reduced TRM when compared with the haplo-SCT group, resulting in similar PFS (70.5% versus 74.9%, P = 0.880) and improved OS (83.0% versus 77.0%, P = 0.044). Furthermore, ASCT patients exhibited a higher GRFS (70.5% versus 57.4%, P<0.001) attributed to the absence of GVHD. The OS trend was accentuated in the favorable-risk cohort, while comparable OS was observed in the intermediate-risk cohort. Multivariate analyses indicated that haplo-SCT, advanced age, MLL-AF9 rearrangement, graft cell dosage, and hematopoietic engraftment time independently impacted outcomes.

Table 1. Patient Characteristics.

Auto (n = 184)

Haplo (n = 184)

P

Median age (range)

36 (18-64)

35 (18-60)

0.078

Gender

Male

104

95

0.346

Female

80

89

Risk stratification

Favorable

94

85

0.348

Intermediate

90

99

WBC at diagnosis (median, 109/L)

8.83

15.42

0.003

Abnormal karyotype at diagnosis

51

81

0.013

Abnormal molecular at diagnosis

FLT3-ITD

4

11

0.065

MLL-AF9

3

5

0.475

Induction courses

1

134

133

0.907

>1

50

51

Consolidation courses

≤2

67

139

<0.001

>2

117

45

HiDAC before transplant

91

18

<0.001

Conclusions: In conclusion, both ASCT and haplo-SCT proved to be viable approaches for the post-remission treatment of patients with favorable-and intermediate-risk AML. Notably, ASCT demonstrated superior outcomes in the favorable-risk cohort.

Clinical Trial Registry: Haplo-SCT vs ASCT With or Without Decitabine in AML CR1 - Full Text View - ClinicalTrials.gov (ClinicalTrails.gov Identifier: NCT02059720)

Disclosure: Nothing to declare

19: Acute Leukaemia

P002 OUTCOME OF ALLOGRAFTED ACUTE LYMPHOBLASTIC LEUKEMIA PATIENTS TREATED WITH THE PEDIATRIC-INSPIRED, MRD-ORIENTED GIMEMA LAL 1913 PROTOCOL IN THE REAL-LIFE: A CAMPUS ALL STUDY

Gianluca Cavallaro 1, Davide Lazzarotto2, Chiara Pavoni1, Francesca Valsecchi1, Cristina Papayannidis3, Marco Cerrano4, Sabina Chiaretti5, Nicola Fracchiolla6, Fabio Giglio7, Michelina Dargenio8, Monia Lunghi9, Silvia Imbergamo10, Maria Ilaria Del Principe11, Silvia Trappolini12, Monica Fumagalli13, Patrizia Zappasodi14, Prassede Salutari15, Mario Delia16, Crescenza Pasciolla17, Federico Mosna18, Barbara Scappini19, Fabio Forghieri20, Patrizia Chiusolo21, Cristina Skert22, Benedetta Cambò23, Marzia Defina24, Giuseppe Lanzarone25, Mauro Endri26, Massimiliano Bonifacio27, Carla Mazzone28, Lidia Santoro29, Antonino Mulè30, Valentina Mancini31, Paola Minetto32, Giorgia Battipaglia33, Alessandro Cignetti34, Lara Aprile35, Robin Foà5, Anna Candoni2,20, Federico Lussana1,36

1ASST Papa Giovanni XXIII, Bergamo, Italy, 2Azienda Sanitaria Universitaria Friuli Centrale, Udine, Italy, 3IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy, 4AOU Città della Salute e della Scienza – Presidio Molinette, Torino, Italy, 5Sapienza University, Roma, Italy, 6IRCCS Ca’ Granda Ospedale Maggiore Policlinico di Milano, Milano, Italy, 7IRCCS Ospedale San Raffaele, Milano, Italy, 8Ospedale Vito Fazzi, Lecce, Italy, 9University of Eastern Piedmont, Novara, Italy, 10Azienda Ospedale Università di Padova, Padova, Italy, 11University of Rome Tor Vergata, Roma, Italy, 12Azienda Ospedaliero - Universitaria Ospedali Riuniti Umberto I, Ancona, Italy, 13Ospedale San Gerardo, Monza, Italy, 14Fondazione IRCCS Policlinico San Matteo, Pavia, Italy, 15Azienda USL di Pescara, Pescara, Italy, 16Azienda Ospedaliero-Universitaria Consorziale Policlinico di Bari, Bari, Italy, 17IRCCS Istituto Tumori Giovanni Paolo II, Bari, Italy, 18Azienda Sanitaria dell’Alto Adige, Bolzano, Italy, 19Azienda Ospedaliera Universitaria Careggi, Firenze, Italy, 20Azienda Ospedaliero Universitaria di Modena, Modena, Italy, 21Fondazione Policlinico Universitario A. Gemelli IRCCS, Roma, Italy, 22Ospedale dell’Angelo, Venezia, Italy, 23University of Parma, Parma, Italy, 24Azienda Ospedaliero Universitaria Senese, Siena, Italy, 25A.O.U. Città della Salute e della Scienza di Torino, Torino, Italy, 26Ospedale Cà Foncello, Treviso, Italy, 27Azienda Ospedaliera Universitaria Integrata di Verona, Verona, Italy, 28St. Eugenio Hospital, Roma, Italy, 29Azienda Ospedaliera San Giuseppe Moscati, Avellino, Italy, 30A.O. Ospedali Riuniti Villa Sofia-Cervello, Palermo, Italy, 31ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy, 32IRCCS Ospedale Policlinico San Martino, Genova, Italy, 33Azienda Ospedaliero-Universitaria Federico II, Napoli, Italy, 34Azienda Ospedaliera Ordine Mauriziano, Torino, Italy, 35Ospedale San Giuseppe Moscati, Taranto, Italy, 36University of Milan, Milano, Italy

Background: The GIMEMA LAL 1913 was a pediatric-inspired and minimal residual disease (MRD)-oriented phase 2 chemotherapy protocol that included peg-asparaginase for the frontline treatment of adult Philadelphia-negative acute lymphoblastic leukemia (Ph- ALL) patients (Bassan et al, Blood Advances, 2023). This protocol represents the standard treatment for adult Ph- ALL in Italy. The outcome of patients treated with the same protocol in the real-life setting and who underwent an allogeneic stem cell transplant (SCT) was the aim of this study.

Methods: Within the framework of the Campus ALL network in Italy, we analyzed the post-transplant data of newly diagnosed adult Ph- ALL patients treated according to the LAL 1913 protocol and who underwent a SCT between August 2016 and January 2023 in 35 Italian centers. Patients in 1st remission (CR1) were considered eligible for a SCT as consolidation based on the joint assessment of the disease risk profile at diagnosis (high white blood cell, immunophenotype or adverse cytogenetics/molecular biology) and post-consolidation MRD status. We also included relapsed patients in 2nd CR (CR2). Endpoints were the 2-year overall survival (OS), disease-free survival (DFS), non-relapse mortality (NRM) and cumulative incidence of relapse (CIR). Outcomes were analyzed from the day of SCT.

Results: Among 322 consecutive newly diagnosed Ph- ALL, 201 patients who underwent a SCT were included in this analysis (Table 1). The median age at diagnosis was 38 years (18-66). Median follow-up was 28 months. Patients allografted in CR1 were associated with a significantly superior 2-year OS (77% vs 32%, p<0.001), DFS (67% vs 35%, p = 0.003) and CIR (24% vs 47%, p = 0.006) compared to patients transplanted in CR2. Pre-transplant MRD negativity was strongly associated with a superior OS (81% vs 50%, p<0.001), DFS (71% vs 44%, p = 0.003) and CIR (21% vs 43%, p = 0.006). MRD negativity also impacted favorably on the prognosis of patients transplanted in 2nd CR in terms of OS and disease-free survival (Fig. 1). The outcome was similar between B- and T-lineage ALL, patients’ age (< or > 55 years) and baseline risk class. A myeloablative conditioning was adopted in 156 (79%) patients and total-body irradiation (TBI) in 125 (66%). There was no significant difference when using TBI 800 cGy vs TBI 1200 cGy and TBI-fludarabine vs TBI-alkylating agents. The use of ATG in sibling and unrelated donors did not affect CIR. The 2-year NRM was 11% and it was not significantly affected by pre- and post-transplant factors.

Table 1.

Patients’ characteristics

N = 201

Age at diagnosis, n(%)

<55

163 (81.1)

>=55

38 (18.9)

Cell lineage, n(%)

B-ALL

97 (48.3)

T-ALL

104 (51.7)

Baseline risk, n(%)

Standard Risk

55 (27.4)

High Risk

25 (12.4)

Very High Risk

121 (60.2)

Disease status at transplant, n(%)

CR1

171 (85.1)

CR2

29 (14.4)

Pre transplant MRD, n(%)

Negative

130 (68.8)

Positive

58 (30.7)

Donor, n(%)

Sibling

61 (30.7)

Matched unrelated donor

68 (34.2)

Aploidentical

37 (18.6)

Mismatched unrelated donor

33 (16.6)

Conditioning regimen, n(%)

Myeloablative

156 (78.8)

Reduced intensity

42 (21.2)

TBI, n(%)

No

64 (33.9)

Yes

125 (66.1)

Figure 1: 2-years DFS

The 50th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians – Poster Session (P001-P755) (1)

Conclusions: Our study on a series of patients treated with a modern therapeutic strategy confirms the higher risk of relapse in patients with pre-transplant MRD positivity. Given the availability of pre-transplant immunotherapies, all efforts should be made to eradicate MRD prior to undergoing the SCT, or with post-transplant pre-emptive treatment. An advantage in survival was observed when transplant was performed in CR1 compared to CR2, highlighting the importance of an early identification of high-risk patients candidate to transplant consolidation. Importantly, a significant improvement in NRM outcome was recorded.

Disclosure: Nothing to declare.

19: Acute Leukaemia

P003 FREQUENCY AND IMPACT OF SOMATIC MUTATIONS ON OUTCOMES OF ACUTE MYELOID LEUKEMIA PATIENTS RECEIVING ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION: FROM THE EBMT ACUTE LEUKEMIA WORKING PARTY

Ali Bazarbachi 1, Jacques-Emmanuel Galimard2, Myriam Labopin2, Iman Abou Dalle1, Jaime Sanz3, Huang He4, Jiri Mayer5, Carlos Solano6, Celestine Simand7, Laimonas Griskevicius8, Johan Maertens9, Maija Itäla-Remes10, Ain Kaare11, Maria-Pilar Gallego-Hernanz12, Gesine Bug13, Josep-Maria Ribera14, Alain Gadisseur15, Christoph Schmid16, Mi Kwon17, Xavier Poiré18, Paola Coccia19, Manuel Jurado Chacón20, Frédéric Baron21, Eolia Brissot22, Arnon Nagler23, Fabio Ciceri24, Mohamad Mohty25

1American University of Beirut Medical Center, Beirut, Lebanon, 2EBMT Statistical Unit, Sorbonne University, Saint-Antoine Hospital, Paris, France, 3University Hospital La Fe, Valencia, Spain, 4First Affiliated Hospital of Zhejiang University School of Medicine, Kunming, China, 5University Hospital Brno, Brno, Czech Republic, 6Hospital Clínico Universitario. University of Valencia, Valencia, Spain, 7ICANS, Strasbourg, France, 8Hôpitaux Universitaires Strasbourg, Strasbourg, France, 9University Hospital Gasthuisberg, Leuven, Belgium, 10Turku University Hospital, Turku, Turkey, 11Tartu University Hospital, Tartu, Estonia, 12Hopital La Miletrie, Poitiers, France, 13Goethe-Universitaet, Frankfurt Main, Germany, 14ICO-Hospital Universitari Germans Trias i Pujol, Josep Carreras Research Institute, Badalona, Spain, 15Antwerp University Hospital (UZA), Antwerp E, Belgium, 16University Hospital and Medical Faculty, University of Augsburg, Augsburg, Germany, 17Hospital General Universitario Gregorio Marañón, Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain, 18Cliniques Universitaires St. Luc, Brussels, Belgium, 19Azienda Ospedali Riuniti di Ancona, Ancona, Italy, 20Hospital Univ. Virgen de las Nieves, Granada, Grenada, 21University of Liege, Liege, Belgium, 22Sorbonne University, Paris, France, 23Hematology Division, Chaim Sheba Medical Center, Tel-Hashomer, Israel, 24IRCCS Ospedale San Raffaele, Milano, Italy, 25Sorbonne University, Saint-Antoine Hospital, Paris, France

Background: Acute myeloid leukemia (AML) is a very heterogeneous hematological malignancy, which includes numerous genetically defined subsets. In the context of allogeneic hematopoietic cell transplantation (allo-HCT), the frequency and prognostic value of different gene-gene interactions has not been studied and may differ from that of patients treated with chemotherapy alone.

Methods: This is a registry-based analysis from the EBMT with the approval of the EBMT Acute Leukemia Working Party. Adult patients aged more than 18 years with a diagnosis of AML who received an allo-HCT between 2013-2022, with an available genetic profile determined at diagnosis by next generation sequencing (NGS) were included.

Results: We identified 836 allografted AML patients who had NGS performed at diagnosis. Most of these patients had de novo AML (88%), with a median age of 53 years (range: 18-78 years). Karyotype was favorable in 7%, intermediate in 69% and adverse in 24% of patients. At transplant, 74% of patients were in first remission (CR1) and 13% in CR2. The most frequent detectable mutations by frequency were DNMT3A (33%), FLT3 (29%), NPM1 (29%), TET2 (28%), NRAS (23%), RUNX1 (22%), WT1 (22%), BCOR (19%), ASXL1 (17%), IDH2 (17%), IDH1 (15%), SRSF2 (13%), STAG2 (12%), CEBPA (11%), TP53 (10%), KRAS (10%), and PTPN11 (10%). By multiple correspondence analysis, two independent groups of co-occurring mutations were identified, the first group included DNMT3A, NPM1 and FLT3, the second group included ASXL1, SRSF2 and RUNX1. Outcome analysis was performed on the subset of 298 patients allografted in CR1 with available data for DNMT3A, NPM1, FLT3, ASXL1, SRSF2 and RUNX1. Most of these patients had de novo AML (90%), with a median age of 53 years (range: 19-75 years). Seventy percent had intermediate-risk cytogenetics, while 27% were adverse-risk. Median follow up was 2.5 years. When outcome analysis was performed according to the presence of single mutations, none of the six mutations significantly affected RI or LFS. The 2-year OS was positively affected by the presence of NPM1 mutation (78% vs 66%; p = 0.02) and FLT3 (79% vs 65%, p = 0.01) but not significantly affected by the other 4 mutations. When mutations were investigated in groups, the 2-year RI, LFS and OS were 24%, 70% and 78%, respectively, for patients with NPM1 mutation regardless of other co-mutations, 35%, 56% and 69% for patients with FLT3-ITD and/or DNMT3A mutation, wild type NPM1, regardless of other co-mutations, 17%, 70% and 74% for patients with RUNX1 and/or ASXL1 and/or SRSF2 mutation without FLT3-ITD and with wild type NPM1 and wild type DNMT3A, and 20%, 56% and 61% for patients with all six genes unmutated.

Conclusions: NGS at diagnosis can be extremely useful in risk stratification of AML patients undergoing allo-HSCT, potentially allowing adequate post-transplant interventions. Notably, the 2-year LFS of 70% for patients harboring RUNX1 and/or ASXL1 and/or SRSF2 mutation indicates that allo-HSCT can overcome the adverse risk associated with these somatic mutations at diagnosis.

Disclosure: Nothing to declare.

19: Acute Leukaemia

P004 ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR ELDERLY ACUTE LYMPHOBLASTIC LEUKEMIA PATIENTS: A STUDY FROM THE SOCIÉTÉ FRANCOPHONE DE GREFFE DE MOELLE ET THÉRAPIE CELLULAIRE (SFGM-TC)

Yves Chalandon 1, Raynier Devillier2, Ariane Boumendil3, Stephanie Nguyen4, Claude-Eric Bulabois5, Patrice Ceballos6, Eolia Brissot7, Marie-Thérèse Rubio8, Hélène Labussière-Wallet9, Johan Maertens10, Patrice Chevallier11, Natacha Maillard12, Xavier Poiré13, Cristina Castilla-Llorente14, Yves Beguin15, Jérôme Cornillon16, Sébastien Maury17, Tony Marchand18, Etienne Daguindau19, Jacques-Olivier Bay20, Pascal Turlure21, Amandine Charbonnier22, Anne-Lise Menard23, Karin Bilger24, Gaelle Guillerm25, Sylvie François26, Ali Bazarbachi27, Sylvain Chantepie28, Philippe Lewalle29, Ambroise Marçais30, Michael Loschi31, Malek Benakli32, Paul Chauvet33, Edouard Forcade34, Anne Huynh35, Marie Robin36, Stavroula Masouridi-Levrat1

1Hôpitaux Universitaire Genève (HUG) and Faculty of Medicine, Geneva, Switzerland, 2Institut Paoli-Calmettes, Marseille, France, 3SFGM-TC, Paris, France, 4Hôpital de la Pitié Salpêtrière, AP-HP, Paris, France, 5CHU Grenoble-Alpes, Grenoble, France, 6CHU de Montpellier, Montpellier, France, 7Hôpital Saint-Antoine, AP-HP, Paris, France, 8CHRU de Nancy-Brabois, Nancy, France, 9Hôpital Lyon Sud, Lyon, France, 10UZ Leuven, Leuven, Belgium, 11CHU Nantes, Nantes, France, 12CHU Poitiers, Poitiers, France, 13Cliniques Universitaires Saint-Luc, Brussels, Belgium, 14Gustave Roussy Cancer Campus, Villejuif, France, 15CHU de Liège, Liège, Belgium, 16CHU St-Etienne, Saint-Etienne, France, 17Hôpital Henri-Mondor, AP-HP, Créteil, France, 18CHU Rennes, Rennes, France, 19CHU de Besançon, Besançon, France, 20CHU de Clermont-Ferrand, Clermont-Ferrand, France, 21Limoges University Hospital, Limoges, France, 22CHU Amiens, Amiens, France, 23Centre Henri Becquerel, Rouen, France, 24CHRU de Strasbourg, Strasbourg, France, 25CHRU de Brest, Brest, France, 26CHU Angers, Angers, France, 27American University of Beirut, Beirut, Lebanon, 28CHU de Caen, Caen, France, 29Hôpital Universitaire de Bruxelles (HUB), Institut Jules Bordet, Brussels, Belgium, 30Hôpital Necker, AP-HP, Paris, France, 31CHU de Nice, Nice, France, 32CPMC d’Alger, Alger, Algeria, 33CHU de Lille, Université de Lille, Lille, France, 34CHU Bordeaux, Bordeaux, France, 35CHU Toulouse, Toulouse, France, 36Hôpital Saint-Louis, AP-HP, Paris, France

Background: There are very scarce data regarding the outcome of elderly patients with ALL who received alloHSCT as consolidation therapy in CR. Thus, the optimal conditioning regimen still need to be determined. We here present the outcome of ALL patients older than 59 years from the SFGM-TC.

Methods: The primary outcome of this registry study was OS. Secondary outcomes were PFS, NRM, RI, aGvHD grade II-IV, cGvHD, engraftment and GRFS. Competing risks analyses were performed to analyze NRM, aGvHD grade II-IV, cGvHD and neutrophil engraftment. Univariable analyses were performed using the log-rang test for OS and PFS, while Gray’s test was used for CI. Multivariable analyses were performed using the Cox proportional hazards regression model including age, ALL subtype, time from diagnosis to alloHSCT, disease status at alloHSCT, donor to patient CMV status, donor to patient sex, ATG use, MAC, TBI use.

Results: A total of 316 patients ≥ 60 years old transplanted for ALL from 2012 to 2022 in 36 participating centers were included. Patient’s characteristics are described in Table 1.

With a median follow up of 34.5 months (IQR 29.5-38.8), 3-year OS was 46% (95% CI 40-53%) with disease status at transplant impacting negatively OS, 53% in CR1, 32% in CR2, 29% in advanced disease, p = 0.002 and ALL subtype, 59% in Ph+ ALL, 40% in Ph- ALL, 34% in T-ALL, 20% in other/NA, p<0.001.

3-year PFS was 41% (95% CI 35-48%) with disease status at transplant impacting negatively, 49% in CR1, 26% in CR2, 22% in advanced disease, p<0.001, ALL subtype, 51% in Ph+ ALL, 41% in Ph- ALL, 21% in T-ALL, 21% in other/NA, p<0.001, year of HSCT worse < 2018, p = 0.007, CMV -/- worse, p = 0.033, absence of TBI worse, p = 0.018. 3-year NRM was 23% (95% CI 18-28%). 3-year RI was 36% (95% CI 31-42%) with disease status at transplant impacting negatively, 29% in CR1, 50% in CR2, 56 in advanced disease, p = 0.0042, ALL subtype, 26% in Ph+ ALL, 43% in Ph- ALL, 57% in T-ALL, 42% in other/NA, p = 0.0064, year of HSCT worse < 2018, p = 0.0216, CMV -/- worse, p<0.001, absence of TBI worse, p = 0.0069, MRD worse, p = 0.0111. 3-year GRFS was 30% (95% CI 25-37%) with disease status at transplant impacting negatively, 35% in CR1, 22% in CR2, 23% in advanced disease, p = 0.029, ALL subtype, 37% in Ph+ ALL, 33% in Ph- ALL, 15% in T-ALL, 17% in other/NA, p = 0.0029, year of HSCT worse < 2018, p<0.001.

CI of aGVHD grade II-IV was 33% (95% CI 28-38%), grade III-IV 11% (95% CI 8-15%), cGVHD 35% (95% CI30-41%), extensive cGVHD 21% (95% CI 16-26%).

Multivariable analyses confirmed a worse OS and PFS for advanced disease, with a HR of 1.79 (95% CI 1.22-2.64), p = 0.00322 and ALL subtype with a HR for other than Ph+ ALL of 1.99 (95%CI 1.42-2.79).

Characteristics

N = 316

Age at HSCT median (IQR)

63.82 (61.8-66.5)

Age at diagnosis median (IQR)

63.02 (61-65.4)

Time from diagnosis to HSCT median (IQR) months

7.05 (5.7-10.3)

Year of HSCT median (IQR)

2017.5 (2015-2020)

ALL subtype

B-ALL Ph-

81 (25.9%)

B-ALL Ph+

156 (49.8%)

T-ALL

42 (13.4%)

Other/unknown

37 (11.7%)

Patient’s sex

Female

156 (49.4%)

Male

160 (50.6%)

Disease status at HSCT

CR1

224 (70.9%)

CR2 and +

74 (23.4%)

Not in CR

18 (5.7%)

Molecular CR

Yes

121 (38.3%)

No

79 (25%)

Missing

116 (36.7%)

Type of donor

Haploidentical

56 (17.7%)

MSD

83 (26.3%)

MUD

142 (44.9%)

MMUD

23 (7.2%)

Missing

12 (3.8%)

Source of stem cell

BM

22 (7%)

PBSC

294 (93%)

Donor to patient’s sex

Female to male

44 (14%)

Other

271 (86%)

Missing

1

CMV donor/patient

Neg/Neg

84 (26.8%)

Neg/Pos

93 (29.7%)

Pos/Neg

24 (7.7%)

Pos/Pos

112 (35.8%)

Missing

3

ATG

Yes

220 (69.6)

No

96 (30.4%)

Conditioning

RIC

204 (64.6%)

MAC

112 (35.4%)

TBI

No

203 (64.2%)

Yes

113 (35.8%)

TBI & Dose

No TBI

203 (64.4%)

TBI < 8 Gy

43 (13.7%)

TBI 8 Gy

69 (21.9%)

Missing

1

Disease Risk Index

Intermediate

224 (71.3%)

High

72 (22.9%)

Very high

18 (5.7%)

Missing

2

Comorbidity index (Sorror)

>=3

76 (32.5%)

1-2

53 (22.6%)

105 (44.9%)

Missing

82

Conclusions: This study suggests that alloHSCT is a reasonable option for elderly ALL patients without any impact of age but advanced disease and ALL subtype other than Ph+ ALL negatively influenced the outcome.

Disclosure: YC: Y.C. has received consulting fees for advisory board from MSD, Novartis, Incyte, BMS, Pfizer, Abbvie, Roche, Jazz, Gilead, Amgen, Astra-Zeneca, Servier; Travel support from MSD, Roche, Gilead, Amgen, Incyte, Abbvie, Janssen, Astra-Zeneca, Jazz, Sanofi all via the institution.

EF: EF received funding for congress participation from Alexion, Gilead, Jazz, MSD, Novartis; and also honoraria for boards and speaker bureau participation from Alexion, GSK, Novartis, Gilead, Astellas.

ML: honorari : Alexion, Astra Zeneca, BMS Celgene, Gilead, GSK, Jazz, Kartos, Medac, MSD, Novartis, Pfizer, Sanofi, Sobi, Telios

TM: Consulting fees : Servier, Jazz Pharmaceutical, Sobi, Astellas. Travel support from Servier, Jazz Pharmaceutical

AH : AH has received consulting fees advisory board from Jazz, Pfizer, Servier, Novartis, Astellas; Travel support from Medac, Jazz, Neovii all via the Institution.

All the others do not have any conflict of interest.

19: Acute Leukaemia

P005 ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION FOR OLDER PATIENTS WITH PHILADELPHIA-POSITIVE ACUTE LYMPHOBLASTIC LEUKEMIA. A SURVEY BY THE ACUTE LEUKEMIA WORKING PARTY OF THE EBMT

Sebastian Giebel 1, Myriam Labopin2, Ryszard Swoboda1, Didier Blaise3, Ibrahim Yakoub-Agha4, Stephanie Nguyen5, Eva Maria Wagner-Drouet6, Cristina Castilla-Llorente7, Panagiotis Kottaridis8, Thomas Schroeder9, Renato Fanin10, Jakob Passweg11, Jurjen Versluis12, Charles Crawley13, Ludovic Gabellier14, Stephan Mielke15, Xavier Poiré16, Erfan Nur17, Carlos Pinho Vaz18, Matthias Eder19, Riccardo Saccardi20, Peter Dreger21, Zinaida Peric22, Mohamad Mohty2, Fabio Ciceri23

1Maria Sklodowska-Curie National Research Institute of Oncology, Gliwice Branch, Gliwice, Poland, 2EBMT Unit, Sorbonne Universités, UPMC University of Paris 06, INSERM, Centre de Recherche Saint-Antoine (CRSA), AP-HP, Saint Antoine Hospital, Paris, France, 3Programme de Transplantation & Therapie Cellulaire, Marseille, France, 4CHU de Lille, University of Lille, INSERM U1286, Infinite, Lille, France, 5Universite Paris IV, Hopital la Pitié-Salpêtrière, Paris, France, 6University Medical Center Mainz, Meinz, Germany, 7Gustave Roussy Cancer Campus, Villejuif, France, 8University College London Hospital, London, United Kingdom, 9University Hospital Essen, Essen, Germany, 10Azienda Ospedaliero Universitaria di Udine, Udine, Italy, 11University Hospital | Basel, Basel, Switzerland, 12Erasmus University Medical Center Cancer Institute, Rotterdam, Netherlands, 13Addenbrookes Hospital Cambridge, Cambridge, United Kingdom, 14University Hospital of Montpellier, Montpellier, France, 15Karolinska University Hospital, Stockholm, Sweden, 16Cliniques Universitaires St. Luc, Brussels, Belgium, 17Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands, 18Inst. Português de Oncologia do Porto, Porto, Portugal, 19Hannover Medical School, Hannover, Germany, 20Azienda Ospedaliera Universitaria Careggi, Firenze, Italy, 21University of Heidelberg, Heidelberg, Germany, 22University Hospital Center Rijeka and School of Medicine, University of Rijeka, Rijeka, Croatia, 23Ospedale San Raffaele s.r.l., Haematology and BMT, Milano, Italy

Background: Tyrosine kinase inhibitors (TKIs) with or without chemotherapy, followed by allogeneic hematopoietic cell transplantation (allo-HCT) are the standard of care for patients with Philadelphia-positive acute lymphoblastic leukemia (Ph+ ALL). In older patients, intensity of the conditioning regimens is frequently reduced, which may result in increased risk of relapse. However, introduction of alternative approaches using 2nd or 3rd generation TKIs in combination with blinatumomab may restrict the role of allo-HCT. The goal of this study was to evaluate results of recent allo-HCTs for patients aged ≥55 years, and to identify prognostic factors.

Methods: This was a retrospective analysis based on data from the EBMT registry, including 566 patients with Ph+ ALL treated with allo-HCT in first complete remission between the years 2016 and 2022.

Results: Median recipient age was 60 (range, 55-76) years. Allo-HCT was performed using either a matched sibling (n = 138, 24%), unrelated (n = 343, 61%) or haploidentical (n = 85, 15%) donor. Conditioning regimen was myeloablative in 47% of cases and based on total body irradiation (TBI) in 49% of patients. Status of measurable residual disease was reported as negative in 59.5% of patients.

The probability of overall survival (OS) and leukemia-free survival (LFS) at 2 years was 71% and 59.5%, respectively. The incidence of relapse (RI) and non-relapse mortality (NRM) was 18% and 22.5%, respectively. The rate of graft-versus-host disease (GVHD)-free, relapse-free survival (GRFS) was 50%. The incidence of grade 3-4 acute GVHD was 9% while that of extensive chronic GVHD it was 15%.

In univariate analysis the use of TBI-based as compared to chemotherapy-based regimens was associated with reduced RI (15% vs. 20.5%, p = 0.04), improved LFS (67% vs. 53%, p = 0.002) and OS (77% vs. 66%, p = 0.01), as well as a tendency toward reduced incidence of NRM (18% vs. 27%, p = 0.1). On the other hand, it was also associated with increased incidence of both overall and extensive chronic GVHD (46% vs. 27.5%, p = 0.001 and 21% vs. 10%, p = 0.001, respectively). In a multivariant model, the use of TBI was the only factor affecting outcomes, being associated with reduced risk of NRM (hazard ratio, [HR] = 0.46, p = 0.004), improved LFS (HR = 0.53, p<0.001) and OS (HR = 0.47, p<0.001) as well as increased risk of chronic GVHD (HR = 1.68, p = 0.009) and extensive chronic GVHD (HR = 1.84, p = 0.04).

Conclusions: Based on this large-scale analysis we conclude that results of allo-HCT for patients with Ph+ ALL aged ≥55 years in the last few years are very encouraging with approximately 60% LFS at 2 years. TBI-based conditioning appears preferable in this patient population. Our data can serve as reference for results of prospective trials.

Clinical Trial Registry: Not applicable

Disclosure: SG received honoraria from Angelini and Novartis

19: Acute Leukaemia

P006 OUTCOME OF PATIENTS WITH IDH-MUTATED AML FOLLOWING ALLOGENEIC STEM CELL TRANSPLANTATION

Thomas Schroeder 1, Sarah Flossdorf1, Caroline Pabst2, Michael Stadler3, Johannes Schetelig4, Claudia Wehr5, Claudia Schuh6, Matthias Stelljes7, Elisa Sala8, Andreas Burchert9, Jennifer Kaivers1, Christian Reinhardt1, Nicolaus Kroeger10, Katharina Fleischhauer1, Christina Rautenberg1

1University Hospital Essen, Essen, Germany, 2University Hospital Heidelberg, Heidelberg, Germany, 3MHH Hannover, Hannover, Germany, 4University Hospital Dresden, Dresden, Germany, 5University Hospital Freiburg, Freiburg, Germany, 6DRST, Ulm, Germany, 7University Hospital Muenster, Muenster, Germany, 8University Hospital Ulm, Ulm, Germany, 9University Hospital Marburg, Marburg, Germany, 10University Hospital Hamburg, Hamburg, Germany

Background: Somatic mutations in the isocitrate dehydrogenase 1 and 2 genes (IDH1 and IDH2) are found in about 15% to 20% of patients with acute myeloid leukemia (AML). While the prognostic impact of these mutations is still controversial, IDH inhibitors have been developed and introduced as targeted treatment for patients with IDH-mutated AML. They are currently under investigation also as maintenance therapy after allogeneic transplantation (allo-SCT), although outcomes of IDH1- and IDH2-mutated (IDHmut) AML patients after allo-SCT have not been well described.

Methods: To address this, we retrospectively analyzed the outcome of IDHmut patients, who were allografted between 2014 and 2021, had available data collected within the German Registry for hematopoetic Stem Cell Transplantation and cellular therapy (DRST) and a follow-up of at least 6 months. Overall (OS) and event-free survival (EFS) were estimated by Kaplan–Meier method and logrank tests were applied for univariable comparisons. Relapse incidence and non-relapse mortality (NRM) were considered as competing risks and calculated using cumulative incidence (CI) estimates employing Gray test for univariable comparisons.

Results: Overall, 356 IDH-mutated AML patients (IDH1 n = 142 40%, IDH2 n = 214 60%) with a median age of 60 (18 to 76) received a first allo-SCT from a related (30%) or unrelated (70%) donor following myeloablative (50%) or reduced intensity (50%) conditioning. According to ELN 2016 genetic risk stratification 21% belonged to the favorable, 42% to intermediate and 27% to adverse category (missing 10%), with 71% of patients being in CR at transplant. Of 262 patients with available information 10 (4%) had received an IDH inhibitor outside clinical trials prior transplantation. After a median follow-up of 24 months, IDH1mut and IDH2mut patients had similar estimated 3-year probabilities of overall survival (78% vs 70%, p = .64). Non-relapse mortlity was comparable (10% vs 14%, p= .48). Three-year probabilities of relapse were numerically higher for IDH1mut compared with IHD2mut patients (34% vs 24%, p= .18) without reaching statistical significance, and concomitantly a numerically lower 3-year event-free survival (56% vs 62% respectively; p= .14).

Conclusions: Taken together, these data from a large multicenter cohort provide benchmarks for analysis and interpretation of results emerging from clinical trials evaluating maintenance IDH1 and IDH2 inhibitor therapy for AML patients after allo-SCT

Clinical Trial Registry: not applicable

Disclosure: Thomas Schroeder: Advisory Boards:BMS; lecture fees BMS, research funding: BMS

Elisa Sala: honoraria for consultancy or travel support from Gilead, Novartis, BMS, Jazz, Neovii, Therakos/Mallinckrodt, MSD, Priothera.

Johannes Schetelig: Advisory Boards: Abbvie, AstraZeneca, BeiGene, BMS, Janssen, and MSD und Lecture Fees: Astellas, AstraZeneca, BeiGene, BMS, Novartis, Eurocept, Medac and Janssen

Claudia Wehr: Travel support/honoraria from Takeda, Jazz Pharmaceuticals.

Christian Reinhardt: consulting and lecture fees from AbbVie, AstraZeneca, Roche, Janssen-Cilag, Novartis, Vertex and Merck. H.C.R. received research funding from Gilead and AstraZeneca. H.C.R. is a co-founder of CDL Therapeutics GmbH.

19: Acute Leukaemia

P007 CD22-TARGETED IMMUNOTHERAPY FOR ADULT PATIENTS WITH RELAPSED OR REFRACTORY B-ALL WHO PREVIOUSLY EXPOSED TO CD19-TARGETED IMMUNOTHERAPY

Mingming Zhang1,2, Yongxian Hu1,2, Peihua Lu3,4, Liang Huang5, Shan Fu1,2, Jingjing Feng1,2, Ruimin Hong1,2, Alex H. Chang6, He Huang 1,2

1Bone Marrow Transplantation Center, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China, 2Liangzhu Laboratory, Hangzhou, China, 3Hebei Yanda Lu Daopei Hospital, Langfang, China, 4Lu Daopei Institute of Hematology, Beijing, China, 5Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China, 6Shanghai YaKe Biotechnology, Shanghai, China

Background: CD19-targeted immunotherapy effectively induce remission in relapsed or refractory (r/r) B-cell acute lymphoblastic leukemia (B-ALL). Patients who fail or relapse after CD19-targeted immunotherapy have an extremely poor prognosis, and immunotherapy targeting CD22 is one of the few possible therapeutic options, but there is currently limited data.

Methods: We conducted a multicenter, retrospective study of CD22-targeted immunotherapy for adult patients with r/r B-ALL who previously exposed to CD19-targeted immunotherapy. Primary objective was complete remission (CR) rate at 1 month.

Results: A total of 30 patients were included, and the median age was 32 (18-67) years old. Four (13.3%) patients were Ph-positive, 10 (33.3%) patients were primary refractory and 10 (33.3%) patients relapsed after allogeneic stem cell transplantation. Six (20.0%) patients were exposed to blinatumomab only, 20 (66.7%) patients were exposed to CD19 CAR-T cell therapy only, and 4 (13.3%) patients were exposed to both. 20 (66.7%) patients received CD22 CAR-T cell therapy, and 10 (33.3%) patients received inotuzumab ozogamicin. In the target expression analysis before CD22-targeted immunotherapy, all patients had CD22-positive expression except one patient was CD22-dim. As for the expression of CD19, 13 (43.3%) patients were CD19-positive, 12 (40.0%) patients were CD19-negative, and 5 (16.7%) patients were CD19-dim or partially expression. Totally 17 (56.7%) patients achieved CR at 1 month after CD22-targeted immunotherapy. The CR rate was 55.0% (11/20) in the CD22 CAR-T group, and 60.0% (6/10) in the inotuzumab ozogamicin group. There was no significant difference between the two groups (P = 0.79). The CR rate for patients exposed to both blinatumomab and CD19 CAR-T seemed to be low and was 25% (1/4). Other factors including primary refractory, post-transplantation relapse, and CD19 expression status had no effect on CR rate. Of the 17 patients who achieved CR, 10 had subsequent relapses, 2 lost to follow-up, 1 died of a post-CAR-T infection, and 1 died of complications of transplantation. As of December 15, 2023, excluding the 2 patients lost to follow-up, only 7 patients remained in MRD negative CR.

Conclusions: CD22-targeted immunotherapy is an effective treatment option for patients with r/r B-ALL who previously exposed to CD19-targeted immunotherapy. However, the relapse rate post CD22-targeted immunotherapy remains high. Therefore, new strategies are still needed to improve the prognosis of this group of patients.

Disclosure: Alex H. Chang is an employee of Shanghai YaKe Biotechnology Ltd., the other authors declare no conflict of interest.

19: Acute Leukaemia

P008 COMPARISON OF THE PROGNOSTIC IMPACT BETWEEN ELN2022 AND ELN2017 RISK CLASSIFICATION IN ALLOGENIC HEMATOPOIETIC STEM CELL TRANSPLANT RECIPIENTS WITH AML

Weihao Chen1, Yeqian Zhao1,2,3,4, Jimin Shi1,2,3,4, Yi Luo1,2,3,4, Jian Yu1,2,3,4, Yamin Tan5,6, Xiaoyu Lai1,2,3,4, Lizhen Liu1,2,3,4, Huarui Fu1,2,3,4, Yishan Ye1,2,3,4, Luxin Yang1,2,3,4, Congxiao Zhang1,2,3,4, He Huang1,2,3,4, Yanmin Zhao 1,2,3,4

1Bone Marrow Transplantation Center, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China, 2Liangzhu Laboratory, Zhejiang University Medical Center, Hangzhou, China, 3Institute of Hematology, Zhejiang University, Hangzhou, China, 4Zhejiang Province Engineering Research Center for Stem Cell and Immunity Therapy, Hangzhou, China, 5Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), Hangzhou, China, 6Institute of Cancer and Basic Medicine(IBMC), Chinese Academy of Sciences, Hangzhou, China

Background: Risk classification based on genetic aberrations plays a pivotal role in predicting prognosis and guiding treatment decisions in patients with acute myeloid leukemia (AML). In 2022, the European LeukemiaNet (ELN) issued an updated recommendations for diagnosis and risk classification, building upon the ELN2017 guidelines. While many studies have validated and compared the two versions of ELN risk classifications in chemotherapy cohorts, there remains a scarcity of research comparing the prognostic impact of ELN2017 and ELN2022 criteria in the context of allogeneic hematopoietic stem cell transplantation (allo-HSCT).

Methods: We conducted a retrospective study which compared the the prognostic impact between the 2017 and 2022 ELN risk classifications in a real-life cohort of de novo AML patients who underwent allo-HSCT (n = 641) in our center from January 2015 to January 2022. We enrolled patients who had sufficient clinical and genetic information available for ELN risk classification. Patients diagnosed with acute promyelocytic leukemia or whose who received a second transplantation were excluded. Gene mutations or fusion genes detection were performed using polymerase chain reaction before 2017 and next-generation sequencing after 2017.

Results: 623 patients were included in this retrospective study, with a median follow-up time of 2.8 years after allo-HSCT. The median age at allo-HSCT was 40 years (range 10-67). According to ELN2017 risk categories, 32% (n = 202) patients at diagnosis were classified into ELN2017 favorable group, 43% (n = 264) into ELN2017 intermediate group, and 25% (n = 157) into ELN2017 adverse group. In ELN2022, the classification was 32% (n = 202) in favorable, 45% (n = 277) in intermediate, and 23% (n = 144) in adverse group. Patients in adverse group had significantly lower RFS (relapse-free survival) and OS (overall survival) after allo-HSCT compared to those in favorable and intermediate group, regardless in ELN2017 or ELN2022. Nonetheless, RFS of ELN2022 intermediate patients was worse than favorable patients (68.8 vs 82.3%, P = 0.015), and we did not obverse this statistic difference in ELN2017. The c-statistic (area under the curves [AUC]) from ELN2022 for RFS after allo-HSCT was not obviously better compared to ELN2017 (AUCELN22 = 0.637 vs AUCELN17 = 0.616, P = 0.096). The univariate analysis indicated that adverse ELN classification, NR status at allo-HSCT, and CR patients with MRD positivity at allo-HSCT might be associated with worse RFS and OS after allo-HSCT. Therefore, we further refined the ELN2022 system into four categories by incorporating the remission and MRD status at allo-HSCT (favorable: ELN2022 favorable with MRDneg, intermediate: ELN2022 favorable with MRDpos and ELN2022 intermediate with MRDneg, adverse: ELN2022 intermediate with MRDpos and ELN2022 adverse with MRDneg, and very adverse: NR patients at allo-HSCT and ELN2022 adverse with MRDpos). The refined ELN risk classification showed that there was statistical significance between groups for RFS after allo-HSCT, and the AUCRefined ELN22 was significantly better than AUCELN22 (0.703 VS 0.637, P<0.001).

Table 1. Univariate analysis of clinical characteristics in RFS and OS

Variables

RFS

OS

HR (95% CI)

P Value

HR (95% CI)

P Value

Patient age at HSCT

1.01(1.00-1.02)

0.150

1.01(1.00-1.03)

0.066

WBC at diagnosis

1.00(0.99-1.00)

0.734

1.00(0.99-1.00)

0.981

ELN2017 risk classification

<0.001

<0.001

Favorable

1.00[Reference]

1.00[Reference]

Intermediate

1.22(0.83-1.80)

0.316

1.31(0.84-2.03)

0.232

Adverse

2.52(1.71-3.70)

<0.001

2.63(1.70-4.07)

<0.001

ELN2022 risk classification

<0.001

<0.001

Favorable

1.00[Reference]

1.00[Reference]

Intermediate

1.64(0.98-2.74)

0.058

1.45(0.82-2.59)

0.205

Adverse

4.58(2.90-7.23)

<0.001

4.40(2.65-7.28)

<0.001

Remission status at time of HSCT

<0.001

<0.001

CR1

1.00[Reference]

1.00[Reference]

≥CR2

1.05(0.70-1.57)

0.826

1.25(0.81-1.94)

0.312

NR

2.91(2.02-4.20)

<0.001

3.44(2.31-5.11)

<0.001

Pretransplant MRD status in CR patents

<0.001

<0.001

Negative

1.00[Reference]

1.00[Reference]

Positive

2.88(1.95-4.26)

2.70(1.74-4.19)

HLA match, n (%)

0.053

0.127

HLA-identical sibling transplant

1.00[Reference]

1.00[Reference]

Haploidentical transplant

0.85(0.56-1.29)

0.455

0.90(0.56-1.44)

0.669

Unrelated transplant

1.45(0.84-2.49)

0.185

1.48(0.80-2.74)

0.185

Conclusions: The updated ELN2022 risk classification did not demonstrate improved predictive performance for outcomes after allo-HSCT compared to ELN2017. We refined the stratification system into four groups by incorporating disease status at transplant, aiming to more accurately identify patients with different outcomes following allo-HSCT.

Disclosure: Nothing to declare

19: Acute Leukaemia

P009 EFFICACY AND SAFETY OF THE THIRD-GENERATION TKI OLVEREMBATINIB IN ADULT PH + ACUTE LYMPHOBLASTIC LEUKEMIA WITH RELAPSED DISEASE OR PERSISTENT MRD BRIDGING TO ALLO-HSCT

XiaoYu Zhang 1, Yanhong Zhao1, Rongli Zhang1, Erlie Jiang1

1Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, China

Background: To investigate the efficacy and safety of an olverembatinib regimen in adult Ph/BCR-ABL1 + ALL patients with relapsed disease or persistent MRD prior to allo-HSCT.

Methods: We retrospectively enrolled Ph+ ALL patients with relapsed disease or persistent MRD who were treated with an olverembatinib-based regimen before bridging to HSCT between February 2022 and February 2023.

Results: Seventeen Ph+ ALL patients were treated with olverematinib because of disease recurrence (n = 3) and persistent molecular positivity (n = 14). BCR: ABL1 p190 and p210 fusions were found in nine and eight patients, respectively. Six patients harbored a T315I mutation. In all, 13 patients achieved CMR, and the overall CMR rate by PCR was 76.47%, whereas the MRD neg rate by flow cytometry was 100%. All patients successfully underwent bridging allo-HSCT. With a median follow-up time of 342 (60-509) days post-HSCT, the one-year overall survival rate and recurrence-free survival rate were 94.1±5.71% (95 % CI 83.6~100%) and 88.2±7.81% (95% CI 74.2~100%), respectively. Only one patient experienced extramedullary relapse on day 129. One patient died due to CNS complications.

Conclusions: The findings of this study suggest that in Ph+ ALL patients with disease recurrence and persistent MRD positivity, olverembatinib showed a profound molecular response rate and was well-tolerated in MRD clearance prior to allo-HSCT

Disclosure: The authors declare that they have no competing interests.

19: Acute Leukaemia

P010 INTRACELLULAR CYTOKINE ASSAYS IN COMBINATION WITH DEGRANULATION ASSAY CONTRIBUTE SIGNIFICANTLY TO DETECT AND QUANTIFY LEUKEMIA SPECIFIC IMMUNE CELLS IN AML PATIENTS’ BLOOD OR CULTURE SETTINGS

Olga Schutti1, Lara Klauer2,1, Tobias Baudrexler2,1, Christoph Schmid3, Andreas Rank3, Joerg Schmohl4, Markus Hentrich5, Doris Kraemer6, Helga Schmetzer 1

1Klinikum Grosshadern, Ludwig-Maximilians-University, Working-Group Immune-Modulation, Munich, Germany, 2Contributed Equally, Munich, Germany, 3University Hospital of Augsburg, Augsburg, Germany, 4University Hospital of Tuebingen, Tuebingen, Germany, 5Red Cross Hospital of Munich, Munich, Germany, 6University Hospital of Oldenburg, Oldenburg, Germany

Background: Novel (immune) therapies are needed to stabilize remissions or the disease in AML. Leukemia derived dendritic cells (DCleu) can be generated ex vivo from AML patients’ blasts in whole blood using approved drugs (GM-CSF and PGE-1 (Kit-M)). After T cell enriched, mixed lymphocyte culture (MLC) with Kit-M pretreated (vs. untreated WB) antileukemically directed immune cells of the adaptive and innate immune system were already shown to be significantly increased.

Aims: To evaluate the use of leukemiaspecific assays intracellular cytokine production (INFy, TNFa) INCYT, degranulation (CD107a) DEG for a detailed quantification of leukemiaspecific cells in correlation with functional cytotoxicity and patients’ clinical data.

Methods: Whole blood (WB) samples were collected from 26 AML patients at first diagnosis, during persisting disease, or at relapse after allogeneic stem cell transplantation (SCT), and from 18 healthy volunteers. WB samples were treated with vs. without Kit-M to generate DC/DCleu. After MLC with Kit-M treated vs. untreated WB antigenspecific/ anti-leukemic effects were assessed through INCYT, DEG and a cytotoxicity fluorolysis assay. Quantification of cell subtypes was performed via flowcytometry.

Results: We generated significantly higher frequencies of (mature) DCleu without induction of blast proliferation in Kit-M treated vs. untreated samples. After MLC with Kit-M treated vs. untreated WB, frequencies of immunoreactive cells (e.g. non-naive T-cells, Tprol) as well as in INCYT/DEG ASSAYS leukemiaspecific adaptive - (e.g. B, T(memory)) or innate immune cells (e.g. NK, CIK) were significantly increased. The results of the intracellular production of INFy and TNFa were comparable. The cytotoxicity fluorolysis assay revealed a significantly enhanced blast lysis in Kit-M treated vs. untreated WB. Significant correlations could be shown between induced leukemiaspecific cells of several lines and improved blast lysis.

Conclusions: We successfully detected and quantified immunoreactive cells at a single-cell level using the functional assays (DEG, INCYT, and CTX) ex vivo, allowing us to evaluate the impact of Kit-M pretreated (DC/DCleu containing) WB on the provision of leukemia specific immune cells. Kit-M pretreatment (vs no pretreatment) was shown to significantly increase leukemia-specific IFNγ and TNFɑ producing, degranulating cells and to improve blast-cytotoxicity after MLC.

In vivo treatment of AML patients with Kit-M may lead to anti-leukemic effects and contribute to stabilize the disease or remissions. INCYT and DEG assays qualify to quantify potentially leukemia specific cells on a single cell level and to predict the clinical course of patients under treatment.

Disclosure: Conflict of interest: Modiblast Pharma GmbH (Oberhaching, Germany) holds the European Patent 15 801 987.7-1118 and US Patent 15-517627 ‘Use of immunomodulatory effective compositions for the immunotherapeutic treatment of patients suffering from myeloid leukemias’, with whom H.M.S. is involved with.

19: Acute Leukaemia

P011 TOTAL MARROW AND LYMPHOID IRRADIATION IN COMBINATION WITH POST-TRANSPLANT CYCLOPHOSPHAMIDE-BASED GRAFT VERSUS HOST DISEASE PROPHYLAXIS CONFERS FAVORABLE GVHD-FREE/RELAPSE-FREE SURVIVAL IN PATIENTS WITH ACUTE MYELOID LEUKEMIA

Anthony Stein 1, Monzr Al Malki1, Dongyun Yang1, Joycelynne Palmer1, Ni-Chun Tsai1, Ibrahim Aldoss1, Haris Ali1, Ahmed Aribi1, Andrew Artz1, Savita Dandapani1, Len Farol1,2, Susanta Hui1, An Liu1, Ryotaro Nakamura1, Vinod Pullarkat1, Eric Radany1, Amandeep Salhotra1, James Sanchez1, Ricardo Spielberger1,2, Guido Marcucci1, Stephen Forman1, Jeffrey Wong1

1City of Hope, Duarte, United States, 2Southern California Permanente Medical Group, Los Angeles, United States

Background: We have conducted a phase 2 study of a conditioning regimen of total marrow and lymphoid irradiation (TMLI) at 2000cGy, together with post-transplant cyclophosphamide (PTCy) for patients with acute myeloid leukemia in first or second complete remission (CR). This approach employs PTCy to attenuate the risk of chronic graft-versus-host-disease (GVHD), while using escalated targeted radiation conditioning before allografting to offset the possible increased risk of relapse.

Methods: We evaluated to date the first 25 patients with a median follow-up of ≥1yr (Table) who enrolled between 2018–2023. Key criteria: ages 18–60, first or second CR, minimal residual disease negative by multi-color flow cytometry, and normal organ function. TMLI was administered on days -4 to 0 without addition of chemotherapy. The radiation dose for all patients (n = 25) was 2000cGy, delivered in 200cGy fractions twice daily. The radiation dose delivered to the liver and brain was kept at 1200cGy. Remaining organs were considered non-targeted. All patients received peripheral blood stem cells on day 0. Cyclophosphamide was given on days +3 and +4, 50mg/kg each day for GVHD prevention. Tacrolimus, 1mg continuous infusion adjusted to maintain levels from 5–10ng/mL, was given from day +5 to day +90, and G-CSF 5µg/kg daily was administered at day +5 until recovery of neutrophil counts.

Endpoints included toxicity, engraftment, overall survival (OS), non-relapse mortality (NRM), and GVHD/relapse-free survival (GRFS) at 1yr. Toxicities were defined according to the Bearman and CTCAE 4.03 scales, the latter for hematologic toxicity. A patient safety lead-in segment (n = 6) was conducted to ensure there were no unexpected toxicities. GRFS was defined as the absence of grade 3-4 acute GvHD, chronic GvHD requiring systemic treatment, relapse, or death (from any cause).

Results:

Variable

Median (range) or N (%)

Age at transplant (yrs)

39 (19-56)

Cytogenetic risk (ELN criteria)

favorable

1 (4%)

intermediate

9 (36%)

unfavorable

8 (32%)

missing

7 (28%)

KPS at HSCT

80

3 (12%)

90

17 (68%)

100

5 (20%)

HCT-CI

16 (64%)

1

6 (24%)

≥2

3 (12%)

Donor source

MSD

11 (44%)

MUD

14 (56%)

Female donor to male recipient

Yes

4 (16%)

No

21 (84%)

CMV

Negative

8 (32%)

Positive

17 (68%)

  1. Patient characteristics. Abbreviations: ELN, European LeukemiaNet; HCT-CI, Hematopoietic Cell Transplantation-specific Comorbidity Index; KPS, Karnofsky Performance Score; MSD, matched sibling donor; MUD, matched unrelated donor; CMV, cytomegalovirus.

The median follow up was 47.1 months (range: 5.9-59.9) for surviving patients (n = 22). Bearman toxicity data are available for all patients. Among these patients, grade 2 toxicities were bladder toxicity and stomatitis. No grade 3-4 toxicities or toxicity-related deaths were observed. All patients engrafted. Median times to neutrophil and platelet recovery were 14 days (range: 13-32) and 20 days (range: 11-49), respectively.

Acute GVHD (aGVHD) developed in 2 patients (100-day Grade II-IV aGVHD: 8.0%, 95%CI: 1.3-22.9); of those, only 1 patient developed Grades III-IV (100-day Grade III-IV aGVHD: 4.0%, 95%CI: 0.3-17.4). Six patients developed chronic GVHD (2-year cGVHD rate: 27%, 95%CI: 11%-47%), which was mild in 5 patients and moderate/severe in 1 patient.

Two-year estimates of OS and leukemia-free survival were 89% (95%CI: 62-97) and 84% (95%CI: 62-94). Disease relapse at 2yrs was 16% (95%CI: 4.9-33). The estimate of NRM at 2yrs was 0%. Relapsed disease after transplant occurred in 5 patients, which led to 3 deaths from relapsed disease. The GRFS rate at 2yrs was 61% (95%CI: 37-78).

Conclusions: 1) This chemotherapy-free conditioning regimen, together with PTCy and tacrolimus, is safe and feasible, with no NRM. 2) All patients achieved engraftment. 3) Participants with ≥1yr follow-up have discontinued immunosuppressive therapy, reducing financial burden and leading to improved quality of life. The results to date suggest a favorable GRFS rate.

Clinical Trial Registry: clinicaltrials.gov, NCT#03467386

Disclosure: Anthony Stein: Sanofi: Current Employment, Current holder of stock options.

19: Acute Leukaemia

P012 INCREASED MESENCHYMAL STROMAL CELLS SENESCENCE AND HIGH CXCL14 LEVELS IN BONE MARROW ARE LINKED WITH THE OCCURRENCE OF GVHD AFTER HEMATOPOIETIC STEM CELLS TRANSPLANTATION

Alexandra Guelton 1, Meriem El Ouafy1, Romain Perouf1, Naceur Charif1, Simona Pagliuca1, Marie-Thérèse Rubio1, Natalia de Isla1

1University of Lorraine, Vandoeuvre-les-Nancy, France

Background: The acute myeloid leukemia (AML) is an hematological malignancy with a bad pronostic with an estimated survival of 50% at 1 year, and 27% at 5 years. The allogenic hematopoietic stem cells transplantation (allo-HSCT) is the only curative treatment of AML, marked by two major adverse effects: graft versus host disease and relapse. Although medullary microenvironment is composed of many cellular actors, mescenchymal stromal stem cells (MSC) constitute key players, both for their role in hematopoiesis and for their immunomodulatory capacities, particulary toward T cells. The aim of our work was to study the link between medullary microenvironment (MSC, cytokines…) in pre-transplantation, and the occurrence of GVHD.

Methods: We conducted a prospective, single-center study at the Nancy University Hospital, involving HSC allograft patients with AML. Inclusion criteria were: graft conditioning including a combination of fludarabine and busulfan, homogeneous graft-versus-host disease (GVHD) prophylaxis (anti-lymphocytic serum, cyclosporin and mycophenolate mofetil. Medullary MSC from bone marrow of patients before HSCT were isolated and cultured. MSC used as control provided from patients without AML, and were obtained after surgical hip arthroplasty. MSC were characterized based on the International Society of Cellular Therapie (ISCT) criteria as their adhesion to plastic, their surface phenotype (CD73 + , CD90+, HLA-DR−, CD45−, CD34−) and their self-renewal capacity.

Then, MSC senescence was studied thanks to β-galactosidase test coupled with EdU proliferation test (5-Methyl-2′-deoxycytidine), to distinguish senescents and proliferative cells, and avoid false positives. Moreover, proteins involved in cell senescence (p16, p21, p53, p38) were evaluated by Western-Blot. Then, many cytokines involved in cell senescence (IL10, IL6, IL1, IL13…) and in immune surveillance (CXCL14) were quantified by CBA and ELISA method. In parallel, MSC immunomodulatory properties were determined by coculture experiments between MSC and T cells from healthy donnors.

T statistical tests and Pearson correlation tests was performed thanks to GraphPad Prism. Principal component analysis (PCA) was performed thanks to XLSTAT.

Results: Our results showed that high levels of medullary MSC senescence from AML patients before HSCT, correlated with a decrease of MSC immunomodulatory properties toward T cells, was associated with the occurrence of GVHD, three months after HSCT. Moreover, a positive correlation between the level of medullary MSC senescence and the medullary concentration of CXCL14 was observed. Among the other cytokines studied, no correlation was shown between their concentration and medullary MSC senescence.

Conclusions: Our results showed that a pro inflammatory microenvironment before HSCT, characterized by the presence of senescent MSC with disturbed immunomodulatory properties, and the presence of CXCL14, would be favorable to the occurrence of GVHD after HSCT.

Disclosure: Nothing to declare

19: Acute Leukaemia

P013 CORRELATION OF THE OVERALL SURVIVAL IN MIXED-PHENOTYPE ACUTE LEUKAEMIA AND ACUTE LYMPHOBLASTIC LYMPHOMA WITH THE REFINED DISEASE RISK INDEX APPLIED IN AN UPPER-MIDDLE INCOME COUNTRY

Naty López-Córdova 1, Jessica Meza-Liviapoma1, Jule Vasquez-Chavez1, Claudio Flores-Flores2, Shirley Quintana-Truyenque1

1Instituto Nacional de Enfermedades Neoplásicas (INEN), Lima, Peru, 2Universidad Peruana San Juan Bautista, Lima, Peru

Background: The Refined Disease Risk Index (R-DRI; 4 risk groups: low [LR], intermediate [IR], high [HR] and very high [V-HR]) is a score used to estimate overall survival after allogeneic hematopoietic stem cell transplantation (Allo-HSCT) in patients with haematological malignancies, however, both in its original version and in the R-DRI does not consider certain diagnoses, such as mixed-phenotype acute leukaemia (MPAL) and acute lymphoblastic lymphomas (LBL). These diagnoses constitute an important population since they have a very aggressive course and fatal outcomes in most cases. The objective of the study is to determine the correlation of overall survival in patients with MPAL and LBL after Allo-HSCT, in relation to R-DRI. These results will allow these patients to be assigned to one of the existing risk groups in order to have an estimate of their post HSCT prognosis.

Methods: We reviewed retrospectively the data of 166 patients who had an Allo-HSCT between 2012 and 2023 in the Bone Marrow Transplant (BMT) unit of the National Institute of Neoplastic Diseases (INEN). The information was extracted from the unit registry and was completed through the electronic medical records. Patients diagnosed and transplanted for MPAL and LBL were subjected to the analysis and their overall survival was evaluated, which was compared with the data of patients with acute lymphoblastic leukaemia (ALL) and acute myeloid leukaemia (AML). Survival was estimated using the Kaplan-Meier method and comparisons were made using the Log-Rank test.

Results: The median age at HSCT was 26 years (range: 15 to 63), 84 patients were men (50.6%). 85 patients had ALL; 41, AML; 11, Chronic myeloid leukaemia (CML); 13, MPAL; and 16, others (Myelodysplastic syndrome: 8, LBL: 6, Hodgkin lymphoma: 1, aggressive T/NK cell leukaemia: 1). According to the R-DRI classification (does not include MPAL and LBL), 4.8% of patients were LR, 38.1% IR, 35.4% HR, and 21.8% V-HR. Median follow-up was 3.9 years and median overall survival (OS) was not reached for the entire cohort. According to R-DRI, the 4-year OS rate was 100% in LR, 57.4% in IR, 53.5% in HR, and 38.3% in V-HR, respectively. The 4-year OS in patients with MPAL was 76.9%, and in LBL 44.4%. The OS of patients with MPAL was superior to those with IR, presenting a significant difference in relation to the HR group (p = 0.015).

Conclusions: The OS of patients with MPAL is superior to those with IR, presenting a significant difference in relation to those with V-HR. These results suggest that there would be a group that is similar to that of IR, but with a better prognosis than that described in the R-DRI and that could give rise to a new “low-intermediate” group in which the MPAL could be included.

Disclosure: Nothing to declare.

19: Acute Leukaemia

P014 SIGNIFICANT IMPROVEMENT OF SURVIVAL AFTER ALLOGENEIC STEM CELL TRANSPLANTATION IN ACUTE LYMPHOBLASTIC LEUKEMIA OVER TWO DECADES – A SINGLE CENTER RETROSPECTIVE ANALYSIS

Ben-Niklas Baermann1, Paula Kessler 1, Astrid Tautges2, Paul Sebastian Jäger1, Mustafa Kondakci3, Kathrin Nachtkamp1, Sascha Dietrich1, Guido Kobbe1

1Medical Faculty and University Hospital Düsseldorf, Düsseldorf, Germany, 2Office for general practice Dirk Röhlich, Trier, Germany, 3Lukas Hospital Solingen, Solingen, Germany

Background: Acute lymphoblastic leukemia (ALL) treatment landscape has dramatically changed within the last two decades. Especially tyrosine kinase inhibitors in Philadelphia positive (BCR-ABL) ALL as well as Blinatumomab, Inotuzumab and chimeric antigen receptor t-cell therapy for B-cell precursor ALL (B-ALL) were the most prominent pharmacologic milestones. Moreover the german multicenter ALL study group (GMALL) made strong efforts to improve conventional and transplant strategies to reduce non relapse mortality.

Methods: We retrospectively analyzed clinical outcome of 146 patients (61% male, 39% female, median age at transplant 36 years, range 17-74) with acute lymphoblastic leukemia (B-ALL 76%, T-ALL 24%) receiving allogeneic stem cell transplantation (alloHSCT) at the UKD, Heinrich Heine University of Düsseldorf between 1989 and 2022. Of Patients with B-ALL 33% were Philadelphia chromosome positive.

The majority of patients (92%) received myeloablative conditioning almost all containing total body irradiation (TBI) with at least 8 Gy. Matched related donors were used in 32%, 40% had matched unrelated donors and 27% mismatched or haploidentical donors. Median time from diagnosis to alloHSCT was 6 months (range 2-80). Haematologic remission could be achieved in 95% prior to transplant.

Results: Median follow up after alloHSCT was 5.6 years for surviving patients. Median overall survival (OS) from transplant for all patients was 2.8 years (95% CI 0.0-6.1 years). OS after two and five years were 51% (95% CI 43-59) and 47% (95% CI 39-55). For T-ALL median OS was not reached, for B-ALL median OS was 1.3 years (95% CI 0-2.9 years).

For patients with first diagnosis from 2000 to 2010, median OS from alloHSCT was 1.2 years, whereas after 2010 median OS is not reached with a significant difference between these subgroups (p<0.05). OS after two and five years for patients with first diagnosis after 2010 were 66 % (95% CI 55-78) and 64 % (95% CI 52-76). These findings can be reproduced for BCR-ABL positive as well as negative B-ALL subgroups but not for patients with T-ALL.

MRD persistence before alloHSCT was associated with significant worse OS even in haematologic complete remission (median OS 1.4 years vs. not reached, p < 0.05), not significantly differing for patients with first diagnosis before or after 2010.

Median OS after alloHSCT could not be improved by application of higher doses of TBI (12Gy vs. 8Gy, median OS 2.9 years vs. not reached, p = 0.5).

Conclusions: Prognosis of B-lineage acute lymphoblastic leukemia after alloHSCT significantly improved over time and reducing TBI toxicity by dose reduction did not negatively influence OS. Achieving MRD negativity before alloHSCT especially with new targeted therapies seems to play an important role. Nevertheless worse OS in patients with MRD persistence could not be overcome in recent years.

Disclosure: Ben-Niklas Baermann: Travel support: Medac, Kite-Gilead; Advisory Role or Speaker Honoraria: Kite-Gilead, Incyte

Paula Kessler: Nothing to declare.

Astrid Tautges: Nothing to declare

Paul Sebastian Jäger: Nothing to declare

Mustafa Kondakci: Nothing to declare

Sascha Dietrich: Nothing to declare

Kathrin Nachtkamp: Nothing to declare.

Guido Kobbe: Advisory Role or Speaker Honoraria: MSD, Pfizer, Amgen, Novartis, Gilead, BMS-Celgene, Abbvie, Biotest, Takeda, Eurocept; Financing of Scientific Research: BMS-Celgene, Amgen, Abbvie, Eurocept, Medac.

19: Acute Leukaemia

P015 OUTCOMES OF ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION FOLLOWING BLINATUMOMAB IN CHILDREN AND YOUNG ADULTS WITH B-CELL ACUTE LYMPHOBLASTIC LEUKEMIA

Mattia Algeri 1, Michele Massa2, Federica Galaverna2, Daria Pagliara2, Ilaria Pili2, Francesca Del Bufalo2, Marco Becilli2, Emilia Boccieri2, Roberto Carta2, Francesco Quagliarella2, Chiara Rosignoli2, Carmen Dolores De Luca2, Barbarella Lucarelli2, Pietro Merli2, Franco Locatelli3

1IRCCS Bambino Gesù Children’s Hospital - Magna Graecia University, Rome - Catanzaro, Italy, 2IRCCS Bambino Gesù Children’s Hospital, Rome, Italy, 3IRCCS, Bambino Gesù Children’s Hospital, Catholic University of the Sacred Heart, Rome, Italy

Background: Blinatumomab, a CD3-CD19 bispecific T-cell engager, demonstrated high efficacy in inducing and consolidating remission in relapsed/refractory (r/r) B-cell acute lymphoblastic leukemia (B-ALL). Available evidence suggests that r/r B-ALL patients have a better outcome if they received allogeneic hematopoietic stem cell transplantation (HSCT) after blinatumomab. However, the effect of blinatumomab on HSCT outcomes in children and young adults (YA) remains to be fully elucidated.

Methods: We retrospectively analyzed 78 children and YA with B-ALL who underwent allogeneic HSCT at our Institution, from February 2016 to June 2023, after receiving blinatumomab as last therapy before transplant either as part of reinduction/consolidation or as MRD-clearing strategy. Most patients (n = 55) received a single 28-day course. Median interval from blinatumomab discontinuation to HSCT was 23 days (IQR 19-31.75).

Median age at HSCT was 5 years (range 1-24). Patients received unmanipulated grafts from HLA-identical related (MFD, n = 13) or matched unrelated donors (MUD, n = 33), or αβT-cell depleted HSCT from HLA-haploidentical relatives (TCD-Haplo, n = 32) after TBI- (n = 72, 92.3%) or chemo-based myeloablative conditioning regimen (n = 6, 7.7%). All subjects were in complete remission (CR) at time of HSCT, associated with MRD-negativity (<10^-4) in 94% of cases. Thirty-one (39.7%) patients harbored at least one very high-risk (VHR) disease feature (Table 1). Further patient and transplant characteristics are reported in Table 1.

Sex (female/male)

31 (40)/47(60)

CR number at Blinatumomab2

• CR1

15 (19.2)

• CR2

58 (74.4)

• CR3

5 (6.4)

Age group

• ≤ 4 years

17 (21.8)

• 5-11 years

38 (48.7)

• ≥12 year

23 (29.5)

Very high-risk disease features

• TCF3-Rearranged

2 (2.6)

• Hypodiploidy

2 (2.6)

• KMT2A/AF4

5 (6.4)

• IKZF1plus and poor MRD response after induction

4 (5.1)

• No CR at Day33 without cytogenetic abnormalities

2 (2.6)

• Very early relapse (<18 months from diagnosis) for CR2 patients

21 (26.9)

Therapy before HSCT:

• Chemotherapy + Blinatumomab

49 (62.9)

• Chemotherapy + Inotuzumab + Blinatumomab

14 (17.9)

• Chemo-free treatment of relapse (Inotuzumab OR TKI + Blinatumomab)

15 (19.2)

Results: All patients achieved sustained donor engraftment, median time to neutrophil and platelet recovery being 17 (IQR 14-19) and 15 (IQR 11-20) days, respectively. After a median follow-up of 26 months, disease-free survival (DFS) of the whole cohort was 74.2% (95%CI 63.3-85.1), overall survival (OS) 84.3% (95%CI 74.5-94.1) and non-relapse mortality (NRM) 2.6% (95%CI 0-6.2). Cumulative incidence (CI) of grade II-IV acute graft-versus-host disease (aGvHD) was 17.9% (95%CI 9.08-26.6), with only two cases of grade III; CI of extensive chronic GvHD (cGvHD) was 4.6% (95%CI 0-9.7). No unexpected toxicities were observed. Patients aged ≤4 years had significantly lower DFS as compared to those aged 5-11 years or ≥12 years (45.6% 95%CI 20.1-71.1, 82% 95%CI 70-100 and 85.6% 95%CI 68.8-95.5, respectively, p = 0.02), due to a higher cumulative incidence of relapse (CIR 51.5% 95%CI 24-79.1, 18% 95%CI 4.9-31.1, 18.6 95%CI 8.6-28.9, respectively, p = 0.05). Neither the use a specific conditioning, nor MRD status and presence of VHR features influenced the probability of DFS. A trend toward better DFS was observed in CR1 patients (94.1%, 95%CI 82.95-100) versus CR2-3 (69.5%, 95CI 57-83.04, p = 0.18) and in those receiving unmanipulated matched grafts (80.1% 95%CI 64.6-95.6) versus TCD-Haplos (64.9%, 95%CI 48.2-81.5, p = 0.058).

Sixteen patients relapsed after HSCT, all with CD19-positive recurrence, after a median time of 9 months following transplantation (range 1-23). Of them, 10 received anti-CD19 CAR-T cells while 2 received inotuzumab, the 2-year OS after relapse being 52.7% (95%CI 27.1-78,3).

Conclusions: HSCT following blinatumomab in children/YA with r/r B-ALL is safe and highly effective, with remarkably low NRM (only 2 patients died for NRM) and absence of unexpected toxicities. These findings indicate that blinatumomab represents a suitable strategy to achieve long-term disease eradication and that it doesn’t preclude successful salvage with CAR-T cells in case of relapse.

Disclosure: Mattia Algeri: Vertex: Membership on an entity’s Board of Directors or advisory committees; Neovii: Speakers Bureau.

Pietro Merli: Sobi: Membership on an entity’s Board of Directors or advisory committees; Jazz: Membership on an entity’s Board of Directors or advisory committees; Miltenyi: Speakers Bureau; Amgen: Speakers Bureau.

Franco Locatelli: Miltenyi, Jazz Pharm, Medac, Sobi, Gilead, BluebirdBio: Speakers Bureau; Sanofi, Vertex: Membership on an entity’s Board of Directors or advisory committees; Bellicum, Amgen, Neovii, Novartis. Sanofi, SOBI, Vertex: Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau

19: Acute Leukaemia

P016 THE ROLE OF ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION IN CONSOLIDATION OF MINIMAL RESIDUAL DISEASE-NEGATIVE REMISSION IN RELAPSED/REFRACTORY B-CELL ACUTE LYMPHOBLASTIC LEUKEMIA IN ADULTS AFTER PHARMACOLOGIC IMMUNOTHERAPY

Kseniia Afanaseva1, Ivan Moiseev 1, Bella Ayubova1, Elena Babenko1, Ildar Barkhatov1, Tatiana Gindina1, Anna Smirnova1, Olesya Smykova1, Yulia Vlasova1, Sergey Bondarenko1, Alexander Kulagin1

1RM Gorbacheva Research Institute, Pavlov University, St. Petersburg, Russian Federation

Background: Allogeneic hematopoietic cell transplantation (allo-HCT) is a standard consolidation strategy for B-cell precursor acute lymphoblastic leukemia (BCP-ALL) patients with relapsed/refractory (r/r) disease and persistent minimal residual disease (MRD). Long-term outcomes of pharmacologic immunotherapy in r/r BCP-ALL is relatively modest, but MRD-negative patients have better prognosis, which was not directly compared to the results of allo-HCT in large studies.

Methods: The study included 101 BCP-ALL patients who achieved MRD-negative complete remission (CR) with two consecutive evaluations after either blinatumomab or inotuzumab ozogamicin treatment from November 2014 to September 2023 (Table 1). Median age was 22 years (range, 18 - 67 years). MRD response was assessed both by flow cytometry and molecular analysis for patients with known molecular markers. Median blinatumomab courses were 1 (range, 1-7), inotuzumab ozogamicin – 1 (range, 1-3). Consolidation with allo-HCT was performed in 62 patients, not performed in 39 patients within the frame of the routine clinical practice. Long-term outcomes after immunotherapy according to allo-HCT consolidation were estimated by landmark analysis.

Table 1. Patients’ characteristics of the study group

Characteristics

Immunotherapy followed by allo-HCT

N = 62

Immunotherapy only

N = 39

P-value

Blinatumomab/Inotuzumab ozogamicin

40 (65%)/22 (35%)

32 (82%)/7 (18%)

0,06

High cytogenetic risk

(yes/no)

23 (37%)/39 (63%)

11 (28%)/28 (72%)

0,36

Extramedullary disease in r/r

(yes/no)

17 (27%)/45 (73%)

3 (8%)/36 (92%)

0,02

Indication to immunotherapy (MRD/r/r*)

16 (26%)/46 (74%)

19 (49%)/20 (51%)

0,02

*R/R status

(refractory/1st relapse/>1 relapse)

5 (11%)/24 (52%)/17 (37%)

0 (0%)/8 (40%)/12 (60%)

0,12

Previous allo-HCT

(yes/no)

4 (6%)/58 (94%)

15 (38%)/24 (62%)

0,001

Subsequent immunotherapy

(yes/no)

10 (16%)/52 (84%)

8 (21%)/31 (79%)

0,58

Donor

(Haploidentical/other)

21 (34%)/41 (66%)

-

-

Results: Median follow-up time in the group of patients who received allo-HCT after immunotherapy was 55 months (range, 2-95), in immunotherapy without allo-HCT group – 56 months (range, 5 - 101) for those who survived by follow-up. Median time from achievement of MRD-negative CR to allo-HCT was 2 months (range, 2 - 27). Median time from achievement of MRD-negative CR to relapse was 12 months (range, 2 - 72) in immunotherapy followed by allo-HCT group and 13 months (range, 2 – 61) in immunotherapy without HCT group. In a landmark analysis of 5-year overall survival (OS) and relapse-free survival (RFS) by allo-HCT at 2 months after MRD-negative CR establishment no difference between outcomes in two groups was demonstrated: OS was 44,1% (95% CI 29,3 – 66,3) in allo-HCT group and 49,6% (95% CI 38,4 – 64,1) in immunotherapy without allo-HCT group, p = 0,19; RFS was 31% (95% CI 17,9 – 53,7) and 36,1% (95% CI 25,3 – 51,5), p = 0,25, respectively. Results were similar when assessed for 4-months (p = 0,46 for OS and p = 0,67 for RFS) and 6-months landmark points (p = 0,61 for OS and p = 0,83 for RFS). Subgroup univariate analysis showed no influence of any predictors (blinatumomab versus inotuzumab ozogamicin, high cytogenetic risk, extramedullary disease in relapse, MRD or relapse as an indication to immunotherapy, previous allo-HCT) for RFS in immunotherapy without subsequent allo-HCT group, while extramedullary disease in relapse and haploidentical donor increased risk of RFS after allo-HCT, which was confirmed in a multivariate model (HR 2,8 (95% CI 1,38 – 5,6), p = 0,004 and HR 2,3 (95% CI 1,06 – 4,9), p = 0,03).

Conclusions: The study demonstrated that responders to pharmacologic immunotherapy with r/r BCP-ALL with sustainable MRD-negative status have no benefit from all-HCT consolidation in the general group. Nonetheless, heterogeneity in allo-HCT outcomes indicates that further cooperative studies and consolidation of multicenter data is required to define the group which will benefit from allo-HCT in MRD-negative CR.

Disclosure: Nothing to declare

19: Acute Leukaemia

P017 FLAG-IDA/VENETOCLAX IS ASSOCIATED WITH HIGHER REMISSION RATES AND IMPROVED POST-TRANSPLANT SURVIVAL COMPARED TO VENETOCLAX/AZACITIDINE IN RELAPSED/REFRACTORY AML PATIENTS

Evgeny Klyuchnikov1, Anita Badbaran1, Radwan Massoud 1, Normann Steiner1, Petra Freiberger1, Franziska Modemann1, Martin Schönrock1, Sophia Cichutek1, Walter Fiedler1, Micha Peeck2, Nico Gagelmann1, Christine Wolschke1, Francis Ayuk1, Ulrike Bacher3, Nicolaus Kröger1

1University Cancer Center of Hamburg, Hamburg, Germany, 2Agaplesion Diakonie Clinic, Rotenburg, Germany, 3Bern University Hospital, Bern, Switzerland

Background: Patients (pts) with relapsed/refractory (R/R) AML experience poor remission rates and short durations of response. Combinations of BCL2 inhibition have proven to be synergistic with low intensity and intensive chemotherapy, leading to high remissions. In this monocentric study, we compared post-transplant outcomes in R/R AML pts who received low (azacitidine [AZA]) or intensive (FLAG-Ida) regimen combined with venetoclax [VEN] as “bridging” strategies before allogeneic stem cell transplantation (allo-SCT).

Methods: 90 pts (male, n = 53; median, 59 years [range, 19-75]) with R/R AML who received allo-SCT (related, n = 58) between 2019-2023 at the Department of Stem Cell Transplantation (University Medical Centre Hamburg) were included if they received VEN-based “bridging” strategies. The measurable residual disease (MRD) detection was performed by flow cytometry (“different from normal”; ELN guidelines). Primary endpoint was the difference in overall survival (OS) from allo-SCT. Secondary endpoints were differences in leukaemia-free survival (LFS), relapses and non-relapse mortality (NRM) from allo-SCT.

Results: The majority of allografts were performed after myeloablative conditioning (n = 57, 63%) with ATG as GvHD prophylaxis (n = 65, 72%). 62 pts underwent 1st whereas 26 (29%) 2nd and two 3rd allo-SCT. At allo-SCT,62 pts (69%) were in complete remission (CR). Bridging therapy consisted of AZA-VEN (one or two cycles) in 41 pts or FLAG-Ida-VEN in 49 pts. Pre-transplant MRD data were available in 49 pts. The rate of MRDnegCR (16/27, 59% vs 11/27, 41%) and MRDpos CR (16/22, 73% vs 6/22, 27%) was higher in the FLAG-Ida-VEN group. The rate of non-CR (17/28, 61% vs 11/28, 39%, p = 0.055) was higher in the AZA-VEN group.

During a median follow up of 13 months (2-140), there were 34 mortalities, 27 relapses and 13 NRM events. The 2-year OS (61%, 43-77% vs 46%, 29-64%, p = 0.089) and LFS (46%, 27-66% vs 39%, 24-52%, p = 0.045) were better in FLAG-Ida-VEN. The relapse and NRM rates were similar between two groups. Other factors, significant in univariate analysis included remission status and donor type. In the multivariate analysis, CR at allo-SCT had significant independent impact on OS (HR 0.17, 0.08-0.35, p<0.0001), LFS (HR 0.18, 0.1-0.35, p<0.0001) and relapses (HR 0.19, 0.08-0.43, p<0.0001).

In addition, we performed an analysis (n = 77) focusing on remission status augmented by MRD. The 1 y OS for MRDneg CR, MRDpos CR and pts with non-CR was 93% (77-98%), 63% (40-81%) and 30% (16-49%, p<0.001), respectively. The 1-y LFS for MRDneg CR, MRDpos CR and pts with non-CR was 92% (76-98%), 59% (37-78%) and 21% (11-51%, p<0.001), respectively. The relapse rate at 1 y for MRDneg CR, MRDpos CR and pts with non-CR was 9% (2-39%), 21% (8-44%) and 55% (36-72%, p<0.001), respectively. In multivariate analysis, MRDposCR and non-CR had adverse impact on OS (HR 5.2, 1.1-24.4, p = 0.035; HR 11.5, 2.7-49.9, p = 0.001; Wald test, p = 0.002), LFS (HR 2.9, 0.9-9.2, p = 0.076; HR 8.6, 2.9-25, p<0.001; Wald test, p<0.001) and relapses (HR 2.6, 0.5-14.2, p = 0.24; HR 10.1, 2.5-39.8, p<0.001; Wald test, p<0.001) compared to MRDnegCR, respectively.

Conclusions: Intensive venetoclax-based “bridging” regimen with FLAG-Ida is associated with higher CR rates than AZA-VEN, leading to overall better outcomes.

Disclosure: Nothing to declare.

19: Acute Leukaemia

P018 COMPARISON OF OUTCOMES OF HAPLOIDENTICAL HEMATOPOIETIC STEM CELL TRANSPLANTATION USING POST-TRANSPLANTATION CYCLOPHOSPHAMIDE AND EX-VIVO TCRΑΒ + CD19 DOUBLE-NEGATIVE SELECTED GRAFT IN ACUTE MYELOID LEUKEMIA

László Gopcsa 1, Hajnalka Andrikovics1, Alexandra Balogh1, Anikó Barta1, Judit Bogyó2, Zoltán Csukly1, Katalin Dobos1, János Dolgos1, Apor Hardi1, János Fábián1, Laura Giba-Kiss1, József Harasztdombi1, Kinga Kerner1, Ágnes Király1, Gergely Lakatos1, Viktor Lakatos1, Lilla Lengyel1, Nóra Meggyesi1, Noémi Németh1, Melinda Paksi1, Laura Regáli1, Marienn Réti1, János Sinkó1, Bálint Szabó1, Anikó Szilvási2, Éva Torbágyi1, Andrea Várkonyi1, Nikolett Wohner1, István Vályi-Nagy1, Péter Reményi1

1Central Hospital of Southern-Pest, National Institute of Hematology and Infectious Diseases, Budapest, Hungary, 2The Hungarian National Blood Transfusion Service, Budapest, Hungary

Background: Haploidentical hematopoietic stem cell transplantation (Haplo-HSCT) represents a curative therapeutic option for the treatment of patients suffering from acute leukemia. Moreover, the incidence of severe acute and extensive chronic GVHD in the case of Haplo-HSCT has proven to be more favorable compared to the other donor types. Currently, Haplo-HSCT with post-transplantation cyclophosphamide (PTCY) GVHD prophylaxis is considered the “gold standard” procedure. However, a less common approach to performing Haplo-HSCT involves ex-vivo T-cell depletion, employing various methods, with the most recognized being the use of a graft produced through TCRαβ + CD19 double-negative depletion (TCDαβ + CD19). Experiencies with pediatric HSCT using haploidentical grafts generated through TCDαβ + CD19 have been notable for their compelling outcomes. There is limited clinical experience in adult HSCT practice with this method.

Methods: In our retrospective analysis, we compared the outcomes of Haplo-HSCT performed between 2015 and 2022 for AML using PTCY (N = 60) and TCDαβ + CD19 (N = 28).

Results: In the PTCY group, 37 males (62%) and 23 females (38%) were included, with a median age of 50.5 years, while in the TCDαβ + CD19 group, there were 15 males (54%) and 13 females (46%) with a median age of 50 years. Mostly myeloablative conditioning regimens were used in both groups, primarily involving Thiotepa-Busulfan-Fludarabine and Thiotepa-Treosulfan-Fludarabine. All patients in the PTCY group received PTCY+tacrolimus+MMF GVHD prophylaxis. In the TCDαβ + CD19 group, 64% of patients did not received post-graft immunosuppression, however, GVHD prophylaxis was administered in 36% of cases (18% with MMF, 11% with tacrolimus, and 7% with ruxolitinib). The incidence of acute GVHD in the PTCY and TCDαβ + CD19 groups was 39% and 25%, respectively, with severe cases being 7% and 4%. The majority of acute GVHD cases were grade 2 and responded well to steroid treatment. The incidence of chronic GVHD in the PTCY and TCDαβ + CD19 groups was 31% and 21%, respectively. The extensive chronic GVHD was similar in the two groups (14% versus 10,5%). The relapse rates were low in both groups: 13% and 11%. Prolonged poor graft function was observed in 22% of patients receiving PTCY. Non-relapse mortality (NRM) was identical in both groups: PTCY and TCDαβ + CD19 34% and 28%, respectively. The overall survival (OS), disease-free survival (DFS), and refined GVHD-free and relapse-free survival (rGRFS) were more favorable in the TCDαβ + CD19 group: 61% and 53%, 61% and 51%, 53% and 46%.

Conclusions: The presented results are unique in terms of comparing both PTCY and TCDαβ + CD19 methods within one center. The OS, DFS, and GRFS were favorable with the TCDαβ + CD19 method, but larger studies are necessary for confirmation. Unlike in ALL, the occurrence of rejection with the TCDαβ + CD19 method does not significantly impact long-term outcomes. Therefore, the use of TCDαβ + CD19 method in AML can be safely employed, resulting in faster engraftment, shorter hospital stays, and a clearly lower incidence of poor graft function. The relapse rate was low in both patient groups, indicating a significant graft-versus-leukemia effect. The incidence of severe acute GVHD was low. Moreover, the use of post-graft maintenance therapeutic strategies in AML can further enhance long-term patient survival.

Disclosure: Disclosure of conflict of interest: None.

19: Acute Leukaemia

P019 AZACITIDINE AND VENETOCLAX WITH OR WITHOUT DLI IN RELAPSED MYELOID MALIGNANCIES AFTER ALLOGENIC HEMATOPOIETIC STEM CELL TRANSPLANTATION – A RETROSPECTIVE MULTICENTER STUDY OF THE SFGM-TC

Turot Mélanie 1, Loschi Michael2, Chantepie Sylvain3, Arnautou Pierre4, Poire Xavier5, Maillard Natacha6, Chalandon Yves7, El-Cheikh Jean8, Ceballos Patrice9, Devillier Raynier10, Alani Mustafa11, Fatrara Thomas12, Rubio Thérèse13, Daguindau Etienne14, Klemencie Marion15, Beauvais David16, Huynh Anne17, Marchand Tony18, Volpari Victoria19, Barette Lauren19, Pivert Cécile20, Maury Sébastien21, Suarez Felipe22, Fuseau Charline23, Lauron Sandrine24, Uzunov Madalina25, Castilla Cristina26, Forcade Edouard27, Bay Jacques-Olivier1, Ravinet Aurélie1

1Clermont-Ferrand University Hospital, Clermont-Ferrand, France, 2Nice University Hospital, Nice, France, 3Basse-Normandie Institute of Hematology, Caen, France, 4Percy Army Training Hospital, Clamart, France, 5Saint-Luc University Clinic, Uclouvain Bruxelles Woluwe, Belgium, 6Poitiers University Hospital, Poitiers, France, 7Geneva University Hospitals, Geneva, Switzerland, 8AUB Medical Center, Beyrouth, Lebanon, 9Montpellier University Hospital, Montpellier, France, 10Paoli-Calmettes Institute, Marseille, France, 11Henri Becquerel Center, Rouen, France, 12Saint-Etienne University Hospital, Saint-Etienne, France, 13Nancy Regional and University Hospital, Nancy, France, 14Besançon University Hospital, Besançon, France, 15Anger University Hospital, Anger, France, 16Lille University Hospital, Lille, France, 17Toulouse Cancer University Institute, Toulouse, France, 18Rennes University Hospital, Rennes, France, 19Grenoble Alpes University Hospital, Grenoble, France, 20Public Assistance - Paris Hospitals, Paris, France, 21Henri-Mondor Hospital Public Assistance - Paris Hospitals, Créteil, France, 22Necker Hospital Public Assistance - Paris Hospitals, Paris, France, 23Strasbourg Europe Cancer Institute, Strasbourg, France, 24Edouard Herriot Hospital-Lyon Civil Hospices, Lyon, France, 25La Pitié Salpêtrière Hospital Public Assistance - Paris Hospitals, Paris, France, 26Gustave Roussy, Villejuif, France, 27Bordeaux University Hospital, Bordeaux, France

Background: Despite the recent therapeutic progress, between 30 to 40 % patients relapse after allogeneic hematopoietic stem cell transplantation (alloHSCT) for acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS). While Azacitidine and Venetoclax (VenAza) combination has been approved in previously untreated patients with AML ineligible for intensive induction therapy, VenAza associated with donor lymphocyte infusion (DLI) is also considered post-transplant as salvage therapy. However, limited data are available regarding outcomes with this specific setting.

Methods: To evaluate efficiency and safety of VenAza with/without DLI in relapsed myeloid malignancies after alloHSCT, we retrospectively collected data from January 1, 2016 to September 1, 2022 in 29 centers from the Société Francophone de Greffe de Moelle et Thérapie Cellulaire (SFGM-TC). We included 173 patients aged 18 years or older treated with the association of VenAza as salvage therapy for AML or MDS after one or more alloHSCT. The data were extracted from the ProMISe database, an international registry coordinated in part by the SFGM-TC.

Results: The median follow up after the transplant was 14 months. Out of the 173 patients, 152 (87,86%) had an AML including 11 cases of secondary acute myeloid leukemia, and 21 (12,14%) had a MDS. The median age at transplant was 53,78 (17,9 – 74,86). DLI was administered to 43 patients (24,86%) who relapsed after alloHSCT.76 patients (44,19%) experienced a relapse within 6 months after alloHSCT (defined as “early relapse”) and 96 patients (55,8%) relapsed more than 6 months after alloHSCT (“late relapse”).117 patients were treated with VenAza after their 1st relapse,39 after their 2nd and 6 after 3 or more relapses. The median number of VenAza cycles per patient was 2 (1-13) (Table 1). The median overall survival time estimate was 18,99 months with a 1-year overall survival (OS) of 62,45% (95% CI 55,52 - 70,23%) and a 2-years OS of 40,32 % (95% CI 33,21 – 48,95%). The median survival was longer (p = 0,001) for patients who were treated by VenAza for a late relapse with a 2-years OS of 62,96% (95% CI 53,60 – 73,96%) and 7,17% (95% CI 2,58-19,89%) for early relapses. The OS and EFS (P<0,001) were better in the DLI group. In multivariate analysis, survival remains better in DLI group. (HR = 0,57 (95% CI 0,36 – 0,92)). A total of 82,75 % patients relapsed after post-transplant VenAza and 10,90 % had a complete remission. Additionally, 17 patients (10,43%) developed chronic graft-versus-host disease (GVHC) after alloHCST, including 6 patients after venAza. The main causes of death were relapse or progression of the original disease (61,81%) and infections (21,18%).

Table 1. Patients’ characteristics.

n = 173

Patient sex, (n) %

Female

76 (43,96)

Male

97 (56,07)

Median age, years (range)

53,78 (17,19; 74,86)

Diagnosis, (n) %

AML

152 (87,86)

De novo AML

142 (92,76)

Secondary AML

11 (7,23)

MDS

21 (12.14)

Score HCT-CI, (n) %

Score > 2

34 (21,79)

Type of transplantation, (n) %

Match related donor

52 (30.06)

Match unrelated donor

82 (47.40)

Haplo identical donor

39 (22.55)

Transplantation conditioning, (n) %

MAC

48 (28.24)

TBI

10 (5.88)

ATG

124 (73.81)

GVHD prophylaxis, (n) %

170 (98.27)

Cyclosporine

31 (18.24)

Cyclosporine and Methotrexate

37 (21.76)

Cyclosporine and Mycophenolate mofetil

54 (31.77)

Cyclosporine, Mycophenolate mofetil and Cyclophosphamide

34 (20,00)

Others

14 (8,24)

DLI before VenAza, (n) %

23 (13.30)

1

18 (78,26)

2

4 (17,39)

3

1 (4,35)

Acute GVHD, (n) %

79 (45.66)

Grade >2

9 (11,38)

Chronic GVHD, (n) %

32 (18,50)

Score NIH >3

5 (10,32)

Relapses after HSCT, (n) %

First relapse

117 (72,22)

Second relapse

39 (24,07)

Three or more relapse

6 (3,70)

Median follow-up after transplant, months (range)

14,08 (1,74; 65,91)

VenAza cycles, (n) % (range)

2 (1;13)

DLI in association to VenAza, (n) %

43 (24,86)

1

26 (60,47)

2

7 (16,28)

3

8 (18,60)

4

2 (4,65)

Relapse after HSCT, (n) %

Early relapse < 6 months

76 (44.19)

Late relapse > 6 months

96 (55.81)

Status post VenAza, (n) %

Complete remission

17 (10,90)

Relapse

113 (85,26)

Conclusions: Notwithstanding the retrospective nature, the results suggest that VenAza is an acceptable salvage therapy after alloHSCT and that the addition of DLI appears to improve survival with superior OS and EFS compared with non-DLI group, according to univariate and multivariate analysis.

Disclosure: Yves Chalandon. has received consulting fees for advisory board from MSD, Novartis, Incyte, BMS, Pfizer, Abbvie, Roche, Jazz, Gilead, Amgen, Astra-Zeneca, Servier; Travel support from MSD, Roche, Gilead, Amgen, Incyte, Abbvie, Janssen, Astra-Zeneca, Jazz, Sanofi all via the institution.

19: Acute Leukaemia

P020 EFFICACY AND SAFETY ANALYSIS OF PROPHYLACTIC BRENTUXIMAB VEDOTIN ADMINISTRATION AFTER PEDIATRIC ACUTE LEUKEMIA HAPLOIDENTICAL HEMATOPOIETIC STEM CELL TRANSPLANTATION

Zhu Huili 1, Cao Xingyu1, Lu Yue1, Zhang Jianping1, Zhao Yanli1, Liu Deyan1, Xiong Min1, Sun Ruijuan1, Liu Hongxing1, Wei Zhijie1

1Hebei Yanda Lu Daopei Hospital, Langfang, China

Background: Acute graft-versus-host disease (aGVHD) is a common complication following allogeneic hematopoietic stem cell transplantation. Currently, the reported incidence of moderate to severe aGVHD in domestic cases is 13%-47%, while the incidence of grade III/IV aGVHD after haploidentical transplantation ranges from 7.9% to 13.8%. This study aims to analyze whether the administration of Brentuximab vedotin after transplantation can reduce the incidence of aGVHD without increasing disease relapse rates and viral infections.

Methods: A retrospective analysis was conducted on 50 pediatric leukemia patients who underwent haploidentical hematopoietic stem cell transplantation at our hospital between June 2017 and July 2022. These patients received prophylactic treatment with Brentuximab vedotin (20mg) on day +1 and day +4 post-transplantation. The median age of the patients was 4.1 years (range: 0.6-16.0 years). Among the cases, 22 were acute lymphoblastic leukemia (ALL), and 28 were acute myeloid leukemia (AML). Before transplantation, 28 patients were in CR1, 14 in CR2, 2 in CR3, and 6 in NR. All patients received myeloablative conditioning regimens, with 33 receiving Bu/Cy, 15 receiving TBI/Cy, 1 receiving Bu/Flu, and 1 receiving TBI/Flu. The median follow-up time was 29.1 months (range: 3.1-70.1 months). Detailed patient data are presented in Table 1.

Results: All 50 patients achieved 100% engraftment of white blood cells, with a median time of 15 days (range: +10 to +21 days). Platelet engraftment occurred in a median time of 9 days (range: +5 to +78 days), except for one patient who did not achieve platelet engraftment. The incidence of aGVHD after transplantation was 44%, with 28% experiencing grade I-II and 16% experiencing grade III-IV aGVHD. The incidence of CMV viremia was 40%, while the incidence of EBV viremia was 8%. During the follow-up period, five patients experienced disease relapse. Seven patients died during the follow-up, including 4 with AML and 3 with ALL. The causes of death were disease relapse in 3 cases, infection in 2 cases, TMA in 1 case, and cGVHD in 1 case. The estimated 5-year overall survival (OS) and leukemia-free survival (LFS) rates were 86%, and the 5-year cumulative relapse rate was 10%. In comparison, a control group of 44 pediatric acute T-cell lymphoblastic leukemia patients who underwent haploidentical transplantation without prophylactic Brentuximab vedotin treatment between January 5, 2021, and June 30, 2022, were analyzed. In the control group, the incidence of aGVHD was 56.8% (P = 0.007), with 36.4% experiencing grade I-II and 20.4% experiencing grade III-IV aGVHD. The incidence of CMV viremia was 68.2% (P = 0.006), and the incidence of EBV viremia was 29.5% (P = 0.007). The relapse rate was 15.9%, and the mortality rate was 27.3%.

Characteristics

Number of Cases

Total Number of Cases

50

Median Age(Range) Years

4.1 (0.6-16 years old)

Gender, Male (Number of Cases, %)

25 (50%)

Disease Diagnosis

Number of Cases

ALL (B-cell)

18 (including 4 cases with CNS involvement)

ALL (T-cell)

4 (including 1 case with CNS involvement)

AML

28 (including 7 cases of acute megakaryocytic leukemia)

Pre-transplant Status (Number, %)

CR1

28 (56%)

≥CR2

16 (32%)

NR

6 (12%)

Pre-conditioning Regimen (Number, %)

Bu/Cy

33 (66%)

TBI/Cy

15 (30%)

Bu/Flu

1 (2%)

TBI/Flu

1 (2%)

Infusion of MNC (Mean, ×108/kg)

14.9

Infusion of CD34+ (Mean, ×106/kg)

7.9

Infusion of CD3+ (Mean, ×108/kg)

3.2

Conclusions: For pediatric acute leukemia haploidentical HSCT, the administration of Brentuximab vedotin (20mg) on days +1 and +4 after transplantation, in addition to conventional aGVHD prophylaxis (CsA+MMF+sMTX), significantly reduced the overall incidence of aGVHD and grade I-II aGVHD. Administering Brentuximab vedotin on days +1 and +4 did not increase the rates of CMV or EBV infection nor did it increase the risk of disease relapse.

Disclosure: Nothing to declare.

19: Acute Leukaemia

P021 OUTCOMES AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR ACUTE LEUKEMIA IN YOUNG ADULTS COMPARED WITH CHILDREN, ADOLESCENTS AND ELDERLY PATIENTS IN GERMANY

Jochen J. Frietsch 1,2, Sarah Flossdorf3,4, Ashrafossadat Ahmadian3,4, Claudia Schuh3, Thomas Schroeder5, Igor-Wolfgang Blau6, Matthias Stelljes7, Nicolaus Kröger3,8, Katharina Egger-Heidrich9, Matthias Eder10, Peter Dreger11, Johanna Tischer12, Eva Wagner-Drouet13, Rita Beier14,15, Peter Bader16, Martin Sauer15, Barbara Meissner14,15, Katharina Fleischhauer3,17, Inken Hilgendorf2

1Medizinische Klinik und Poliklinik II, Universitätsklinikum Würzburg, Würzburg, Germany, 2Klinik für Innere Medizin II, Hämatologie und internistische Onkologie, Universitätsklinikum Jena, Jena, Germany, 3Deutsches Register für hämatopoetische Stammzelltransplantation und Zellherapie e.V., Ulm, Germany, 4Institut für Medizinische Informatik, Biometrie und Epidemiologie, Uniklinikum Essen, Essen, Germany, 5Klinik für Hämatologie und Stammzelltransplantation, Universitätsklinikum Essen, Essen, Germany, 6Medizinische Klinik mit Schwerpunkt Hämatologie, Onkologie und Tumorimmunologie, Campus Virchow-Klinikum, Berlin, Germany, 7Medizinische Klinik A, Hämatologie, Hämostaseologie, Onkologie und Pneumologie, Universitätsklinikum Münster, Münster, Germany, 8Klinik für Stammzelltransplantation, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany, 9Medizinische Klinik I, Universitätsklinikum Carl Gustav Carus, Dresden, Germany, 10Klinik für Hämatologie, Hämostaseologie, Onkologie und Stammzelltransplantation, Medizinische Hochschule Hannover, Hannover, Germany, 11Medizinische Klinik V, Universitätsklinikum Heidelberg, Heidelberg, Germany, 12Medizinische Klinik und Poliklinik III, Klinikum der Ludwig-Maximilians-Universität München, München, Germany, 13III. Medizinische Klinik und Poliklinik, Universitätsmedizin Mainz, Mainz, Germany, 14Pädiatrisches Register für Stammzelltransplantationen und Zelltherapien, Hannover, Germany, 15Klinik für Pädiatrische Hämatologie und Onkologie, Medizinische Hochschule Hannover, Hannover, Germany, 16Klinik für Kinder- und Jugendmedizin, Studienzentralen der Schwerpunkte Onkologie, Hämatologie und Hämostaseologie sowie Stammzelltransplantation, Immunologie und Intensivmedizin, Universitätsklinikum Frankfurt, Frankfurt, Germany, 17Institut für Zelltherapeutische Forschung, Universitätsklinikum Essen, Essen, Germany

Background: The survival after allogeneic hematopoietic SCT is influenced by the patients’ age, diagnosis, donor type and achieved remission. Nevertheless, with a 5-year overall survival (OS) probability of 53%, the outcome of young adults (YA) aged 18 to 39 years is sobering. We sought to provide more detail on outcome by focusing on acute leukemia (AL).

Methods: The German Registry for Hematopoietic Cell Transplantation and Cellular Therapy (DRST) and the German Pediatric Registry for Stem Cell Transplants and Cell Therapies (PRSZT) were screened for patients suffering from AL who received 1st SCT between 2011 and 2019. OS rates were determined by Kaplan-Meier analysis and differences between were evaluated using Score-tests (corresponding to the log-rank test, computed when Hazards are not crossing). Gray’s test was applied to cumulative incidence of NRM using competing risk analysis. To separate relapse from progression, patients not being in complete remission at the time of SCT or within 100 days were excluded from competing risk analysis. A p-value of <0.05 was considered statistically significant.

Results: Altogether 11258 patients were included, with 573, 269, 2158, 4667 and 3591 in the age groups 0-12, 13-17, 18-39, 40-59 and 60-72 years at the time of SCT, respectively. 2424 (21.5%) suffered from acute lymphoblastic leukemia (ALL) and 8834 (78.5%) from acute myeloid leukemia (AML). The majority (89.6%, 10089) of the predominantly male (56.2%, 6331) patients received peripheral blood SCT from a related (28.4%, 3192) or an unrelated (71.6%, 8066) donor with varying degrees of histocompatibility. During the observation period, 4380 (38.9%) patients deceased.

The probability of 5-year OS decreased for AML with increasing patient age: 0-12: 69%; 13-17: 60%; 18-39: 57%; 40-59: 49%; and 60-72 years: 37% and for ALL: 0-12: 73%; 13-17: 71%; 18-39: 53%; 40-59: 51%; and 60-72 years: 37%. Statistically significant differences in the probability of 5-year OS were observed between related and unrelated donors for AML (48% vs. 46%, p = 0.0018), but not for ALL (52% vs. 57%). No statistically significant differences could be observed concerning gender for AML (♀ 49% vs. ♂ 45%, p = 0.0508) and ALL (♀ 57% vs. ♂ 55%).

The 5-year-NRM increased with patient age for both ALL (0-12: 7%; 13-17: 10%; 18-39: 19%; 40-59: 26% and 60-72: 30%; p<0.001) and AML (5%; 14%; 12%; 20% and 30%; p<0.001). The 5-year relapse rate in both entities was lower for 13-17 year old adolescents (AML/ALL 13-17: 26%/18%) than for the other age groups (0-12: 33%/28%, 18-39: 40%/31%, 40-59: 34%/28%, 60-72: 35%/32%).

Conclusions: In this preliminary large retrospective multicenter analysis we show that NRM increases with patient age which also negatively impacts OS. The heterogeneity of the cohort was taken into account by considering diseases separately and age in groups. As differences in patient outcome are being reflected by a distinct disease biology, further investigations are necessary to fully elucidate differences between AML and ALL in age-dependent survival. The increasing NRM with respect to age underlines the relevance of interdisciplinary collaboration between pediatricians and non-pediatricians for the improvement of aftercare concepts, especially for children, adolescents and YA.

Disclosure: IH is chairperson of the board of trustees of the German Foundation for Young Adults with Cancer, received research funding from the H.W. and J. Hector-Foundation and honoraria from AbbVie, Medac, Novartis and Takeda. JF received honoraria from Novartis. All other authors do not declare any conflicts of interest. The Cooperative German Transplant Study group is acknowledged for project development and support.

19: Acute Leukaemia

P022 PHASE I/II STUDY OF CYCLOPHOSPHAMIDE AND BENDAMUSTINE AS POST-TRANSPLANTATION GRAFT-VERSUS-HOST DISEASE PROPHYLAXIS IN REFRACTORY MYELOID NEOPLASMS

Ivan Moiseev 1, Olga Epifanovskaya1, Ksenia Afanasyeva1, Anastasia Beynarovich1, Dmitrii Zhogolev1, Mikhail Kanunnikov1, Yulia Rogacheva1, Tatyana Rudakova1, Nikita Volkov1, Zhamshidbek Khudaiberdiev1, Azamjon Meliboev1, Yulia Vlasova1, Elena Morozova1, Sergei Bondarenko1, Alexander Kulagin1

1RM Gorbacheva Research Institute, Pavlov University, Saint Petersburg, Russian Federation

Background: Efficacy of allogeneic hematopoietic stem cell transplantation (alloHCT) in disease progression of myeloid neoplasms resistant to chemotherapy or targeted therapy is low. Our group recently demonstrated an enhanced graft-versus-leukemia (GVL) effect when replacing cyclophosphamide with bendamustine in a graft-versus-host disease (GVHD) prophylaxis regimen (Moiseev IS et al., TCT, 2021), but there was significant toxicity from this regimen from a poorly controlled cytokine release syndrome (CRS). To reduce toxicity while preserving GVL, we conducted a pilot single-center study of graft-versus-host disease (GVHD) prevention with a combination of cyclophosphamide and bendamustine in refractory myeloid neoplasms.

Methods: Prospective single-center Phase I/II study (NCT04943757) enrolled 50 patients (table 1). Inclusion criteria were myeloid neoplasm, available hematopoietic cell donor, >5% clonal blasts at the start of conditioning, disease refractory to at least one course of induction therapy. Main exclusion criteria: absence of uncontrolled infection and severe concomitant co-morbidities. The protocol included the administration of bendamustine 50 mg/kg/day on days +3, + 4, cyclophosphamide 25 mg/kg/day on days +3, + 4 (PTBC), tacrolimus 0.03 mg/kg from day+5 to day+ 100 day and mycophenolate mofetil 30 mg/kg/day on days 5-35. Patients received FB2 or FB3 conditioning regimen according to their age and performance status.

Characteristics of the study group

N = 50

Diagnosis

Acute myeloid leukemia

37

Myelodysplastic syndrome

9

Chronic myeloid leukemia

2

Chronic myelomonocytic leukemia

1

Atypical chronic myeloid leukemia

1

Age, median years (range)

48 (18-69)

Karnofsky index, median (range)

80% (60-90%)

Gender

Males

34

Females

16

Matched related donor

10

Matched unrelated donor

26

Haploidentical donor

14

Conditioning

FB2 conditioning

33

FB3 conditioning

13

Other conditioning

4

Active antimicrobial therapy at the time of HCT

20

Second HCT

4

Co-morbidity index

HTC-CI 0

24

HTC-CI 1

17

HTC-CI 2

6

HTC-CI >2

3

Primary refractory disease

26

Secondary refractory disease

24

Complex karyotype

10

High-risk somatic mutations

22

Median % of blasts at the start of conditioning (range)

12% (5-86%)

Results: The cumulative engraftment rate was 86%. Only 1 patient died before engraftment assessment. The median time to recovery of white blood cells was 18 days (range 12-35), platelets - 14 days (range 9-104). Remission was achieved in 88% of patients, with 76% of patients negative for minimal residual disease (MRD). Overall survival (OS) was 33% (95%CI 19-48%), event-free survival (EF) - 21% (95%CI 10-35%). Non-relapse mortality (NRM) was 19% (95%CI 9-31%), cumulative relapse incidence was 60% (95%CI 43-74%). Toxicity included development of CRS in 30% of patients, including 2 patients with grade 4-5 CRS. The most common manifestation of CRS was fever, increased ferritin and abnormal liver function tests (24% of patients). The cumulative incidence of grade II-IV acute GVHD was 20% (95%CI 10-33%), grade III-IV – 18% (95%CI 7-31%), moderate and severe chronic GVHD - 18% (95%CI 8 -31%). Grade II-IV acute GVHD was observed predominantly in patients with CRS grades 2-5 (31% vs. 16%, p = 0.02). Survival subanalysis showed that unrelated or haploidentical donor transplantation was associated with better OS (40% vs 0%, p = 0.008). Unique tolerance mechanisms were revealed with a massive expansion of PD-1L positive monocytes by day +30 (17.7±10.9% of all nucleated cells [NC]) with a decline to 7.1±4.3% and 6.9±6.5% of NC by days +60 and +100 (p<0.001). The level of PD-1L granulocytes was also high: 13.2±10.9%, 8.1±9.4% and 9.0±9.0% of NC on days 30, 60 and 100 (p = 0.4). This was accompanied by rapid expansion of effector T-cells (p<0.001), effector memory T-cells (p<0.001), central memory T-cells (p<0.001), naive T-cells (p<0.0001) and CD197-positive activated T-cells (p<0.0001) early post-transplant. In several patients abnormally high levels of monocytes and lymphocytes persisted for 2 years after HCT.

Conclusions: We developed a promising alloHCT platform for refractory myeloid neoplasms with a unique immunological recovery profile.

Clinical Trial Registry: NCT04943757, clinicaltrials.gov

Disclosure: The study was supported by RSF grant №23-15-00327.

19: Acute Leukaemia

P023 REAL-WORLD OUTCOME OF ACUTE MYELOID LEUKEMIA PATIENTS TREATED WITH ALLOGENEIC STEM CELL TRANSPLANTATION WITHOUT STANDARD INDUCTION CHEMOTHERAPY

Francesca Biavasco 1, Kristina Maas-Bauer1, Jesus Duque-Afonso1, Ralph Waesch1, Michael Luebbert1, Justus Duyster1, Robert Zeiser1, Juergen Finke1, Claudia Wehr1

1University Hospital Freiburg, Freiburg, Germany

Background: Allogeneic hematopoietic cell transplantation (allo-HCT) has become an accessible curative option in elderly patients with acute myeloid leukemia (AML) after development of reduced-intensity conditioning regimen and the introduction of hypomethylating agents (HMA) with venetoclax as induction therapy for elderly unfit patients. While a recent prospective randomised trial showed non-inferior efficacy and better tolerance of HMA over standard chemotherapy in elderly patients, only half of the studied cohort underwent allo-HCT and venetoclax was not included in the study (Luebbert et al., Lancet Haematol. 2023 Nov;10(11):e879-e889). Therefore, real-world data on outcomes of patients not eligible for intensive chemotherapy who received allo-HCT in the venetoclax era are needed.

Methods: We retrospectively analysed data of 106 adult AML patients who underwent allo-HCT without receiving intensive chemotherapy at our center between 2010 and 2023.

Results: Forty-two patients received HMA alone, 24 patients received HMA-venetoclax induction therapy, and 40 patients underwent allo-HCT without previous therapy (upfront) due to personalised clinical decision. Patients who received allo-HCT upfront were younger (median 59.1 years) than HMA (64.9 years) and HMA-venetoclax patients (70.9 years respectively, p<0.0001). The groups did not differ in Karnofsky performance status, ELN risk distribution and time from diagnosis to allo-HCT. Forty-three of the HMA treated (83%) and 15 of the HMA-venetoclax treated patients (62%) did not achieve CR before allo-HCT, resulting in a similar mean blast count before transplantation among groups (41.4 for upfront, 26.5 for HMA and 32.2 for HMA-venetoclax). With a median follow-up of 85.5, 75.4 and 18.9 months in upfront, HMA treated and HMA-venetoclax treated patients, the overall survival at median follow-up time (19 months) was 75.7%, 54.8% and 89.0% respectively, showing a better survival for patients treated with addition of BCL-2 inhibitor. Interestingly, the difference in survival was not reflected in marked difference of progression free survival, which was similar among groups (19-months progression free survival 77.8% upfront, 72.3% HMA and 73.9% HMA-venetoclax). Of note, overall survival benefits for HMA-venetoclax treated patients persisted in the subgroup of patients who did not reach a complete remission before transplant (19-months overall survival for HMA 51.5%, for HMA-venetoclax 82.3%). As expected though, the achievement of a complete remission before allo-HCT was associated with a better survival in both groups (19-months overall survival HMA CR 66.7%, HMA non-CR 51.5% vs. HMA-venetoclax CR 100%, HMA-venetoclax non-CR 82.3%).

Conclusions: These real-world retrospective data on the avoidance of intensive chemotherapy in pre-transplant setting suggest that HMA-venetoclax could be the best therapeutic option for patients with AML. Additionally, the advantage of HMA-venetoclax was independent from achieving CR, even though the achievement of CR is associated with better survival. Confirmatory data of prospective randomised trials are urgently needed to establish the best possible pre-transplant treatment for non-highly proliferating AML patients.

Disclosure: K. M-B is supported by a fellowship of the Faculty of Medicine, Freiburg University (Berta-Ottenstein-Programm) and by the Else-Kröner-Fresenius-Stiftung Nr: 2021_EKEA.131

R.W. received research fundings from Janssen, Sanofi, consultancy: from Amgen, BMS/Celgene, Janssen, Kite/Gilead, Novartis, Pfizer, Sanofi, Takeda, honoraria from Abbvie, Alexion/Astra Zeneca, Amgen, BMS/Celgene, Janssen, Kite/Gilead, Novartis, Pfizer, Sanofi, Takeda and travel support from Janssen, Kite/Gilead, Pfizer, BMS.

C.W. received honoraria/travel grant from Takeda and Jazz Pharmaceuticals.

19: Acute Leukaemia

P024 DURING CB TRANSPLANT IN MRD-POSITIVE AML, RELAPSE IS USUALLY EARLY, IS REDUCED BY ACUTE GVHD AND IS INFLUENCED BY CICLOSPORIN EXPOSURE: A MULTICENTER NATIONAL EXPERIENCE

Srividhya Senthil 1, Abdul Moothedath1, Archana Rauthan2, Ioannis Peppas3, Sandeep Potluri4, Pamela Evans5, Valerie Broderick5, Sarah Lawson4, Emma Barrett6, Caroline Furness7, Kanchan Rao2, Robert Wynn1

1Royal Manchester Children’s Hospital, Manchester, United Kingdom, 2Great Ormond Street Hospital, London, United Kingdom, 3Kings College Hospital NHS Foundation Trust, London, United Kingdom, 4Birmingham Children’s Hospital, Birmingham, United Kingdom, 5Royal Crumlin Hospital, Dublin, Ireland, 6Manchester University Foundation Trust, Manchester, United Kingdom, 7Royal Marsden Hospital, Manchester, United Kingdom

Background: Ciclosporin forms the major GVHD prophylaxis in allogeneic stem cell transplantation. It might be expected to reduce the beneficial graft-versus-leukemia [GVL] effect, and previous studies have reported a relationship between ciclosporin exposure and risk of post-transplant relapse in leukaemia. T cell replete Cord blood (TRCBT) HSCT might be considered the preferred donor cell source in AML with superior GVHD-free, Relapse-free survival (RFS). We report a multicentric experience of the relationship between ciclosporin exposure and time to relapse in a large cohort of paediatric AML patients receiving such a graft.

Methods: It is a retrospective study, data was collected from 5 paediatric transplant centers in the UK on the patients who had a TRCBT for HR AML between 2013 and 2023. Case records were analyzed to get patient, donor, transplant characteristics, GVHD prophylaxis, trough ciclosporin levels in the first 8 weeks and the transplant outcomes including GVHD and its treatment, relapse and transplant related mortality (TRM). The primary endpoint was time to disease relapse, and the relationship between this endpoint and ciclosporin AUC, use of additional immunosuppressive treatment (IST) and its total duration was investigated by Cox regression analysis.

Results:

Demographics and outcomes

No of patients / %

Disease Burden:

MRD-positive

64 (59.25%)

MRD-negative

44 (40.7%)

Severe aGVHD:

Skin

25 (23%)

Gut

28 (26%)

Required systemic IST

56 (51.8%)

Mortality in MRD-positive group:

32

Relapse associated

22(68.7%)

TRM

10 (31.2%)

Mortality in MRD-negative group:

12

Relapse associated

5 (41.6%)

TRM

7 (58.3%)

GVHD related deaths:

4

MRD-positive group

2

MRD-negative group

2

Relapse:

Very early (<6 months)

21 (61.7%)

Early (6-12 months)

11 (32.3%)

Late (>12 months)

2 (5.8%)

The cohort included 108 patients, of whom 64 were MRD-positive pre-transplant, with a median follow up of 737.1 days (range: 24-3540 days). All were given ciclosporin and MMF as GVHD prophylaxis for a variable duration post-transplant according to each centers’ protocol. The severe aGVHD was treated with IST which included steroids in all with or without second agents.

The mortality rate was 40.7% of which nearly three-quarters occurred in the MRD-positive group. Overall, relapse formed the leading cause of death, causing 68.7% of the total deaths in MRD-positive group. It constituted only 41.6% of the deaths in the MRD negative group. The median time to relapse was 180 days (range: 32 to 949) and nearly a third occurred very early within 6 months. TRM was 13% and accounted for the most prominent cause of mortality in MRD-negative group. The GVHD related mortality was very low.

The 50th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians – Poster Session (P001-P755) (2)

The RFS is significantly greater in MRD-negative group without severe aGVHD than in those without. By comparison, the RFS is significantly lower in the MRD-positive group without severe aGVHD than in those with it. The COX proportional hazards model using 95% CI confirmed a significant inverse relationship of AUC of Ciclosporin in the first 8 weeks on the time to relapse (p<0.02). However, it did not find any effect of IST or the duration of IST on time to relapse (p = 0.579 and p = 0.623 respectively).

Conclusions: This is the largest homogenous cohort of TRCBT in AML investigating the role of ciclosporin prophylaxis on relapse. It confirms the importance of GVL effect and its relation to GVHD in MRD-positive patients as RFS is significantly better in those who experience aGVHD. Most relapse is early and increased ciclosporin exposure in the first 2 months of HSCT reduces the time to relapse in AML. This study supports the development of novel protocols and alternative IS regimens during CBT in the highest risk AML.

Clinical Trial Registry: Not applicable

Disclosure: The authors have no conflict of interest.

19: Acute Leukaemia

P025 IMPACT OF RESPONSE TO THE FIRST INDUCTION COURSE IN AML PATIENTS ON ALLOHSCT OUTCOMES WITH PTCY

Dmitrii Zhogolev1, Bella Aybova1, Anna Smirnova1, Yulia Vlasova1, Daria Chernyshova1, Elena Babenko1, Tatyana Gindina1, Ildar Barkhatov1, Elena Morozova1, Ivan Moiseev 1, Sergey Bondarenko1, Alexander Kulagin1

1RM Gorbacheva Research Institute, St. Petersburg, Russian Federation

Background: For the majority of patients with acute myeloid leukemia (AML), allogeneic hematopoietic stem cell transplantation (alloHSCT) remains as the sole curative option. Recent advancements in transplant technologies, such as post-transplant cyclophosphamide (PTCy)-based GVHD prophylaxis, have enhanced the overall outcomes of alloHSCT. It is well-established that patients refractory to 2 induction courses, even with subsequent remission achievement, exhibit poorer outcomes after alloHSCT. However, the impact of refractoriness to the first induction course remains unclear, particularly within the context of PTCy.

Methods: A total of 260 adult patients with AML in first complete remission (CR1), who underwent alloHSCT at RM Gorbacheva Research Institute (CIC 725) from 2013 to 2022 were included in this retro- and prospective study. All participants received the “7 + 3” regimen as their initial induction therapy. Overall survival (OS), leukemia-free survival (LFS), and GVHD-free, relapse-free survival (GRFS) were assessed using the Kaplan-Meier method and log-rank test. Multivariate analysis was conducted utilizing a Cox regression model. To estimate relapse incidence (RI) and non-relapse mortality (NRM) within a competing risk framework, cumulative incidence functions were applied.

Results: Achievement of CR1 occurred after 1 induction course in 158 patients, after 2 induction courses in 68 patients, and after more than 2 induction courses in 34 patients. Groups were balanced on key parameters, with the exception of a higher incidence of secondary AML in the non-refractory group (p = 0.026) and a higher prevalence of unfavorable cytogenetics in the 2 courses refractory group (p = 0.041) (Table 1).

Table 1. Patient, disease and transplant characteristics.

Non-refractory

Refractory to 1 induction course

Refractory to 2 induction courses

p. overall

N = 158

N = 68

N = 34

Gender, n(%)

0.332

Female

74 (46.8)

39 (57.4)

16 (47.1)

Male

84 (53.2)

29 (42.6)

18 (52.9)

Diagnosis, n(%)

0.026

De novo AML

133 (84.2)

64 (94.1)

33 (97.1)

Secondary AML

25 (15.8)

4 (5.9)

1 (2.9)

Cytogenetics, n(%)

0.041

Fav/Int

138 (87.3)

59 (86.8)

24 (70.6)

Adv

20 (12.7)

9 (13.2)

10 (29.4)

Age at transplant, median (range)

38 (18-66)

33 (19-65)

36 (18-61)

0.185

MRD status at transplant, n(%)

0.442

Negative

101 (63.9)

43 (63.2)

19 (55.9)

Positive

38 (24.1)

21 (30.9)

10 (29.4)

Missing

19 (12)

4 (5.9)

5 (14.7)

Donor, n(%)

0.122

MRD

38 (24.1)

16 (23.5)

2 (5.8)

MUD

68 (43)

25 (36.8)

14 (41.2)

MMUD

27 (17.1)

18 (26.5)

9 (26.5)

HID

25 (15.8)

9 (13.2)

9 (26.5)

Conditioning intensity, n(%)

0.073

MAC

17 (10.8)

15 (22.1)

6 (17.6)

RIC

141 (89.2)

53 (77.9)

28 (82.4)

GVHD prophylaxis, n(%)

0.105

CyTxMMF

116 (73.4)

51 (75)

26 (76.5)

MonoCy

32 (20.3)

12 (17.6)

2 (5.9)

CyRuxo

10 (6.3)

5 (7.4)

6 (17.6)

Graft source, n(%)

0.539

PBSC

116 (73.4)

50 (73.5)

28 (82.4)

BM

42 (26.6)

18 (26.5)

6 (17.6)

Median follow up after alloHSCT in survivors was 42.3 (3-108.5) months. Engraftment on d28 was attained in 86% (95%CI, 80-91), 90% (95%CI, 79-95), and 88% (95%CI, 70-96) in the non-refractory, refractory to 1, and refractory to 2 courses groups, respectively (p = 0.8). Three-year OS rates were 81.7% (95%CI, 75.7-88.1), 66.5% (95%CI, 55.6-79.5), and 60.1% (95%CI, 44.5-81.2) (p = 0.038), LFS – 78.6% (95%CI, 72.2-85.5), 66.8% (95%CI, 56-79.8), and 40.5% (95%CI, 25.3-64.8) (p<0.001), GRFS – 69.3% (95%CI, 62.2-77.2), 49.5% (95%CI, 38.6-63.6), and 36.5% (95%CI, 22.3-59.8) (p<0.001). The cumulative incidence of NRM at three years was 14% (95%CI, 8.7-19), 16% (95%CI, 8-26), and 19% (95%CI, 7.3-34) (p = 0.8), RI – 7.9% (95%CI, 4.1-13), 17% (95%CI, 9.1-28), and 41% (95%CI, 22-59) (p<0.001). There was no significant statistical difference in aGVHD grades 2-4 (p = 0.22) and grades 3-4 (p = 0.074), cGVHD grades 1-3 (p = 0.93) and grades 2-3 (p = 0.61) incidence.

In the multivariate analysis, failure to achieve remission after one “7 + 3” course was associated with lower OS (HR 1.97, p = 0.02) and GRFS (HR 1.96, p = 0.004) after alloHSCT, with a tendency for lower LFS (HR 1.72, p = 0.056). Age and refractoriness to 2 induction courses were also associated with lower OS, LFS, and GRFS.

Conclusions: This study highlights the failure to respond to one “7 + 3” course as a negative prognostic factor for both OS and GRFS after alloHSCT, when performed with PTCy. The findings underscore the necessity for novel treatment approaches to enhance survival outcomes in these patients. Additionally, there is a crucial need for improved strategies in patients with primary refractory AML and older patients.

Disclosure: Nothing to declare.

19: Acute Leukaemia

P026 POST-TRANSPLANT TYROSINE KINASE INHIBITOR MAINTENANCE IN PH-POSITIVE ACUTE LYMPHOBLASTIC LEUKEMIA DELIVERS BENEFIT TOWARD IMPROVED OVERALL, RELAPSE-FREE, GVHD/RELAPSE-FREE SURVIVAL AND DECREASED NON-RELAPSE MORTALITY WITHOUT REDUCED RELAPSE

Eshrak Al-Shaibani 1, Carol Chen1, Igor Novitzky-Basso1,2, Ivan Pasic1,2, Auro Viswabandya1,2, Rajat Kumar1,2, Wilson Lam1,2, Arjun Law1,2, Armin Gerbitz1,2, Jonas Mattson1,2, Fotios V. Michelis1,2, José-Mario Capo-chichi3, Dennis D. Kim1,2

1Hans Messner Allogeneic Transplant Program, Division of Medical Oncology and Hematology, Princess Margaret Hospital, Toronto, Canada, 2University of Toronto, Toronto, Canada, 3University Health Network and University of Toronto, Toronto, Canada

Background: Post-allogenic hematopoietic cell transplantation (HCT) maintenance therapy with tyrosine kinase inhibitor (TKI) in Philadelphia positive acute lymphoblastic leukemia (Ph+ALL) is expected to reduce the risk of relapse. However, clinical benefit from the post-HCT TKIs maintenance (PTM) in Ph+ALL remains still on debate due to conflicting results from the retrospective studies and lack of randomized controlled trial. Herein, we report the long-term outcomes of the patients who received PTM following allogeneic HCT versus not in Ph+ALL.

Methods: We have retrospectively reviewed 80 patients with Ph+ ALL underwent first HCT in complete remission at Princess Margaret Cancer Center from 2000 till 2022. Relapse was defined as morphologic recurrence of ≥5% blasts in bone marrow or by the presence of extramedullary disease. Overall (OS), graft-versus host disease (GVHD)/relapse-free (GRFS) and relapse-free survival (RFS) was calculated by the Kaplan-Meier method and analyzed using a log-rank test, respectively. Cumulative incidence of relapse (CIR), non-relapse mortality (NRM) and chronic GVHD (cGVHD) were calculated considering competing events and analyzed using Fine-Gray model.

Results: Patients’ and disease characteristic are summarized in Table 1. With a median follow-up duration of 26 months among survivors, 16 patients (20%) had progressed following HCT. Fifty-eight patients (72%) did not receive PTM while 22 (28%) patients received PTM. The median time to start PTM was 5.3 months (range; 2.6-9.2) with imatinib (n = 15), dasatinib (n = 5) or ponatinib (n = 4). ABL1 kinase-domain mutation (KDM) was detected in 8 patients: T315I (n = 2), F317L (n = 3), E255K (n = 1), Y253H (n = 1), Q252H (n = 1).

The analysis for OS, GRFS, RFS, NRM, cGVHD and CIR at 2 years showed improved outcomes in favor of PTM: OS, 81% vs 43.4% (p = 0.01); GRFS, 40% vs 5.3% (p = 0.003); RFS, 81% vs 43.4% (p = 0.02); NRM, 4.8% vs 45.8% (p = 0.003); cGVHD 27.7% vs 41.3% (p = 0.54); CIR, 14.3% vs 10.8% (p = 0.19).

Univariate analysis showed PTM improved OS (HR; 0.39 [0.19-0.85], P = 0.02), RFS (HR: 0.54 [0.29-0.99], P = 0.03), GRFS (HR: 0.41 [0.23-0.75], P = 0.004) and NRM (HR: 0.045 [0.003-0.20], P = 0.003). However, it was not associated with relapse risk (HR: 0.143 [0.03-0.33], P = 0.19).

Besides PTM, age >40 was associated with OS (HR: 2.08 [1.11-3.9], P = 0.02), RFS (HR: 1.85 [1.01-3.37], P = 0.05) and NRM (HR: 0.41 [0.27-0.55], P = 0.04). Time -dependent cGVHD found to be associated with improved OS (HR: 0.36 [0.16-0.78], P = 0.009), RFS (HR: 0.31 [0.14-0.68], P = 0.003) and CIR (HR: 0.1522 [0.04-0.54], P = 0.004). Detectable ABL-KDM at ant time prior-HCT increased risk of relapse (HR: 0.38 [0.07-0.69], P = 0.0005).

Multivariable analysis confirmed that PTM improved OS (HR; 0.28 [0.13-0.62], P = 0.02], RFS (HR: 0.32 [0.15- 0.68], P = 0.003), GRFS (HR: 0.41 [0.23-0.75], P = 0.004) and NRM (HR:0.18 [0.06-0.57], P = 0.003). cGVHD also found to improve OS (HR: 0.28 [0.13-0.64], P = 0.002), PFS (HR: 0.23 [0.10-0.51], P = 0.003) and decreased CIR (HR: 0.33 [0.09-1.14], P = 0.08).

Table 1: patients characteristics

Variables

TKI maintenance

No TKI-maintenance

P

N = 22

N = 58

Median age (range)

54 (19-63)

44 (19- 65)

0.2

Gender, N (%)

0.09

Female

14 (63.6)

24 (41.4)

Male

8 (36.4)

34 (58.6)

Disease status, N (%)

0.04

CR1

15 (68.2)

52 (89.7)

CR2

7 (31.8)

6 (10.3)

BCR/ABL pre-HCT, N (%)

0.57

MMR

18 (81.8)

43 (74.1)

No MMR

4 (18.2)

15 (25.9)

ABL Kinase mutation

0.03

Positive

5 (22.7)

3 (5.2)

Negative

17 (77.3)

55 (94.8)

Conditioning regimen, N (%)

0.09

MAC

13 (59.1)

46 (79.3)

RIC

9 (40.9)

12 (20.7)

GVHD prophylaxis, N (%)

0.005

Dual T-cell depletion

8 (36.4)

5 (8.6)

Others

14 (63.6)

53 (91.4)

PTCY based GVHD, N (%)

<0.001

Yes

10 (45.5)

5 (8.6)

No

12 (54.5)

53 (91.4)

Donor type, N (%)

0.17

MRD

9 (40.9)

27 (46.6)

MUD

10 (45.5)

23 (39.7)

MMUD

6 (10.3)

Haploidentical

3 (13.6)

2 (3.4)

Stem sources

0.49

PBSC

20 (90.9)

48 (82.8)

BMSC

2 (9.1)

10 (17.2)

OS

0.02

Alive

14 (63.6)

19 (32.8)

Death

8 (36.4)

39 (67.2)

NRM

0.005

Alive

19 (86.4)

28 (48.3)

Death

3 (13.6)

30 (51.7)

RFS

0.04

No

13 (59.1)

18 (31)

Yes

9 (40.9)

40 (69)

Relapse

0.49

No

16 (72.7)

48 (82.8)

Yes

6 (27.3)

10 (17.2)

Acute GVHD

0.79

Yes

14 (63.6)

39 (67.2)

No

8 (36.4)

19 (32.8)

Chronic GVHD

0.79

Yes

7 (31.8)

22 (37.9)

No

15 (68.2)

36 (62.1)

  1. Abbreviation: BM: bone marrow, CR: complete remission, HCT: allogenic hematopoietic cell transplantation, MAC: myeloablative conditioning, MMR: Major molecular response, MRD: matched related donor, MUD: matched unrelated donor, MMUD: mismatch unrelated donor, NRM: non-relapse mortality, OS: overall survival, PBSC: peripheral blood stem cell transplant, PFS: progressive-free survival, PTCY: post-transplant cyclophosphamide, RIC: reduce intensity regimen.

Conclusions: PTM in Ph+ALL delivers a clinical benefit toward better OS, improved RFS, decreased NRM and better GRFS. However, it was not confirmed whether PTM can reduce the risk of relapse.

Disclosure: Nothing to declare

19: Acute Leukaemia

P027 IMPACT OF DONOR AND STEM-CELL SOURCE IN ADULTS WITH HIGH-RISK PHILADELPHIA-NEGATIVE ACUTE LYMPHOBLASTIC LEUKEMIA TRANSPLANTED IN FIRST COMPLETE REMISSION: A STUDY FROM GRAALL AND SFGM-TC

Matthieu Jestin1, Sébastien Maury2, Anne Huynh3, Edouard Forcade4, Ibrahim Yakoubagha5, Cristina Castilla-Llorente6, Jean-Baptiste Mear7, Urs Schanz8, Sylvain Chantepie9, Jakob Passweg10, Nathalie Contentin11, Yves Chalandon12, Nicole Raus13, Véronique Lheritier13, Natacha Maillard14, Marie-Thérèse Rubio15, Raynier Devillier16, Patrice Ceballos17, Sylvie François18, Stéphanie Nguyen-Quoc19, Patrice Chevallier20, Hélène Labussière-Wallet13, Hervé Dombret1, Nicolas Boissel1, Nathalie Dhédin 1

1Hôpital Saint Louis, Paris, France, 2Hôpital Henri Mondor, Créteil, France, 3Institut universitaire du Cancer de Toulouse, Toulouse, France, 4CHU de Bordeaux, Bordeaux, France, 5CRHU Lille, Lille, France, 6Institut Gustave Roussy, Villejuif, France, 7CHU de Rennes, Rennes, France, 8Hôpital Universitaire de Zurich, Zurich, Switzerland, 9CHU de Caen, Caen, France, 10Hôpital Universitaire de Bâle, Bâle, Switzerland, 11Centre Henri Becquerel, Rouen, France, 12Hôpitaux Universitaires de Génève, Génève, Switzerland, 13CHU de Lyon, Lyon, France, 14CHU de Poitiers, Poitiers, France, 15CHRU de Nancy, Nancy, France, 16Institut Paoli-Calmettes, Marseille, France, 17CHU de Montpellier, Montpellier, France, 18CHU d’Angers, Angers, France, 19Hôpital Pitié-Salpétrière, Paris, France, 20CHU de Nantes, Nantes, France

Background: Allogeneic hematopoietic stem cell transplantation (HSCT) stands as a cornerstone in managing high-risk (HR) Philadelphia chromosome (Ph)-negative acute lymphoblastic leukemia (ALL) in the first complete remission (CR1). Whereas unrelated donor (UD) has become a standard option in absence of matched sibling donor (MSD), peripheral blood (PB) is mostly used despite a higher incidence of graft-versus-host disease (GVHD). The aim of this study was to evaluate the impact of donor and stem cell source in adults with HR Ph-negative ALL in CR1 prospectively included in the GRAALL-2003 and -2005 trials.

Methods: Between November 2003 and March 2014, 311 patients with HR Ph-negative ALL in CR1 were included in the GRAALL-2003/05 trials and received a HSCT from MSD or UD after a myeloablative conditioning (MAC) regimen. Cord blood (n = 17) or haploidentical transplant (n = 2) were excluded. The primary objective was to assess the impact of donor and stem cell source on acute grade III-IV or chronic extensive GVHD-free relapse-free survival (GRFS). Type of donor (MSD versus UD), use of anti-thymocyte globulin (ATG) and total body irradiation (TBI), stem cell source (PB versus bonne marrow (BM)) and age at transplant were included in univariate and multivariate analyses for GRFS, overall survival (OS), event-free survival (EFS), cumulative incidence of relapse (CIR), non-relapse mortality (NRM), incidence of aGVHD grade III-IV and of extensive cGVHD.

Results: Among the 311 patients, 100 had a T-ALL and 211 a Ph-negative BCP-ALL. Median age at transplant was 31.8 years (IQR, 29.7 – 34.5) with 60% of male. All received a MAC regimen, 293 (94%) a TBI-based, 14 (5%) a busulfan-based, and 4 another regimen. Transplant was performed from a MSD in 156 patients (50%) and from a 9/10 or 10/10 matched UD in 155 patients (50%). PB and BM were used in 105 patients (34%) and 206 patients (66%), respectively. ATG was part of the conditioning regimen in 58 patients (19%). In univariate and multivariate analysis for GFRS, after adjustment on age at transplant, use of ATG and TBI, and type of donor, stem cell source (PB vs BM) emerges as the sole variable significantly associated with GRFS (Table). Of note, the type of donor and the use of ATG did not show significant association with GRFS, and also lacked significant correlation with OS, EFS, CIR, TRM, cGVHD and aGVHD. In multivariate analysis using the same covariates, PB was significantly associated with an increased risk of NRM (SHR 2.03, 95%CI(1.19-3.48)), an increased incidence of cGVHD (SHR 3.20, 95%CI(1.79-5.76)) and a decreased CIR (SHR 0.51, 95%CI(0.27-0.96)), but did not correlate with OS and EFS. Interestingly, in sub-groups analysis, GRFS was significantly improved using BM versus PB from UD (HR 2.25, 95%CI(1.46-3.47)) whereas no impact of stem cell source was observed in transplant from MSD.

Variables

Hazard ratio value

95%CI

p

Age at HSCT (y)

1.00

0.99-1.01

0.95

UD vs MSD

1.11

0.79-1.56

0.56

ATG

0.68

0.43-1.08

0.10

PB vs BM

1.54

1.11-2.14

0.01

TBI

0.95

0.60-1.18

0.87

Conclusions: In adults with HR Ph-negative ALL in CR1, PB and BM are two acceptable options when a MSD is available. Despite the absence of impact of stem cell source on OS, the use of UD BM should be preferred over PB, since it improves long-term quality of life.

Clinical Trial Registry: NCT00327678

Disclosure: Nothing to declare.

19: Acute Leukaemia

P028 HOW DISEASE STATUS IMPACTS ON LONG-TERM SURVIVAL AFTER ALLOGENEIC TRANSPLANT IN ACUTE MYELOID LEUKEMIA: ANALYSIS ON 456 PATIENTS

Alessandro Bruno1, Matteo Giovanni Carrabba1, Simona Piemontese1, Raffaella Greco1, Sarah Marktel1, Sara Mastaglio1, Daniela Clerici1, Francesca Farina1, Elisa Diral1, Luca Vago1, Lorenzo Lazzari1, Edoardo Campodonico1, Giulia Furnari1, Alessandro Criscimanna1, Chiara Secco1, Magda Marcatti1, Consuelo Corti1, Massimo Bernardi1, Jacopo Peccatori1, Fabio Ciceri1,2, Maria Teresa Lupo-Stanghellini 1

1IRCCS Ospedale San Raffaele, Milan, Italy, 2Università Vita-Salute San Raffaele, Milan, Italy

Background: Acute myeloid leukemia (AML) is the most frequent indication for allogeneic hematopoietic stem cell transplant (allo-HSCT). The number of patients undergoing allo-HSCT for AML has steadily increased in the last decades, with improving outcomes. Both the incidence of disease relapse and treatment related mortality (TRM) decrease over time after transplant. While risk factors for disease relapse and TRM in the first years after allo-HSCT are well known, their correlation with long-term survivorship is unclear.

Methods: We retrospectively collected data of 456 consecutive patients (193 females and 263 males) with a diagnosis of AML who received a first allogeneic hematopoietic stem cell transplant in our centre between 2004 and 2019. Ninety-six patients had a matched related donor, 221 a mismatched related donor, 120 an unrelated donor and 19 underwent allo-HSCT from a cord blood unit. Sixty-four (14%) patients had secondary AML. Patients were included regardless of conditioning intensity and graft-versus-host disease (GvHD) prophylaxis. Two hundred and four patients (44%) received allo-HSCT in first complete remission (CR1), 62 patients (14%) in CR>1, and 190 patients (42%) in active disease (AD). Factors impacting on long-term survival after allo-HSCT were evaluated through a multivariate analysis using Cox proportional-hazards model in the whole cohort and subsequently in landmark analysis at 1, 2 and 3 years after allo-HSCT.

Results: Two-hundred and thirty-nine patients (52%) were alive 2 years after allo-HSCT, with a median follow-up of 5.1 years. In this subset, 51 patients died (21%) during subsequent follow-up: 31 of progressive disease (13%), 18 of treatment related complications (8%) and two due to unknown causes (1%), while 15 patients were lost at follow-up (6%). As expected, a better 5-years overall survival (OS) was observed in the overall cohort among patients in CR1 (63%) in comparison to patients in CR>1 (38%) or AD (25%). Nevertheless, in the landmark analysis the impact of disease status on long-term survival was progressively less meaningful: for example, for patients alive at 2 years landmark, the probability of being alive for 3 more years was 86% for patients in CR1, 72% for patients in CR>1 and 79% for patients in AD, with no statistically significant difference between CR>1 and AD. Similar results were found for progression free survival (PFS), TRM and relapse risk. Of note, better long-term outcomes in the overall cohort were associated with younger patient age, allo-HSCT performed after 2013 and using a female donor for a male recipient. Only being younger was still significantly associated with better outcomes in the various landmark analysis. Furthermore, our study confirmed that relapse is still the main cause of death even for long-term survivors: 13% of patients alive at 2 years eventually relapsed.

Conclusions: In conclusion, the negative impact on outcomes of a more advanced disease at allo-HSCT seems to decline progressively after transplant, fostering the importance of strategies that may enhance the anti-leukemic effect of allo-HSCT in the following first months and years.

Disclosure: Nothing to declare.

19: Acute Leukaemia

P029 TLS::ERG FUSION GENE PREDICTS A POOR PROGNOSIS AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION IN ACUTE MYELOID LEUKEMIA: A SINGLE CENTER STUDY

Gele Tong 1, Yanli Zhao1, Jianping Zhang1, Min Xiong1, Xingyu Cao1, Deyan Liu1, Ruijuan Sun1, Zhijie Wei1, Jiarui Zhou1, Yue Lu1

1Hebei Yanda Lu Daopei Hospital, Langfang, China

Background: Acute myeloid leukemia (AML) patients with the TLS::ERG fusion gene tend to show poor outcomes to traditional chemotherapy. Allogeneic hematologic stem cell transplantation (allo-HSCT) may serve as a potential curative treatment, aiming to enhance the overall survival (OS). However, the long-term safety and efficacy of this treatment for these patients require further exploration.

Methods: A total of 30 AML patients with the TLS::ERG fusion gene were consecutively analyzed, who underwent allo-HSCT in our center between August 2012 and December 2022.

Results: The median age for these patients was 13(2-53) years, with 18 patients 18 years or younger. Before HSCT, the median disease course was 6(3-60) months. Of these patients, 17 (56%) had complex karyotypes, 10(30%) exhibited extramedullary disease, and 10(30%) had additional gene mutations. Prior to HSCT, the disease status was as follows: 18 patients in the first complete remission(CR1),6 in ≥CR2, and 6 in non-remission (NR). In 24 of morphologic CR patients, regular monitoring of TLS::ERG transcript levels before HSCT revealed that 10 patients were TLS::ERG negative, and 14 were TLS::ERG positive. Twenty-seven patients received intensified myeloablative conditioning regimens and the remaining 3 received standard regimens. The transplant donors were haploidentical (n = 23), matched unrelated (n = 5), and matched related (n = 2). In total, eight patients received celluar immutherapy to prophylaxis relapse after transplantation, of them 4 patients received received modified donor lymphocyte infusion (DLI) and another four received IFN-α.eight patients received TLS::ERG positive guided preemptive therapy after transplantation, of them 6 patients received received chemotherapy plus DLI and another two received IFN-α. The median follow-up time for the survivors was 42(12-86)months. The 5-year cumulative incidence of relapse (CIR), and 5-year leukemia-free survival (LFS) and overall survival(OS) after HSCT were 81.6%(95%CI:73.3-89.9),13.2%(95%CI:6.5-19.9), and 13.4%(95%CI:6.4-20.4%), respectively. Relapse occurred in 22 patients with a median relapsed time post-HSCT of 6(3-18) months, among whom 11 simultaneously merged with the extramedullary disease (EMD), among them, twenty patients died from relapse, one patient received therapy and achieved CR, the other one was in relapse status but still alive. Two patients died from treatment-related mortality(TRM). According to disease status (CR/TLS::ERG negative vs. CR/ TLS-ERG positive vs. NR) before allo-HSCT, no significant differences were observed in the 5-year CIR [83.1%(69.8-97.4%) vs. 71.4%(59.3-83.5) vs. 100%), p = 0.602], LFS[15.0%(2.2-27.8%) vs. 21.4%(10.4-32.4) vs 0%), p = 0.548], and OS[18.0%(2.9-33.1%) vs. 16.3%(5.8-26.8%) vs. 16.7%(1.5-31.9%), p = 0.568. Univariate analysis also showed that other factors did not affect the HSCT outcomes.

TABLE1 patient characteristics

Parameters(at diagnosis) n = 30

Median age, y(range) 13(2-53)

≤18y 18(60%)

Cytogenetics:

Complex karyotype 7(56%)

With other gene mutation 10(30%)

Disease status when receiving HSCT

CR1 18(60%)

≥2st CR 6(20%)

NR 6(20%)

With extramedullary disease 10(30%)

HCT-CI

0 27(90%)

1 2(6%)

2 1(3%)

Median disease course(months) before HSCT 6(3-60)

Donor type

HID 23(76%)

MUD 5(16%)

MSD 2(6%)

Conditioning regimen (Intensified MAC) 27(90%)

Conclusions: The presence of TLS::ERG fusion gene in AML is strongly associated with complex karyotype and EMD. Although allo-HSCT is a promising treatment option, the prognosis remains poor due to a high early relapse rate, even in patients with negative TLS::ERG transcript levels before HSCT.

Disclosure: Nothing to declare.

19: Acute Leukaemia

P030 HIGH TOLERABILITY OF PROLONGED AZACITIDINE MAINTENANCE AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION IN PATIENTS WITH AML LACKING A TARGETABLE MUTATION

Cuong An Do 1, Anne-Claire Mamez1, Amandine Pradier1,2, Sarah Morin1, Chiara Bernardi1,2, Sarah Prati-Perdikis1, Yan Beauverd1, Thomas Longval1, Maria Mappoura1, Sarah Noetzlin1, Laetitia Dubouchet1, Evgenia Laspa1, Marie Maulini1, Thien-An Tran1, Carmen de Ramon Ortiz1, Stavroula Masouridi-Levrat1, Federico Simonetta1,2, Yves Chalandon1,2, Federica Giannotti1

1Geneva University Hospitals and Faculty of Medicine, University of Geneva, Geneva, Switzerland, 2Translational Research Center for Oncohematology, University of Geneva, Geneva, Switzerland

Background: Maintenance therapy after allogeneic hematopoietic stem cell transplantation (HSCT) aims to reduce relapse. Targeted maintenance is available for only about 25% of acute myeloid leukemia (AML). Studies employing hypomethylating agents for maintenance in patients without targetable mutations have shown conflicting results.

Methods: We retrospectively analyzed outcomes and tolerability of azacitidine as post-transplant maintenance in a cohort of 23 adult patients with FLT3neg AML, transplanted at our institution between March 2018 and September 2021. Azacitidine was started at hematological reconstitution from day 60 post-transplant, in patients without active GVHD, evidence of relapse or MRD + . It was administrated subcutaneously at 32.5-50 mg/m2 for 5 days every 4 weeks for 2 years, if tolerated. Till May 2020, patients eligible for azacitidine maintenance were FLT3neg AML patients with MRD+ or active disease at transplant. Thereafter, we proposed azacytidine maintenance for all FLT3neg AML. Overall, 48 patients were screened: 25 did not start azacitidine due to MRD positivity (n = 7), relapse (n = 2), prolonged cytopenia (n = 7), GVHD (n = 5), death (n = 1), insurance refusal (n = 2) and physician choice (n = 1). Tolerability was evaluated by total number of cycles administrated, hematological toxicity, infections or other adverse events leading to withdrawal or delay of maintenance schedule.

The 50th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians – Poster Session (P001-P755) (3)

Results: Median follow-up was 30 months (range 11-62). Among 23 patients, one had active disease and 10 were MRD+ before transplant. Median age at transplant was 57 years (range 39-74). Median time from transplant to azacitidine initiation was 102 days (range 66-244). The median number of cycles was 11 (range 1-25). Overall, 7 patients completed the 2-years schedule and 1 is still ongoing. Among these 8, one extended administration intervals to 6 weeks due to cytopenias occasionally requiring G-SCF, another developed recurrent grade 3 neutropenia at higher doses of azacitidine (50 mg/m2), rapidly resolved with G-CSF. One patient on ruxolitinib had grade 3 neutropenia requiring G-CSF once. None of these 3 patients developed infections related to hematological toxicity. Three patients stopped maintenance for mild adverse events (fatigue, myalgias and pruritis) after 11, 12 and 21 cycles, respectively. Among the remaining 12 patients, 3 permanently stopped maintenance due to GVHD (2 chronic moderate, 1 late acute grade 2) after a median of 2 cycles; 9 switched to pre-emptive or curative treatment due to MRD+ occurrence (n = 8) or relapse (n = 1), after a median of 3 cycles. Overall, 5 patients had GVHD or infections not related to azacitidine leading to temporary interruptions (>28 days) for a median time of 73 days (range 49-168). The probability of 2-years OS and PFS were 82.6% (95%CI 68.5%-99.6%) and 69.6% (95%CI 53.1%-91.2%), respectively. Overall, 7 patients died, 1 of lung cancer and 6 of relapse. The 2-years CI of relapse and NRM were 30%±9.85% and 0%±0% respectively.

Conclusions: In our cohort of AML patients lacking targetable mutations, prolonged post-transplant maintenance with azacitidine was relatively well tolerated and outcomes were encouraging. These data support azacitidine maintenance in AML when targeted therapy is not an option.

Disclosure: Y.C. has received consulting fees for advisory board from MSD, Novartis, Incyte, BMS, Pfizer, Abbvie, Roche, Jazz, Gilead, Amgen, Astra-Zeneca, Servier; Travel support from MSD, Roche, Gilead, Amgen, Incyte, Abbvie, Janssen, Astra-Zeneca, Jazz, Sanofi all via the institution.

F.S. has received institutional consulting fees from BMS/Celgene, Incyte, Kite/Gilead; Speaker fees from Kite/Gilead, Incyte; Travel support from Kite/Gilead, Novartis, AstraZeneca, Neovii, Janssen; Research funding from Kite/Gilead, Novartis, BMS/Celgene.

19: Acute Leukaemia

P031 OUTCOME OF ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION IN ACUTE MYELOID LEUKAEMIA FLT3 IN THE ERA OF FLT3 INHIBITORS – STUDY OF THE POLISH ADULT LEUKAEMIA GROUP (PALG)

Elzbieta Patkowska1, Anna Czyz2, Alicja Sadowska-Klasa3, Andrzej Szczepaniak4, Lukasz Bolkun5, Marta Sobas2, Michal Gorka6, Edyta Subocz7, Anna Koclega8, Renata Guzicka-Kazimierczak9, Jan Zaucha3, Lidia Gil4, Marta Libura6, Agnieszka Pluta10, Dorota Bartosinska11, Ewa Lech-Maranda1, Agnieszka Wierzbowska10, Sebastian Giebel12, Barbara Nasilowska-Adamska 1

1Institute of Hematology and Transfusion Medicine, Warsaw, Poland, 2Wroclaw Medical University, Wroclaw, Poland, 3Gdansk Medical University, Gdansk, Poland, 4Poznan University of Medical Sciences, Poznan, Poland, 5Medical University of Bialystok, Bialystok, Poland, 6Warsaw Medical University, Warsaw, Poland, 7Independent Public Health Care Ministry of the Interior of Warmia and Mazury Oncology Center, Olsztyn, Poland, 8Medical University of Silesia, Katowice, Poland, 9Pomeranian Medical University, Szczecin, Poland, 10Medical University of Lodz, Lodz, Poland, 11Centre of Postgraduate Medical Education, Warsaw, Poland, 12National Institute of Oncology, Gliwice, Poland

Background: Allogeneic hematopoietic cell transplantation (allo-HCT) offers a potential survival benefit for patients with FLT3-positive acute myeloid leukemia (AML), particularly those harboring the FLT3-internal tandem duplication mutation (FLT3-ITDmut), which is associated with a poorer prognosis compared to point mutations in the tyrosine kinase domain (FLT3-TKDmut). Little is known about the impact of FLT3-TKDmut in the context of allo-HCT, especially with the use of FLT3 inhibitors. This study aims to analyze the outcomes of allo-HCT in FLT3-positive AML patients, considering the type of FLT3 mutation and post-transplant maintenance treatment.

Methods: This retrospective analysis includes FLT3-positive AML patients, encompassing FLT3-ITDmut and/or FLT3-TKDmut, who received intensive chemotherapy combined with midostaurin and underwent allo-HCT between 2017 and 2023.

Results: The study involved 88 patients, with a median age of 50.3 years (IQR 37.1-62.2), predominantly female (n = 58; 65.91%). FLT3-ITDmut was observed in 67 (76.1%) patients, FLT3-TKDmut in 15 (17%), and both mutations in 6 (6.8%) patients. All patients received intensive chemotherapy with midostaurin, initiated either after the first or second induction in 70 (80%) patients or after consolidation in 18 (20%) patients. The median follow-up period post allo-HCT was 15.7 months (IQR: 8.8-28.7). Allo-HCT was performed in the first complete remission (CR) in 68 (77%) patients, subsequent CR in 12 (13.63%) patients, or active disease in 8 (9%) patients. Most patients received myeloablative conditioning (MAC), including TBI-based MAC (n = 5; 5.6%), with grafts from matched related donors (MRD) (n = 24; 27%), matched unrelated donors (MUD) (n = 45; 51%), mismatched unrelated donors (mMUD) (n = 6; 6.8%), or family haploidentical donors (n = 13; 15%). The median overall survival (OS) post allo-HCT was 11 months, with a 2-year OS probability rate of 62%. Subgroup analysis of 60 patients who initiated midostaurin after the first or second induction and were tested for both FLT3 mutations showed a 2-year OS advantage for AML FLT3-TKDmut and AML FLT3-TKDmut co-occurring with FLT3-ITDmut patients compared to AML FLT3-ITDmut patients (rates: 81% vs 80% vs 67%, respectively), although this difference was not statistically significant (p = 0.289). Sorafenib was administered as maintenance treatment post allo-HCT to 22 (30%) of 73 AML FLT3-ITDmut patients. Univariate analysis of OS for the entire group identified age as the only significant prognostic factor, with better survival in patients under 60 years of age (HR = 0.44; 95% CI 0.2-0.93). In the FLT3-ITDmut subgroup, sorafenib maintenance (HR = 0.08; 95% CI 0.01-0.58), age under 60 years (HR 0.36; 95% CI 0.16-0.82) and male gender (HR 0.33; 95% CI 0.11-0.97) were prognostic factors associated with improved OS in univariate analysis. However, in the multivariate analysis of this subgroup, only sorafenib maintenance remained a favourable prognostic factor for improved OS (HR 0.11; 95% CI 0.01-0.89).

Conclusions: Allo-HCT emerges as an effective curative treatment option, providing satisfactory survival outcomes for both AML FLT3-ITDmut and FLT3-TKDmut patients. In the entire patient group, age stands out as the only significant prognostic factor for OS. However, among FLT3-ITDmut patients, post allo-HCT maintenance treatment with sorafenib remains the sole favorable prognostic factor for OS.

Disclosure: E. Patkowska: KCR- consultancy, Astellas Pharma, Servier, Amgen, Novartis - Honoraria.

19: Acute Leukaemia

P032 CLINICAL CHARACTERISTICS AND PROGNOSIS OF ADULT T CELL ACUTE LYMPHOBLASTIC LEUKEMIA PATIENTS WITH ACTIVATING RAS MUTATIONS

Mimi Xu 1,2,3, Yuqing Tu1,2,3, Mengqi Xiang1,2,3, Yi Fan1,2,3, Xiang Zhang1,2,3, Tiemei Song1,2,3, Lian Bai4, Xiaoli Li5, Yang Xu1,2,3, Yuejun Liu1,2,3, Depei Wu1,2,3

1National Clinical Research Center for Hematologic Diseases, Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University, Suzhou, China, 2Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China, 3Key Laboratory of Stem Cells and Biomedical, Materials of Jiangsu Province and Chinese Ministry of Science and Technology, Suzhou, China, 4Canglang of Suzhou Hospital, Suzhou, China, 5Soochow Hopes Hematonosis Hospital, Suzhou, China

Background: Several studies indicated that RAS mutations were associated with a poorer outcome in T cell acute lymphoblastic leukemia (T-ALL) patients. However, data regarding the clinical outcomes of adult RAS mutated T-ALL patients undergoing different consolidation treatment are limited. This study was conducted to analyze the clinical characteristics and prognosis of adult T-ALL patients with RAS mutations.

Methods: From January 2016 to December 2022, 137 newly diagnosed adult T-ALL patients were explored for activating RAS mutations in our center. We retrospectively analyzed the clinical characteristics of adult RAS mutated T-ALL patients and compare the efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT) with chemotherapy in these patients. About statistical analysis, overall survival (OS) and event free survival (EFS) were estimated by the Kaplan-Meier method and the log-rank test. The cumulative incidence of relapse (CIR) was estimated using Gray’s test, with non-relapse morality considered a competing risk. The covariates with a P value < 0.2 in univariate analyses were used in the multivariate analyses (Fine-Gray model). A P value < 0.05 was considered statistically significant. Statistical analyses were carried out with SPSS 20.0 and R 4.3.0.

Results: KRAS and NRAS mutations were identified in four (2.9%) of 137 and 15 (11%) of 137 patients, respectively. Overall, 19 (13.9%) of 137 T-ALLs harbored activating RAS mutations, without any accompanying PTEN gene changes. The early precursor T (ETP) was the most common immunophenotype (68.4%), with chromosomal abnormalities accounting for 36.8%, and 3 cases of SET-NUP214 fusion gene positivity. The complete response (CR) rate in one course of treatment for 19 patients was 78.9%, and the total CR rate in two courses was 93.3%, one patient with continuous non-remission died on 5.7 months after diagnosis. The median follow-up of survivals was 26.2 months. The 3-year OS rate was (60±12)%, EFS rate was (41±12)%, and CIR was (61.6±1.9)%. Six patients who only received chemotherapy died within 2 years after diagnosis; The 3-year OS rate and EFS rate of 13 patients who underwent allo-HSCT as consolidation were (90.0±9.5)% and (62.3±15.2)%, respectively. Multivariate analyses revealed that achieved CR after first induction chemotherapy (P = 0.036, HR = 0.075, 95%CI: 0.007-0.849) and allo-HSCT (P = 0.008, HR = 0.031, 95%CI: 0.002-0.398) were independent good factors affecting CIR.

Table 1 Characteristics of 19 adult T-ALL patients with activating RAS mutations.

Total

(n = 19)

Allo-HSCT

(n = 13)

Chemothreapy

(n = 6)

P value

Gender, male/female, n

13/6

10/3

3/3

0.241

Age at diagnosis [years, M (range)]

44(21-67)

38(21-55)

60(44-67)

0.001

WBC at diagnosis [×109/L, M (range)]

5.18(0.62-204.7)

4.82(0.62-204.7)

8.81(1.55-95.09)

0.831

Blasts in bone marrow [%, M (range)]

72.5(24-97.5)

84(47.5-97.5)

54.5(24-89)

0.244

Immunophenotype, n(%)

0.018

Pro-T

3(15.8)

0(0.0)

3(50.0)

Pre-T

3(15.8)

2(15.4)

1(16.7)

ETP

13(68.4)

11(84.6)

2(33.3)

Chromosomal, n(%)

0.829

Normal

12(63.2)

8(61.5)

4(66.7)

Abnormal

7(36.8)

5(38.5)

2(33.3)

Fusion gene, n(%)

0.200

SET-NUP214

3(15.8)

3(23.1)

0(0.0)

Negative

16(84.2)

10(76.9)

6(100.0)

RAS mutations, n(%)

0.126

NRAS mutation

15(78.9)

9(69.2)

6(100.0)

KRAS mutation

4(21.1)

4(30.8)

0(0.0)

Accompany by NOTCH1/FBXW7 mutations, n(%)

12(63.2)

7(53.8)

5(83.3)

0.216

Conclusions: We concluded that RAS mutations were common in adult T-ALL without accompanying PTEN changes, and had more frequently an immature immunophenotype. Adult RAS mutated T-ALL patients had a high induction response rate, but were prone to relapse. Allo-HSCT might effectively reduce the recurrence rate and improve their survival.

Disclosure: Nothing to declare

19: Acute Leukaemia

P033 PREVENTION AND TREATMENT OF ACUTE MYELOID LEUKEMIA RELAPSE FOLLOWING ALLOGENEIC STEM CELL TRANSPLANT: A NATIONAL SURVEY BY GITMO (GRUPPO ITALIANO TRAPIANTO MIDOLLO OSSEO)

Francesco Saraceni1, Eliana Degrandi2, Simona Piemontese3, Francesco Saglio4, Giorgia Battipaglia 5, Marta Lisa Battista6, Patrizia Chiusolo7, Jacopo Mariotti8, Stefania Bramanti8, Anna Grassi9, Fabio Benedetti10, Manuela Tumino11, Giorgia Saporiti12, Salvatore Leotta13, Sadia Falcioni14, Martina Chiarucci15, Gladis Bortoletto16, Elisabetta Terruzzi17, Annalisa Imovilli18, Carlo Borghero19, Eugenia Piras20, Francesco Zallio21, Vincenzo Federico22, Irene Maria Cavattoni23, Andrea Gilioli24, Alessandra Picardi25, Domenico Pastore26, Anna Paola Iori27, Valentina Giudice28, Carmen Di Grazia29, Luca Castagna30, Michele Malagola31, Attilio Olivieri1, Francesca Bonifazi32, Massimo Martino33

1Azienda Ospedaliero Universitaria delle Marche, Ancona, Italy, 2GITMO Trial Office, Bologna, Italy, 3Ospedale S. Raffaele, Milano, Italy, 4CIttà della Salute e della Scienza, Torino, Italy, 5Università degli studi di Napoli Federico II, Napoli, Italy, 6Azienda sanitaria universitaria Friuli Centrale, Udine, Italy, 7Università Cattolica del Sacro Cuore, Roma, Italy, 8Istituto Humanitas, Rozzano - Milano, Milano, Italy, 9ASST Papa Giovanni XXIII, Bergamo, Italy, 10Ospedale Borgo Roma di Verona, Verona, Italy, 11Azienda Ospedaliera di Padova, Padova, Italy, 12Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico Milano, Milano, Italy, 13Azienda Ospedaliero - Universitaria Policlinico - Vittorio Emanuele, Catania, Italy, 14AOC Ascoli Piceno, Ascoli Piceno, Italy, 15Azienda Ospedaliera Marche Nord, Pesaro, Italy, 16IRCCS Istituto Oncologico Veneto, Mestre, Italy, 17Azienda Ospedaliera San Gerardo, Monza, Italy, 18AUSL Reggio Emilia, Reggio Emilia, Italy, 19Ospedale S. Bortolo Vicenza, Vicenza, Italy, 20Centro Trapianti Midollo Osseo, Università di Cagliari, Cagliari, Italy, 21Azienda Ospedaliera di Alessandria, Alessandria, Italy, 22ASL Lecce, Lecce, Italy, 23Ospedale Generale Regionale Bolzano, Bolzano, Italy, 24Azienda Ospedaliero Universitaria di Modena, Modena, Italy, 25Ospedale A. Cardarelli - Divisione di Ematologia, Napoli, Italy, 26ASL Brindisi, Brindisi, Italy, 27Università la Sapienza, Roma, Italy, 28Università degli studi di Salerno, Salerno, Italy, 29UO Ematologia e Terapie Cellulari. IRCCS Ospedale Policlinico San Martino, Genova, Italy, 30Azienda Ospedaliera Ospedali Riuniti Villa Sofia - Cervello, Palermo, Italy, 31Università degli Studi di Brescia, Brescia, Italy, 32IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy, 33Azienda Ospedaliera “Bianchi-Melacrino-Morelli” di Reggio Calabria, Reggio Calabria, Italy

Background: Leukemia relapse remains the main cause of treatment failure in patients undergoing allogeneic stem cell transplant (allo-SCT) for acute myeloid leukemia (AML). There is currently no general agreement concerning management of patients at high risk of leukemia recurrence or with overt hematological relapse after allo-SCT.

Methods: We conducted the present survey with the aim to evaluate the current practice in Italy concerning prevention and treatment of AML relapse after allo-SCT. A questionnaire was sent to GITMO centers including specific questions on three main topic: maintenance, preemptive therapy and treatment of hematological relapse. Most of the agents discussed below currently represent off label prescriptions.

Results: In all, 34/60 (57%) of centers performing allo-SCT in Italy completed the questionnaire. 22/34 (65%) routinely employ maintenance strategies (in the absence of measurable residual disease (MRD) or mixed chimerism) after allo-SCT in patients considered at high risk of relapse basing on pre-transplant features (high risk according to ELN 2022 or presence of FLT3-ITD, positive MRD or active disease). Among institutions who deliver maintenance therapy after allo-SCT, in patients harbouring FLT3-ITD 86% administer FLT3 inhibitors (95% Sorafenib, 5% Gilteritinib). In the absence of FLT3-ITD 68% use hypometilating agents (87% azacitidine, 13% decitabine); 2 centers consider addition of venetoclax to hypometilating agents, while one institution prescribes venetoclax as single agent. Interestingly, 26% of institutions administer prophylactic DLI in high risk AML patients, in the absence of MRD relapse or mixed chimerism. With respect to preemptive therapy, the trigger to start treatment is represented by MRD relapse in all centers; 74% of institutions consider mixed chimerism as trigger to start preemptive therapy as well. In patient harbouring FLT3-ITD 82% of centers prescribe FLT3 inhibitors (48% sorafenib +/- azacitidine, 52% gilteritinib). In the absence of FLT3-ITD 62% of institutions use azacitidine (19% with the addition of venetoclax), one institution use venetoclax monotherapy, while 29% use DLI as single approach especially in case of mixed chimerism in the absence of MRD relapse. Nevertheless, 32/34 (94%) use DLI in addition to pharmacologic preemptive therapy.

In patients experiencing haematological relapse after transplant 76% of institutions perform NGS analysis at the time of relapse, while 50% look for HLA loss in case of relapse after haploidentical transplant. In patients harbouring FLT3-ITD 91% of centers treat AML relapse with gilteritinib. In fit patients, in the absence of FLT3-ITD, 44% employ conventional chemotherapy, while 56% consider as first option hypometilating agents (mostly azacitidine) in combination with venetoclax.

All institutions consider second allo-SCT after salvage treatment in patients who relapse after first transplant. 62% of centers perform second allo-SCT only in patients achieving CR2, while 38% regardless achievement of response to salvage. Finally, 97% of institutions prefer a different donor for second allo-SCT, if available.

Conclusions: Most Italian transplant institutions currently implement strategies to prevent AML relapse after allo-SCT, despite the lack of approved agents in this setting. In patients with haematological relapse a second allo-SCT remains a main option after salvage treatment with standard chemotherapy or hypometilating agents in combination with venetoclax.

Disclosure: Nothing to declare.

19: Acute Leukaemia

P034 TRENDS IN THE USE OF HEMATOPOIETIC CELL TRANSPLANTATION FOR ADULTS WITH ACUTE LYMPHOBLASTIC LEUKEMIA: A REPORT FROM THE ACUTE LEUKEMIA WORKING PARTY OF THE EBMT

Sebastian Giebel 1, Myriam Labopin2, Frederic Baron3, Ali Bazarbachi4, Eolia Brissot5, Gesine Bug6, Jordi Esteve7, Norbert-Claude Gorin8, Francesco Lanza9, Arnon Nagler10, Annalisa Ruggeri11, Jaime Sanz12, Bipin Savani13, Christoph Schmid14, Roni Shouval15, Alexandros Spyridonidis16, Jurjen Versluis17, Zinaida Peric18, Mohamad Mohty5, Fabio Ciceri19

1Maria Sklodowska-Curie National Research Institute of Oncology, Gliwice Branch, Gliwice, Poland, 2EBMT Unit, Sorbonne Universités, UPMC University of Paris 06, INSERM, Centre de Recherche Saint-Antoine (CRSA), AP-HP, Saint Antoine Hospital, Paris, France, 3GIGA-I3, University and CHU of Liège, Liège, Belgium, 4American University of Beirut Medical Center, Beirut, Lebanon, 5Sorbonne Universités, UPMC University of Paris 06, INSERM, Centre de Recherche Saint-Antoine (CRSA), AP-HP, Saint Antoine Hospital, Paris, France, 6University Hospital, Goethe University Frankfurt, Frankfurt am Main, Germany, 7Hospital Clínic of Barcelona, IDIBAPS, University of Barcelona, Barcelona, Spain, 8European Society for Blood and Marrow Transplantation, Paris Office, Hopital Saint-Antoine, Paris, France, 9Romagna Transplant Network, Ravenna, Italy, 10Chaim Sheba Medical Center, Tel-Hashomer, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel, 11IRCCS Bambino Gesù Children’s Hospital, Rome, Italy, 12Hospital Universitari i Politecnic La Fe. Instituto de Investigación Sanitaria La Fe, Valencia, Spain, 13Vanderbilt University Medical Center, Nashville, United States, 14Augsburg University Hospital, Augsburg, Germany, 15Memorial Sloan Kettering Cancer Center, New York, United States, 16University of Patras, Patras, Greece, 17Erasmus University Medical Center Cancer Institute, Rotterdam, Netherlands, 18University Hospital Center Rijeka and School of Medicine, University of Rijeka, Rijeka, Croatia, 19Ospedale San Raffaele s.r.l., Haematology and BMT, Milano, Italy

Background: Indications for hematopoietic cell transplantation (HCT) for adults with acute lymphoblastic leukemia (ALL) evolve over time and vary among countries. In our previous survey we reported continues increase of the number of allogeneic (allo)-HCT procedures between years 2001-2015 [Giebel S, et al., Ann Hematol 2019]. In recent years the role of HCT has been challenged by new protocols incorporating bispecific antibodies or immunotoxins in first-line treatment. The goal of this study was to assess general trends in the number of various types of HCTs performed between years 2010 and 2021 in Europe.

Methods: Data reported to the EBMT registry were used for this analysis. Altogether, 14389 first allogeneic (n = 13795) or autologous (auto-, n = 594) HCTs were performed in the period 2010-2021.

Results: The number of allo-HCTs analyzed in 2-year periods increased from 2074 for years 2010-2011 to 2428 between 2018-2019 (17% increase) and then dropped to 2282 for years 2020-2021 (6% decrease). Similar pattern was observed for the largest European countries (Germany, UK, France, Italy, Spain).

Comparing years 2020-2021 and 2010-2011, median recipient age increased from 37.3 to 41.1 (p<0.0001), the proportion of matched sibling donor transplants decreased from 39% to 24.2%, while the rate of unrelated donor and haploidentical donor transplants increased from 50.8% to 54.3% and 5.1% to 20.2%, respectively; the proportion of cord blood transplants decreased from 5.1% to 1.2% (p<0.0001) (Table). In respective periods the proportion of patients with Ph-negative B-ALL increased from 28.6% to 43.2%, for Ph-positive B-ALL it decreased from 38% to 32.7% while for T-ALL it dropped from 33.4% to 24.1% (p<0.0001). Most patients were treated in the first complete remission: 70.2% between years 2010-2011 and 70.9% between 2020-2021. The proportion of patients administered allo-HCT in active disease decreased from 10.5% to 4.7% in respective periods (p<0.0001). Peripheral blood was used as a source of stem cells for allo-HCT in 74.1% of patients between 2010-2011 and 90.3% of patients between 2020-2021. The use of post-transplant cyclophosphamide increased from 1.7% to 29.6% in respective periods (p<0.0001).

The total number of auto-HCTs was 130 between years 2010-2011 and 48 between 2020-2021 (63% decrease).

Year

2010-2011

2012-2013

2014-2015

2016-2017

2018-2019

2020-2021

Total allo-HCT

2074

2319

2309

2383

2428

2282

MSD-HCT

809

800

721

780

665

553

URD-HCT

1054

1242

1250

1269

1285

1240

Haplo-HCT

105

190

278

293

434

462

Cord blood

106

87

60

41

44

27

Auto-HCT

130

98

127

112

79

48

Conclusions: Results of our analysis indicate moderate increase of allo-HCT procedures for adults with ALL in the period 2010-2019 followed by a slight decrease between 2020-2021 that might be related to SARS-CoV-2 pandemic. The profile of allo-HCTs has changed over time with more frequent use of haploidentical donors, post-transplant cyclophosphamide – based immunosuppression and the use of peripheral blood as predominant source of stem cells. In recent years less patients have been treated with allo-HCT in active disease which may reflect higher efficacy of immunotherapy-based salvage regimens. Auto-HCT is rarely used for the treatment of adults with ALL.

Clinical Trial Registry: Not applicable

Disclosure: GB has received honoraria from Novartis, Jazz, BMS and Gilead and travel grants from Jazz, Gilead and Neovii

19: Acute Leukaemia

P035 ALLOGENEIC STEM CELL TRANSPLANTATION FOR ADULT ACUTE LYMPHOBLASTIC LEUKEMIA - A SINGLE CENTER 25-YEARS EXPERIENCE

Veronika Válková 1,2, Cyril Šálek1,2, Antonín Vítek1, Markéta Marková1,2, Ludmila Nováková1, Mariana Koubová1, Michal Kolář1, Barbora Čemusová1, Hana Bartáková1, Petr Cetkovský1,2, Jan Vydra1,2

1Institute of Hematology and Blood Transfusion, Prague 2, Czech Republic, 2Faculty of Medicine of Charles University, Prague 2, Czech Republic

Background: Allogeneic stem cell transplantation (allo-SCT) may be curative for patients with high risk acute lymphoblastic leukemia (ALL). The aim of our analysis was to compare the results of allo-SCT in ALL over more than two decades and to identify the parameters that influence these results.

Methods: All patients (pts) older than 18 years who underwent allo-SCT at our center from March 1989 to July 2023 were included in the analysis. In total, there were 183 pts, median age 38 years (18-65, only 17% over 55 years), 116 (63%) were male, B-ALL-Ph pos 37%, T-ALL 17%, donors were MSD (26%), MUD (42%), MMUD (23%) and haplo (8%). The majority of grafts were PBPC (82%). Myeloablative conditioning (TBI based) received 158 (86%) pts, 62% of whom received Vep/12Gy TBI. A more detailed analysis in terms of GVHD and MRD was performed on a cohort of patients from 2007 (n = 136). At allo-SCT 105 pts (77%) were in CR1, 23 (17%) in CR2, 6% with active disease. In terms of MRD, 60 patients were negative and 59 positive before allo-SCT.

Results: With a median follow-up of 6.5 years (living pts), 5-year OS was 56% and EFS of 49%. The cumulative incidence of relapse and NRM was 30% and 27% respectively at 5 years. Acute GVHD grade 2-4 occurred in 23%, moderate/severe chronic GVHD in 11%. GRFS at 5 years was 42%. Relapse occurred in 23% of patients, at a median of 8 months. OS after relapse was 22% at 5 years (26% vs 19% in the last decade vs earlier, p= ns). In univariate analysis, significantly better outcomes in terms of OS were observed in the last decade (5y-OS 68%), optimal conditioning seems to be Vep/TBI, worse outcomes were observed in patients over 55 years. Survival was significantly better in pts reaching CR before allo-SCT, and also significantly better in MRD neg versus MRD pos pts (no difference between MRD neg CR1 or CR2), both before allo-SCT and at 3 months after allo-SCT. A multivariate Cox regression analysis confirmed the survival benefit for pts who reached MRD negativity before allo-SCT (p = 0.047) and for transplants from MSD (p = 0.02) or MUD (p = 0.02) over the other donors.

The 50th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians – Poster Session (P001-P755) (4)

Conclusions: The outcomes of allo-SCT in ALL have improved significantly in the last decade, in our setting mainly due to the reduction of NRM. The role of novel therapies has been observed more in terms of of the possibility of achieving more CR (and even more MRD neg CR) before allo-SCT, rather than in the treatment of relapses after allo-SCT. Our results confirm the essential role of MRD monitoring during ALL treatment and in particular achieving MRD negativity before allo-SCT.

Disclosure: nothing to declare

19: Acute Leukaemia

P036 STRUCTURAL ANALYSIS OF LEUKEMIA-ASSOCIATED PROTEIN PTPN21 REVEALS A DOMINANT-NEGATIVE EFFECT OF THE FERM DOMAIN ON ITS PHOSPHATASE ACTIVITY

Zijun Qian 1,2, Lu Chen1,2, Jie Zhang2, Yuyuan Zheng1, Chun Zhou1,2, Haowen Xiao1,2

1Zhejiang University, Hangzhou, China, 2Sir Run Run Shaw Hospital, Hangzhou, China

Background: High expression level of protein tyrosine phosphatase non-receptor type 21 (PTPN21) has been detected in B-cell non-Hodgkin’s lymphoma and its mutations are associated with disease relapse in B-cell acute lymphoblastic leukemia (B-ALL) patients who received allo-HSCT. Recently, PTPN21 has been shown to be pivotal in maintaining cell mechanical properties and helps retain hematopoietic stem cells (HSCs) in the bone marrow niche through dephosphorylating the cytoskeleton-associated protein Septin1. However, the molecular structure and functions of PTPN21 have been less understood compared to other tyrosine phosphatases like PTP1 B. PTPN21 is a relatively large protein with two structured domains, FERM domain and the catalytic domain (PTP), and a long intrinsically disordered region in the middle. The mechanisms of regulation of PTPN21 phosphatase activity and the effect of mutations on its functions need to be explored.

Methods: We used protein purification and crystallization to determine structures of FERMPTPN21, PTPPTPN21 and a complex structure of the PTP and FERM domains. GST pulldown and MST titration as well as phosphatase assays and site direct mutagenesis were used to determine the interaction of PTP and FERM domains.

Results: Through biochemical assays, we found that PTPN21 FERM domain can interact with PTP domain, resulting in negatively regulating its phosphatase activity in vitro and in vivo. We further explored the structures of FERMPTPN21, PTPPTPN21 as well as a complex structure of the combination of PTP and FERM domains. The FERM-PTP complex structure allowed us to identify critical interface residues and mutations of these residues led to enhanced phosphatase activity of PTPN21 and induced activation of downstream ERK. More importantly, these mutations only activated ERK in the context of wild-typed PTP but not the catalytic inactive C1108S, indicating PTPN21’s phosphatase activity is indispensable.

Conclusions: We’ve demonstrated that PTPN21 catalytic domain PTP is autoinhibited by the FERM domain. Disruption of FERM-PTP interaction results in enhanced PTPN21 activity and activation of downstream MAPK signal pathway. Our work provides novel insights into understanding the role of PTPN21 in various cellular processes by discovering the molecular structure of the FERM and PTP domains of PTPN21. These findings are likely extendable to other FERM-containing tyrosine phosphatases like PTPN14 and PTPN3, which opens up new avenues for further mechanistic studies.

Disclosure: Nothing to declare.

19: Acute Leukaemia

P037 EARLY DETECTION OF RELAPSE AND PROMPT TREATMENT WITH DLI FACILITATED BY PROPHYLACTIC LYMPHOCYTE STORAGE PERI-TRANSPLANT RESULTS IN EFFECTIVE DISEASE CONTROL IN ACUTE LEUKAEMIA AND MDS

Daire Quinn 1, Anne Parker1, Grant McQuaker1, Anne-Louise Latif1, David Irvine1, Ailsa Holroyd1, Dimitris Galopoulos1, Andrew Clark1

1Queen Elizabeth University Hospital, Glasgow, United Kingdom

Background: Relapse following allogeneic stem cell transplant carries a poor prognosis. DLI has been used in this setting but is less effective if delayed or given in the context of haematological relapse.

Methods: Aliquots of DLI from the PBSC collection were stored prophylactically pre-transplant. The transplant dose was always protected and was never < 4x106 CD34 cells/Kg. No DLI were stored if stem cell dose was lower than this threshold. Patients with relapsed acute leukaemia (AL) or MDS were detected early and treated with an effective salvage regimen followed by escalated doses of DLI, starting at 3x105 CD3 cells/Kg (VUD) or 1x106 CD3 cells/Kg (MRD). First dose DLI was given at 6-8 weeks post commencement of salvage treatment. Subsequent DLI doses (3x106, 1x107, 3x107 CD3 cells/Kg) were delivered at 8-12 week intervals intercalated with salvage therapy. Maximum dose was 3x107 CD3 cells/Kg (max cumulative dose 4.63 x107 CD3 cells/Kg). Patients were excluded if they had rapidly progressive disease, BM blasts >50% or ECOG >2.

Results:

Acute Leukaemia

Myelodysplasia

Specific Disease

AML 15, ALL 4

12

Median Age

51 (21-66)

60 (51-66)

Male sex

11

10

Conditioning

RIC

11

12

MAC

8

Mode of Presentation

MRD 10, Haematological 9

Mixed myeloid chimerism + cytopenia 12

2 year DFS

53%

42%

Median FU

30 months

22 months

Between 2015 and 2022 thirty one patients were treated with DLI for relapsed AL (n = 19) or MDS (n = 12). Strikingly, only 4 of these interventions occurred before 2019. Before that time selecting patients with low disease burden and being able to acquire DLI in a rapid time frame was frequently not possible. After 2019 four factors facilitated effective DLI administration- Early disease relapse, detection using MRD combined with assessment of myeloid chimerism, newer agents to achieve remission responses and the ready availability of DLI.

In relapsed MDS all patients had recurrent cytopenias associated with: NGS abnormalities, increasing blast % or cytogenetic abnormalities. Myeloid chimerism ranged from 4-64% at diagnosis returning to 100% donor in all responding patients. In the AL group 10 were diagnosed by MRD methods and 9 had haematological relapse. Median Time to relapse was 10 months in AL and 19 months in MDS

In AL salvage treatment included FLAG, Dasatinib, Gemtuzumab, Ven/Aza, Gilteritininb, Blinatumomab, Inotuzumab, Azacitidine alone or no therapy while MDS patients all received Azacitidine for 4-12 cycles. Median number of DLI infusions was 3. Median total dose was 1.4x107 CD3 cells/Kg in both groups. In responders the median total dose was 4.4x107 CD3 cells/kg. Median FU post DLI was 20 and 30 months overall or for responders in AL and 19 and 22 months in MDS.

CR was achieved in 63% of acute leukaemia and 58% of MDS patients. Two leukaemic patients relapsed at 16 and 34 months. Responses were otherwise durable, 80% remained in CR at 3 years. Three additional MDS patients responded transiently. Acute GvHD occurred in 2 patients. Two patients have moderate chronic GvHD. One died of acute neurotoxicity. Two year DFS was 53% in AL and 42% in MDS.

Conclusions: Combining early detection of disease relapse, followed by treatment with novel therapies and consolidation with DLI provides effective salvage therapy. High levels of durable disease control are achieved and low rates of GvHD are seen resultant on DLI dose escalation. Prophylactic storage of DLI allows this approach and is cost effective.

Clinical Trial Registry: None

Disclosure: None

19: Acute Leukaemia

P038 THIOTEPA, BUSULFAN, AND FLUDARABINE CONDITIONING REGIMEN IN T-CELL REPLETE HLA-HAPLOIDENTICAL BONE MARROW TRANSPLANTATION FOR ADULTS WITH ACUTE MYELOBLASTIC LEUKEMIA IN SECOND COMPLETE REMISSION

Ahmad Ibrahim 1, Ahmad Khalil2, Kamal Al Zahran3, Mohamad Hachem4, Pamela Sfeir5, Amin Abyad6, Jad Ibrahim7, Hussein Abou Abbas8, Ali Youssef8, Charbel Khalil2, Tamima Jisr9

1Makassed University Hospital, Middle East Institute of Health, University of Balamand and Lebanese University, Beirut, Lebanon, 2Middle East Institute of Health, Beirut, Lebanon, 3Middle East Institute of Health and Lebanese University, Beirut, Lebanon, 4Makassed University Hospital and Lebanese University, Beirut, Lebanon, 5University of Balamand, Beirut, Lebanon, 6Burjeel Medical City, Abu Dhabi, United Arab Emirates, 7American University of Beirut, Beirut, Lebanon, 8Makassed University Hospital, Beirut, Lebanon, 9Makassed University Hospital and Beirut Arab University, Beirut, Lebanon

Background: Haploidentical stem cell transplantation (HaploSCT) with thiotepa/busulfan/fludarabine (TBF) conditioning and post-transplant cyclophosphamide (PT-Cy) can achieve comparable outcomes for relapsed acute myeloblastic leukemia (AML) patients (pts) in complete remission (CR) to those of HLA-matched sibling or unrelated donor transplantation. However, a higher incidence of acute and chronic GVHD was reported with peripheral blood stem cell source (PBSC) compared to bone marrow (BM) in adult acute leukemia. In this study, we report the outcomes of adult pts (>18yo) with AML in second CR who underwent HaploSCT with unmanipulated BM source using TBF conditioning and PT-Cy.

Methods: This study is a retrospective analysis conducted between 2/2018 and 2/2023. The TBF-MAC included thiotepa IV 5mg/kg/d on d-7 and -6, IV busulfan 3.2mg/kg/d on d-4, -3, -2, and IV fludarabine 30mg/kg/d from d-5 to d-1. The TBF-RIC, for pts >60yo, involved reduced doses of thiotepa (5mg/kg on d-6) and busulfan (3.2mg/kg/d on d-3 and -2), with identical fludarabine doses. BM was infused on d0. The PT-Cy dose was 50mg/kg/d d + 3 and +4, followed on d + 5 by IV cyclosporine 3mg/kg/d, then tapered over 6 weeks after d + 60 if no GVHD. MMF was given at a dose of 15mg/kg every 12 hours d + 5 to d + 35. GCSF was started d + 5 until neutrophil recovery. Prophylaxis for VOD was ensured by ursodeoxycholic acid. Anti-microbial prophylaxis was given. Pts were monitored by PCR for CMV, EBV, HHV6 until d + 100, and for BK virus if indicated. Azacitidine was given as maintenance therapy after Haplo SCT for all pts, and sorafenib was given in case of FLT3 mutations.

Results: Thirty-two pts were included. Median age was 36yo (19-71). There were 17 females and 15 males. Twenty-four pts (75%) received TBF-MAC, and 8 (25%) TBF-RIC. Median number of nucleated cells infused was 5.2×108 kg (4.1-6.7). All pts achieved neutrophil recovery within a median of 17d (14-31), and platelet recovery (>20 109/L) within a median of 19d (10-42). All pts had full donor chimerism before d + 90. Seven pts (22%) developed grade II-IV aGVHD, including 2 (6%) with grade III–IV. Three pts (9%) developed non-severe cGVHD. Acute GVHD was refractory to steroids in 2 pts and was fatal in one. Fatal VOD occurred in 1 pt (3%). Eight pts (25%) had bacteremia, and 2 (6%) developed invasive fungal infections. Two pts (6%) developed fatal COVID-19. CMV reactivation, successfully treated with ganciclovir, occurred in 14 pts (44%). Seven pts (22%) died of infection, including 2 of COVID-19 and 5 of sepsis. Five pts (16%) relapsed within a median of 9 months (6-25) after Haplo SCT and died from AML between 1 and 6 months after relapse. Within a median follow-up of 22 months (1-68), 18 pts (56%) are still alive in CR with a median of 33 months (11-68). The 3y-OS and-DFS were 57% and 52%, respectively.

Conclusions: HaploSCT with BM source offers a curative therapy for adult AML pts in 2nd CR with low risk of GVHD, and low incidence of relapse. However, infections remained the main cause of death.

Disclosure: Nothing to declare.

19: Acute Leukaemia

P039 REDUCED INTENSITY CHEMOTHERAPY WITH TYROSINE KINASE INHIBITOR FOLLOWED BY ALLOGENEIC STEM CELL TRANSPLANTATION WAS EFFECTIVE IN PATIENTS WITH PHILADELPHIA CHROMOSOME POSITIVE ACUTE LYMPHOBLASTIC LEUKEMIA

Dong Won Baek 1, Jung Min Lee1, Hyukjin Choi1, Joon Ho Moon1, Sang Kyun Sohn1

1Kyungpook National University Hospital, Daegu, Korea, Republic of

Background: With the introduction of tyrosine kinase inhibitors (TKI), survival outcomes of adult patients with Philadelphia chromosome positive (Ph-positive) acute lymphoblastic leukemia (ALL) has improved remarkably. Intensive chemotherapy plus TKI is still the standard approach to induce hematologic complete remission (CR) before allogeneic stem cell transplantation (allo-SCT). However, intensive chemotherapy before transplantation may have negative impacts on allo-SCT outcomes, including treatment-related mortality, worsening performance at the time of transplantation. In the current study, we compared the survival outcomes of intensive chemotherapy plus TKI and reduced intensity chemotherapy plus TKI in patients with newly diagnosed Ph-positive ALL. In addition, the clinical role of allo-SCT in the treatment of adult Ph-positive ALL was also evaluated.

Methods: We retrospectively analyzed data from 97 patients with newly diagnosed Ph-positive ALL who received intensive chemotherapy plus TKIs or reduced intensive chemotherapy plus TKIs over the past 10 years. Patients aged ≥ 20 years were included in this study. Patients who were in suitable condition for transplantation and had HLA matched donor underwent allo-SCT. Relapse-free survival (RFS) was determined from the date of diagnosis to the date of disease relapse or death from any cause. Overall survival (OS) was determined from the date of diagnosis to the date of death or last follow-up.

Results: In total, 97 patients were analyzed. Intensive chemotherapy was administered to 69 patients, and median age was 45 (range, 20-73) years old. Reduced intensity chemotherapy was administered to 28 patients, and their median age was 68.5 (range, 27-80) years old. In patients with intensive chemotherapy plus TKI, 55 patients (79.7%) achieved molecular CR after induction chemotherapy, and four patients (5.8%) died during induction therapy. In patients with reduced intensity chemotherapy plus TKI, 20 patients (71.4%) achieved molecular CR, while no one has died during induction therapy. In the intensive chemotherapy group, 46 patients (66.7%) underwent allo-SCT, and 20 patients showed disease relapse and three patients died after transplantation. In the reduced intensity chemotherapy group, 12 patients (42.9%) received allo-SCT, and four patients had relapsed disease and one died. In an analysis targeting only transplanted patients, there was no statistically significant difference in RFS and OS between patients who received intensive chemotherapy and patients with reduced intensity chemotherapy.

Conclusions: Reduced intensity chemotherapy decreased induction mortality compared to intensive chemotherapy. In addition, reduced intensity chemotherapy plus TKI was able to sufficiently induce molecular CR, and subsequent allo-SCT could improve long-term survivals.

Disclosure: The authors declare no conflict of interest.

19: Acute Leukaemia

P040 IMPACT OF CO-MUTATIONS ON THE TRANSPLANT OUTCOMES IN AML PATIENTS WITH DNMT3A MUTATION

Feng-ming Tien1, Xavier Cheng-Hong Tsai 1, Min-Yen Lo1, Hsin-An Hou1, Hwei-Fang Tien1

1National Taiwan University Hospital, Taipei, Taiwan, Province of China

Background: Acute myeloid leukemia (AML) with DNMT3A mutations is classified within intermediate-risk category according to ELN-2022 criteria. However, the impact of co-mutations on the transplant outcomes in this particular group remains to be explored.

Methods: A total of 148 patients (16.7%) with DNMT3A mutations were enrolled from a retrospective cohort of 887 AML patients homogeneously treated with intensive chemotherapy. Gene mutations were examined via targeted NGS, using the TruSight myeloid panel. Notably, none of the patients received oral azacitidine as maintenance therapy. Survival analysis modified according to Simon-Makuch method were used to compare outcomes between allogeneic stem cell transplantation (allo-HSCT) and postremission chemotherapy (PR-CT) in the first complete remission (CR1).

Results: The most frequent co-mutations in DNMT3A mutated patients were NPM1 (52.7%), FLT3-ITD (31.1%), and IDH2 (26.4%). 111 out of 148 (75%) patients achieved CR1. 68 patients received allo-HSCT: 30 with myeloablative conditioning, 38 with reduced intensity conditioning; 15 with a haploidentical donor, 23 with a matched sibling donor, 30 with a matched unrelated donor. Specifically, 30 patients received allo-HSCT at CR1, 11 at CR2, 27 at other disease statuses, resulting in a 5-year overall survival (OS) of 46%, 29%, 15%, respectively. For those with PR-CT without further transplant, the 5-year OS was 13%. Allo-HSCT in CR1 was associated with a better OS than PR-CT (median, not reached (NR) vs 15.3 months, P<0.0001).

Next we delved into the specific genetic subgroup within the DNMT3A mutated patients. In the NPM1-/FLT3-ITD- subgroup, the most frequent co-mutations were IDH2 (47.3%), ASXL1 (18.2%), NRAS (16.4%), IDH1 (16.4%). 37 out of 55 patients attained CR1. The relapse rate was 75% in those receiving PR-CT, and 50% in those receiving allo-HSCT in CR1. The lower relapse rate translate into a significantly better OS (median, 75.1 vs. 19.6 months, P = 0.015) and event-free survival (EFS)(median, 75.1 vs. 8.9 months, P = 0.001) in the allo-HSCT group.

In the NPM1 + /FLT3-ITD- subgroup, currently an ELN-2022 favorable-risk category, 39 out of 47 patients attained CR1. The relapse rate was 36.8% in those receiving PR-CT, and 0% in those receiving allo-HSCT in CR1. Allo-HSCT in CR1 was associated with a significantly better OS (median, NR vs. 98.2 months, P = 0.042) and EFS (median, NR vs. 18.7 months, P = 0.006). Lastly, in the IDH2 mutated subgroup, allo-HSCT in CR1 was associated with a significantly better EFS, while the OS remained similar.

Conclusions: The results indicated that NPM1-/FLT3-ITD- and NPM1 + /FLT3-ITD- subgroups in DNMT3A mutated AML benefit from allo-HSCT in CR1. Larger cohorts are warranted to validate these findings.

Disclosure: No relevant conflict of interest to declare.

19: Acute Leukaemia

P041 SALVAGE TREATMENTS HAVE EXTREMELY POOR OUTCOMES FOR PATIENTS WITH RELAPSED T-ACUTE LYMPHOBLASTIC LEUKAEMIA POST TRANSPLANT

Alexandros Rampotas 1, Fotios Panitsas2, Maximillian Brodermann1, Sridhar Chaganti3, Styliani Bouziana4, Emma Nicholson5, Samantha Drummond6, Sharon Allen7, Andrew King7, Henry Crosland3, Anne-Louise Latif6, Daniele Avenoso4, Claire Roddie1

1University College London Hospital NHS Foundation Trust, London, United Kingdom, 2Laikon University Hospital, Athens, Greece, 3University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom, 4King’s College London Hospital NHS Foundation Trust, London, United Kingdom, 5The Royal Marsden NHS Foundation Trust, London, United Kingdom, 6Queen Elizabeth University Hospital, Glascow, United Kingdom, 7Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom

Background: Relapse following allogeneic hematopoietic stem cell transplantation (allo-HCT) in T-Acute Lymphoblastic Leukemia (T-ALL) poses a formidable clinical challenge. Diverse treatment modalities have been employed, showcasing variable efficacy. Notably, recent years have witnessed the emergence of novel therapeutic strategies for T-ALL such as Chimeric Antigen Receptor T-cells targeting CD7, CD5 and CXCR7 among others with a few phase I/II trials being underway. This study examines outcomes in relapsed T-ALL post allo-HCT, spanning the period from 2010 to 2022, across six major UK transplant centers. Our findings underscore the pressing need for innovative therapeutic interventions in this context, emphasizing the urgency for further research and the development of novel approaches to address the poor outcomes of relapsed T-ALL after transplantation.

Methods: Retrospectively, we compiled data from adult cases experiencing post-transplant relapse in T-ALL. Survival analysis, employing Kaplan-Meier methodology and log-rank tests, was conducted. Descriptive analysis was undertaken to assess baseline and disease characteristics. Approval for this project was obtained from the British Society of Blood and Marrow Transplantation. All data management adhered strictly to the principles outlined in the Declaration of Helsinki.

Results: Twenty-one patients with relapsed T-ALL post allo-HCT were identified, and 20 with sufficient data underwent analysis, with a median follow-up of 32.6 months. Baseline and disease characteristics are detailed in Table 1, Median age was 37 years, while high-risk features included a mediastinal mass in 4/20, early T-cell precursor leukemia in 7/19, high white cell count in 8/19, and CNS disease in 4/20. Relapse occurred at a median of 6 months post-transplant. Intensive chemotherapy, including FLAG-IDA (N = 1), Nelarabine (N = 2), Venetoclax and UKALL14 phase 2 (N = 1), Nelarabine and UKALL14 induction (N = 1), was employed in 5/20 patients, while the rest received non-intensive chemotherapy or palliative and supportive options. Donor Lymphocyte Infusions were not utilised for any patient. Out of 5 patients who received intensive chemotherapy, only 1 achieved CR and four patients went on to receive a second transplant. Among them, one succumbed to transplant complications, while three achieved CR. Two patients relapsed after 12 and 18 months, respectively, while one remains in remission at 26 months post-transplant. Median overall survival was 3.18 months (2-5).

Total cohort

N = 20

Sex

Male 15/20 (75%)

Female 5/20 (25%)

Age (years) (median, IQR)

37, 23-51

Mediastinal mass at diagnosis

Yes 4/20 (20%)

No 16/20 (80%)

Early T-cell precursor leukaemia

Yes 7/19 (37%)

No 12/19 (63%)

Not known 1/19

High White cell count at diagnosis (>100 x10^9/L)

Yes 8/19 (42%)

No 11/19 (58%)

CNS disease

Prior to transplant

Yes 4/20 (20%)

No 16/20 (80%)

At Relapse

Yes 5/20 (25%)

No 15/20 (75%)

Prior line of therapy

1 9/20 (45%)

2 9/20 (45%)

3 2/20 (10%)

Type of relapse post allo-HCT

MRD only 2/20

Extramedullary Relapse 2/20

Morphological Relapse 15/20

CNS only 1/20

Testicular relapse 0/20

Time to relapse post allo-HCT (months) (median, IQR)

6, 4-12

Type of salvage treatment used

Intensive chemotherapy

FLAG IDA 1/20 (5%)

Nelarabine 2/20 (10%)

Nelarabine and UKALL induction protocol 1/20 (5%)

Venetoclax and UKALL phase 2 1/20 (5%)

Non-intensive chemotherapy

Vincristine, steroids and Daratumumab 1/20 (5%)

VIncristine and steroids 4/20 (20%)

Vincristine 1/20 (5%)

Other treatments

Radiotherapy 1/20 (5%)

Palliative treatment 5/20 (25%)

Intrathecal Methotrexate 3/20 (15%)

Second transplant

Yes 4/20 (25%)

No 16/20 (75%)

Donor Lymphocyte Infusion

Yes 0/20 (0%)

No 20/20 (100%)

Median Overall survival (months)

3.18 (2-5)

The 50th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians – Poster Session (P001-P755) (5)

Conclusions: The prognosis for post allo-HCT relapsed T-ALL is notably grim, with limited success observed in second transplant cases. Even within this context, outcomes remain disheartening. The anticipation for improved strategies is fervent, emphasizing the crucial need for innovative treatments. Ongoing investigations into CAR-T cell therapies, specifically CD7 and CXCR7, offer promising avenues. It is imperative that these novel approaches are actively incorporated into clinical practice, and patients are encouraged to participate in relevant trials. The urgency to explore and adopt these advanced therapeutic modalities underscores the commitment to enhancing outcomes for individuals grappling with relapsed T-ALL post allo-HCT.

Disclosure: Alex Rampotas received conference fees by Gilead. Claire Roddie declares Honoraria: Gilead Sciences Consulting or Advisory Role: Autolus, Kite/Gilead, Bristol Myers Squibb/Celgene Speakers’ Bureau: Novartis Pharmaceuticals UK Ltd, Gilead Sciences Travel, Accommodations, Expenses: Gilead Sciences, Autolus. Anna Louise Latif declares honoraria from Kite and Novartis. All other authors declare no conflicts of interest.

19: Acute Leukaemia

P042 FEASIBILITY OF ALLOGENEIC STEM CELL TRANSPLANTATION (HSCT) IN PATIENTS WITH ACUTE MYELOID LEUKEMIA PREVIOUSLY TREATED WITH CPX-351: REPORT FROM A SINGLE CENTER

Sabrina Giammarco 1, Elisabetta Metafuni1, Maria Assunta Limongiello1, Federica Sorá2, Eugenio Galli1, Filippo Frioni2, John Marra2, Patrizia Chiusolo2, Simona Sica2

1Fondazione Policlinico Universitario A. Gemelli, Rome, Italy, 2Universitá Cattolica del Sacro Cuore, Roma, Italy

Background: CPX-351 (VYXEOS®), a dual-drug liposomal encapsulation of daunorubicin and cytarabine in a synergistic 1:5 molar ratio, was approved for the treatment of t-AML or AML-MRC, based on improved survival and remission and comparable safety versus 7 + 3 chemotherapy in a randomized trial in older adults.

The increased use of CPX 351, in association with reduced intensity conditioning regimen and new strategies of GvHD prophylaxis such as PTCY, allows to proceed with HSCT in older patients or previously heavily treated, improving outcomes.

Methods: To assess the feasibility of HSCT in patients with s-AML and t-AML treated with CPX-351, we collected clinical data on 27 consecutive patients submitted to HSCT at our center from February 2019 to October 2023. Then we compared data with 30 patients with AML submitted to HSCT, previously treated with 7 + 3 induction chemotherapy from January 2019 to April 2020.

Results: Of 49 patients treated with CPX-351 from February 2019, all 27 patients with indication to proceed with HSCT, underwent to transplant to consolidate the obtained response. There were 14 males and 13 female, with a median age of 62 yrs (range 43-69). They were all in complete remission except two. Median HCT-CI was 4 (range 0-7). Unrelated donors were the source in 18 patients, haploidentical donors in 8 pts, sibling donors in 1 patient. Stem cell source was peripheral blood in 23 pts, bone marrow in 3 pts and CBU in 1 patient. The median CD34+ cell dose was 4x106/kg (range 0.1-12.779). The main conditioning regimen was the association of Thiotepa, Busulfan and Fludarabine, modulating the busulfan dose according to patient’s comorbidities and performance status, defined by HCT-CI. GVHD prophylaxis regimen was performed with cyclosporine, mycophenolic acid, and cyclophosphamide at day +3 and +5 after HSCT. Engraftment was reached in all patients except one patient who received CBU. Sepsis were identified in 14 patients out 27.

Seven patients developed acute GvHD, all with skin involvement (Stage 2-3); two patients also with gut involvement (Stage 3)and one patient with pulmonary involvement (severe).

1 years OS was 73%. Comparing the two populations, there was no difference in term of gender, disease status at transplant, donor type, donor sex, stem cell source, conditioning regimen, GVHD prophylaxis, sepsis occurrence and GVHD incidence. Significantly statistical difference was found in terms of median age (p = 0.0016), HCT-CI (p = 0.002) as expected, and in terms of median CD34+ stem cell infused, which were significantly higher in the younger comparison population (p = 0.04). (Table 1).

CPX-351

7 + 3 induction

p>0.05

Patients

27

30

Gender male/female

14/12

18/12

p = 0.3

Median age (range)

62 (43-69)

50 (24-68)

p = 0.00016

Disease status at transplant

CR/Refractory

25/2

25/5

p = 0.2

Median HCT-CI (range)

4 (0-7)

1 (0-6)

p = 0.002

Donor type

MUD 8/8

11

10

p = 0.2

MUD 7/8

6

3

Sibling donor

1

6

Haploidentical donors

8

8

CBU

1

3

Donor gender male/female

19/8

23/7

p = 0.2

Stem cell source

PBSC

23

20

p = 0.2

BM

3

7

CBU

1

3

Conditioning regimen

p = 0.5

Myeloablative

26

27

Reduced intensity regimen

1

3

Median CD34 cell dose

x106/kg (range)

4 0.1-1277()

9.45 (0.09-8.9)

P = 0.04

GVHD prophylaxis

p = 0.6

PTCY

31

32

OTHER

3

1

GVHD Incidence n°(%)

7/27 (26%)

14/30 (46%)

p = 0.2

Sepsis n°(%)

14/27 (51%)

16/30 (53%)

p = 0.9

Relapse n°(%)

8/27 (29%)

7/30 (23%)

p = 0.8

Overall Survival n°(%)

19/27 (70%)

23/30 (76%)

p = 0.8

Conclusions: Our monocentric experience showed data in line with those reported in the literature. The growing use of CPX-351 appears to be a safe and effective bridge therapy for HSCT in patients with a poorer prognosis, reproducing outcomes similar to younger population.

Disclosure: No disclosure to declare

19: Acute Leukaemia

P043 COMPARISON OF VENETOCLAX-BASED NON-ANTHRACYCLINE INDUCTION THERAPY VERSUS 3 + 7 FOLLOWED BY HEMATOPOIETIC STEM CELL TRANSPLANTATION IN NEWLY DIAGNOSED ACUTE MYELOID LEUKEMIA PATIENTS

Tran-Der Tan 1, Lun-Wei Chiou1

1Koo Foundation Sun Yat-Sen Cancer Center, Taipei, Taiwan, Province of China

Background: The current standard treatment for fit newly diagnosed acute myeloid leukemia patients is idarubicin or daunorubicin plus cytarabine (3 + 7 regimen), followed by allogeneic hematopoietic stem cell transplantation. However, less than half of them could enter into allotransplant because of not remission or the occurrence of treatment-related morbidity or mortality. Venetoclax plus azacytidine or low-dose cytarabine could achieve a high CR rate in unfit or elderly patients in phase III trials.

Methods: We conducted a treatment protocol of venetoclax 100 mg and posaconazole 300 mg a day according to the pharmacokinetics plus a standard dose of cytarabine (100 mg/m2/d x 7 days) as the induction and consolidation therapy, followed by allogeneic hematopoietic stem cell transplantation for newly diagnosed transplant-eligible patients. And we compared the efficacy and outcome with our prior 3 + 7 induction followed by allo-transplant patients.

Results:

The 50th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians – Poster Session (P001-P755) (6)

Between Mar 2019 and Dec 2023, we had 22 consecutive newly diagnosed transplant-eligible AML patients, including 8 therapy-related and 14 de novo AML. Eighteen underwent venetoclax plus standard-dose cytarabine, four underwent venetoclax plus azacitidine induction therapy, and twenty out of twenty-two were followed by allogeneic hematopoietic stem cell transplantation. CRc rate was 94.4% in our cohort and 90.9% in the adverse group of patients. Twenty of twenty-two of our patients were transitioned to allo-transplant, as compared with 46.9% in our previous 3 + 7 induction era between 2009 and 2018. Three-year overall survival was improved from 23% to 53% with the transplant patients’ median age from 43 to 52.8. The duration of neutropenia is similar but there was no significant severe watery diarrhea or oral mucositis in our present cohort as compared to the previous 3 + 7 group of patients.

Conclusions: Venetocla-based non-anthracycline induction therapy is feasible and has more propensity to allogeneic transplant in newly diagnosed AML patients and the pre-transplant CR rate and overall survival were improved as compared with conventional 3 + 7 induction, without more safety concerns.

Disclosure: No disclosure of conflict of interest.

19: Acute Leukaemia

P044 MYELOFIBROSIS GRADE II-III IS AN INDEPENDENT RISK FACTOR FOR RELAPSE OF ACUTE MYELOID LEUKEMIA AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION

Haixiao Zhang1, Erlie Jiang 2

1Peking Union Medical school, Tianjin, China, 2Peking Union Medical School, Tianjin, China

Background: Acute myeloid leukemia (AML) is a heterogeneous and aggressive disease caused by leukemia blasts. Bone marrow microenvironment (BMM) contributes to AML cell development. Myelofibrosis (MF) is characterized by excessive deposition of bone marrow reticulin fibrosis and other extracellular matrix proteins. MF of unknown etiology in hematological malignancies is acknowledged to be a reactive response to leukemic BMM.

AML with MF (AML-MF) is not recognized as an AML entity by the World Health Organization (WHO) classification system [6]. However, MF was approximately 30-72% at the time of diagnosis of AML and myelodysplastic syndromes (MDS), and 15% was marked reticulin fibrosis. Previous studies have shown that moderate to severe MF is a more advanced risk factor in patients with MDS [8-10]. Data pertaining to the AML-MF treatment and prognosis are very limited [11,12]. As far the only therapy to cure AML has been allogeneic hematopoietic stem cell transplantation (allo-HSCT). MF’s prognostic effect, which can be assessed by regular evaluation at diagnosis, in transplant AML patients is remains unknown.

Methods: To evaluate the prognostic impact of myelofibrosis (MF) on allogeneic hematological stem cell transplantation (allo-HSCT) outcomes in patients with acute myeloid leukemia (AML), we analyzed newly diagnosed patients with AML who received allo-HSCT in the National Longitudinal Cohort of Hematological Disease (NICHE, NCT04645199) from January 2014 to April 2023. Among the 532 patients, 255 (47.93%) patients were classified into the MF-0 group, 209 (39.29%) into the MF-1 group, and 68 (12.78%) into the MF-2-3 group at initial diagnosis according to the European consensus on the grading of MF.

Results: The MF-2-3 group showed poor overall survival, disease-free survival and cumulative incidence of relapse (CIR). Multivariate analyses showed that MF-2-3 (hazard ratio [HR] =2.17, P = 0.023) was an independent risk factor for CIR post-transplantation. Furthermore, MF delayed neutrophil and platelet engraftment and delayed B cell recovery post-transplantation. The MF-2-3 group had a higher cumulative incidence of acute graft-versus-host disease and a lower cumulative incidence of EBV-emia and CMV-emia post-transplantation than the MF-0 and MF-1 groups, however, the difference was not statistically significant.

Conclusions: These findings demonstrate the importance of MF in transplant outcomes and has attracted more attention to AML-MF.

Disclosure: none

19: Acute Leukaemia

P045 INCIDENCE AND MANAGEMENT OF ADULT ACUTE LYMPHOBLASTIC LEUKAEMIA RELAPSE AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION IN LIMITED RESOURCE COUNTRIES

Rihab Ouerghi1, Nour Ben Abdeljelil 1, Sabrine Mekni1, Insaf Ben Yaiche1, Ines Turki1, Rim Dachraoui1, Dorra Belloumi1, Lamia Torjemane1, Rimmel Kanoun1, Saloua Ladeb1, Tarek Ben Othman1

1Service d’Hématologie et de Greffe, Centre National de Greffe de Moelle Osseuse, Tunis, Tunisia

Background: Relapse remains the major cause of failure in adults with high-risk acute lymphoblastic leukemia (ALL) after allogeneic hematopoietic stem-cell transplantation (AHSCT). The management of relapsed patients is a clinical challenge, especially in limited resource countries. The aim of our study was to evaluate the cumulative incidence of relapse (CIR) post AHSCT, identify predictive factors of relapse and evaluate the outcome and management of relapsed ALL in adult patients.

Methods: A retrospective study was conducted in adult patients who underwent AHSCT from HLA-identical sibling donors between November 2003 and December 2022. Conditioning regimens consisted of fractionated TBI (F-TBI) (3fractions/9.9Gy) with etoposide or cyclophosphamide or chemotherapy-based regimen (intravenous busulfan). GVHD prophylaxis consisted of cyclosporine and short course of methotrexate. Stem cell sources were bone marrow (BM) or peripheral blood stem cell.

Results: One hundred and five patients (69 males and 36 females) were included. Median age is 30 years (18-50 years): 60 B-ALL (57%) and 45 T-ALL (43%). Cytogenetic analysis was available for 83 patients: 33% of patients had high-risk cytogenetic abnormalities (25% had t(9,22) or positive BCR-ABL transcript). Before AHSCT, 86% of patients were transplanted in first complete remission (CR1). MRD was performed in 66% patients (MFC and/or molecular biology) and was positive in 55% of patients. The median time from diagnosis to AHSCT was 6 months (2-137m). Conditioning regimens were TBI-based in 60% of patients and 51% of patients received peripheral blood stem cell. CMV reactivation was observed in 41% of patients. The CI of acute GVHD (≥grade 2) and chronic GVHD were 32% and 50%, respectively. The CI of NRM was 17.6%. The 2-year CIR was 30% (medullary and combined relapse n = 26, extramedullary relapse n = 6, molecular relapse n = 4). The median time of relapse was 9 months (2-46m). Twenty-two patients were managed with palliative cares and 14 received salvage therapy (chemotherapy +/- radiotherapy n = 9, donor lymphocyte infusion n = 1, ITK only n = 4). A second CR was obtained in 8 patients and 3 patients underwent a second AHSCT. At last follow-up, 7 patients are alive. After a median follow up of 29 months (1-207m), the 2-year OS and EFS for the entire cohort and relapsed patients were 60% vs 31% and 53% vs 14%, respectively. At last follow-up, 49 patients (47 %) died. The main cause of death was relapse (n = 26; 53%). In univariate analysis, chemotherapy-based conditioning regimen was the only significant factor of CIR (p = 0.01).

Conclusions: The prognosis of adult patients relapsing after AHSCT is dismal. To reduce the risk of relapse TBI based conditioning regimen and immunotherapy should be considered when possible.

Disclosure: Nothing to declare

19: Acute Leukaemia

P046 IMPACT OF BODY MASS INDEX ON OUTCOME IN ADULT PATIENTS WITH ACUTE MYELOID AND ACUTE LYMPHOBLASTIC LEUKEMIA UNDERGOING ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION

Iveta Oravcova1,2, Zuzana Rusinakova1, Eva Mikuskova1, Miriam Ladicka1, Ludmila Demitrovicova1, Alica Slobodova1, Vanda Mikudova1, Jana Spanikova1, Radka Vasickova1, Denis Urban1, Kristina Bandurova1, Lubos Drgona1,2, Silvia Cingelova 1

1National Cancer Institute, Bratislava, Slovakia, 2Faculty of Medicine Comenius University, Bratislava, Slovakia

Background: Obesity has been recognized as risk factor for many types of cancer and at the same time it is considered as an adverse prognostic factor associated with cancer survival. This study assessed the effect of body mass index (BMI) on transplantation outcomes in allogeneic hematopoietic cell transplantation (HCT) in AML and ALL recipients.

Methods: We retrospectively analyzed 98 adult AML and ALL patients who were followed up after alloSCT in National Cancer Institute in Slovakia between March 2013 and October 2023.

According to the World Health Organization (WHO) international BMI classification, patients were classified as obese when BMI was ≥ 30kg/m2. We divided patients into 2-groups: BMI < 30kg/m2 (non-obese patients) and BMI ≥ 30kg/m2 (obese patients).

Results: At median follow up 22,3 (4,1-125,8) months, 98 patients entered the analysis (median age at alloSCT 49 years, 53 (54,5%) male). Median BMI value was 24,84 kg/m2. We identified 80 patients with BMI < 30kg/m2 (81,6%) and 18 (18,4%) with BMI ≥ 30kg/m2. There was no difference in the prevalence of obesity between the genders (p = 0,299).

1 and 3- year overall survival (OS) for the BMI < 30kg/m2 group was 68,6% (CI 95%; 58,1% - 79,0%) and 45,9% (CI 95%; 33,3% - 58,5%) with median OS 34,5 months (CI 95% 18,3-57,0); and for the obese group 32,5% (CI 95%; 9,4% - 55,6%) and 13,0% (CI 95%; 0,0% - 27,9%) with median OS 4,6 months (CI 95% 3,0-8,5). The difference between groups was statistically significant, HR 0,34 (95% CI 0,15-0,79); (p = 0,0002).

1 and 3- year relapse free survival (RFS) for the BMI < 30kg/m2 group was 58,8% (CI 95%; 47,8% - 69,8%) and 41,2% (CI 95%; 29,1% - 53,4%) with median RFS 30,1 months (CI 95% 8,5-42,9); and for the obese group 20,7% (CI 95%; 0,4% - 41,1%) and 13,8% (CI 95%; 0% - 31,3%) with median RFS 3,5 months (CI 95% 1,9-4,4). The difference between groups was statistically significant, HR 0,39 (95% CI 0,18-0,87); (p = 0,001).

Obese patients have higher 12-months cumulative incidence of relapse rates than non-obese patients: 53,7% (CI 95%; 29,1%-99,3%) vs 29,5% (CI 95%; 20,5%-42,3%). There was no difference in non-relapse mortality between obese and non-obese patients.

Conclusions: Patients with BMI ≥30kg/m2 had significantly lower one and three-year survival rates and higher cumulative incidence of relapses than those with BMI <30kg/m2.

Disclosure: Nothing to declare.

19: Acute Leukaemia

P047 VENETOCLAX COMBINED WITH HMAS-BASED THERAPY AS PRE-EMPTIVE TREATMENT FOR ACUTE MYELOID LEUKEMIA PATIENTS AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION

Mimi Xu 1,2,3, Yuqing Tu1,2,3, Mengqi Xiang1,2,3, Yi Fan1,2,3, Xiang Zhang1,2,3, Tiemei Song1,2,3, Lian Bai4, Xiaoli Li5, Yang Xu1,2,3, Yuejun Liu1,2,3, Jia Chen1,2,3, Depei Wu1,2,3

1National Clinical Research Center for Hematologic Diseases, Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University, Suzhou, China, 2Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China, 3Key Laboratory of Stem Cells and Biomedical, Materials of Jiangsu Province and Chinese Ministry of Science and Technology, Suzhou, China, 4Canglang of Suzhou Hospital, Suzhou, China, 5Soochow Hopes Hematonosis Hospital, Suzhou, China

Background: Accumulating evidences indicated the effectiveness and importance of measurable residual disease (MRD) guided pre-emptive therapy in acute myeloid leukemia (AML) patients after allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, limited data is available on the pre-emptive utility of venetoclax (VEN) for MRD positive in AML patients post-HSCT. This study was conducted to explore the efficiency and tolerability of VEN combined with hypomethylating agents (HMAs) based treatment for AML patients with MRD positive post-HSCT.

Methods: We collected retrospectively the data from 10 patients who underwent first allo-HSCT with high-risk AML between July 2020 and April 2022 and initiated VEN-based pre-emptive threapy for MRD positivity between March 2021 and July 2022 in our center for analysis. Patients who experienced haematological relapse before VEN-based pre-emptive treatment were excluded. The VEN combined with HMAs-based treatment regimen comprised 100 mg VEN daily on day 1 to day 21 and 15 mg/m2 decitabine on day 1 to day 3 or 75mg/m2 azacytidine on day 1 to day 5 (or day 7). FLT3-ITD positive patients also added FLT3 inhibitor sorafenib (400mg scheduled for days 1 to 21). The primary endpoints of this study were MRD response, overall survival (OS) and event free survival (EFS). The secondary endpoints included adverse events (AEs), cumulative incidence of relapse (CIR) and nonrelapse mortality (NRM).

Results: 10 patients were included. The median age of the patients at the time of transplantation was 49 (range, 16-57)y. The rate of MRD response was 70.0% (7/10) and 71.4% (5/7) of whom achieved MRD response after first circle of VEN-based combination threapy. The median time from initiating VEN-based pre-emptive threapy to MRD response was 64 (10-175) d. For MRD response patients, two of whom appeared hematologic relapse on day 271 and 336 after MRD response respectively. Three patients had not achieved MRD response, 2 of whom experienced hematological relapse and 1 died from severe GVHD and transplantation associated thrombotic microangiopathy. During the study, we found no tumor lysis syndrome and severe AE for all patients. The median follow-up was 440.5 (88-872) d. 5 patients still had EFS and were alive with MRD negative CR at the time of last follow-up. Overall, the 1-y OS and EFS after VEN-based pre-emptive threapy were (80.0±12.6)% and (60.0±15.5)%, respectively. The cumulative incidence of relapse (CIR) at one years was (30.0±2.4)%, and nonrelapse mortality was (10.0±1.0)%.

Table 1 Patient characteristics

Total patients

10

%

Median age at transplantation, y (range)

49(16-57)

Gender

Male/Female

5/5

MRD positive detection method before pre-emptive threapy

Flow cytometry

4

40

PCR

8

80

DNA sequence

2

20

Disease status at transplant

CR

9

90

MRD−

1

10

MRD+

8

80

NR

1

10

Donor type

Haploidentical

7

70

Identical sibling

1

10

Unrelated

2

20

Median days of neutrophils ≥0.5 × 109/L after transplant

11(10-14)

Median days of platelets ≥20 × 109/L after transplant

12.5(10-74)

Conclusions: We conclude that VEN combined with HMAs-based regimen as pre-emptive treatment is efficient for patients with AML post-HSCT and with acceptable side effects.

Disclosure: Nothing to declare

19: Acute Leukaemia

P048 VENETOCLAX, AZACITIDINE, COMBINED WITH LOW-DOSE CYTARABINE IMPROVE THE REMISSION RATE IN OLDER OR UNFIT PATIENTS WITH NEWLY DIAGNOSED ACUTE MYELOID LEUKEMIA

Xiao Han1, Qingxiao Song 1, Kai Wan1, Mengyun Zhang1, Xue Liu1, Hongju Yan1, Cheng Zhang1, Qin Wen1, Xi Zhang1

1Medical Center of Hematology, Xinqiao Hospital of Army Medical University, Chongqing, China

Background: Older or unfit patients with acute myeloid leukemia (AML) have a dismal prognosis. The combination of venetoclax with azacitidine had promising efficacy, but the minimal residual disease (MRD) negative rate is only 30-40%. In most cases measurable residual disease (MRD) positivity predicts hematologic relapse potentially allowing early therapeutic intervention.

Methods: This is a prospective, one-arm, multicenter, open clinical trial, Adults age ≥18 years with newly diagnosed AML ineligible for intensive chemotherapy were enrolled. Patients received induction treatment with venetoclax 100mg d1, 200mg d2, 400mg d3-28, azacytidine 75mg/m2 d1-7, cytarabine 10mg/m2 q12h d1-7. The primary observation was the remission rate (CR/CRi) and the negative rate of MRD.

Results: The baseline characteristics of 46 older or unfit patients who can evaluate the efficacy are presented in Table 1. Following the first course of Ven+AZA + LDAC treatment, the outcomes were as follows: 27 patients (58.7%) achieved complete remission (CR) with negative minimal residual disease (MRD), 14 patients (30.4%) achieved CR with positive MRD, 1 patients (2.2%) experienced partial remission (PR), and 4 patient (8.7%) did not achieve remission (NR). The overall response rate (ORR) was 91.3%. Subgroup analysis revealed that out of the 23 older patients, 16 (69.6%) achieved CR with negative MRD, 6 (26.1%) achieved CR with positive MRD. Among the 23 initially diagnosed unfit patients, 11 (47.8%) reached CR, with 8 (34.8%) showing negative MRD, 1 (4.3%) experiencing PR, and 3 (13.0%) not achieving remission. The median follow-up time was 8.3 months (range: 3-24.3 months), and the estimate median overall survival (OS) was 20.34 months. Subgroup analysis revealed that older patients had better survival outcomes compared to unfit patients, although the difference was not statistically significant. Among them, 9 patients had underwent allogeneic hematopoietic stem cell transplantation (HSCT), and 8 of the 9 HSCT patients were alive at the time of manuscript writing, One patient died because of SCT related thrombotic microangiopathy (TMA). This observation might be attributed to the limited sample size, indicating the necessity of gathering more data for comprehensive analysis. Safety: All the 23 older patients had neutropenia, which controlled after therapy, without severe infection and bleeding complications. 23 patients with unfit had severe complications such as severe infection, respiratory failure, or intracranial hemorrhage before treatment, but no treatment-related deaths occurred during the induction period.

Characteristic

N = 46

Frequency

Median (range)

59.29(32-73)

Older (average age)

23 (49.7)

50%

unfit (average age)

23 (66.4)

50%

Male, n (%)

25

54.35%

Baseline neutropenia, n(%)

Grade 3

7

15.2%

Grade 4

15

32.6%

FAB classification, n (%)

AML-M1

7

15.2%

AML-M2

20

43.5%

AML-M4

6

13.1%

AML-M5

10

21.7%

others

3

6.5%

Cytogenetic risk category, n (%)

Favorable

9

19.6%

Intermediate

20

43.5%

Adverse

17

36.9%

Somatic mutations

DNMT3A

12

30.77%

NPM1

11

28.21%

FLT3-ITD

10

25.64%

IDH2

7

17.95%

CEBPA

6

15.38%

IDH1

5

12.82%

TP53

3

7.69%

Transfusion dependent at baseline, n (%)

Red blood cells

15

32.6%

Platelets

13

28.3%

Conclusions: The incidence of remission was higher among newly diagnosed older patients who received Ven+AZA + LDAC, especially CR with negative MRD. However, the remission rate of unfit AML patients has been improved compared to traditional chemotherapy, but the negative rate of MRD has not improved. Infection, chemotherapy-related mortality, and the tolerability were acceptable. At the same time, it would be contribute to provide transplant conditions for patients and prolong survival. However, it is necessary to further expand the sample size and extend the follow-up time to assess the long-term survival rate.

Clinical Trial Registry: ChiCTR2200063804

Disclosure: Nothing to declare.

19: Acute Leukaemia

P049 TARGET THERAPY IN ACUTE LEUKAEMIA RELAPSES AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION

Riccardo Boncompagni 1, Chiara Camerini1, Ilaria Cutini1, Mirella Giordano1, Antonella Gozzini1, Chiara Nozzoli1, Edoardo Simonetti1, Riccardo Saccardi1

1BMT Unit, Careggi University Hospital, Firenze, Italy

Background: New drugs targeting acute leukaemia antigens or cellular survival/proliferation pathways are granting promising results in patients with relapsed and/or refractory acute leukaemia leading more patients to achieve a control of disease and access to allogenic hematopoietic stem cell transplantation (HSCT), the only potentially curative treatment. Here we investigated if target-therapy can confer a real-life survival advantage also in patients who relapse following HSCT, a population characterized from a very poor prognosis.

Methods: We retrospectively analysed data from patients affected by acute myeloid, mixed-phenotype, lymphoblastic leukaemia (AML, MPAL, ALL respectively) and blast crisis of chronic myeloid leukaemia (CB-CML) who performed allogeneic HSCT at Careggi University Hospital of Florence in the last 10 years. Primary endpoint of the current research was to compare overall survival (OS) and progression free survival (PFS) between patients treated or not with target therapy. Target therapy was administered based on availability at our institution.

Results: We found 288 HSCT performed for 275 patients. Indication for HSCT was AML for 196 (68%), ALL for 74 [24%; 25 (34%) with BCR/ABL mutation, 12 (16%) of T-lineage], CB-CML for 11 (4%) and MPAL for 10 (3%). Median age was 50 (19 – 69) and median comorbidity index (HCT-CI) was high (3; 0 – 9); however reduced intensity conditioning regimen was used only in 93 (32%). A significant number of AML was in active disease status at the time of HSCT (74, 38%), and molecular or cytofluorimetric minimal residual disease was detectable in more than half of the others (86 out of 122, 70%). Median OS was not reached, with 57% of patients alive with a 69 months median follow-up. Relapse incidence after HSCT was 36% (n = 100) and median PFS was reached at 18 months (95% confidence interval [CI]: 7 – 29). In the group who received a target therapy (n = 63) we observed both an OS (45 vs 7 months; p < 0,001) and PFS advantage (26 vs 2 months; p 0<,001). Donor lymphocytes infusions (DLI) was administered in 38% (n = 24) of target therapy group and conferred a further OS advantage (11 vs 42 months; p = 0,022). Finally, 3 out of 13 (23%) patients who performed a second HSCT after savage therapy with target therapy were alive and in complete remission at the time of their last follow-up.

Conclusions: Despite the low potency of monocentre retrospective study, our results support the hypothesis that new therapies for acute leukaemia are effective for patients who relapse following HSCT, and the possibility of combination of DLI and of a subsequent second HSCT may grant a longer survival in this very high-risk population.

Disclosure: We declare no potential conflict of interest.

19: Acute Leukaemia

P050 ALLOGENEIC STEM CELL TRANSPLANTATION IN THE MANAGEMENT OF ADULT ACUTE LYMPHOBLASTIC LEUKAEMIA: A TEN YEAR EXPERIENCE IN IRELAND’S NATIONAL ADULT ALLOGENEIC TRANSPLANT CENTRE

Conor Browne 1, Micheal Brennan1, Mairead Ni Chonghaile1, Sarah Maher1, Greg Lee1, Deirdre Waldron1, Nicola Gardiner1, Michelle Regan1, Lorraine Brennan1, Carmel Waldron1, Catherine M. Flynn1, Eibhlin Conneally1, Patrick J. Hayden1, Robert Henderson1, Elisabeth Vandenberghe1, Christopher L. Bacon1

1St James Hospital, Dublin 8, Ireland

Background: Adult acute lymphoblastic leukaemia (ALL) historically carries a poor prognosis with cure rates of less than 40%. Despite advances in therapeutics, allogeneic stem cell transplantation (AlloSCT) remains pivotal in the management of patients with high risk adult ALL.

Methods: The records of consecutive ALL patients receiving AlloSCT between 01/01/2013 and 31/12/2022 were retrieved from the St. James’ Hospital transplant-database and their electronic medical records. Progression free survival (PFS) and overall survival (OS) were estimated via the Kaplan-Meier method.

Results: 89 patients with ALL received AlloSCT. Clinical details are shown in Table-1. 74 (83%) had B-ALL with a median white cell count (WCC) of 30x109/L (0.5-830) at diagnosis. 15 (17%) had T-ALL with a median WCC of 100x109/L (4.9-470) at diagnosis.

38 patients (43%) had high-risk cytogenetics defined as having either a Philadelphia chromosome t(9;22)(q34;q11), N = 17 (9%), KMT2A rearrangement t(4;11)(q21;q23) N = 12 (13%), complex karyotype N = 2 (2%), low-hypodiploid N = 4 (4%) or near-triploid haplotype N = 3 (3%). 64 patients (72%) achieved complete remission (CR) post induction therapy. 13 (15%) had primary refractory disease and 16 (18%) in remission relapsed prior to transplant requiring re-induction. 73 (82%) were transplanted in CR1, 14 (16%) in CR2, 1 in CR3 and CR4.

The median time from diagnosis to transplant was 6 months (2-85). The median CD34 cell count infused was 3.32x106/kg (0.67-5.7) with a median CD3 cell count of 3.08x107/kg (1.21-52). The median days to neutrophil engraftment was 21 (10-34) and to platelet engraftment was 18 (9-96).

66 patients (74%) developed graft-versus-host-disease (GVHD); 63 (71%) acute-GVHD and 30 (34%) chronic-GVHD. Acute-GVHD occurred at a median of 30 days (13-298) post-transplant. 16 (18%) experienced Grade I, while 47 (53%) developed Grade II-IV acute-GVHD. Of those with acute-GVHD, 15 cases (24%) were steroid refractory requiring additional therapies including ruxolitinib, mycophenolate-mofetil, extracorporeal-photopheresis and ATG.

30 patients (34%) developed viral reactivation involving CMV, EBV or adenovirus. 5 patients had associated EBV post-transplant lymphoproliferative disorder.

9 patients (10%) received donor-lymphocyte infusions (DLI) at a median time of 12 months (4-33) post-transplant. 8 received pre-emptive DLI for mixed chimerism, 1 received therapeutic-DLI for relapsed disease. 3 patients developed acute-GVHD post-DLI. 7 cases (80%) achieved complete donor chimerism post-DLI.

The median duration of follow-up was 36 months (1-129). 18 patients (20%) relapsed at a median time of 8.5 months (1-63) post-transplant. Treatment strategies at relapse included blinatumomab, inotuzumab, Hyper-CVAD, nelarabine, TKIs, palliation and CAR-T therapy.

27 patients (30%) died during follow-up at a median time of 9 months (1-71) post-transplant; relapse-related mortality N = 11 (12%), transplant-related mortality (TRM) N = 14 (16%), lost to follow-up N = 2 (2%). Causes of TRM included GVHD (N = 3), veno-occlusive disease (N = 1), infection (N = 7), EBV-PTLD (N = 1), neurological complication (N = 1) and secondary malignancy (N = 1). The 100-day TRM rate was 6%.

The 5-year OS was estimated at 69% with a 5-year PFS of 62% as shown in Graph-1. OS or PFS didn’t differ significantly between those with acute-GVHD and those without (p = 0.7).

Table 1. Clinical Details

N = 89

Transplant Details

N = 89

Stem Cell Source: no. (%)

Median Age at Transplant (Range)

36 (16-61)

Bone Marrow

58 (65)

Peripheral blood

31 (35)

Gender: no. (%)

Conditioning Intensity: no. (%)

Male

50 (56)

Myeloablative

68 (76)

Female

39 (44)

Reduced Intensity

21 (24)

Induction Regimen: no. (%)

UKALL 12/14

64 (72)

MAC Conditioning Regimen: no. (%)

UKALL 03/11

14 (15)

Cyclophosphamide/TBI

60 (67)

Hyper-CVAD

9 (10)

Cy/TBI + ATG

4 (4)

FLAG-Ida

1 (1)

Busulphan/Cyclophosphamide

2 (2)

N/A

1 (1)

Fludarabine/TBI+PTCy

2 (2)

Donor Status: no. (%)

RIC Conditioning Regimen: no. (%)

Related

35 (39)

Flu/Melphalan/Alemtuzumab

20 (22)

Unrelated

54 (61)

Cy/TBI/Alemtuzumab

1 (1)

Co-Morbidity Index: no. (%)

GVHD Prophylaxis: no. (%)

HCT-CI 0-1

49 (55)

Tacrolimus

49 (55)

HCT-CI >/ = 2

28 (32)

Ciclosporin

38 (43)

HCT-CI N/A

12 (13)

PTCy/MMF

2 (2)

Recipient Viral Status: no. (%)

HLA status: no. (%)

CMV IgG +ve

39 (44)

Matched 10/10

76 (85)

EBV IgG +ve

81 (91)

Mismatched (single allelic)

13 (15)

The 50th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians – Poster Session (P001-P755) (7)

Conclusions: AlloSCT in high-risk patients is an effective strategy for the management of adult ALL with a 5 year OS of 69% in this cohort.

Disclosure: Nothing to declare.

19: Acute Leukaemia

P051 FLT3-MUTATED AML: MANAGEMENT AND LONG-TERM OUTCOME OVER 24 YEARS AT A SINGLE CENTER

Saveria Capria 1, Silvia Maria Trisolini1, Lorenzo Torrieri2, Elena Amabile2, Giovanni Marsili3, Alfonso Piciocchi3, Walter Barberi1, Daniela Diverio1, Daniela Carmini1, Massimo Breccia2, Maurizio Martelli2, Clara Minotti1

1AOU Policlinico Umberto I, Rome, Italy, 2Sapienza University, Rome, Italy, 3GIMEMA Foundation, Rome, Italy

Background: The introduction of tyrosine kinase inhibitors (TKIs) in the treatment of FLT3-mutated AML has been a therapeutic breakthrough. However, prognosis remains challenging.

Methods: We retrospectively analyzed all patients with FLT3-mutated AML who were eligible for intensive therapy and treated at our institution since 1999, focusing on changes in management over time and the impact of TKI treatment.

Results: The cohort comprised 140 patients (68M/72F) with a median age of 51 years (14-73), 28 (21%) had WBC ≥100,000/µl at diagnosis and 38 were older than 60 years. The ITD/TKD ratio was 120/20 and 73 patients (52%) had NPM1 co-mutation.

Until 2018, 101/140 patients received the DCE regimen without TKI, while 39/140 patients diagnosed since 2018 received 3 + 7+midostaurin.

The overall CR rate was 64% (90/140), and 73% (53/73) in NPM1-mutant patients, regardless of TKI treatment during induction.

The CR rate was similar in both younger and older patients and was positively influenced by co-existing NPM1 mutation (p: 0.032) and WBC count <100,000/µl (p = 0.013) in univariate analysis. TKI administration during induction did not have a significant effect.

In a multivariate model adjusting for sex and age, only WBC count was confirmed to have an independent prognostic impact on response (OR 3.04 – CI 1.23-7.71 – p = 0.017).

Allogeneic transplantation was performed in 41/90 patients who achieved CR1 (22/60 no-TKI and 19/30 TKI), the transplantation rate between no-TKI and TKI patients is not statistically significant. Autologous transplantation was performed in 18 patients. No transplantation was performed in 31 patients.

The median probability of EFS at 3 and 6 years is comparable between autografted and allografted patients (1.1 vs. 1.6 years respectively – p = 0.9).

The cumulative incidence of 1-year non-relapse mortality was 0.00% for autologous and 28% (CI: 15-42) for allogeneic transplantation (p = 0.007), while the cumulative incidence of 1-year and 3-year relapse was 39% (CI: 17-61) vs. 15% (CI: 6.1-28) and 57% (CI: 30-77) vs. 21% (CI: 9.5-35), respectively (p = 0.004).

There was no statistical difference in outcome based on TKI administration at induction, although these data may be affected by the smaller number of patients in the TKI group.

Forty-three patients (34 no-TKI and 9 TKI) were refractory to induction. Twenty-five received salvage treatment (10 CHT + TKI, 4 single-agent TKI, 11 standard CHT). Of the 14 patients who received a TKI-containing regimen, 11 underwent allogeneic transplantation while none of the patients in the standard CHT group underwent transplantation. The 5-year OS of transplanted patients after salvage treatment is 51%.

Overall, 70/140 patients received stem cell transplantation, 18 autologous and 52 allogeneic (41 CR1 and 11 refractory). In 8/52 cases, preemptive TKI treatment was administered post-transplant due to FLT3 mutation recurrence in morphologic CR; all patients are alive at a median of 65 months (range 16-98) post-transplant and TKI treatment was discontinued after 2 years of continuous CR.

Conclusions: Allogeneic transplantation remains crucial in FLT3-mutated AML. However, several unanswered questions remain, such as how to optimize the use of different inhibitors to achieve the best pre-BMT response, and the potential impact of preemptive post-transplant therapy.

Disclosure: Nothing to declare.

19: Acute Leukaemia

P052 THE ROLE OF TOLEROGENIC DENDRITIC CELLS IN SUPPRESSING AND DCLEU IN INCREASING ANTILEUKEMIC CYTOTOXICITY

A.S. Hartz1, L. Li1, H. Aslan1, E. Pepeldjiyska1, E. Rackl1, T. Baudrexler1, P. Bojko2, J. Schmohl3, A. Rank4, C. Schmid4, H.M. Schmetzer 1

1Working-Group: Immune-Modulation, Klinikum Grosshadern, Ludwig-Maximilians-University, Munich, Germany, 2Rotkreuzklinikum Munich, Munich, Germany, 3Department of Hematology and Oncology, Stuttgart, Germany, 4University Hospital of Augsburg, Augsburg, Germany

Background: Novel immunotherapies that overcome immunescape of acute myeloid leukemia (AML) cells are urgently needed. AML establishes a tolerant, immune-inert microenvironment e.g. by accumulating tolerogenic dendritic cells (tDCs). TDCs are dendritic cells and can be generally characterized by a modified cytokine production, ultimately leading to T-cell anergy. In this study we focused on tDCs expressing ILT-3, CTLA4, PD-1, IL3RA.

Leukemia-derived dendritic cells (DCleu) can be generated ex vivo directly from leukemic whole blood (WB) by using (clinically approved) GM-CSF and PGE-1 (Kit-M), leading to antileukemic immune responses after mixed lymphocyte culture enriched with patients’ T-cells (MLC).

Aims: To evaluate Kit-M on frequencies of DCleu or tDCs and on DC mediated (antileukemic) effects and to correlate results with patients’ clinical characteristics.

Methods: WB samples from 18 AML patients and 5 healthy WB samples were treated with vs without Kit-M to generate DC/DCleu and to quantify tDCs. After MLC, leukemia specific/antileukemic effects were assessed through the degranulation-, the intracellular IFNγ production- and the cytotoxicity fluorolysis assay. Quantification of cell subtypes was performed via flow cytometry.

Results: Treating leukemic WB with Kit-M vs control increased significantly frequencies of (mature) DCleu without induction of blast proliferation and significantly decreased frequencies of tDCs (DCs co-expressing ILT-3, CTLA4, PD-1 or IL3RA). After T-cell enriched MLC of Kit-M treated vs. not pretreated WB, frequencies of immunoreactive cells (e.g. non-naïve T-cells, CIK cells) were (significantly) increased, of regulatory T-cells (e.g. CD152 + T-cells) were (significantly) decreased, of activated T-cells (e.g. CD154 + T-cells) were increased and degranulating (CD107a + ) and intracellular IFNγ positive (e.g. CD107a+ non-naïve, - central memory, - non-naïve) T-cells were (significantly) increased. A cytotoxicity fluorolysis assay showed an improved blast lysis in Kit-M treated WB compared to control. We found negative correlations between frequencies of tDCs and improved blastolytic functionality and confirmed positive correlations between frequencies of DC/DCleu and improved blastolytic functionality. In patients with favourable (vs adverse) ELN risk stratification and response to chemotherapy (vs no response) lower frequencies of tDCs were found.

Conclusions: Kit-M treatment of leukemic WB was shown to induce DC/DCleu, to reduce tDCs and to induce leukemia-specific antileukemic immune cells after mixed lymphocyte culture. Reduction of tDCs correlated negatively with improved blastolytic functionality. Kit-M in vivo treatment could lead to an improved immune response and overcoming the immunosuppressive tumor environment in vivo.

Disclosure: Modiblast Pharma GmbH (Oberhaching, Germany) holds the European Patent 15 801 987.7-1118 and US Patent 15-517627 ‘Use of immunomodulatory effective compositions for the immunotherapeutic treatment of patients suffering from myeloid leukemias’, with whom H.M.S. is involved with.

19: Acute Leukaemia

P053 TREATMENT EFFICACY OF BLINATUMOMAB FOR MAINTENANCE THERAPY OF PATIENTS WITH B-LINEAGE ACUTE LYMPHOBLASTIC LEUKEMIA RECEIVING ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION

Jiayu Huang1, Luxiang Wang1, Chuanhe Jiang1, Zilu Zhang1, Zengkai Pan1, Ling Wang2, Jieling Jiang2, Jiong Hu2, Jun Zhu3, Lijing Shen4, Suning Chen5, Yang Cao6, Xiaoxia Hu 1

1State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, National Research Center for Translational Medicine at Shanghai, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China, 2Shanghai Institute of Hematology, Blood and Marrow Transplantation Center, Collaborative Innovation Center of Hematology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China, 3GoBroad Medical Institute of Hematology (Shanghai Center), Liquan Hospital, Shanghai, China, 4Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China, 5National Clinical Research Center for Hematologic Diseases, Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University, Suzhou, China, 6Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China

Background: Allogeneic hematopoietic cell transplantation (allo-HSCT) is still a potentially curative therapy for high-risk B-lineage acute lymphoblastic leukemia (B-ALL). However, relapse is the major cause for transplant failure, especially within the first two years after allo-HSCT.

Methods: This multicenter, retrospective study was designed by the First Affiliated Hospital of Soochow University, Wuhan Tongji Hospital, Shanghai Renji Hospital, Shanghai Zhaxin Hospital and Shanghai Ruijin Hospital, to evaluate the efficacy and safety of blinatumomab as maintenance therapy after allo-HSCT in B-ALL patients. Consecutive patients diagnosed with B-ALL from November 2021 to April 2023 were screened, and the eligibility criteria were as followed: (1) aged ≥ 14 years; (2) patients were MRD-negative measured by flow cytometry with a sensitivity of 0.02%; (3) B-ALL with CD19 expression; (4) patients with complete medical information. The last follow-up was November 30, 2023. As pre-determined schedule, blinatumomab was administrated as a continuous infusion for 14-21 days.

Results: A total of 17 patients were retrospectively enrolled. The median age was 30-year old (range, 14-60). Before allo-HSCT, one patient was in relapse, four in second complete remission (CR) and the other patients (n = 12) in first CR. 76.5% patients (n = 13) were categorized as high-risk B-ALL according to NCCN 2023. 88.2% (n = 15) patients received graft from haploidentical donors. The median interval from transplant to the start of blinatumomab maintenance was 102 days (range, 42 to 227), with a median course of 1 (range, 1-6). Only four treatment courses were temporarily discontinued due to infection in the first cycle of blinatumomab maintenance, but the remaining thirty treatment courses were completed without interruptions. With a median follow-up of 269 days (range, 120-674), the 1-year overall survival (OS), event-free survival, relapse, and graft versus host disease (GVHD)-free and relapse-free survival for all patients were 69.1% (95% CI 44.2%-100%), 72.6% (95% CI 49.9%-100%),10.4% (95% CI 8.3-12.5%) and 72.9% (95% CI 50.3%-100%) respectively. One patient (P15) received one cycle of blinatumomab at 3-month after allo-HSCT, and relapsed at 8.5 months. Outcomes of patients based on different classification were shown in Table 1. Patients with negative MRD pre-HSCT had a superior OS as compared to those with positive MRD (not reached vs. 286 days P = 0.024). Two patients died of non-relapse causes related to blinatumomab, including transplant-associated thrombotic microangiopathy (n = 1) and blood stream infection (n = 1). The incidence of grade III-IV acute GVHD associated with blinatumomab was 2.9% (n = 1).

Table 1: Follow-up outcome of allo-HSCT patients based on MRD pre-allo-HSCT or R-DRI or NCCN 2023 risk

Classification

Total (n)

Outcome

Sustained remission (n,%)

Relapse (n,%)

NRM (n,%)

Pre-allo-HSCT

MFC-MRD-

14

13(92.9)

0(0)

1(7.1)

MFC-MRD+

3

1(33.3)

1(33.3)

1(33.3)

R-DRI

Intermediate risk

12

11(91.7)

0(0)

1(8.3)

High risk

5

3(60)

1(20)

1(20)

NCCN 2023

Standard risk

4

3(75)

0(0)

1(25)

High risk

13

11(84.6)

1(7.7)

1(7.7)

Conclusions: Blinatumomab maintenance after allo-HSCT is safe and feasible, however, its long-term effect on immune reconstitution should be concerned.

Clinical Trial Registry: Not applicable.

Disclosure: This work was supported by the National Natural Science Foundation (82170206 to X.H.) and all authors have no conflict of interest to declare.

19: Acute Leukaemia

P054 EFFICACY, SAFETY AND TOLERABILITY OF MITOXANTRONE HYDROCHLORIDE LIPOSOME CONTAINING REGIMEN IN TREATING RELAPSED ACUTE MYELOID LEUKEMIA AFTER ALLOGENIC STEM CELL TRANSPLANTATION

Li Liu 1, Yigeng Cao1, Ni Lu1, Erlie Jiang1

1Center of Hematopoietic Stem Cell Transplantation, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, China

Background: Disease relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a prevalent cause of poor prognosis and decreased survival rate for patients (pts) diagnosed with acute myeloid leukemia (AML). Currently, chemothrapy is one of the common strategies, however its efficacy is still limited. Mitoxantrone hydrochloride liposome (Lipo-MIT) is an innovative drug which could potentially provide a new approach for relapsed AML after allo-HSCT.

Methods: From April 29, 2022 to April 19, 2023, 13 adults with relapsed AML after allo-HSCT were enrolled (patient’s characteristics in Table 1). All ofpatients received the Lipo-MIT containing regimen with the dose levels of Lipo-MIT between 20 mg/m2 to 24 mg/m2, followed with donor lymphocyte infusion (DLI). The median dose of Lipo-MIT administered in clinical practice was 19.90 (range 17.00-31.51) mg/m2 per cycle.

Results: The study included a total of 13 pts with a median age of 35 (range 20-53) years old. The risk classification at initial diagnosis, based on the 2022 European LeukemiaNet (ELN) criteria, was favorable (1/13), intermediate (8/13) and adverse (4/13). Prior to the last allo-HSCT, all patients achieved remission, with 9 pts in complete remission 1 (CR1), 1 pts in CR2, and 3 pts in CR3 or higher. The pre-HSCT minimal residual disease (MRD) status, assessed by flow cytometry, was negative in 9 pts and positive in 4 pts. Three patients had extramedullary infiltration but not central nervous system (CNS) leukemia. Before the enrollment, 9 pts experienced their first relapse, with 5 relapsing within 12 months and 4 after 12 months, as well as 4 ptshad relapsed more than one time.

After one cycle of treatment, 4 pts achieved CR with negative MRD, 1 patient achieved CR but MRD remained positive, and 4 pts achieved CR with incomplete hematologic recovery (CRi). Both overall response rate (ORR) and composite (CRc) was 69.23% (95% CI 38.57-90.91%). The most common treatment regimen among patients who achieved CR/CRi was a MAC-based regimen (Lipo-MIT, cytarabine and cyclophosphamide, with or without targeted drugs), used in 6 out of 9 pts.

The median follow-up period was 6.41 months (range 2.10-16.43). Disease progression occurred in 4 out of 13 pts. Seven patients died after treatment, however, no correlation with treatment was obeserved. The median progression-free survival (PFS) was 3.06 months (range 0.62-7.62), while the median overall survival (OS) was 9.49 months (range 2.10-16.43). The hematological grade 3/4 TRAEs were anemia (53.85%), thrombocytopenia (46.15%), leukopenia (38.46%), and neutropenia (23.08%). The most common non-hematological grade 3/4 TRAEs was infections (76.92%), but no fetal infections were occoured.

Conclusions: Lipo-MIT containing therapy, particularly the MAC-based regimen, appears to be an effective and tolerable treatment for relapsed AML after allo-HSCT. It is worthwhile to further explore safety and more effective combination therapy of Lipo-MIT.

Disclosure: Nothing to declare.

19: Acute Leukaemia

P055 STUDY ON THE EFFICACY AND SAFETY OF BLINATUMOMAB MAINTENANCE THERAPY OF HIGH RISK PH NEGATIVE ALL AFTER ALLO-HSCT

Zhang Jianping1, Li Nannan1

1Hebei Yanda Ludaopei Hospital, Langfang, China

Background: Immunotherapy provides more opportunities for Allo-HSCT after complete remission for refractory/recurrent B-ALL. However, it is still difficult to achieve long-term survival after Allo-HSCT recurrence, especially recurrence in the early stage. Therefore, how to reduce the recurrence of high-risk PH-negative B-ALL through prevention is still an urgent problem to be solved.

Methods: Group entry criteria:

  1. 1.

    With high-risk cytogenetic and molecular biological changes in accordance with the definition of ELN.

  2. 2.

    Receiving an immunotherapy before transplantation, there is still MRD positive or MRD returning to positive in a short time after turning negative.

  3. 3.

    Extramedullary leukemia occurred before transplantation.

  4. 4.

    MRD 10-6 to 10-4 after transplantation. Treatment: two months after Allo-HSCT, if there’s no active GVHD or uncontrolled infection, we’ll give two weeks Blinatumomab continuous injection. If there’s no contraindication after 45 days we’ll give another cycle of Blinatumoma. During the course we observe the infusion reaction, hepatorenal toxicity, hematotoxicity, GVHD and other complications.

Results: There are ten patients accepted Blinatumomab after Allo-HSCT. 3 patients got fever, 1patient got hypertension. 1patient got TA-TMA. 1patient developed chromosome clone from the donor, which returned to normal after three months. 2patients developed limited cGVHD. All other patient survive disease-free.

Conclusions: It is safe and feasible to Blinatumomab maintenance therapy of high risk PH negative ALL after Allo-HSCT

Disclosure: no

19: Acute Leukaemia

P056 THE IMPACT OF PRE-TRANSPLANT MDS-ASSOCIATED SOMATIC MUTATIONS AND CO-MUTATIONS IN PATIENTS WITH AML ON POST-TRANSPLANT OUTCOMES

Khalid Halahleh 1, Ayat Taqash1, Isra Muradi2, Farah Alul1, Osama Alsmadi1, Mohamad Ma’koseh1

1King Hussein Cancer Center, Amman, Jordan, 2Ahliyya Amman University, Al-Salt, Jordan

Background: Acute myeloid leukemia (AML) with myelodysplasia-associated gene mutations (MDS + ) is a new disease entity introduced in the International Consensus Classification of Myeloid Neoplasms 2022(ICC 2022). MDS-associated somatic mutations (MDS +) include SRSF2, SF3B1, U2AF1, ZRSR2, ASXL1, EZH2, BCOR, and STAG2. The aim of this study is to assess the frequency of this disease entity of AML, and evaluate the impact of pre-transplant MDS-associated somatic mutations on post-transplant outcomes.

Methods: Using King Hussein Cancer Center Registry, out of 176 newly diagnosed AML patients, 162 had available genomic abnormalities using targeted next-generation sequencing gene panel at diagnosis between “2016 – 2023”. 117 patients achieved complete remission (CR) and included in this analysis. Leukemia free survival (LFS) and overall survival (OS) were calculated using Kaplan Meier methods using a log-rank test and a Cox proportional hazard model was used for unadjusted analyses of time-to-event endpoints. Cumulative incidence of relapse (CIR) and nonrelapse mortality (NRM) were calculated using the Gray method. Factors with P < 0.05 in univariate analyses were included in multivariate analyses. P < 0.05 was considered statistically significant.

Results: 100 patients (85.5%) had de novo AML. Median age was 46y (18-78y). 82 patients (70%) were males. Pathogenetic mutations were detected in 104 (89%), -VUS in eight (6.7%) and 5 patients (4.3%) had negative on targeted gene panel. We identified 23 patients (20%) with at least one of MDS-associated mutations (MDS + ) and 94(80%) were negative (MDS-). 72 patients (69%) were in CR1, 54 (46%) received allo-HSCT (17 in CR1). Patients-disease-transplant-related covariate were comparable between the two groups, except patients age was younger (P-0.001) and more secondary AML in MDS+ group (P-0.016).

The median follow-up for survivors (n-45) was 16 months (0.5-52 months). 3-year CIR, LFS and OS were 39% (95% CI: 23%-55%), 61% (95% CI: 49%-76%), and 26% (95% CI: 16%-37%) respectively. The MDS+ group had less relapses (3-year CIR, 5% vs 40%) (Hazard ratio [HR]:1.327, 95% confidence interval [CI]: 0.758-2.323; P-0.79), comparable LFS (75.5% vs 60%) (HR: 0.853, 95% CI: 0.249-2.928; P-0.8), and OS of 24% vs 26%) (HR: 1.327, 95%CI: 0.758-2.323; P-0.322). In univariable cox regression analysis for LFS and OS, and NRM, none of the factors analyzed including gender, age (< 45y vs ≥ 45y), ELN 2022 AML classification, and MDS+ vs MDS- groups, was statistically significant for OS or NRM (all P>0.05). Younger age was statistically significant for LFS (P-0.018). Among the 23 MDS+ patients who achieved CR, and received allogeneic HSCT (n -7) showed better OS (3-year OS, 86% (53% vs Zero) (HR: 0.061, 95% CI: 0.008-0.476, P-0.0076), a trend toward improvement in LFS (3-year,100% vs zero%) (HR: NA, 95% CI: NA vs NA, P-0.9972) than those who received consolidation chemotherapy considering allo HSCT as non-time dependent covariate. No patients relapsed in the allogeneic HSCT patients (3-year, zero vs 49%) (95% CI: 8%- 82%; P-0.063), and NRM was comparable between the two groups (P-0.998).

Conclusions: MDS-associated somatic gene mutations are an independent prognostic factor for adverse outcomes in AML that might be overcome by allotransplant.

Disclosure: Nothing to declare.

19: Acute Leukaemia

P057 TRIALS IN PROGRESS: A PHASE 1B SINGLE-ARM, OPEN-LABEL STUDY OF EMAVUSERTIB IN COMBINATION WITH AZACITIDINE AND VENETOCLAX IN AML PATIENTS IN COMPLETE RESPONSE WITH MRd

Adolfo de la Fuente 1, Claudio Cerchione2, Sebastian Scholl3, Jan Moritz Middeke4, Gaurav S. Choudhary5, Dora Ferrari5, Reinhard von Roemeling5, Uwe Platzbecker6

1MD Anderson Cancer Center, Madrid, Spain, 2Istituto Romagnolo per lo Studio dei Tumori, Meldola, Italy, 3Universitätsklinikum Jena, Jena, Germany, 4Technische Universität Dresden, Dresden, Germany, 5Curis Inc, Lexington, United States, 6University Hospital Leipzig, Leipzig, Germany

Background: Emavusertib is a novel potent oral inhibitor of interleukin-1 receptor-associated kinase 4 (IRAK4) with additional inhibitory activity against FMS-like tyrosine kinase 3 (FLT3) and CDC-like kinases (CLK1/2/4). Inhibition of these onco-proteins may induce remission thereby addressing a critical unmet need for novel therapies in acute myeloid leukemia (AML). Clinical studies with emavusertib monotherapy have demonstrated a significant reduction in AML blasts with clinical and molecular responses, including patients with relapsed or refractory AML, previously treated with an HMA and/or FLT3 inhibitors (Metzeler 2022).

Azacitidine + venetoclax (aza+ven) has been approved in newly diagnosed, unfit patients with AML. In the VIALE-A study, composite complete response (CRc) (CR, CRh, or CRi) in the absence of measurable residual disease (MRD) of <1 residual blast/1000 leukocytes (MRD negative [MRD−]) resulted in longer duration of response (DOR), event-free survival, and overall survival (OS), and better HSCT outcome compared with patients who achieved CRc but were MRD+ (Pratz, 2022). In pre-clinical studies, emavusertib in combination with aza+ven demonstrated synergistic antileukemic effects in AML cell lines, including azacitidine- or venetoclax-resistant cell lines. Adding emavusertib to aza+ven in MRD+ patients at the time of CR may convert MRD status without adding significant toxicity and confirm that emavusertib can be safely added to aza+ven as a potential new regimen in front-line therapy.

Methods: This is a single-arm, open-label Phase 1b trial evaluating safety and tolerability, PK, and conversion of MRD status with emavusertib as an add-on agent to aza+ven in AML patients who achieved CR or CRh with MRD+ based on local testing (EU CT Number 2023-505828-58-00). The primary objective of the study is to determine a safe and tolerable dosing schedule for the triple combination. Secondary objectives include MRD conversion rate, DOR, OS, and pharmacokinetics. The study will enroll approximately 24 patients at 5 to 10 sites globally. Patients will have received azacitidine and venetoclax as first line therapy and achieved CR or CRh after 1-6 cycles of aza/ven. If MRD status remains positive, emavusertib will be added to the existing well tolerated aza+ven regimen. The starting emavusertib dose is 200 mg BID for 7 days per cycle of 28 days. If well tolerated, duration of emavusertib treatment will be extended to 14 and 21, respectively; no intra-patient change of emavusertib dosing duration is planned. The patients will continue triple treatment (emavusertib+aza+ven) until consent withdrawal, disease progression, intolerable toxicity, or not achieving MRD- within 6 cycles of triple treatment. In this Phase 1b trial, MRD can be evaluated by local testing of bone marrow. Key exclusion criteria include residual toxicities and significant comorbidities.

Results: Not applicable.

Conclusions: Not applicable.

Clinical Trial Registry: EU CT Number 2023-505828-58-00

Disclosure: Nothing to Declare.

19: Acute Leukaemia

P058 PREVALENCE OF ELIGIBILITY FOR GERMLINE MUTATION TESTING IN PATIENTS WITH MDS/AML UNDERGOING ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANT IN A US ACADEMIC MEDICAL CENTER

Tyler Fugere 1, Samuil Ivanovsky1, Gomathy Nageswaran1, Brad Fugere1, Urooj Hudda1, Sravani Gundarlapalli1, Lakshmi Yarlagadda1, Zhongning “Jim” Chen1, Cesar Gentille1

1University of Arkansas for Medical Sciences, Little Rock, United States

Background: Predisposition to acute myeloid leukemia (AML) is increasingly recognized and referral for genetic counseling, germline testing, and extension of these services to family members should be considered in select patients. The National Comprehensive Cancer Network (NCCN) and European LeukemiaNet (ELN) have outlined suggestive disease features to prompt germline testing. Recognition of these familial syndromes is important to support clinical decision-making and assess the risk for hematological malignancies for family members. Given their rarity, it is unclear how many patients are actually screened. Our goal was to assess the prevalence of patients that met criteria for testing and that were referred for further evaluation in an academic medical center in the US.

Methods: We identified 132 patients who received a hematopoietic cell transplant for myelodysplastic syndrome (MDS) or AML at University of Arkansas Medical Sciences from July 1, 2018 to October 5, 2023. We determined the prevalence of eligibility for testing by considering patients who were either <40 years old at diagnosis or had a mutation with VAF >30% and had either a personal or family history of cancer as being eligible based on NCCN guidelines. We collected diagnosis date, transplant date, relapse date, and date of last contact or death to determine progression free survival (PFS) and overall survival (OS) per Kaplan-Meier. Age, disease type, conditioning regimen and eligibility for testing were analyzed using Cox proportional hazard regression.

Results: Overall, 102 patients had AML and 30 had MDS; 36 received a myeloablative and 96 a reduced intensity transplant. Thirty-six patients (27.3%) met criteria for germline testing but only 4 were tested. Of patients who met criteria for testing, median age was 55 years. NPM1 was the most prevalent mutation (10.3%) followed by DNMT3A (8.9%), FLT3 (7.6%), RUNX1 (6.3%) and TP53 (6.3%); 24 of these patients had at least 1 mutation that has been reported to be potentially germline. Outcomes for PFS and OS were not different between patients eligible for testing and ones who were not per Kaplan-Meier or multivariate analysis; median PFS and OS were not reached for either group.

Conclusions: Prior studies have identified a prevalence of germline mutations in AML of 7-14%, however, the prevalence of patients meeting eligibility for testing or getting tested in routine clinical practice has not been described. In our cohort, more than 20% of transplanted patients with MDS/AML met criteria and less than 5% were tested despite most of them having at least 1 potential germline mutation. Even though there was no apparent effect on outcomes, our sample size and lack of germline confirmatory testing makes interpretation of these results challenging. We believe awareness of the features suggestive of a germline disease is paramount and needs to increase to capture as many patients as appropriate as it could affect conditioning and donor options for transplant as well as help prevention or early detection of other hematologic or solid cancers.

Disclosure: Nothing to declare.

19: Acute Leukaemia

P059 REFINED DISEASE RISK INDEX APPLIED IN AN UPPER-MIDDLE INCOME COUNTRY AS A TOOL TO ESTIMATE OVERALL SURVIVAL AFTER ALLOGENEIC STEM CELL TRANSPLANTATION IN HAEMATOLOGICAL MALIGNANCIES

Shirley Quintana-Truyenque1, Naty López-Córdova 1, Jessica Meza-Liviapoma1, Lourdes López-Chavez1, Cindy Alcarraz-Molina1, Victor Mallma-Soto1, Claudio Flores-Flores2, Jule Vasquez-Chavez1

1Instituto Nacional de Enfermedades Neoplásicas (INEN), Lima, Peru, 2Universidad Peruana San Juan Bautista, Lima, Peru

Background: Allogeneic haematopoietic stem cell transplantation (Allo-HSCT) is a potentially curative option in a greater number of haematological malignancies. There are some prognostic models developed to estimate risks and survival in patients who will have this treatment. The Refined Disease Risk Index (R-DRI) stratifies neoplasms based on the status of the disease and remission before transplantation, there are 4 risk groups: low (LR), intermediate (IR), high (HR) and very high (V-HR), which correlate with overall survival (OS) at 2 years and have demonstrated to not been affected by age, conditioning intensity, graft source or donor type. The aim of the study was to estimate the overall survival post Allo-HSCT in our institution in relation to the R-DRI with the objective of implement its use in the Peruvian patients.

Methods: We reviewed retrospectively the data of 172 adults who underwent an Allo-HSCT between 2012 and 2023 in the Bone Marrow Transplantation (BMT) unit of the National Institute of Neoplastic Diseases (INEN). The information was extracted from the unit registry and was completed using the electronic medical record. Patients over 15 years of age were included. All donors were related, and the source used was peripheral blood. Risk classification was performed according to the R-DRI. Survival was estimated using the Kaplan-Meier method and comparisons were made using the Log-Rank test.

Results: The median age at HSCT was 26 years (range: 15 - 63), 51% of patients were male. Most frequent diagnoses were acute lymphoblastic leukaemia (ALL), Acute Myeloid Leukaemia (AML), Mixed-Phenotype Acute Leukaemia (MPAL), and Chronic myeloid leukaemia (CML), with 85, 41, 13 and 11 cases, respectively. Other diagnoses were (Myelodysplastic syndrome (MDS), Acute lymphoblastic lymphoma [LBL], Hodgkin lymphoma, and aggressive T/NK cell leukaemia with 8, 6, 1 and 1 cases, respectively. According to the R-DRI classification (does not include MPAL and LBL), patients were stratified as LR, IR, HR, and V-HR in 5%, 38%, 35% and 22% of cases, respectively. The risk that predominated in each diagnostic group was as follows: for ALL, AML, CML, and MDS were IR (46%), HR (51.2%), LR (45.5%) and HR (75%), respectively. The median follow-up was 3.9 years. The median OS for the entire cohort was not reached, and the survival rate at 2 and 4 years according to R-DRI for LR, IR, HR, V-HR were 100%, 68.3% and 57.4%, 64.7 and 53.5%, 47.4 and 38.3%, respectively. The 4y-OS rate of the combined IR and HR group vs V-HR was 54.6% and 38.3%, respectively (p = 0.071).

Conclusions: OS in our patients according to the R-DRI was higher than the reported in the literature, with a greater difference between the intermediate and high versus very high-risk groups. The R-DRI is an important tool that allows to estimate the prognosis after allogeneic transplant in our population; however, it must be taken into consideration that this study is retrospective and there are patients who did not reach the median follow-up, so it is recommended to continue with prospective studies.

Disclosure: Nothing to declare.

19: Acute Leukaemia

P060 PREEMPTIVE DONOR LYMPHOCYTE INFUSION AFTER ALLOGENEIC STEM CELL TRANSPLANTATION IN PATIENTS WITH ACUTE MYELOID LEUKEMIA – SINGLE CENTRE ANALYSIS OF EFFECTIVENESS AND SAFETY

Anna Łojko Dankowska 1, Ewa Bembnista1, Paula Matuszak1, Magdalena Matuszak1, Bartosz Małecki1, Andrzej Szczepaniak1, Anna Wache1, Dominik Dytfeld1, Lidia Gil1

1Poznan University of Medical Sciences, Poznań, Poland

Background: Acute myeloid leukemia (AML) is a disease with intermediate sensitivity to donor lymphocyte, therefore effectiveness in patients (pts) with relapse of disease after allogeneic stem cell transplantation (alloHCT) is limited. However, donor lymphocyte infusion (DLI) can be used earlier to prevent relapse as a prophylaxis in pts with complete remission or as a preemptive treatment in patients with mixed chimerism or with positive minimal residual disease (MRD + ) in flow cytometry.

Methods: We retrospectively analyzed records of twenty adult patients with AML treated in our center with alloHCT from HLA-identical sibling (n = 5) or matched unrelated (n = 6) or haploidentical (n = 9) donor, conditioned with myeloablative (n = 12) or reduce intensity conditioning, who received DLI between 2018 and 2023 as a preemptive treatment due to decrease chimerism (n = 8) or MRD+ (n = 12). Median age at the transplantation was 44 years (range 23-65), median time between transplantation and first DLI was 9 months (range 4-50). Three pts were after second alloHSCT. At the time of first infusion all pts were without immunosuppression and without any symptoms of graft versus host disease (GvHD).

Results: The median follow up among survivors since first DLI was 22 months (range 1-58). Median number of DLI received per patient was 4 (range 1-8), the median CD3+ lymphocyte count per one infusion was 2,3x10e6 per kilogram of body weight (/kg) (range 0,1-20). The cumulative lymphocytes count per one patient was 7,64x10e6 CD3+ cells/kg, range 0,1-54,88. The minimum time between two infusions was 4, the maximum 30 and the median 7 weeks. DLI was effective (increase chimerism above 95% or negative MRD) in 11 pts (55%), 9 (45%) of them remained alive in remission of disease to date. One patient died due to secondary malignancy and one due to infection. Relapse of disease occurred in 8 pts and 7 of them died due to relapse. Acute GvHD were observed in only 3 pts (G2 = 2, G4 = 1), all these pts responded to DLI, but one died due to infection complications. Median overall survival (OS) was 24 months for whole group, 2 years OS for responders was 80%. 12 pts (60%) currently alive.

Among pts who responded to DLI the median cumulative lymphocyte count per one patient was 16,21x10e6 CD3+ cells/kg, (range 1,27-53,54). Among pts who did not respond to DLI the median cumulative lymphocyte count per one patient was 4,09x10e6 CD3+ cells/kg (range 0,1-54,88). Pts with GvHD received the median cumulative lymphocyte count 51,19x10e6 CD3+ cells/ kg (range 16,21-53,54). The difference was not statistically significant p = 0,57.

Conclusions: The relapse of AML after alloHCT remains the major reason for failure and is connected with poor prognosis. DLI can be effective tool to prevent relapse, but the optimal application, timing and dosage, has not yet been established. Our results confirm that this method is safe and associated with low risk of death. The effectiveness of DLI in preventing relapse could be increased in AML pts by combining with other drugs, but perhaps also by increasing the lymphocyte dose.

Disclosure: Nothing to declare.

19: Acute Leukaemia

P061 IN CHILDREN WITH RELAPSED/REFRACTORY ACUTE LYMPHOBLASTIC LEUKEMIA GIVEN ALLOGENEIC-HSCT EMPLOYING REDUCED-INTENSITY CONDITIONING, GVHD IS LESS FREQUENT IF THE PROCEDURE IS CONDUCTED ON AN OUTPATIENT BASIS

Edgar Jared Hernández-Flores1, Moisés Manuel Gallardo-Pérez2, Max Robles-Nasta2, Daniela Sánchez-Bonilla2, Merittzel Abigail Montes-Robles3, Guillermo Ocaña-Ramm1, Olivia Lira-Lara4, Juan Carlos Olivares-Gazca2, David Gómez-Almaguer5, Óscar González Llano5, Yajaira Valentine Jiménez-Antolinez5, Guillermo José Ruiz-Delgado 2,1, Guillermo José Ruiz-Arguelles2,1

1Universidad Popular Autónoma del Estado de Puebla, Puebla, Mexico, 2Centro de Hematología y Medicina Interna, Clínica Ruiz, Puebla, Mexico, 3Universidad Anáhuac Puebla, Puebla, Mexico, 4Universidad Veracruzana, Veracruz, Mexico, 5Servicio de Hematología del Hospital Universitario “Dr. José Eleuterio González”, Monterrey, Mexico

Background: Advance in transplant technology (donor matching, alternative donor source, conditioning regimens), and supportive care have significantly improved the post-hematopoietic stem cell transplantation (HSCT) survival. Allogeneic HSCT is employed in the treatment of relapsed/refractory acute lymphoblastic leukemia (RR-ALL) in children. Outpatient conduction of reduced intensity allografting is being employed more frequently.

Methods: Compare the long term results of allografting children with B cell RR-ALL employing reduced intensity conditioning, the procedure being conducted either as inpatients or outpatients.

Results: 37 patients were analyzed. 18 were allografted as inpatients (IP) and 19 as outpatients (OP). In the statistical analysis, the two comparative groups have no significant differences in terms of age, sex, platelets recovery and acute GVHD. The table shows the salient features of these two groups. The median follow up for outpatient group is 35 months (IQR: 9-59) meanwhile the median follow up for inpatient is 20 months (IQR: 11-33). The median OS for the OP was 33 months, whereas for IP was 50 months (p = 0.342). Time to recover >500 neutrophils in was shorter in OP (12 versus 14 days), whereas the prevalence of chronic GVHD was significantly lower in OP (10% versus 61%).

Table 1. Salient features of 37 patients given allo-HSCT employing reduced intensity conditioning as inpatient or outpatient. a= p value obtained by chi square. b= p value obtained by Mann-Whitney´s U. c = p value obtained by student’s T-test. d= p value obtained by log-rank chi square.

Outpatient (n = 19)

Inpatient (n = 18)

p

Female

10

6

0.130 a

Male

7

12

Mean Age

8.1 + 4.1

7.8 + 4.2

0.840 c

Relapsed/ refractory

10/9

16/2

Days to >500neutrophils

12 (IQR = 3)

14 (IQR = 4.25)

0.022 b

Days to >20,000 platelets

13 (IQR = 1)

14(IQR = 2.25)

0.090 b

Acute GVHD, II-IV

8

7

0.842 a

Chronic GVHD

2

11

0.001 a

Median OS

33

50

0.342 d

Median follow up (months)

35 (IQR = 50)

20 (IQR = 22)

0.620 b

The 50th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians – Poster Session (P001-P755) (8)

Conclusions: These results suggest that allo-HSCT employing a reduced-intensity conditioning can be conducted safely as outpatients in children with RR-ALL could indicate. Moreover, the prevalence of chronic GVHD is lower in patients allografted as outpatients outside that there is no difference in children survival given outcome or income Allo-HSCT.

Clinical Trial Registry: NCT05780554

Disclosure: Nothing to declare.

19: Acute Leukaemia

P062 IMPLEMENTATION OF NON-TBI CONDITIONING AND POST-TRANSPLANT CYCLOPHOSPHAMIDE FOR PEDIATRIC ACUTE LYMPHOBLASTIC LEUKEMIA IN RESOURCE-LIMITED SETTINGS

Lusine Krmoyan 1,2, Inga Khalatiani1,2, Mane Gizhlaryan1, Karen Meliksetyan1

1YEOLYAN Hematology and Oncology Center, Yerevan, Armenia, 2Yerevan State Medical University, Yerevan, Armenia

Background: Resource limitations in countries such as Armenia often impede access to advanced medical interventions, including haploidentical hematopoietic stem cell transplantation (HSCT). Consequently, patients with acute leukemia requiring allogeneic HSCT encounter significant challenges in seeking treatment abroad. This study documents innovative strategies employed in a resource-limited setting to facilitate HSCT for three pediatric patients without the option of international treatment.

Methods: A comprehensive preparatory protocol was established for two patients necessitating haploidentical HSCT due to the unavailability of high-resolution typing, chimerism assessment, donor-specific antibodies (DSA) testing, total body irradiation (TBI), and T cell depletion. The protocol included pre-treatment with rituximab to reduce DSA, followed by a conditioning regimen of fludarabine, treosulfan, and thiotepa. Cyclosporine A (CsA) from day -2 and mycophenolate mofetil (MMF) from day -1 were supplemented for acute graft-versus-host disease (aGVHD) prophylaxis, and post-transplant cyclophosphamide (PTCy) was administered on days +3 and +4 for in vivo T cell depletion. Peripheral blood and bone marrow were used as stem cell sources for one patient each. In a separate case involving allogeneic HSCT from a fully matched sibling donor, a similar preparatory protocol was implemented, with bone marrow as the stem cell source. Fludarabine, treosulfan, and thiotepa constituted the conditioning regimen, supplemented by CsA from day -2 and methotrexate on days +1, +3, and +6 to prevent graft-versus-host disease (GVHD).

Results: Despite resource constraints and the absence of advanced testing and treatment options, the patients exhibited promising outcomes. Post-transplantation assessments on days +30, +60, and +90 revealed chimerism levels more than 99% and negative minimal residual disease (MRD). Noteworthy complications, including severe gastrointestinal tract acute GVHD (grade II-III), HHV6 reactivation, and severe CMV reactivation, were encountered and managed in one patient.

Conclusions: This study demonstrates the successful implementation of non-TBI-based conditioning regimens and emphasizes the role of PTCy in achieving favorable outcomes in a resource-limited setting. PTCy emerges as a crucial strategy in reducing GVHD risks and facilitating HSCT despite limited technological resources, offering hope for patients facing similar constraints worldwide.

Disclosure: Nothing to disclouse.

19: Acute Leukaemia

P063 RELAPSE AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION IN PATIENT WITH ACUTE MYELOBLASTIC LEUKEMIA

Insaf Ben Yaiche1, Nour Ben Abdejelil 1, Rihab Ouerghi1, Ines Turki1, Sabrine Mekni1, Lamia Torjemane1, Dorra Belloumi1, Rimmel Kanoun1, Saloua Ladab1, Tarek Ben Othman1

1Centre National de Greffe de Moelle Osseuse, Tunis, Tunisia

Background: Allogeneic hematopoietic stem-cell transplantation (AHSCT) is the only curative treatment for high-risk acute myeloid leukemia (AML). However, the relapse remains a substantial risk of after AHSCT

Methods: A retrospective descriptive study, included all consecutive patients with AML, who underwent AHSCT from HLA-matched sibling donor, between January 2018 and December 2022. Conditioning consisted on busulfan-iv and cyclophosphamide (BU/CY) or fludarabine-based. GVHD prophylaxis included cyclosporine and short course of methotrexate +/- antithymocyte-Globulin. Stem cell source was bone marrow or peripheral blood stem cells (PBSC). The study aimed to estimate cumulative incidence of relapse (CIR) after AHSCT and describe management therapy of relapsed patients.

Results: Sixty-three patients (9 children, 54 adults) were included with a median age of 33 years (6-49y). The sex-ratio was 1.86. At diagnosis, 21% patients were classified as low-risk (n = 13), 49% intermediate risk (n = 31), 24% high-risk (n = 15), unclassified risk in 6% (n = 4: missing data).

The median time from diagnosis to AHSCT was 7 months (4-54 months). At transplant, 84% of patients were in first complete remission (CR1). Conditioning regimen was BU/CY in 83% of patients. Stem cell source was PBSC in 59% of patients.

After a median follow-up of 32 months (2-67 months), the CIR was 27% (early n = 6, late n = 9). Median time of relapse was 15 months (3-20 months). Relapses were medullary and combined (n = 11), extramedullary (n = 2), molecular (PML-RARA, n = 1) and Cytogenetic (11q23 n = 1).

Among the 15 relapsed patients, 11 (73%) received salvage therapy (chemotherapy n = 8, DLI +/- azacitidine n = 2, ATRA n = 1). Second CR was observed in 6 patients, among them, 5 underwent a second AHSCT. At last follow-up, 45 patients are alive, 18 patients (28%) died (relapse n = 10, NRM n = 8). CI of NRM was 13%.

The 3-year overall survival and event-free survival were 31% vs 83% (p = 0.001) and 7% vs 82% (p<10-3), in relapsed and non-relapsed patients, respectively.

Conclusions: The prognosis of patients with AML relapsing after AHSCT is poor. Adapted risk stratification treatment at diagnosis, before and after AHSCT may improve outcomes.

Disclosure: Nothing to declare.

19: Acute Leukaemia

P064 IAMP21 ACUTE LYMPHOBLASTIC LEUKEMIA WITH DELETION AROUND SUBTELOMERIC REGION OF CHROMOSOME 21: REPORT OF ONE CASE AND REVIEW OF LITERATURE

Jiantuo Liu 1, Hongrui Li1, Xiangjun Chen2, Yanli He2

1Cytogenetics Laboratory, Wuhan Kindstar Medical Laboratory Co., Ltd, Wuhan, China, 2Union Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China

Background: Herein, our report describes the case of a 4-year-old man who presented initially with fever and bilateral instep pain in july 2023.

Methods: we performed a retrospective study to analyze the clinical characteristics, laboratory examination, and treatment.

Results: Physical examination were as follows, T 37.8°C, B 23/min, HR 101/min, BP 88/60mmHg, he was mentally ill and pale. One lymph node with a diameter of 1.5cm is palpable in the right neck. One or two lymph nodes with a diameter of 0.5cm is palpable in the bilateral groin, with soft texture, easy movement and no tenderness. Superficial lymph nodes in the left neck and armpit were not touched. Bilateral tonsil degree I, no exudate attachment. Normal cardiopulmonary function, no liver and spleen enlargement, limbs without muscle tension, extremity warm. Blood routine examination showed that, white blood cell count (WBC) 2.62×109/L, red blood cell count (RBC) 3.25×1012/L, hemoglobin (Hb) 82g/L, neutrophil absolute value 0.48×109/L, lymphocyte absolute value 1.82×109/L, monocyte absolute value 0.14×109 /L. platelet count 165×109/L, C-reactive protein 9.16mg/L, primitive naive cells 8%. The bone marrow examination showed 68.4% of naive lymphocytes, and the immunotype was consistent with B-ALL diagnosis. The RNA-seq showed normal result in tumor cells. RT-PCR test were negative by screened 43 fusion genes of leukemia. The patient showed a normal karyotype. Interphase FISH were as follows, MLL(-), BCR/ABL(-), PBX1/TCF3(-), MEF2D(-), the ETV6/RUNX1 probe observed the cluster of green signals indicates the amplification of RUNX1. The Tel21q probe captured one green signal indicates the deletion around subtelomeric region of chromosome 21. Above these characteristics defined iAMP21. According to the Chinese Children’s Cancer Group study ALL 2020(CCCG-ALL-2020), the patient was divided into intermediate risk group. Induction regimens were typically based on a backbone that included a combination of vincristine, prednisone and pegaspargase with daunorubicin, the patient remained MRD + (0.06%,>0.01%)after induction therapy(day46). High-dose methotrexate (HD-MTX), 6-mercaptopurine (6-MP) were incorporated into consolidation regimens, the patient achieved MRD negative(<0.01%) over a duration of 3 months. Maintenance regimens were based on a backbone of daily 6-MP and weekly methotrexate with the addition of periodic vincristine and prednisone. To date, the patient remained MRD negative after a total of five months of treatment.

Conclusions: Intrachromosomal amplification of chromosome 21 (iAMP21) defines a distinct cytogenetic subgroup of B-cell acute lymphoblastic leukaemia (B-ALL). It has since been estimated that B-ALL with iAMP21 accounts for 2% of all pediatric B-ALLs. In this study, we have validated the existence of iAMP21 with deletion around subtelomeric region of chromosome 21. iAMP21 is associated with inferior outcome, who require more intensive therapy.

Disclosure: Nothing to declare.

20: Aplastic Anaemia

P065 RESULTS OF HSCT WITH TCRΑΒ AND CD19-DEPLETION FROM MATCHED RELATED DONORS AND INFUSIONS OF CD45RA DEPLETED DONOR LYMPHOCYTES IN PEDIATRIC SEVERE APLASTIC ANEMIA

Daria Shasheleva1, Larisa Shelikhova1, Anna Bogoyavlenskaya1, Rimma Khismatullina1, Svetlana Radygina1, Dmitriy Balashov1, Yakov Muzalevsky1, Tatiana Salimova1, Dina Baidildina1, Elena Kurnikova1, Dmitriy Pershin 1, Pavel Trakhtman1, Galina Novichkova1, Alexei Maschan1, Michael Maschan1

1Dmitry Rogachev Federal Research Centre of Pediatric Hematology, Oncology and Immunology, Moscow, Russian Federation

Background: HSCT from matched family donors results in most favorable outcomes among children with severe aplastic anemia (SAA). Despite overall success, morbidity, associated with acute and chronic graft-versus-host disease (GVHD) is not completely prevented with current standard of pharmacologic prophylaxis. Depletion of ab T cells from the graft prevents GVHD, and improves outcome of hematopoietic stem cell transplantation from haploidentical donors, while infusions of donor memory lymphocytes (mDLI) (CD45RA-depleted) are able to transfer pathogen-specific immunity without the risk of GVHD. We evaluated the outcomes of ab T cell depletion and add-back of intermediate-dose mDLI among the pediatric SAA recipients of matched related grafts.

Methods: A total of 24 children with SAA (11 female, 13 male, median age 9,8 y) underwent allogenic HSCT from matched family donors (MFD) between February 2015 and May 2023, for all pts it was the first allo HSCT. TCR αβ + /CD19+ depletion of HSCT with CliniMACS technology was implemented in all cases. The median dose of CD34+ cells was 7,1 x106/kg (range 2,76-13,2), αβ T cells - 23x103/kg (range 1-184). All pts received an additional injection of memory T-cell (CD45RA-depleted) on day 0 at 1 million T cells per kg.

All patients received cyclophosphamide at 100 mg/kg, fludarabine at 100 mg/m2, rituximab 100mg/m2 and serotherapy with either rabbit ATG at 5 mg/kg (n-1) or horse ATG at 100 mg/kg (n-23).

Post-transplant GVHD prophylaxis included calcineurin (CNI)-based regimen and abatacept 10mg/kg on days -1, +7, +14 and +28. 22 pts received a graft from a 10/10 HLA-matched sibling, 2 from 9/10. Median time of follow-up for survivors was 2,9 years (range: 0.8 – 9.8).

Results: Primary engraftment was achieved in all evaluable patients (100%) with donor chimerism, the median time to neutrophil and platelet recovery was 11 (6-18) and 13 (9-19) days, respectively. One patient had aGvHD grade II and there were no incidence of grade III-IV aGvHD and TRM. The CI of CMV viremia was 17% with no incidence of CMV disease. No cases of ADV and EBV viremia and EBV disease were recorded. Two pts had thrombotic microangiopathies (TMA) with good response to rituximab, one pt. had partial red cell aplasia. The median recovery of T cells was on day+60 was 0,26 (0,04-0,9). Event-free and overall survival were 100%.

Conclusions: ab T cell-depleted transplantation with intermediate dose memory T cell add-back definitively prevents GvHD and provides a platform for safe HSCT from matched family donors in patients with SAA.

Disclosure: M. Maschan - Miltenyi Biotec: Honoraria

D. Balashov - Octafarm: Other: Lecture fee

20: Aplastic Anaemia

P066 MITOCHONDRIAL METABOLISM IN FANCONI ANEMIA PATIENTS POST HEMATOPOIETIC STEM CELL TRANSPLANTATION

Filomena Pierri1, Enrico Cappelli1, Stefano Regis1, Silvia Ravera2, Federica Grilli1, Gianluca Dell’Orso1, Stefano Giardino1, Maura Faraci 1

1IRCCS Istituto Giannina Gaslini, Genova, Italy, 2University of Genoa, Genova, Italy

Background: Fanconi anaemia (FA) is a rare genetic condition characterized by congenital abnormalities, progressive bone marrow failure (BMF), chromosome fragility, and cancer susceptibility. In addition to a DNA repair defect, FA patients present a pro-inflammatory condition with increased cytokine production and sensitivity and defective mitochondrial metabolism associated with a poor cellular response to oxidative stress. These defects are involved in the pathogenesis of BMF, concerning not only hematopoietic stem cells (HSCs) but also bone marrow (BM) derived mesenchymal stromal cells (MSCs), which are responsible for organizing a functional HSC niche in vivo and secrete cytokines and matrix proteins that function in HSC self-maintenance and marrow retention.

Hematopoietic Stem Cell Transplantation (HSCT) is the only curative treatment option for FA haematological manifestations. However, this procedure does not result in gene correction of MSCs and other somatic cells, which lead to a persistence of some FA features in the BM microenvironment of transplanted patients that are not fully explored so far.

In this study, we analysed the peripheral blood (PB) mononuclear cells (MNCs) energy metabolism of transplanted FA patients, comparing to their healthy donors and to patients affected by idiopathic severe aplastic anaemia (SAA) to investigate the persistence of some FA features in BM microenvironment post-HSCT.

Methods: We studied, before HSCT and at different time points after HSCT, MNCs metabolism from 4 FA patients undergoing haploidentical α/β/CD19 depleted HSCT (one for BMF and 2 for cytogenetic abnormalities without myelodysplasia), and 4 patients with SAA, 2 transplanted from a Matched Unrelated Donor (MUD), 1 from a Matched Related Donor (MRD), 1 from a haploidentical donor (Post Transplant Cyclophosphamide platform). We also collected samples of the 4 healthy donors of FA patients at the same time points of the recipients.

Oximetric, spectrophotometric, and enzymatic analyses have been used to analyse mitochondria metabolism and antioxidant response in pre and post HSCT peripheral blood (PB) in FA patients compared to PB from their healthy donor and SAA patients.

Results: MNCs from transplanted FA patients showed impaired mitochondrial function and reduced ATP synthesis compared to healthy donors and transplanted SAA. However, the associated oxidative stress was counteracted by antioxidant defences, although a slight increase in lipid peroxidation (MDA) was observed. Interestingly, treatment of MNCs with cytokine inhibitors corrects the mitochondria impairment, suggesting the persistence of a pro-inflammatory state in the bone marrow niche that can alter the mitochondrial metabolism.

Conclusions: In transplanted FA patients, the molecular signals secreted in the microenvironment remain, at least in part, those before transplantation, as the niche in the bone marrow consists of the patient’s somatic cells. This condition justifies the persistence of a pro-inflammatory state even after transplantation, which could lead to mitochondrial dysfunction not observed in healthy donors and SAA.

Therefore, understanding the composition of the bone marrow microenvironment in FA patients after HSCT could lead to the development of new therapeutic approaches to improve the long-term outcomes of transplanted FA patients.

Disclosure: None conflict of interest

20: Aplastic Anaemia

P067 ATLG HAS BETTER SAFETY THAN RATG IN THE TREATMENT OF ADULT AA WITH ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION

Zhang Jianping 1, Lu Yue1, Zhao Yanli1, Xiong Min1, Liu Deyan1, Cao Xingyu1, Wei Zhijie1, Sun Ruijuan1, Zhou Jiarui1

1Hebei Yanda Ludaopei Hospital, Langfang, China

Background: rATG has stronger immunosuppressive effect than ATLG, therefore rATG is the main choice for AA to receive Allo-HSCT. ATLG is only used as an alternative choice for patients who have received ATG treatment. Some studies have shown that the application of ATLG in Allo-HSCT in patients with leukemia can achieve the same efficacy as rATG, and has better safety. Our study is to observe whether ATLG can achieve the same curative effect as rATG and has better safety when AA patients receive Allo-HSCT.

Methods: In this study, a retrospective analysis was made of adult AA patients who received Allo-HSCT in our hospital from March 1, 2012 to June 1,2023. through the analysis of OS, GFFS, GVHD, CMV/EBV activation we explore whether ATLG can achieve the same curative effect as rATG and has better safety.

Results: A total of 218 eligible patients, male 110cases, female 108cases, median age 29y(18-58). VSAA 41cases, SAA 79cases, AA-PNH 34cases, TD-NSAA 64cases. Conditioning with rATG149 cases, ATLG 58 cases. Donor: MSD 39cases, URD 76cases, HID 103cases; Stem cell source: PBSC 86cases, BMSC + PBSC 132 cases. Graft count: MNC8.3 (2.99-18.52)×108/kg, CD34 + 5.0 (1.14- 18.31)×106/kg, CD3 + 1.75 (0- 20.44)×108/kg. Of the 218 patients, there were 212 assessable by neutrophil engraftment, median time 13d(9-41). There were 200 assessable by platelet engraftment, median time 13d(4-78). Median follow-up 34m(1-136), 5y OS 82.72%(0.76-0.88). 5y GFFS 68.41%(0.61-0.75). 5y OS: rATG 85.8%, ATLG76%, P = 0.390; 5y GFFS: rATG69.3%, ATLG64.1%, P = 0.178. Primary engraftment failure 2cases(0.0091%), secondary engraftment failure 1case(0.0045%). aGVHD (II-IV) in 100day rATG 22.15% (16.39%-29.93%), ATLG 27.59%(18.18%-41.86%), P = 0.39240. cGVHD in 5 years rATG31.54%(24.35%-40.86%), ATLG 33.87%(22.89%-50.10%), p = 0.66537. CMV recurrence rate in 180d:rATG65.44% (58.20%-73.57%), ATLG 46.95%(35.65%-61.82%); P = 0.00957. Incidence of EBV in 360days rATG33.56%(26.77%-42.06%); ATLG: 8.77%(3.80%-20.26%); P<0.001.

Conclusions: In AA patients who received Allo-HSCT, compared with rATG, ATLG had equivalent OS and GFFS, and equivalent aGVHD and cGVHD, and the incidence of CMV and EBV decreased significantly. ATLG is safe and reliable for GVHD prophylactic in patients with AA undergoing Allo-HSCT.

Disclosure: none

20: Aplastic Anaemia

P068 TREATMENT WITH DARATUMUMAB IN 4 PATIENTS WITH IMMUNE ANEMIA AFTER HSCT WITH ABO INCOMPATIBILITY OR OTHER IMMUNE-ERYTHROCYTE DISCREPANCIES

Marina Aranguren Ostolaza1, Candela Ceballos Bolaños 1, Itziar Oiartzabal Ormategui1, Nerea Arratibel Zalacain1, Pamela Millacoy Austenrritt1, Mónica Fernández Pérez1, Maria Cruz Viguria Alegria1, Carlos Manuel Panizo Santos1, Irene Sánchez Prieto1, Monserrat Lozano Lobato1

1Donostia University Hospital, Donostia-San Sebastian, Spain

Background: ABO group incompatibility is observed in up to 50% of HSCT cases. This increases the recipient’s risk of experiencing acute or delayed hemolytic reactions, delayed engraftment of red blood cells, and pure red cell aplasia (PRCA), which can lead to anemia with clinical repercussions, increased transfusion requirements, and related consequences such as iron overload or increased alloimmunizations. Although there is no standardized therapy for this group of complications, recently described severe post-transplant immune anemia cases have responded favorably to Daratumumab treatment. Its effectiveness is believed to stem from the direct immunosuppressive effect on antibody-producing plasma cells. However, we propose the additional hypothesis that the presence of CD38 receptors on the recipient’s red blood cell membrane and the antigen-antibody binding at this level may confer protection against hemolysis.

Methods: We present a descriptive study of 4 patients undergoing HSCT at the Donostia University Hospital between 2019 and 2022. All 4 patients received peripheral blood stem cell infusion from HLA identical unrelated donors and a conditioning regimen. All showed mixed chimerism by day +30, with two achieving complete chimerism by day +100. All 4 patients, due to major AB0 group incompatibility or other immune-erythrocyte discrepancies, presented PRCA or peripheral hemolytic anemia with severe clinical and analytical impact. After failed transfusion support and Rituximab therapy, all 4 received Daratumumab treatment.

Results: Patients with PRCA received between 3 and 8 weekly Daratumumab cycles. The mean pre-transplant packed red cell transfusion was 15.3 (range 1-27), during transplantation was 38 (range 12-61), and after completing Daratumumab treatment until now was 0.33 (range 0-1). Therefore, we observed a 99.13% reduction in transfusion support. Hemoglobin levels before Daratumumab initiation were 3.4 g/dL, 6.8 g/dL, and 8 g/dL. After the last cycle, they increased to 4.8 g/dL, 7 g/dL, and 13.9 g/dL, respectively. Patients reached maximum levels of 17.3 g/dL, 14.2 g/dL, and 14.5 g/dL without transfusion support. The mean days to achieve the target Hb>9g/dL after the last cycle were 44.66 days, and to maintain Hb>12 g/dL were 66.33 days.

The patient diagnosed with hemolytic anemia is analyzed separately due to the uniqueness of their evolution and response to treatment. In this case, we observed an optimal response to Daratumumab but also dependency on treatment due to episodes of severe anemia after its withdrawal. The outcome was the administration of 18 cycles and ultimately a second HSCT.

Lastly, laboratory findings showed significantly reduced agglutination and hemolysis when exposing AB red blood cells from a patient on Daratumumab treatment to anti-A and anti-B antibodies compared to the control using AB red blood cells without Daratumumab against these antibodies.

Full size table
The 50th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians – Poster Session (P001-P755) (9)

Conclusions:

  • Daratumumab is effective in post-transplant immune anemia confirmed by the increase in hemoglobin levels from early treatment phases, with a mean of 44.66 days to reach Hb>9g/dL after the last cycle.

  • Patients treated with Daratumumab reduced packed red cell transfusion requirements.

  • The binding of anti-CD38 on red blood cell membranes might exert a protective function against hemolysis by preventing the binding between anti-A or anti-B antibodies in ABO incompatibility.

Disclosure: Nothing to declare

20: Aplastic Anaemia

P069 UPFRONT T-REPLETE HAPLO-IDENTICAL HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR CHILDREN WITH SEVERE APLASTIC ANEMIA: A SINGLE CENTER EXPERIENCE FROM JORDAN

Ayad Ahmed Hussein 1, Nour Awni Ghanem1, Bayan Majed Alaaraj1, Tariq Ahmed Abdelghani1, Dina Mohammad Abu Assab1, Hadeel Hassan Al-Zoubi1

1Bone Marrow and Stem Cell Transplantation Center, Istishari Hospital, Amman, Jordan

Background: Severe aplastic anemia (SAA) is a potentially fatal disease that can be cured with hematopoietic stem cell transplantation (HSCT). Matched sibling donors are not always readily available, leading to delayed referral for HSCT after immunosuppressive therapy, which has a poor prognosis.

Methods: This is a retrospective analysis of all pediatric patients with SAA who received upfront haplo-identical HSCT at Dr. Ayad Bone Marrow and Stem Cell Transplantation center, Istishari Hospital, Amman-Jordan from October 2016 till November 2021.

Results: Seven patients with a median age of 7 years (2-10) were included. Five were males. All patients received rabbit anti-thymocyte globulin (rATG) 0.5 mg/kg on day −9 and 2 mg/kg on days −8 and −7, fludarabine 30 mg/m2/day IV on days −6 to −2, cyclophosphamide 14.5 mg/kg/day IV on days −6 to −5, and 200 cGy TBI in a single fraction on day-1. The graft versus host disease (GVHD) prophylaxis was with post-transplant cyclophosphamide (PT/Cy) at 50 mg/kg/day IV on days +3 and +4 post-HSCT. Mycophenolate Mofetil and tacrolimus were started on day +5 and stopped on days +28 and +365 post-HSCT, respectively. The donor was one of the parents in all cases. Four donors were 5/10, two 7/10 and one 8/10 HLA-matched. Five donor-recipient pairs had major blood group incompatibilities. Five patients received peripheral blood stem cells (PBSC), and two received GCSF-primed bone marrow (BM) grafts. The median time for neutrophil and platelet engraftment was 14 (12–17) and 18 (16–22) days, respectively. One patient developed primary graft failure and was successfully engrafted after a second transplant. None of the patients required ICU admission. Grade I- II acute GVHD occurred in four patients. Three patients had CMV reactivation, one EBV reactivation, and one BK virus cystitis. Two patients had chronic GVHD, of which one was extensive. At a median follow-up time of 55 months (26–90), all patients are alive and transfusion-independent.

Conclusions: Matched related donor (MRD) HSCT is recommended for patients with SAA and proven to improve the long term survival. Upfront T-replete haplo-identical HSCT is an effective and safe option in patients who lack MRD. Our data indicates that this approach might be feasible in countries with limited resources. This approach might change treatment algorithm for patients with SAA in the future. More prospective studies with a larger sample size are required.

Disclosure: Nothing to declare.

20: Aplastic Anaemia

P070 PERIPHERAL BLOOD AS GRAFT SOURCE FOR APLASTIC ANEMIA TRANSPLANT: OUTCOMES OF YOUNG ADULTS AND ADULTS IN A MEXICAN PUBLIC HOSPITAL

Guillermo Sotomayor Duque 1, Severiano Baltazar Arellano1, Roxana Saldaña Vazquez1, Humberto Guerra Ramos1, Raul Ramos1, Alma Fabiola Alvarado Charles1, Karen Machuca Adame1, Luis Omar Gudiño Cobos1, Victor Valerio Bugarin1, Rosa Elva De leon Cantú1, Roberto Hernandez Valdez1, Jose Marcelino Chavez Garcia1

1IMSS UMAE 25 Monterrey, Monterrey, Mexico

Background: Aplastic anemia (AA) is a benign hematologic pathology characterized by an autoimmune T-cell mediated attack on marrow niche and its consequent failure. Allogeneic transplant is the curative treatment of choice for patients under 40 years of age with a matched related donor (MRD); for patients who do not have an identical donor, or who have failed immunosuppressive therapy; related haploidentical transplantation has become a feasible option in several centers around the world.

Methods: Retrospective study in IMSS UMAE 25 Monterrey, Mexico. Descriptive analysis was performed with measures of central tendency, medians, and frequencies. Survival analysis was performed with the Kaplan Mier method and comparative with log rank with a significant p value <0.05.

Results: A total of 16 patients were included in a period from January 2017 to January 2023; 9 male (56%) and 7 female (44%) with a median age of 32 years (15-58). Only 4 patients had a MRD, 12 underwent an haploidentical transplant. Median follow-up was 8 months (1-20). Conditioning was based on a non-myeloablative scheme (ATG-Flu-Cy) in 83% and RIC scheme (Bu-Flu-Cy) in 17%. GVHD prophylaxis, was based on methotrexate and cyclosporine for the MRD group and tacrolimus, mycophenylate mofetil and post transplantation cyclophosphamide for the haploidentical one. Median CD34+ was 12.74 x 106 (6.9-21.6); graft source was peripheral blood in all patients and the donor was male in 100% of cases. Blood group compatibility was 94%. Previous to transplantation 3 patients underwent desensitization for donor-specific anti-HLA antibodies using a protocol that included plasma exchange, IVIg, Rituximab and MMF. Median chimerism of 99% (2-100%) was reach by day 30. Primary graft failure occurred in 1 patient and secondary failure in two. CMV reactivation befall in 31%. The incidence of GVHD at 18 and 24 months was 28% and 52% respectively (G I/II), with no patient developing acute or extensive severe GVHD.

The 50th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians – Poster Session (P001-P755) (10)

Median time the follow-up was 9 months (1-27). Overall survival (OS) was 80% at 24 months in all patients; 75% in the MRD group and 83% for the haploidentical (log rank 0.049, p = 0.82). Patients younger than 40 years had OS at 24 months of 100% and for those older than 40 years it was 54% (log rank 4.71, p = 0.029)Fig 1. The sustained hematological response was 75% for MRD and 52% for HAPLO at 2 years (log rank 0.25, p 0.63) Fig 2. Transplant related mortality (TRM) was 19% (one patient due to primary graft failure, one due to CMV infection and one patient due to cerebral hemorrhage).

Conclusions: In our small cohort peripheral blood as graft source proved no difference in OS and GVHD frequency in either group, with a TRM below 20%. Patients under 40 years of age benefits the most from transplantation in a timely and early manner.

Disclosure: No disclosure

20: Aplastic Anaemia

P071 UPFRONT HEMATOPOIETIC STEM CELL TRANSPLANTATION (HSCT) IN CLASSICAL PAROXYSMAL NOCTURNAL HEMOGLOBINURIA (PNH)

Lorie Gandhi 1, Col (Dr) Rajiv Kumar1, Brig(Dr) Rajan Kapoor1

1Army Hospital Research and Referral, New Delhi, India

Background: Paroxysmal Nocturnal Hemoglobinuria (PNH) is a rare acquired hematological disorder characterized by episodic intravascular hemolysis. While Eculizumab is the standard of care in the West, the drug is seldom used in India due to its prohibitive cost. Hematopoietic Stem Cell Transplantation (HSCT) remains the only curative therapy.

Methods: A retrospective, observational study was conducted comprising classical/hemolytic PNH patients who underwent HSCT at our center from the year 2009 to 2023.

Results: Nine patients (five male, four female) with classical PNH who underwent HSCT were identified. Indication for transplant was hemolysis and recurrent need for blood transfusion for all patients. The median age was 28 years (Range 17-48 years). Median time from diagnosis to transplant was 15 months (8 months- 7 years). 3 patients initially presented as non- severe aplastic anemia with a small PNH clone size and later progressed to classical PNH. Out of 9, 7 patients were previously treated with androgens and steroids, 1 patient with Cyclosporine and 1 with Cyclosporine and Eltrombopag. One patient had a pulmonary thromboembolic episode. All patients had hyper-cellular marrow before transplant and median PNH clone size was 76% (28%- 92%). All patients underwent matched sibling donor (MSD) transplant. All received Myeloablative conditioning regimen (MAC): 5 received FLU-BU-ATG(BU-Busulphan, FLU- Fludarabine, ATG- Antithymocyte Globulin) 3 BU-CY-ATG, (CY-Cyclophosphamide) 1 FLU-BU-CY-ATG and 1 BU-CY. Median CD34+ stem cell dose was 6.0 × 106/kg (range 4.38–12.93 × 106/kg). All received cyclosporine and methotrexate as GVHD prophylaxis. Stem cells were derived from peripheral blood for all patients. All patients showed successful engraftment. Clone size at 90 days was <1% for all patients. Acute Graft Versus Host Disease (GVHD) Grade I–II occurred in 3 patients. Grade I-II Chronic GVHD occurred in three patients. Out of 9, 5 patients had CMV reactivation. 3 patients (33.33%) died. One patient (28-year-old male, received BU-CY conditioning) succumbed to Grade IV gut GVHD, 161 days post- transplant. One patient (48-year-old female received FLU-BU-CY-ATG) succumbed to veno-occlusive disease (VOD) post 23 days of transplant and one patient (31-year-old-male, received FLU-BU-ATG conditioning, with a history of thrombosis and a time from diagnosis to transplant of 7 years) died at day 256 post-transplant due to fungal pneumonia. The 6 surviving individuals are transfusion independent. Their median follow up was 8.5 months (3 months- 10 years).

Conclusions: Findings in this study suggest that in the setting of non availability of complement inhibitors, allogenic transplant with matched sibling donor has a curative potential in classical hemolytic PNH. Myeloablative conditioning is preferred. We found 100% engraftment with PBSC in patients with a history of multiple blood transfusions. Addition of ATG may prevent grade IV GVHD. Use of two alkylating agents as a part of conditioning regimen may increase chance of VOD. Early tapering of immunosuppression may prevent life threatening fungal pneumonia in PNH patients who have prior long term steroid exposure.

Disclosure: Nothing to declare

20: Aplastic Anaemia

P072 A REAL-WORLD ANALYSIS OF TREATMENT ADHERENCE AND CLINICAL OUTCOMES FOR PATIENTS WITH PAROXYSMAL NOCTURNAL HAEMOGLOBINURIA (PNH) RECEIVING PEGCETACOPLAN

Koo Wilson 1, Carly Rich1, Zalmai Hakimi1, Regina Horneff1, Jesse Fishman2, Jennifer Mellor3, Lucy Earl3, Yasmin Taylor3, Alice Simons3

1Sobi Pharmaceuticals, Stockholm, Sweden, 2Apellis Pharmaceuticals, Massachusetts, United States, 3Adelphi Real World, Manchester, United Kingdom

Background: Paroxysmal nocturnal haemoglobinuria (PNH) is a rare, multi-systemic disease, which can be fatal if left unmanaged. It is characterised by thrombosis, impaired bone marrow function and complement mediated haemolysis. Currently available treatments include complement protein 5 inhibitor (C5i), which inhibit intravascular haemolysis (IVH), however patients can still experience anaemia and fatigue due to residual IVH and emerging extravascular haemolysis (EVH). Pegcetacoplan is the first approved complement protein 3 inhibitor (C3i), for adults with PNH. It proximally blocks complement activation resulting in broader control of both IVH and EVH. Currently, there is limited real-world data to understand how adherence and administration of pegcetacoplan may impact clinical outcomes for patients with PNH. The aim of this study was to describe the effectiveness and treatment adherence of patients with PNH receiving pegcetacoplan.

Methods: Data were drawn from the Adelphi PNH Disease Specific Programme™, a real-world cross-sectional survey of physicians, and their patients with PNH from January-November 2022 in the United States (US), France, Italy, Germany, and Spain. Patients were eligible for inclusion if prescribed PEG for ≥1 month. Physicians completed surveys utilising data from patients’ medical charts alongside their own clinical judgement regarding patient demographics, pegcetacoplan dosing and frequency of administration, treatment adherence, and clinical outcomes. Descriptive statistics were reported.

Results: Fourteen physicians completed record forms for 61 patients receiving pegcetacoplan. Mean ± SD age was 37.1 ± 11.3 years and 59.0% were male. Patients had been diagnosed with PNH for a mean of 3.7 ± 3.3 years and were receiving pegcetacoplan for 5.9 ± 4.0 months. All patients received 1080 mg of pegcetacoplan per dose, with 98.3% receiving it every 3-4 days and 68.9% self-administered their treatment. Physicians reported 95.1% of patients receiving pegcetacoplan were completely adherent to their treatment regimen. At data collection, physicians reported a mean haemoglobin score of 11.5 ± 1.6 g/dL which was improved from 9.0 ± 1.5 g/dL at pegcetacoplan initiation. Improvement in lactate dehydrogenase (LDH) was seen from PEG initiation to date of data collection (30.0% vs 57.4% reporting LDH <1.5 x ULN), and a higher proportion reported no fatigue (1.6% vs 31.1%, respectively). Physicians considered all patients to have ‘well or very well controlled’ disease.

Conclusions: This study demonstrates high adherence in a real world setting to pegcetacoplan, with almost all patients receiving this treatment in line with the label indication. Physicians reported improvement in patient haemoglobin, LDH levels and reported a high level of disease control for these patients. Further research is needed to understand the long-term adherence and utilisation of pegcetacoplan in a real-world setting.

Disclosure: Wilson, Koo; Rich, Carly; Hakimi Zalmai, and Horneff, Regina are employees of Sobi and may own stocks/shares of the company. Fishman, Jesse is an employee of Apellis Pharmaceuticals and owns stocks/shares of the company. Mellor, Jennifer; Earl, Lucy; Taylor, Yasmin; Simons, Alice are full-time employees of Adelphi Real World, which received funding for participating in this research.

20: Aplastic Anaemia

P073 EXPERIENCE OF SALVAGE HAPLO-HSCT WITH PTCY FOR ACQUIRED SEVERE APLASTIC ANEMIA

Yuliya Mareika1, Nina Minakovskaya1, Natalia Kirsanava 1, Dmitriy Prudnikov1, Mariya Naumovich1, Lubov Zherko1, Aliaksei Kakunin1, Aliaksei Lipnitski1, Volha Mishkova1, Katsiaryna Vashkevich1, Anzhalika Solntsava1

1Republican Scientific and Practical Center for Pediatric Oncology, Hematology and Immunology, Minsk, Belarus

Background: Hematopoietic stem-cell transplantation (HSCT) from the human leucocyte antigen (HLA)-matched sibling donor (MSD) is the first choice for the treatment of severe aplastic anemia (SAA). An improvement over last decade’s results of HSCT from HLA-match unrelated donor (MUD) has made HSCT from MUD the front-line option treatment with no prior failed immunosuppressive therapy (IST) for young. Unfortunately, half of the patients do not have an available HLA-identical donor. They are considered for IST or alternative donor HSCT in case of treatment failure.

Methods: Two patients, diagnosed with idiopathic SAA, underwent a haploidentical HSCT from HLA 6/10 mismatch-related donor (fathers) after the failure of IST with severe infection complications and repeated granulocyte transfusions for the life-saving treatments (table 1). Conditioning regimen consisting total lymphoid irradiation (TLI) 4 Gy, antithymocyte globulin (ATG) (Genzyme) 7,5 mg/kg, fludarabin 150 mg/m2, thiotepa 10 mg/kg, cyclophosphamide (Cy) 30mg/kg, rituximab 200 mg/m2, was followed by transfusion of unmanipulated hematopoietic stem cells. Post-transplant Cy (PtCy) (40 mg/kg on days +3 and +4) was given to reduce the incidence of acute graft-versus-host disease (aGVHD). Granulocyte colony-stimulating factor (G-CSF) 5 μg/kg (from day +5) has been used post-HSCT for earlier neutrophil engraftment. MSC infusion was performed (day +11) to neutrophil and platelet engraftment, a lower risk of aGVHD.

Results: Both patients are alive and well at six and three months. Recovery of neutrophils and platelets was prompt with 100% donor chimerism. None severe toxic or infectious complications were diagnosed after HSCT. Nobody developed acute GVHD or any other immune complications. Immune reconstitution (CD4 + >100 microL) was achieved early. (Table 1).

Conclusions:

Granulocyte transfusion is a reasonable option to control infections and prepare the patients for HSCT. Conditioning regimen TLI/ATG/fludarabin/thiotepa/Cy/rituximab with PtCy reduces the incidence of graft rejection and severe aGVHD. Haplo-HSCT with PtCy in patients with SAA who failed IST with life-threatening comorbidity is a feasible salvage treatment with stable engraftment and an acceptable complication profile.

Table 1

Patient

1

2

Age (year)/sex

2 y.o., female

18 y.o., male

Prior IST

CSA + ATG+steroids+G-CSF

CSA + ATG+steroids+G-CSF

Heavily transfused preHSCT

Yes

Yes

Complications preHSCT

Cardiomyopathy with heart failure, enterocolitis, bronchiolitis

acute kidney failure, granulomatosis with polyangiitis, pneumonia, sepsis, EBV, HHV-6

Granulocyte transfusions preHSCT (n)

7

9

Time to HSCT from 1st day IST (days)

205

85

Source of HSC

Bone marrow

Peripheral blood

CD 34+ (x106/kg)

5,52

5,32

CD 3+ (x106/kg)

56,9

357

aGvHD prophylaxis

CSA, MMF→medrol

Medrol, ruxolitinib (w/o CSA – high risk TMA)

Granulocyte recovery (day)

+25

+14

Thrombocyte ≥20 (day)

+24

+39

Chimerism +30 day (%)

100

100

Chimerism +60 day (%)

100

100

Acute GVHD

no

no

Complications

Local cellulitis, CMV

ВKV hemorrhagic cystitis and nephropathy, mucositis HSV, CMV

CD4 + > 100microL (day)

+30

+71

Follow up

Alive and well (6 mo post)

Alive and well (3 mo post)

  1. F – female, M – male, CSA - cyclosporine A, EBV - Epstein-Barr Virus, HHV-6 - human herpes virus 6, MMF - Mycophenolate mofetil, TMA - thrombotic microangiopathy, CMV – Cytomegalovirus, ВКV – BK-virus, HSV - herpes simplex virus

Disclosure: Nothing to declare

21: Autoimmune Diseases

P074 THYMIC SIZE LONGITUDINAL CHANGES ON CHEST HIGH-RESOLUTION COMPUTED TOMOGRAPHY AFTER AUTOLOGOUS HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR DIFFUSE CUTANEOUS SYSTEMIC SCLEROSIS

Gregory Pugnet 1, Samia Collot1, Antoine Petermann1, Pauline Lansiaux2, Gwenaëlle Lorillon3, Nassim Ait Abdallah2, Mathieu Resche-Rigon4, Cécile Borel1, Zora Marjanovic5, Dominique Farge2

1CHU Toulouse, Toulouse, France, 2Unité de Médecine Interne (UF 04), CRMR MATHEC, Maladies Auto-Immunes et Thérapie Cellulaire, Centre de Référence des Maladies Auto-Immunes Systémiques Rares d’Ile-de-France MATHEC, AP-HP, Hôpital St-Louis, Paris, France, 3Service de Pneumologie et Allergologie, AP-HP, Hôpital St-Louis, Paris, France, 4SBIM Hôpital St-Louis, AP- HP, Université de Paris, Paris, France, 5Hématologie Clinique et Thérapie Cellulaire- Hôpital Saint-Antoine, AP-HP, Paris, France

Background: The thymus is a central lymphatic organ responsible for T-cell differentiation and maturation throughout life. The thymus reaches its maximum absolute weight at puberty, and thymic involution then begins, with fatty infiltration of the gland. Incomplete thymus involution is observed in 12 to 15% of systemic scleroderma (SSc) patients and Meunier et al. reported an association between SSc-related interstitial lung disease and incomplete thymus involution. However, few data exist on thymic evolution after resetting the “immunologic clock” by autologous stem cell transplantation (aHSCT) in early diffuse cutaneous systemic scleroderma. The aim of this study was, therefore, to evaluate thymic involution frequency in SSc patients who underwent aHSCT and thymic size longitudinal changes on chest high-resolution computed tomography (HRCT) after transplant.

Methods: Chest HRCT evaluation was performed before aHSCT and afterwards during yearly routine clinical and paraclinical follow-up in 33 consecutive dcSSc-patients between January 2000 and January 2016. Two independent chest radiologist experts blindly assessed the thymus. Patients were retrospectively classified as clinical responders or clinical non-responders according to: at least 25% improvement in mRSS and/or 10% improvement in FVC or carbon monoxide diffusing lung capacity as compared with baseline, and without need for additional immunosuppression within the 24 months after transplant.

Results: Altogether we evaluated 33 SSc patients (20 female, 13 male) with a mean age at transplantation of 45.5 ±13.5 years and a disease duration of 28.0 ±17.7 months. 27.3% (n = 9) of the evaluated patients showed incomplete involution of the thymus at baseline. At 24 months after aHSCT, significant enlargement of thymus tissue were observed as compared with before aHSCT (p = 0.001). Among the 24 patients with complete involution of the thymus at baseline two of them grows after transplant.

Nineteen patients were clinical responders at 2 years (probability of response 0.68, 95% CI (0.49;0.82). All the patients with an increase in thymic size were in the clinical responders group. The mean absolute change from baseline in thymic size at month 24 was +23.6 mm2 in the clinical responders group and −38.1 mm2 in the clinical non-responders group (p = 0.002).

Table 1: Patients (n = 33) clinical and functional characteristics and Systemic Sclerosis organ involvement before treatment by autologous hematopoietic stem cell transplantation

Characteristics

n (%)

or mean ± SD

n

Age at aHSCT, years

45.5 ±13.5

33

Sex, female

20 (60.6)

33

Disease duration since SSc diagnosis, months

28.0 ±17.7

33

Body mass index (kg/m2)

24.0 ±3.7

33

Smoking status (ever vs never)

9 (27.3)

33

Skin involvement

Modified Rodnan Skin Score (0-51)

24.0 ±10.9

32

Lung involvement

33

Interstitial lung disease

29 (87.9)

33

Pulmonary Hypertension

3 (9.1)

33

Cardiac involvement

17 (51.5)

33

Gastrointestinal involvement

16 (48.5)

33

Immunological status and biological values

Antitopoisomerase-1 antibody positive

23 (69.7)

33

Thymic size (mm2)

88.8 ±173.7

33

Incomplete involution

9 (27.3)

33

  1. SD: standard deviation; BMI: body mass index; AHSCT: autologous hematopoietic stem cell transplantation

Conclusions: Real-world data show a significant thymic size increase within two years after aHSCT for early diffuse cutaneous systemic scleroderma which is associated with clinical response.

Disclosure: The authors declare non conflict of interest for this work.

21: Autoimmune Diseases

P075 LONG TERM PERSISTENCE OF T MEMORY STEM CELLS FOLLOWING AUTOLOGOUS HAEMATOPOIETIC STEM CELL TRANSPLANTATION FOR MULTIPLE SCLEROSIS

Melissa Khoo1,2, Carole Ford1, Jennifer Massey1,2,3, Kevin Hendrawan4, Malini Visweswaran1,2, John Zaunders1,2, Ian Sutton3, Barbara Withers3, David Ma1,2,3, John Moore 1,2,3

1St Vincent’s Centre for Applied Medical Research, Sydney, Australia, 2The University of New South Wales, Sydney, Australia, 3St Vincent’s Hospital Sydney, Sydney, Australia, 4The University of Queensland, Brisbane, Australia

Background: Autologous haematopoietic stem cell transplantation (AHSCT) is a high-efficacy therapy for severe autoimmune diseases, including Multiple Sclerosis (MS). While the mechanisms underlying the clinical benefits are still under investigation, the regeneration of a diverse T-cell repertoire is thought to play a critical role in the re-establishment of self-tolerance. T memory stem cells (Tscm) have been reported to be important novel players in post-transplant immune reconstitution in the haploidentical allogeneic setting. The role of Tscm in autoimmune AHSCT is however unknown. Here, we present the first study to examine Tscm in patients with MS undergoing AHSCT, and also in a non-autoimmune non-Hodgkin’s lymphoma (NHL) comparator group.

Methods: Multicolour flow immunophenotyping of T-cell subpopulations (Tscm (CD3+CCR7+CD45RO-CD45RA+CD27+CD95+), naïve (Tn), central memory (Tcm), transitional memory (Ttm), effector memory (Tem), and terminal effector (Tte) T-cells, recent thymic emigrants (RTE)) was performed on PBMCs (pre-AHSCT; d8, d14, 3m, 6m, 12m, 24m, 36m post-AHSCT) and leukapheresis product cryopreserved from MS and NHL patients undergoing AHSCT with BEAM conditioning (following written informed consent (HREC SVH 10/206), according to the Declaration of Helsinki; MS: n = 22, NHL: n = 5, Healthy Controls (HC): n = 4). Alterations in plasma levels of IL-7 and IL-15 were detected using Milliplex High-Sensitivity Bead-Based Assays. Statistical analysis was performed using: repeated measures ANOVA with Holm-Sidak Post-Hoc test (timepoint analysis), and 2-way ANOVA (mixed-effects) with Sidak Post-Hoc test (MS vs NHL), with logarithmic transformations if required after residual analysis (p<0.05); non-parametric Mann-Whitney U test (pre-AHSCT vs HC; p<0.05); using GraphPad Prism 8.

Immunophenotyping of longitudinal PBMC samples revealed significantly elevated levels of both CD4+ and CD8+ Tscm in MS patients post-AHSCT (p<0.03 and p<0.04 respectively), with this difference persisting long-term to at least 36m. In contrast, no changes in Tscm levels were detected in NHL patients post-AHSCT. While pre-AHSCT, significantly higher proportions of CD8+ Tscm were observed in both MS and NHL patients compared to HC (MS: 8-fold, p<0.0005; NHL: 13-fold, p<0.02). The kinetics of the remaining T-cell subpopulations (Tn, Tcm, Ttm, Tem, Tte, and RTE) were as expected post-AHSCT for both MS and NHL, with patterns of transient differences that returned to baseline by 12-36m. Early post-AHSCT we detected significantly increased levels (>4-fold) of plasma IL-15 in both MS (d8: p<0.001; d14: p<0.05) and NHL (d8: p<0.01), which subsequently returned to baseline in NHL, but decreased below baseline in MS. Conversely, significantly reduced plasma IL-7 was found at d8, 3m and 6m post-AHSCT for MS (p<0.01), whilst NHL displayed no differences.

Conclusions: To our knowledge, this is the first study to demonstrate Tscm expansion in an autoimmune HSCT setting. Elevated CD4+ and CD8+ Tscm post-AHSCT was specific to MS patients, with the absence of Tscm changes in NHL suggesting this is unique to MS patients and not only a consequence of post-conditioning lymphopenia. Interestingly, this persisted long-term in MS patients with Tscm remaining elevated out to 36m. Furthermore, the surge in IL-15 early post-AHSCT, in conjunction with persistently decreased IL-7 levels, suggests a shift in the IL-15/IL-7 balance, which may contribute to Tscm expansion in MS patients.

Disclosure: Authors: Nothing to declare

21: Autoimmune Diseases

P076 EFFECTS OF HIGH DOSE IMMUNOSUPPRESSIVE THERAPY WITH AUTOLOGOUS HEMATOPOIETIC STEM CELL TRANSPLANTATION IN MULTIPLE SCLEROSIS FROM PATIENT’S PERSPCTIVE: LONG-TERM QUALITY OF LIFE OUTCOMES

Denis Fedorenko 1, Vladimir Melnichenko1, Anatoly Rukavitsin1, Nikolai Vasilev1, Tatiana Nikitina2, Natalia Porfirieva3, Tatiana Ionova2

1Pirogov National Medical Surgical Center, Moscow, Russian Federation, 2Saint-Petersburg State University Hospital, Saint-Petersburg, Russian Federation, 3Multinational Center for Quality of Life Research, Saint-Petersburg, Russian Federation

Background: Multiple sclerosis (MS) is an inflammatory, demyelinating and neurodegenerative disease of the central nervous system which can lead to severe disability and result in profound quality of life (QoL) impairment. Patient’s QoL is an important outcome of MS treatment. It is shown that high-dose immunosuppressive therapy (HDIT) with autologous hematopoietic stem cell transplantation (AHSCT) is a valuable option in MS which results in clinical and QoL improvement. The data about long-term QoL outcomes after HDIT + AHSCT are limited. We aimed to evaluate QoL changes in patients with MS at different time-points terms after HDIT + AHSCT.

Methods: Patients with different types of MS who underwent HDIT + AHSCT were enrolled in a longitudinal, prospective and single-center study. Two low-intensity regimens BEAM-like and Cyclophosphamide were applied. RAND SF-36 was used for QoL assessment before AHSCT, at 6 and 12 months after AHSCT, then every 6 months during 2 years after AHSCT and then every 12 months after 2 years of follow-up. Patients who could not answer the questionnaire themselves were excluded and incomplete questionnaires were eliminated. For comparisons t-test or Wilcoxon test as well as Generalized Estimating Equations were used.

Results: In total, 240 patients with MS were included in the analysis: 132 relapsing-remitting MS (RRMS) (55%), 75 secondary progressive MS (SPMS) (31.3%) and 33 primary progressive MS (PPMS) (13.7%). Median age – 40 years old [Q1; Q3 – 32; 49], 35.8% - males. Median baseline EDSS – 4 [Q1; Q3 – 2; 6]. BEAM-like was used in 85 patients (35.4%), Cyclophosphamide – in 155 patients (64.6%). Mean follow-up was 21 months (range: 6-97). We found a significant increase of all 8 SF-36 scales in 12 months post-transplant as compared with base-line in the entire group (p<0.05). In RRMS patients the values of all SF-36 scales significantly improved (p<0.01) In patients with progressive MS statistically significant improvement was registered for 4 out of 8 SF-36 scales (p<0.01); changes for role functioning scales, bodily pain and mental health scales were not statistically significant. During the entire period of follow-up in patients without progression or relapse QoL further improved. Significant positive changes by all SF-36 scales as compared to baseline were observed for the whole group (p≤0.001). For patients with both remitting and progressive MS positive changes for physical and mental health components of SF-36 were revealed during the follow-up post-transplant (p<0.001 for physical and mental health components in remitting MS and physical component of progressive MS; p = 0.012 for mental health component in progressive MS).

Conclusions: HDIT + AHSCT resulted in significant and sustained improvement of QoL in MS patients post-transplant. Meaningful QoL improvement was observed both in patients with remitting and progressive MS at long-term follow-up.

Clinical Trial Registry: No

Disclosure: Nothing to declare

21: Autoimmune Diseases

P077 THE MATHEC-SFGM-TC REGISTRY FOR CELL THERAPY IN AUTOIMMUNE DISEASES: A DEDICATED TOOL FOR REAL-WORLD DATA COLLECTION

Pauline Lansiaux1, Manuela Badoglio2, Grégory Pugnet3, Mathieu Puyade4, Emmanuel Chatelus5, Thierry Martin5, Louis Terriou6, Alexandre Maria7, Marc Ruivard8, Jacques-Olivier Bay8, Bertrand Dunogué9, Matthieu Allez1, Hélène Zéphir10, Arsène Mékinian11, Eric Deconinck12, Sabine Berthier13, Françoise Sarrot-Reynaud14, Frédéric Garban14, Nicolas Maubeuge4, Guillaume Mathey15, Cristina Castilla-Llorente16, Céline Labeyrie17, Régis Peffault de la Tour18, Marie Robin19, Zora Marjanovic11, Dominique Farge 1

1AP-HP, Hôpital Saint-Louis, Paris, France, 2EBMT Paris Study Office, Paris, France, 3CHU Toulouse, Toulouse, France, 4CHU Poitiers, Poitiers, France, 5CHU Strasbourg, Strasbourg, France, 6CHU Lille, Lille, France, 7CHU Montpellier, Montpellier, France, 8CHU Clermont-Ferrand, Clermont-Ferrand, France, 9AP-HP, Hôpital Cochin, Paris, France, 10CHRU Lille, Lille, France, 11AP-HP, Hôpital Saint-Antoine, Paris, France, 12CHRU Besançon, Besançon, France, 13CHU Dijon, Dijon, France, 14CHU Grenoble, Grenoble, France, 15CHU Nancy, Nancy, France, 16Institut Gustave Roussy, Villejuif, France, 17AP-HP, Hôpital Bicêtre, Le Kremlin-Bicêtre, France, 18AP-HP Hôpital Saint-Louis, Paris, France, 19SFGM-TC, Hôpital Saint-Louis, Paris, France

Background: The European Society for Blood and Marrow Transplantation (EBMT) and International Society for Cellular Therapy (ISCT) Joint Accreditation Committee (JACIE) guidelines underline the necessity to yearly report all consecutive hematopoietic stem cell transplantation (HSCT) and patient’s real world data (RWD) monitoring in the EBMT registry, which allows healthcare professionals to assess activity, practices and treatment outcomes and ultimately to improve patient care. A 2015 European Medicines Agency (EMA) initiative encouraged better use of existing registries or development of new, high-quality registries where no existing RWD is available. In orphan rare autoimmune diseases (AD), registries represent an important source of safety and RWD, specifically for patients receiving HSCT or other Cellular Therapies (CT), as Mesenchymal Stroma Cell (MSC) or CAR-T. The EBMT Registry minimum data-set for AD contains transplant data and short-term (Day 100) post-transplant complications with a need to develop AD specific and longer-term monitoring RWD acquisition both at national and European levels.

Methods: Based on a tight collaboration with EBMT under the auspices of the French-speaking Society for Marrow Transplantation and Cellular Therapy (SFGM-TC), the MATHEC-SFGM-TC registry www.mathec.com)) was developed to register and follow-up all AD patients treated by CT in France. It is hosted by Epiconcept certified Health Data Host and compliant with the French independent administrative authority (CNIL) controlling the use of personal data. The selection of variables was based on those collected for the EBMT Registry core dataset and those used for studies promoted by the AD working part. RWD to be collected, include: a) CT treatments (HSCT/ other CT type, donor, source and associated procedures, complications and survival status) plus b) AD specific diagnosis, clinical biological RWD at baseline and during routine follow-up evaluation after CT at 3, 6 and 12 months, then biannually until 5 years and annually at least until 10 years for long-term follow-up. The MATHEC-SFGMTC centers were asked to include all consecutive AD patients receiving HSCT or other CT, with repeated alerts to update the follow-up as recommended by EBMT and by SFGM-TC. Informed consent was obtained for all patients before inclusion. Data managers were adequately trained and supervised by relevant CT and AD specialists to optimize data quality. All registry data are reported here.

Results: On December 6th 2023, 248 AD patients were included in the MATHEC-SFGM-TC registry: 225 patients with 229 HSCT (228 autologous, 1 allogeneic) since 1997 were followed in 31 centers for a median duration of 48 (19-115) months. CT and AD-specific and long-term RWD were collected for HSCT in 152 rheumatologic (138 scleroderma, 5 polychondritis), 55 neurological (43 multiple sclerosis, 7 CIPD) and 11 Crohn disease patients after either standard cyclophosphamide (n = 122), BEAM (n = 12), low dose cyclophosphamide (n = 62), or other (n = 16) conditioning with ATG (n = 179) and/or Rituximab (n = 45). RDW for MSC (20 Scleroderma, 8 Lupus) and CAR-T (1 lupus) patient were collected.

Conclusions: Combining RWD from multiple centres at registry national level are essential to conduct robust studies in rare AD with a sufficient number of patients and disease specific data.

Disclosure: Nothing to declare

21: Autoimmune Diseases

P078 ATG AND OTHER SEROTHERAPY IN CONDITIONING REGIMENS FOR ASCT IN AUTOIMMUNE DISEASES: A SURVEY OF THE EBMT AUTOIMMUNE DISEASES WORKING PARTY (ADWP)

Azza Ismail1, Rosamaria Nitti 2, Basil Sharrack1, Manuela Badoglio3, Pascale Ambron3, Myriam Labopin3, Tobias Alexander4, John Snowden5, Greco Raffaella2

1Sheffield NIHR Translational Neuroscience BRC, Sheffield Teaching Hospitals NHS Foundation Trust & University of Sheffield, Sheffield, United Kingdom, 2Unit of Hematology and Bone Marrow Transplantation, IRCCS San Raffaele Hospital, Vita-Salute San Raffaele University, Milan, Italy, 3EBMT Paris study office / CEREST-TC - Saint Antoine Hospital - INSERM UMR 938 - Université Pierre et Marie Curie, Paris, France, 4Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany, 5Sheffield Teaching Hospitals NHS Foundation Trust; Division of Clinical Medicine, School of Medicine and Population Health, The University of Sheffield, Sheffield, United Kingdom

Background: Serotherapy is a key component of conditioning regimens for autologous hematopoietic stem cell transplant (ASCT) in autoimmune diseases (AD), however, it may be delivered in various dosing combinations across different centers.

Methods: Between December 2022 and November 2023, a survey on the current use of serotherapy for ASCT in ADs, with a focus on anti-thymocyte globulin (ATG), was undertaken by the Autoimmune Diseases Working Party (ADWP) among European Society for Blood and Marrow Transplantation (EBMT) centers, having performed more than 5 ASCTs for AD in adult patients since 2015.

Results: Forty-six EBMT centers (66%) responded to the survey. Among responding centers, 23.9% perform ASCT for neurological AD indications, 15.2% for rheumatological ADs, 58.7% for multiple indications. All centers use ATG, 12 centers (26.1%) also use Rituximab (91.7% of them use it in addition to ATG administration), no center uses Alemtuzumab.

Many centers (58.7%) use the same conditioning regimen for all AD indications. Cyclophosphamide-ATG is the most frequently used regimen (88.8% of centers), followed by BEAM-ATG (22.3%), whereas RIC regimens like cyclophosphamide-fludarabine-ATG were used less frequently. Most centers (93.5%) use ATG for all AD indications. Only one center uses serotherapy-free regimen (cyclophosphamide only), for neurologic indications.

Thymoglobuline is the most commonly used ATG type (89.1% of centers). Four centers report using Grafalon and one center uses Atgam. Among centers using Thymoglobuline, 41.5% administer a total dose (TD) of ≥7.5 mg/kg, while 53.6% administer <7.5 mg/kg. Each center using Grafalon administers a different TD (range 7.5-90 mg/kg). ATG administration is always fractionated over multiple days, most frequently 3 (32.6%) or 5 days (37%); half of centers divide the TD equally for each day of administration.

Rituximab TD is 500 mg (25% of centers) or 1000 mg (75%), the 1000 mg TD is equally fractionated in two days by 6/9 centers. Most centers administer ATG during chemotherapy (63%), while Rituximab is administered before chemotherapy (25%) or before chemotherapy and after HSC infusion (50%).

Test dose is used by 34.8% of centers before ATG administration (ranges 0.28-25 mg or 0.5-1 mg/kg), no center uses rituximab test dose. ATG administration is slower (48.9% of centers administer it over 12 hours) than Rituximab administration (41.7% of centers administer it over 4 hours and 41.7% over 6 hours).

Premedication is used to prevent serotherapy-related adverse events, including antihistamines (100% of centers), paracetamol (91.1%) and steroids (98%), in particular 37.8% of centers administer methylprednisone 1 mg/kg or equivalent and 35.6% administer methylprednisone 2 mg/kg or equivalent. One third of centers repeats premedication at fixed times during a single infusion.

For ATG, 80.4% of centers successfully administer the planned TD to all patients, for Rituximab, 75% of centers administer the TD to all patients. Among HSCT performed for neurologic indications, about half of patients develop clinical relapse during serotherapy administration.

Conclusions: This survey reveals a high degree of consistency across EBMT centres regarding the use of serotherapy in ASCT for AD. However, a wide variability in doses suggests the need for consensus guidelines to best standardize practice.

Disclosure: None related to the manuscript. AI and RN contributed equally to the work.

21: Autoimmune Diseases

P079 ADOPTING A STANDARD OF CARE: AUTOLOGOUS HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR SCLERODERMA

Ernesto Ayala 1, Madiha Iqbal1, Hemant Murthy1, James Foran1, Vivek Roy1, Mohamed Kharfan-Dabaja1

1Mayo Clinic Florida, Jacksonville, United States

Background: Three prospective comparative trials have proven the superiority of autologous hematopoietic stem cell transplantation (aHSCT) over other treatments in patients with Scleroderma. A position statement from the American Society for Blood and Marrow Transplantation endorses its use as “standard of care”. However, it remains underutilized in the US.

Methods: This is an IRB approved, retrospective review of all patients with Scleroderma that have undergone aHSCT at Mayo Clinic Florida since April 2020, and completed at least 3 months of follow up. Scleroderma diagnosis was made/confirmed by our Rheumatology Department based on published criteria.

Results: Twenty four patients were included. Median age at transplant was 49 years (range 21-68). 70% of patients were female, 54% were Caucasian. Median time from diagnosis to transplant was 33 months (5-188). Skin was involved in 100% patients, lung (interstitial disease) in 79%, esophagus in 75%, heart in 12%. Right heart catheterization was done in 13 patients (when recommended by Cardiology) with mild pulmonary hypertension found in 5. Gastric antral vascular ectasia was found/treated in one patient. Median time from consultation to transplant was 2 months (1-24). Hematopoietic stem cell mobilization was induced with G-CSF (24 patients) with the addition of plerixafor (13 patients). Median number of peripheral blood stem cell harvests was 2 (1-3). Myeloablative conditioning was used in 3 patients: Cyclophosphamide + rabbit ATG + 800 cGy total body irradiation (2 patients) or melphalan + rabbit ATG (1 patient with synchronic multiple myeloma). Non-myeloablative conditioning was used in 21 patients: Cyclophosphamide + rabbit ATG (19 patients) or cyclophosphamide + fludarabine + rabbit ATG. Two patients had modifications of conditioning due to volume overload. Twenty three grafts were CD34+ selected. Median number of infused CD34+ cells was 5.98 x 10^6/kg. Granulocyte engraftment occurred at a median of 12 days (0-14) and platelet engraftment at a median of 12 days (0-15), as well. Median hospital stay was 20 days (2-46). Two patients died during the conditioning regimen, one of them of a spontaneous pneumothorax followed by cardiac arrest, the second one from acute bowel ischemia and ARDS. Both had advanced cardiopulmonary disease from scleroderma. One patient died of severe pneumonitis, attributed to myeloablative radiation therapy. One late mortality (day +60 was due to multilobar pneumonia in the setting of cirrhosis with massive ascites. Median follow up after transplant is 12.5 months. Median modified Rodnan skin score pre-transplant was 24 (4-44), post-transplant was 12 (0-28). Median forced vital capacity (FVC) pre-transplant was 80% (41-103), post-transplant 74% (46-108). Median corrected DLCO pre-transplant was 66%, post-transplant was 60% (47-70). Non-relapse mortality was 16%. Relapse was 14%. For transplanted patients, 1 year overall survival is 91% (CI 80-100) and relapse free survival is 78.5% (CI 61-100).

Conclusions: High dose immune ablation with a non-myeloablative conditioning regimen induces durable remissions in most patients with Scleroderma. Mobilization and harvest of hematopoietic stem cells can be accomplished successfully without chemotherapy, even if CD34 selection is planned. Patients with advanced cardiopulmonary disease have a high risk of morbidity and mortality and should be excluded of this approach.

Disclosure: Nothing to disclose.

21: Autoimmune Diseases

P080 FLUDARABINE AND CYCLOPHOSPHAMIDE AS A SAFE AND EFFECTIVE LYMPHOABLATIVE CONDITIONING REGIMEN FOR MULTIPLE SCLEROSIS (MS)

Denis Fedorenko 1, Anatoly Rukavitsin1, Nikolai Vasilev1, Vladimir Melnichenko1, Tatiana Ionova2

1Pirogov National Medical Surgical Center, Moscow, Russian Federation, 2Saint-Petersburg State University Hospital, Saint-Petersburg, Russian Federation

Background: At present, high-dose immunosuppressive therapy with autologous hematopoietic stem cell transplantation (AHSCT) has been used with increasing frequency as a therapeutic option for MS patients. BEAM and cyclophosphamide 200 mg/kg are mostly common used as conditioning regimens for MS patients, but toxicity of both is still high. Thus, a new approach to reduce toxicity for MS patients is needed. The study is aimed to analyze toxicity of new conditioning regimen based on Fludarabine, Cyclophosphamide and Rituximab (R-Flu/Cph) to compare with traditional Cyclophosphamide and Rituximab (R-Cph) in MS patients.

Methods: 232 MS patients were included in this study, median age - 40 years; men/women – 132/100; relapsing-remitting MS – 125 patients, primary progressive MS – 61 patients, secondary progressive MS - 46 patients. EDSS score was from 1.0 to 7.5 (median - 4.0). All patients received AHSCT. Conditioning regimens were: R-Cph (Cyclophosphamide 200 mg/kg + Rituximab 500 mg/m2) – 49 patients, R-Flu/Cph (Fludarabine 150 mg/m2 + Cyclophosphamide 100 mg/kg + Rituximab 500 mg/m2) – 183 patients.

Results: Hematologic toxicity of regimens: duration of neutropenia was from 7 to 12 days (median - 10 days) in R-Cph group and from 3 to 10 days (median - 6 days) - in R-Flu/Cph group. The median duration of thrombocytopenia in R-Cph regimen was 7 days, in R-Flu/Cph - 4 days. Platelet transfusion received 63% of patients in R-Cph group and only 8.2% of patients in R-Flu/Cph group. Anemia grade I-II was observed in 90% of patients in booth groups. Oral mucositis was observed in 26% patients in R- Cph+R group (Grade I - 61,5 %; Grade II - 38,5 %) and in 4% of patients in R-Flu/Cph group (Grade I - 100 %). Enteropathy was observed more in R-Cph group - 16 % (grade II) to compare with R-Flu/Cph group (11%, mainly grade I) Infections: the incidence of infectious complications was higher in R-Cph group – 26% of patients to compare with R-Flu/Cph group - 11.4% of patients. One patient died from sepsis in R-Cph group (TRM – 2.0%), TRM in R-Flu/Cph group was 0%. Hepatic toxicity: in R-Flu/Cph group 10% of patients had hepatic toxicity (grade I and II). In R-Cph group hepatic toxicity was observed in 18% of patients (grade II). Range of immunosuppression: the minimal count of lymphocytes was significant lower in R-Flu/Cph group 0,0001 – 0,01 х 109/l (median 0.0008 х 109/l), than in R-Cph group (minimal count of lymphocyte - 0,001 – 0,06 х109/l, median 0.009 х 109/l, p<0.05).

Conclusions: R-Flu/Cph is a very promising program with less toxicity profile, less incidence of infections and significantly deeper rate of lymphoablation. Also TRM was 0% in R-Flu/Cph group to compare with 2% in R-Cph group. Further studies are needed to assess long-term effectiveness and toxicity of new conditioning regimen.

Clinical Trial Registry: No

Disclosure: Nothing to declare

21: Autoimmune Diseases

P081 IMMUNE RESET AND GRAFT COMPOSITION IN AUTOLOGOUS TRANSPLANTATION FOR MULTIPLE SCLEROSIS: EARLY RECOVERY OF NATURAL KILLER CELLS MAY BE IMPORTANT IN EFFECTING DURABLE RESPONSES

Latoya Reid 1, Oliver Gittner2, Malia Begley3, Rowayda Peters3, Andy Drake3, Matthias Klammer3

1University Hospital of the West Indies, Kingston, Jamaica, 2Steve Mills Stem Cell and Immunotherapies Laboratory, NHS Blood and Transplant, Southampton, United Kingdom, 3St. George`s University Hospital, NHS Foundation Trust, London, United Kingdom

Background: Autologous Haematopoietic Stem Cell transplantation (ASCT) is an effective therapeutic modality in patients with relapsing/remitting multiple sclerosis (MS) through immune regeneration with a less auto-inflammatory response pattern, but the mechanism of achieving durable responses remains poorly understood.

In malignant disease, we have previously studied graft composition and revealed high variability of NK cell content in the graft, early NK cell recovery post HSCT and an association of absolute lymphocyte count >0.5 x 10e9/L at D + 15 with more durable remission.

Similarly, early NK reconstitution post ASCT in MS may be responsible for later shaping a less auto-inflammatory immune reconstitution.

Methods: We monitored lymphocyte subsets (CD4, CD8, NK and B cells) monthly for three months and at 6 and 12 months after ASCT in 16 patients transplanted for Multiple Sclerosis. Autologous stem cells were mobilized with Cyclophosphamide 1.5 mg/m2 and GCSF and patients underwent HSCT after conditioning with Cyclophosphamide and ATG. The non-stem cell component of the graft was analyzed by flow cytometric analysis for B, T, NK cells and neutrophils using defrosted cryovials.

Results: Patient and disease characteristics are summarized in Table 1. The median age at ASCT was 35.5 years with a median EDSS score of 4. Most patients received Alemtuzumab (38%) followed by Natalizumab (31%) as their last disease modifying therapy prior to transplant. The median lines of therapy were two with a median of 14 months duration between last highly effective immunosuppressive therapy and transplant.

In the post-transplant period, total T cell numbers did not return to the low normal range until day 240. The CD4/CD8 ratio was clearly inverted until beyond Day 180. In contrast, in the early post-transplant period (Day 30), we saw the highest absolute number of NK cells with a sharp fall to low normal number in subsequent time points. This is also reflected in a high, inverted CD 56: CD 4 ratio in the first month post ASCT, only reverting to a physiological range at Day 240.

Table 1: Demographics and Disease Characteristics

Number of Patients

16

Sex No. (%)

Female

11 (69%)

Male

5 (31%)

Age in years

Median

35.5

Range

24-49

Expanded Disability Status Scale (EDSS) score

Median

4

Range

1.5-6.5

Last immunosuppressant prior to transplant No. (%)

Alemtuzumab

6 (38%)

Natalizumab

5 (31%)

Ocrelizumab

4 (25%)

Pulsed Steroids

1(6%)

Lines of immunosuppressive therapy

Median

2

Duration between last highly effective immunosuppressive therapy and transplant (months)

Median

14

Conclusions: Early immune recovery post ASCT in patients with MS is characterized by a high, inverted NK cell/ CD4 ratio, a finding we previously reported in malignant disease (Multiple Myeloma). Recent studies suggest that NK cells have an immunoregulatory function on Th17 responses, a pro inflammatory mediator implicated in Multiple Sclerosis. Further studies into the early kinetics of immune reconstitution in patients with MS post ASCT, the impact of previous therapies and the non-stem cell component of the graft are required to understand if these shape the durable immune reset and it`s mechanism.

Disclosure: Nothing to declare

21: Autoimmune Diseases

P082 REDUCED PRO-INFLAMMATORY INTERLEUKINS IL-6 AND IL-8 SECRETED BY SKIN FIBROBLASTS IN SYSTEMIC SCLEROSIS PATIENTS AFTER HEMATOPOIETIC STEM CELL TRANSPLANTATION

Gunter Assmann 1,2, Jan Weghorn1, Michael Schmidt1, Joerg Henes3, Claudia Pfoehler4, Frank Neumann2

1RUB University Hospital JWK Minden, Minden, Germany, 2Jose Carreras Center of Immungenetics and Gene Therapy, University of Saarland, Homburg, Germany, 3University Hospital Tuebingen, Tuebingen, Germany, 4University Hospital of Saarland Medical School, Homburg, Germany

Background: Systemic sclerosis (SSc) is an autoimmune connective tissue disease defined by fibrosis of skin and internal organs as well as vascular impairment accompanied by a significantly higher mortality rate than in the general population. Early severe courses of SSc should be provided for intensified treatment such as hematopoietic stem cell transplantation (autoTx).

In addition to the fibrosis several features of SSc often show a phenotype of auto-inflammation which is thought to be mediated by the TH17 pathway in addition to other inflammatory factors.

Methods: Here we investigated cultures of skin fibroblasts derived from SSc (3 to 6 months) after successful autoTx as well as without autoTx to evaluate the different expression of pro-inflammatory cytokines (interleukin-1-beta, interleukin-6 (IL-6), interleukin-8 (IL-8)) after stimulation of interleukin-17 (IL-17) and combined with tumor growth factor-beta (TGF-beta), measured by concentrations (ng/ml, +/-standard error) in the cellular supernatant using ELISA tests.

SSc patients (n = 8, aged 43 to 65 years) and three of them after autoTx (n = 3, aged from 54 to 59 years) underwent a skin biopsy of the lateral abdominal wall or forearm.

The cells were stimulated by 25 ng/ml of IL-17 and/or 2.5 ng/ml of TGF-beta for 48h. The differences between SSc and SSc after autoTx were statistically analysed by t-test (with fisher`s correction).

The ethics committee of the Saarland Medical Association has approved the experimental study (EK120/23).

Results: IL-6 secreted by skin fibroblasts showed a significantly higher concentration in SSc patients without autoTx compared to SSc after autoTx. After in-vitro stimulation of the skin fibroblasts by IL-17 the IL-6 as well as IL-8 concentrations were significantly higher in SSc patients without autoTx to SSc without autoTx (figure 1). Furthermore, after IL-17 stimulation together with TGF-beta the concentration of IL-8 (but not IL-6) supernatant concentrations also resulted in significantly higher values for SSc fibroblasts in patients without autoTx compared to patients after autoTx (1.99 + /-0.23 vs. 0.63 + /-0.06 [p = 0.0008]). IL- 1beta concentrations did not show any differences between the subgroups (data not shown).

Conclusions: Skin fibroblasts derived from SSc patients showed significantly stronger IL-6 and IL-8 driven pro-inflammatory properties than skin fibroblasts derived 3 to 6 months after the hematopoietic stem cell transplantation. In what way (1) IL-6 and IL-8 may be a potential biomarker for disease activity of SSc and (2) IL-17 could be a predominant pathway for activity in SSc patients remains the subject of further research.

Disclosure: G. Assmann: advisory boards, research grants from: UCB, Astrazeneca, Boehringer-Inglheim, Novartis, BMS, Vifor Pharm; C. Pfoehler: advisory boards, research grants from UCB, Novartis, BMS, Astrazeneca, AbbVie; J. Henes: advisory boards, research grants from: AbbVie, BMS, Boehringer-Ingelheim, Chugai, GSK, Janssen, NEOVII, Novartis, Pfizer, UCB; remaining authors: no discloser

21: Autoimmune Diseases

P083 THE QUALITY OF LIFE OF PERSONS WITH MULTIPLE SCLEROSIS IMPROVES AFTER AUTOLOGOUS HEMATOPOIETIC STEM CELL TRANSPLANTATION

Olivia Lira-Lara1, Moisés Manuel Gallardo-Pérez2, Miranda Melgar-de-la-Paz3, Paola Negrete-Rodríguez4, Luis Enrique Hamilton-Avilés5, Guillermo Ocaña-Ramm5, Max Robles-Nasta2, Daniela Sánchez-Bonilla2, Juan Carlos Olivares-Gazca2, Guillermo José Ruiz-Delgado 2,5, Guillermo José Ruiz-Arguelles2,5

1Universidad Veracruzana, Veracruz, Mexico, 2Centro de Hematología y Medicina Interna, Clínica Ruiz, Puebla, Mexico, 3Universidad Anáhuac Puebla, Puebla, Mexico, 4Universidad de las Américas Puebla, Puebla, Mexico, 5Universidad Popular Autónoma del Estado de Puebla, Puebla, Mexico

Background: Multiple sclerosis (MS) is a complex inflammatory, demyelinating and neurodegenerative disease of the central nervous system that causes a whole spectrum of neurological disorders as well as patient’s perception of an abnormal physical, emotional or cognitive state, associated with a profound decrease in the quality of life of affected patients. Currently, autologous hematopoietic cell transplantation (ASCT) is a validated therapeutic approach and has been shown to be superior to the use of new immunomodulatory agents. However, the impact of ASCT on the quality of life of patients with MS remains largely unknown. The objective is to identify the impact of autologous HSCT in the quality of life in patients with MS in a single institution.

Methods: A quasi-experimental, longitudinal, prospective and single-center study was conducted in our institution. The quality of life was determined in patients with MS before and one year after ASCT; it was determined by applying the MS-QoL 54 instrument which is a validated instrument for this pathology. The variables related to the physical and mental components of the instrument as well as demographic characteristics were studied. Patients who could not answer the questionnaire themselves were excluded as well as incomplete questionnaires. ASCT was conducted as outpatients following the “Mexican method”, which employs high-dose both cyclophosphamide and rituximab.

Results: 38 patients answered the questionnaire before and one year after the ASCT. 21 (56%) were female. Median age was 47 years (SD ± 8.85). Of the selected patients, 22 (58%) had relapsing-remitting MS, 12 (32%) primary progressive MS, whereas 4 (11%) had secondary progressive MS. The physical and mental components were analyzed between the quality of life in the patients prior to the ASCT and the follow-up after one year. In the energy component the differences observed before and one year after the ASCT were statistically significant (40.73 vs 49.57, p = 0.04), as well as the differences in the health perceptions (47.1 vs 56.31, p = 0.011), health distress component (40.65 vs 55.26, p = 0.002) and chance in health (31.57 vs 63.81, p <0.0001). On the other hand, in the physical component the differences between before and after one year of ASCT were not statistically significant (p = 0.069) as well as the differences in the mental component either (p = 0.218).

Conclusions: The study suggests that ASCT improves some aspects of the quality of life of persons with MS.

Disclosure: Nothing to declare

21: Autoimmune Diseases

P084 AUTOLOGOUS HEMATOPOIETIC STEM CELL TRANSPLANTATION IN THE TREATMENT OF MULTI-REFRACTORY STIFF PERSON SYNDROME: A CASE STUDY

Tamim Alsuliman 1, Dimitri Psimaras2, Nicolas Stocker1, Simona Sestili1, Anne Banet1, Zoé Van de Wyngaert1, Agnès Bonnin1, Manuela Badoglio3, Mathieu Puyade4,5, Dominique Farge6,5, Mohamad Mohty1, Zora Marjanovic1,5

1Saint-Antoine Hospital, APHP Sorbonne University, Paris, France, 2Hôpital Universitaire Pitié-Salpêtrière, Paris, France, 3EBMT Paris Study Office, Paris, France, 4CHU de Poitiers, Poitiers, France, 5MATHEC, Paris, France, 6Saint-Louis Hospital, Paris, France

Background: Autologous hematopoietic stem cell transplantation (AHSCT) has been successfully used to treat several types of autoimmune diseases (AD) such as multiple sclerosis. (1,2)

The “stiff person syndrome” (SPS) is a rare neurological AD with a prevalence of 1 to 2 patients per million (3), predominantly observed in women (2-3 female/1 man). (3) It is characterized by progressive stiffness of skeletal muscles, episodic painful muscle spasms, and prevention of volitional movements and ambulation in severe cases. Lumbar para-spinal rigidity limits the range body mobility. Spasms due to increased muscle stiffness occur spontaneously or secondary to different external and internal stimuli.(3–5)

Methods: Informed consent was obtained from the patient for the publication of this report. AHSCT is indicated with a grade 1 level of evidence for the treatment of multi-refractory / recurrent SPS. The national committee of transplantation in AD (MATHEC) approved the AHSCT, as a “Clinical Option”, for this patient. The mobilization was performed using cyclophosphamide 1g/m2 D1 and D2 plus G-CSF 30 MUI/day from D6. The conditioning regimen was cyclophosphamide 200 mg/kg total dose, Anti-thymoglobulin 6 mg/kg and Rituximab 500 mg before the conditioning and 500 mg in post-AHSCT.

Results: A 53-years-old female was diagnosed, at the age of 48 years (2016), with Stiff Person Syndrome muscular stiffness. One year later, onset of dysarthria and cerebellar instability were noticed. Neurological cerebellar symptoms progressively increased, with pyramidal involvement over 8 years. Contractions associated with instability increased and later she could no longer run. No cognitive disorder was described.

The spinal cord and brain MRI, alongside EMG did not show damage to the peripheral motor neuron. The ocular movement test was in favor of a cerebellar syndrome with defected floculli. The lumbar puncture revealed the presence of high anti-GAD antibodies titer in the CSF and plasma. The PET CT/CT did not show any underlying neoplasia. Diagnostic criteria included lower back and limbs stiffness, stimulated by emotions, oculomotor disorders, very good response to Valium.

She received six courses of IVIG from September 2016 to May 2017, with the onset of dysarthria. Rituximab was administered three times within two years. Cyclophosphamide was also administered concomitantly for six months. Azathioprine showed no efficacy while fampridine was not tolerated.

At the end of 2019, the Scale for the Assessment and Rating of Ataxia (SARA) score was at 11. Ocular movements test showed worsening nystagmus. Gabapentin was consequently initiated, then stopped rapidly for inefficacy. The patient was referred to hematology department and treated by AHSCT without major complications in 2021.

Six months Post-AHSCT the patient had better flexibility and mobility, could walk for 2 hours with mild assistance. Dysarthria improved with a SARA at 7.5.

2-years Post-AHSCT speech comprehension improved. She walks alone> hour without assistance. Maintain good balance on uneven ground. SARA was at 6.

Table1: Neurological manifestations: before, 6 months, and 2-years post-AHSCT

Before AHSCT

Post-AHSCT period

2 years post-AHSCT

SARA

11

7.5

6

Speech comprehension

impacted

Good

Very good

Walking

Very hard, robot-like

Better

Very good

Aide for walking

Permanent

Only if uneven ground

None

Stiffness

Severe

Very mild

Almost no stiffness

Flexibility

No flexibility

Better

Very good

Dysarthria

Severe

Better

Very good

Conclusions: AHSCT, as an intensive immunablation followed by was well tolerated and a very effective treatment for this patient with of immunotherapy -refractory SPS. This experience supports its use for refractory stiff-person syndrome.

Disclosure: Nothing to declare

4: CAR-based Cellular Therapy – Clinical

P085 BRIDGING THERAPY PRIOR TO TREATMENT WITH ANTI-CD19 CAR T CELLS FOR RELAPSED/REFRACTORY ACUTE LYMPHOBLASTIC LEUKEMIA IN CHILDREN AND YOUNG ADULTS - A MULTINATIONAL RETROSPECTIVE ANALYSIS

Maike Breidenbach1, Peter Bader2, Andishe Attarbaschi3, Claudia Rossig4, Roland Meisel5, Markus Metzler6, Marion Subklewe1, Fabian Mueller7, Paul-Gerhard Schlegel8, Irene Teichert von Lüttichau9, Jean-Pierre Bourquin10, Gabriele Escherich11, Gunnar Cario12, Peter Lang13, Ramona Krauss1, Arend von Stackelberg14, Semjon Willier15, Christina Peters3, Tobias Feuchtinger 16,1

1Ludwig Maximilians University Munich, Munich, Germany, 2Goethe University Frankfurt, University Hospital, Frankfurt, Germany, 3St. Anna Children’s Hospital, Vienna, Austria, 4University Children’s Hospital Muenster, Muenster, Germany, 5Medical Faculty, Heinrich-Heine-University, Duesseldorf, Germany, 6University Hospital Erlangen, Erlangen, Germany, 7Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, Germany, 8Pediatric Hematology and Oncology and Stem Cell Transplantation, University Children’s Hospital Wuerzburg, Wuerzburg, Germany, 9TUM School of Medicine, Children’s Hospital Munich Schwabing, Technical University of Munich, Munich, Germany, 10University Children’s Hospital Zurich, Zurich, Switzerland, 11Clinic of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, 12University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany, 13University Children’s Hospital Tübingen, Tübingen, Germany, 14Charité Universitaetsmedizin, Berlin, Germany, 15University Medical Center Freiburg, Freiburg, Germany, 16Pediatric Hematology, Oncology and Stem Cell Transplantation, University Medical Center Freiburg, Freiburg, Germany

Background: Chimeric antigen receptor (CAR) T cells targeting CD19 are a well-established treatment option for children and young adults suffering from relapsed and/or refractory B-lineage acute lymphoblastic leukemia (ALL). Bridging therapy is the treatment between eligibility and administration of CAR T cells. Bridging has been designed to achieve a low leukemia burden prior to CAR T cell infusion. However, systematic data of bridging therapy are still limited and the effect on outcome, side effects and response to CAR T cell therapy is still poorly understood. With this retrospective, multinational, large-scale study, we strive to understand the impact of low- and high-intensity bridging regimens on a variety of outcome parameters in order to improve the basis for clinical decision making in bridging therapy prior to CAR T cell administration.

Methods: Real-world data were collected from 82 patients receiving 87 CAR T cell therapies from twelve sites in Germany, Austria and Switzerland. Treatments were classified into categories 1) no systemic therapy, 2) low-intensity therapy and 3) high-intensity therapy. Bridging therapies were defined as high-intensity if at least one chemotherapeutic agent of the following was given: cyclophosphamide/ifosfamide, etoposide, anthracyclines or other agents with high toxicity potential (intravenous methotrexate, platinum-based antineoplastic drugs, thiotepa, high-dose cytarabine, fludarabine). Low-intensity bridging therapies comprised the administration of steroids, vincristine, low-dose cytarabine, PEG-asparaginase/Erwinia asparaginase and oral maintenance therapy (mercaptopurine, thioguanine, oral methotrexate, hydroxyurea). The administration of specific chemotherapeutic agents as well as immunotherapies and targeted therapies was assessed. CAR therapies comprised CD19 2nd generation CAR T cell products from commercial and academic providers.

Results: 38 of 87 treatments were classified as high-intensity and 34 as low-intensity bridging regimens. Prior to 14 CAR T cell administrations no systemic bridging therapy was given, 1 of 87 bridging regimens could not be stratified. Between eligibility and apheresis, mostly low-intensity therapy or no systemic therapy was given. Within the period between apheresis and CAR T cell infusion, treatment diversified due to the heterogeneity of the cohort. Patient characteristics are listed in Table 1. Patients receiving a high-intensity bridging therapy had a significantly higher tumor burden at time point of eligibility defined by blasts in bone marrow and by measurement of minimal residual disease (MRD) compared to patients treated with a low-intensity or no systemic bridging therapy. Tumor burden within the two groups converged over the time of bridging therapy. However, until time of lymphodepletion, patients in the high-intensity group had significantly more often bacterial adverse events and mucositis and showed a lower performance status (Karnofsky/Lansky) than patients in the low-intensity/no systemic therapy group. High-intensity bridging therapy did not improve overall or disease-free survival.

Conclusions: In this retrospective cohort data, a low-intensity bridging therapy was associated with equivalent outcome of CAR T cell therapy in terms of overall and disease-free survival, when compared to high-intensity regimens. High-intensity bridging therapy was associated with more mucositis, bacterial adverse events and worsened performance status. Our study suggests that a low-intensity bridging regimen may be preferred whenever tumor burden and disease kinetics allow this treatment strategy.

Disclosure: Bader: Medac: Consultancy, Patents & Royalties: medac, Research Funding; Novartis: Consultancy, Research Funding; Neovii: Research Funding; BMS: Research Funding. Attarbaschi: JazzPharma: Honoraria. Rossig: Amgen, BMS, Novartis, Pfizer, Roche, MSD: Honoraria. Meisel: medac: Consultancy, Research Funding, Speakers Bureau; Novartis: Consultancy, Research Funding, Speakers Bureau; CELGENE BMS: Consultancy, Research Funding, Speakers Bureau; Bluebird Bio: Consultancy, Speakers Bureau; CRISPR Therapeutics: Consultancy, Research Funding, Speakers Bureau; Vertex: Consultancy, Research Funding, Speakers Bureau; Miltenyi Biotech: Research Funding; Gilead/KITE: Research Funding. Subklewe: Incyte Biosciences: Consultancy, Honoraria; AvenCell: Consultancy, Honoraria; Ichnos Sciences: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria, Other: Travel Support, Speakers Bureau; AstraZeneca: Speakers Bureau; Takeda: Consultancy, Honoraria, Research Funding; Seagen: Research Funding; Roche: Consultancy, Honoraria, Other: Travel Support, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau; Miltenyi Biotec: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Gilead/Kite: Consultancy, Honoraria, Other: Travel Support, Research Funding, Speakers Bureau; BMS/Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Amgen: Consultancy, Honoraria, Research Funding; Molecular Partners: Consultancy, Honoraria, Research Funding; GSK: Speakers Bureau; LAWG: Speakers Bureau; Springer Healthcare: Speakers Bureau; AbbVie: Consultancy, Honoraria; Autolus: Consultancy, Honoraria; advesya (CanCell Therapeutics): Consultancy, Honoraria; Genmab US: Consultancy, Honoraria; Interius BioTherapeutics: Consultancy, Honoraria; Nektar Therapeutics: Consultancy, Honoraria; Orbital Therapeutics: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Scare: Consultancy, Honoraria. Mueller: Miltenyi, BMS, Novartis, Gilead, Janssen, Incyte, AstraZeneca, Abbvie, Sobi, Beigene: Honoraria; BMS, AstraZeneca, Gilead: Research Funding; AstraZeneca, BMS, Gilead, Janssen, Miltenyi biomedicine, Novartis: Consultancy. Cario: JazzPharma: Speakers Bureau; Servier, Amgen: Research Funding. Peters: AMGEN, Neovii, Jazz: Research Funding; Novartis: Consultancy; Riemser, Medac: Honoraria; AOP Orphan Drugs, Jazz, Neovii: Other: Meeting/Travel grant; Novartis, AMGEN: Membership on an entity’s Board of Directors or advisory committees. Feuchtinger: Servier: Research Funding; Miltenyi Biotec: Research Funding.

4: CAR-based Cellular Therapy – Clinical

P086 SAFETY AND EFFICACY COMPARISON OF HUMANIZED CD19 CAR-T VERSUS BLINATUMOMAB THERAPY FOR RELAPSED/REFRACTORY B-ALL PATIENTS

Kexin Wang 1,2,3,4, Songfu Jiang5, Yongxian Hu1,2,3,4, He Huang1,2,3,4

1Bone Marrow Transplantation Center, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China, 2Liangzhu Laboratory, Zhejiang University Medical Center, Hangzhou, China, 3Institute of Hematology, Zhejiang University, Hangzhou, China, 4Zhejiang Province Engineering Research Center for Stem Cell and Immunity Therapy, Hangzhou, China, 5The First Affiliated Hospital, Wenzhou Medical University, Wenzhou, China

Background: Chimeric antigen receptor T-cells targeting CD19 (CART19) and blinatumomab are 2 major types of novel immunotherapy strategies for patients with relapsed/refractory (R/R) B-cell acute lymphoblastic leukemia (ALL). Choosing which types of immunotherapies to use for individual patients can be a challenge.

Methods: We performed a study to compare the efficacy and safety of blinatumomab versus CART19 for R/R B-ALL. Patient data in CART19 cohort were from the clinical trial (NCT04532268). Data in blinatumomab cohort were from the real-world data. The complete remission (CR) rate, overall survival (OS), leukemia-free survival (LFS), and toxicities were compared in the 2 cohorts.

Results: A total of 106 patients were enrolled including 61 patients in hCART19 cohort and 45 patients in blinatumomab cohort. 36.06% (22/61) patients in hCART19 cohort and 46.67% (21/45) patients in blinatumomab cohort bridged to allogenic hematopoietic stem cell transplantation (allo-HSCT) respectively (P>0.05). The age, gender, prior treatment lines, and extramedullary disease were no statistically different between two cohorts (P>0.05). The tumor burden in hCART19 cohort was higher than blinatumomab (44.60% vs. 2.29%, P<0.001). CR or CR with incomplete count recovery (CRi) rate by day 28 was 96.6% (56/61) in hCART19 cohort with 53 patients having minimal residual disease (MRD) negativity, and 77.8% (35/41) in blinatumomab cohort with 34 patients having MRD negativity, respectively (P = 0.008). With a median follow-up of 10 months, patients receiving allo-HSCT after infusion have similar OS and LFS in two cohorts. For patients not receiving allo-HSCT after infusion, the median LFS was 54 days in blinatumomab cohort and 180 days in hCART19 cohort, the median OS was 300 days in hCART19 cohort and not reached in blinatumomab cohort. In addition, subgroup analysis revealed that patients with higher tumor burden (MRD>20%) before infusion have better CR rate (70.6% vs. 33.3%, P = 0.007) in hCART19 cohort than in blinatumomab cohort, as well as better OS after 30 days from infusion (P = 0.023). For patients with lower tumor burden (MRD≤20%), CR rate and OS are similar in hCART19 and blinatumomab cohort (CR: 83.3% vs. 77.8%, P = 0.514). Patients with higher tumor burden in hCART19 cohort had a higher incidence of severe cytokine release syndrome than blinatumomab (53.7% vs. 31.2%, P = 0.011). The incidence of severe immune effector cell-associated neurotoxicity syndrome in two cohorts were similar (4.9% vs. 0%, P = 0.656). All toxicities were reversible.

Conclusions: Our study suggests that hCART19 has better complete remission efficacy and long-term survival than blinatumomab in R/R B-ALL patients with high tumor burden (MRD>20%). For patients with low tumor burden, blinatumomab has similar therapeutic efficacy with hCART19. Thus, for patients with low tumor burden, blinatumomab is a good choice while for high tumor burden, hCART19 is a good choice.

Disclosure: Nothing to declare.

4: CAR-based Cellular Therapy – Clinical

P087 PREDICTIVE VALUE OF PRE-TREATMENT CIRCULATING TUMOR DNA GENOMIC LANDSCAPE IN PATIENTS WITH R/RMM UNDERGOING ANTI-BCMA CAR-T THERAPY: INSIGHTS FROM TUMOR CELLS AND T CELLS

Rongrong Chen 1, Chunxiang Jin1, Tingting Yang1, Kai Liu1, Mengyu Zhao1, Mingming Zhang1, Pingnan Xiao1, Jingjing Feng1, Ruimin Hong1, Shan Fu1, Jiazhen Cui1, Simao Huang1, Guoqing Wei1, He Huang1, Yongxian Hu1

1The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China

Background: B-cell maturation antigen (BCMA)-directed chimeric antigen receptor T (CAR-T) therapy has demonstrated remarkable efficacy and safety in patients with refractory or relapsed multiple myeloma (R/RMM). Circulating tumor DNA (ctDNA) reportedly exhibits distinct advantages in addressing the challenges posed by tumor heterogeneity in distribution and genetic variations in R/RMM.

Methods: Herein, we performed a comprehensive ctDNA analysis of 108 patients with R/RMM to determine its predictive value for prognosis after CAR-T therapy.

Results: We observed that high ctDNA level (å 1430ng/ml) strongly associated with shorter progression-free survival (PFS)(P = 0.007). Moreover, it was also significantly related to higher percentages of multiple myeloma cells in the bone marrow that was measured using flow cytometry (P = 0.013), lower percentages of CAR-T cells in the peripheral blood at peak (P = 0.037), and higher percentages of CD8+ T cells in the peripheral blood (P = 0.034), which enabled the integration of tumor and T cell effector-mediated factors for assessing treatment failure. Alterations in several individual genes indicated poor outcomes, including IGLL5 (P = 0.004), which plays a significant role in the immune response; IRF4 (P = 0.024), which is involved in NF-κB signaling pathway; and CREBBP (P = 0.041), which participates in the epigenetic regulation of gene expression. Multivariate logistic regression analysis revealed that ERBB4 expression was significantly associated with resistance to CAR-T cell therapy (P = 0.04). Among the five patients with ERBB4 mutation, four failed to achieve a complete response, and all (5/5) of them exhibited progression within 6 months. In addition, patients with two multiple-site ctDNA mutations had poor outcomes, with PFS of less than 6 months (P <0.001).

Conclusions: Finally, we built a ctDNA-based risk model that serves as an adjunct non-invasive measure of substantial tumor burden and a prognostic genetic feature that can assist in predicting the response to anti-BCMA CAR-T therapy.

Clinical Trial Registry: The study was conducted in accordance with the tenets of the Declaration of Helsinki and registered in the Chinese Clinical Trial Registry (ChiCTR2100046474) and National Clinical Trial (NCT04670055, NCT05430945).

Disclosure: Nothing to declare

4: CAR-based Cellular Therapy – Clinical

P088 FINAL RESULTS OF PROSPECTIVE CLINICAL TRIAL EVALUATING OUTPATIENT ADMINISTRATION OF AXICABTAGENE CILOLEUCEL IN HIGH-GRADE B CELL LYMPHOMA

Bhagirathbhai Dholaria1, Shakthi Bhaskar1, Vivek Patel1, Eden Biltibo1, Salyka Sengsayadeth1, Andrew Jallouk1, James Jerkins1, Brittney Baer1, Nur Ali1, David Morgan1, Muhamed Baljevic1, Bipin Savani1, Adetola Kassim1, Olalekan Oluwole 1

1Vanderbilt University Medical Center, Nashville, United States

Background: Pivotal trials of Axicabtagene Ciloleucel (axi-cel) were conducted in the inpatient setting because of the high rate of severe Cytokine Release Syndrome (CRS) and Immune effector Cell-Associated Neurotoxicity Syndrome (ICANS).

Methods: We devised a single-center non-randomized prospective trial (NCT05108805) to evaluate the feasibility and safety of outpatient administration of axi-cel. The primary endpoint of the study was to explore the safety and feasibility of outpatient Axi-cel. Eligible pts with R/R DLBCL per axi-cel FDA package label and met ZUMA 1 criteria were included in the study. They were fitted with wearable devices to measure temp, BP, Pulse-ox and heart rate for continuous remote monitoring. Pts were seen in-person once daily and had remote video telehealth evaluation at 16:00 and 22:00 daily through day 14. Fever up to 102F without other symptoms was managed in outpatient clinic. Here we report the final outcomes of complete study cohort.

Results: Twenty consecutive patients (pts) were treated from January 2022 to October 2023. Data cut off was December 16, 2023. The median pt age was 68 (range: 35-81) yrs and stage III-IV disease in 18 (90%) pts. Before lymphodepletion, baseline LDH was 251 U/L. The median number of therapies was 2.5 (range: 1-4), 10 (50%) pts ≥ 3 lines of therapies. The estimated median follow-up was 178 (95% CI: 81-258) days. Prophylactic dexamethasone 10mg/day, days 0-2 was given to 18 (90%) pts. 18 (90%) pts remained outpatient at least 72 hours after axi-cel administration, and one (5%) pt remained outpatient through day 30. The median time from day 0 to hospitalization was 3 (range 1-6) days and the median hospital stay was 5.5 (range 0-21) days. The reason for hospitalization was CRS in all admitted pts. Overall CRS was reported in 19 (95%) pts (grade 1 = 11, grade 2 = 8), ICANS in 8 (40%) pts (grade 1 = 4; grade 3 = 4). Time onset from day 0 to CRS was 3 (range 1-6) days and ICANS was 5 (range: 4-10) days. No pt had grade ≥3 CRS or grade ≥4 ICANS or treatment-related death by last follow-up. The median duration of CRS and ICANS were 3 days, each (Table 1).

Two (10%) pts required ICU admission (COPD exacerbation, SVT due to CRS) through day 30. By day 30, 14 (70%) pts achieved CR. There were 3 (15%) pts with PD/refractory disease at the last follow-up with one death from relapsed disease. Median EFS or OS was not reached by last follow up. Six-month estimated OS was 91% (95% CI: 0.74-1.0) and EFS was 81% (95% CI: 0.62-1.0). Our results were favorable compared to ZUMA 1 which reported median hospitalization of 15 days, grade ≥ 3 CRS and ICANS in 13% and 28% of pts, respectively and 6-months PFS of 49%.

Table 1: Outcomes of patients

Outcomes

N = 20 (%)

Day 30 responses

CR

14 (70%)

SD

4 (20%)

PD

2 (10%)

Day 90 responses (N = 17)

CR

11 (65%)

PR

1 (6%)

SD

2 (12%)

PD

3 (18%)

Best response

CR

17 (85%)

SD

1 (5%)

PD

2 (10%)

Median Time to hospitalization from day 0 (N = 19), days

3 (1- 6)

Median inpatient days by D + 30, days

5.5 (0-21)

Pts with ICU admission by D + 30, N

2 (10%)

CRS

Grade 0

1 (5%)

Grade 1

11 (55%)

Grade 2

8 (40%)

Median time to CRS from day 0, days

3 (1-6)

Median duration of CRS, days

3 (1-5)

ICANS

Grade 0

12(60%)

Grade 1

4 (20%)

Grade 3

4 (20%)

Median time to ICANS from day 0, days

5 (4-10)

Median duration of ICANS, days

3 (1-9)

Tocilizumab given

17 (85%)

Median doses of tocilizumab

2 (0-3)

Prophylactic dexamethasone

18 (90%)

Systemic steroids in addition to prophylactic dexamethasone

8 (40%)

Conclusions: This prospective feasibility trial confirmed that axi-cel can be safely administered in the outpatient settings with prophylactic steroids and remote monitoring with wearable devices without compromising safety or efficacy of CAR T therapy. Longer follow-up data will be presented at the meeting.

Disclosure: Bhagirathbhai Dholaria: Institutional research funding: Janssen, Angiocrine, Pfizer, Poseida, MEI, Orcabio, Wugen, Allovir, NCI, Atara, Gilead, Molecular templates, BMS, AstraZeneca, Adicet. Consulting/Advisor: MJH, Janssen, Pluri Biotech, BOXER CAPITAL, Ellipsis pharma, Lumanity, Autolus, Acrotech, ADC therapeutics, Gilead

Olalekan Oluwole: Consultancy and advisory board for: Pfizer, Kite, Gilead, AbbVie, Janssen, TGR, ADC, Novartis, Caribou, Cargo, Epizyme, Nektar, Autolus, Allogene. Institution funding: Kite, Pfizer, Daichi Sankyo, Allogene. Honoraria: Pfizer, Gilead

Eden Biltibo: BeiGene (consulting)

Andrew Jallouk: Kite-Gilead (consulting)

Rest of the authors declare no relevant COI.

4: CAR-based Cellular Therapy – Clinical

P089 EUPLAGIA-1: SEVEN-DAY VEIN-TO-VEIN POINT-OF-CARE MANUFACTURED GLPG5201 ANTI-CD19 CAR-T CELLS DISPLAY EARLY PHENOTYPES IN RELAPSED/REFRACTORY CLL INCLUDING RT

Esmée P. Hoefsmit 1, Sandra Blum2, Claire Vennin1, Kirsten Van Hoorde3, Sergi Betriu4, Leticia Alserawan4, Julio Delgado4, Nadia Verbruggen5, Anna D.D. van Muyden1, Henriëtte Rozema1, Ruiz Astigarraga1, Margot J. Pont1

1Galapagos BV, Oegstgeest, Netherlands, 2Galapagos GmbH, Basel, Switzerland, 3Open Analytics NV, Antwerp, Belgium, 4Hospital Clínic de Barcelona, Barcelona, Spain, 5Galapagos NV, Mechelen, Belgium

Background: The efficacy of chimeric antigen receptor T-cell (CAR-T) therapies relies in part on the preservation of early T-cell phenotypes and robust expansion in patients. Our decentralized and automated point-of-care (PoC) manufacturing platform allows administration of fresh autologous GLPG5201 CAR-T cells with a vein-to-vein time of 7 days.

Methods: Euplagia-1 (CTIS: 2022-501686-47-00) is an ongoing Phase 1/2 dose escalation study of PoC manufactured GLPG5201, an anti-CD19 4-1BB/CD3z CAR-T cell product, in patients with relapsed/refractory chronic lymphocytic leukemia or small lymphocytic lymphoma (CLL/SLL), including Richter Transformation (RT). Feasibility of PoC manufacturing, T-cell phenotyping in apheresis starting material and in final product as well as correlation between T-cell phenotypes and in-patient pharmacokinetics were evaluated. Data cut-off was 06 September 2023. T-cell phenotyping was assessed using exploratory flow cytometry (n = 12 evaluable patients at data cut-off) and pharmacokinetics were determined by qPCR (n = 13 evaluable patients at data cut-off).

Results: All phase 1 GLPG5201 clinical batches (n = 15) were successfully manufactured at the PoC facility and infused as a fresh product at one clinical site. Encouraging clinical efficacy was observed, with a 93% best objective response rate and a 57% complete response rate in the intention-to-treat analysis set (clinical data submitted in a separate abstract). The median vein-to-vein time was 7 days (range 7–14), with 80% of patients (12/15) receiving GLPG5201 in 7 days. Characterization of GLPG5201 showed an increase in CD4+ and CD8+ CAR-T cells with early phenotypes (naïve, stem cell memory [TN/SCM] and central memory [TCM]) compared to apheresis starting material. The median increase in percentage of early phenotypes (i.e. TN/SCM + TCM) in CD4+ and CD8+ CAR-T cells was 24.0 (increased in 8/10 patients) for CD4+ T-cells and 52.1 (increased in 10/10 patients) for CD8+ T-cells. Robust in vivo expansion of GLPG5201 was detected in all patients treated with both dose levels (DL1: 35×106 CAR+ T-cells, n = 6; DL2: 100×106 CAR+ T-cells, n = 7). Median peak expansion (Cmax) was 4.4×105 copies/μg DNA (range 0.52×105 – 9.2×105), median time to peak expansion (Tmax) was 14 days (range 9 – 20) and median area under the curve from day 0–28 (AUCd0-28) was 6.1×106 copies/μg DNA x days (range 0.63×106 – 9.6×106). Higher exposure (AUCd0-28) was observed for patients infused with DL2 (median AUCd0-28 8.8×106 copies/μg DNA x days) compared to DL1 (median AUCd0-28 3.5×106 copies/μg DNA x days). Expansion and exposure were similar for patients with CLL and patients with CLL + RT. 8/10 patients had measurable GLPG5201 in peripheral blood at week 14 post-infusion. Persisting CAR-T cells were detected up to 15 months post-infusion. Moreover, abundance of both TN/SCM CD4+ and CD8+ CAR-T cells in the final product positively correlated with CAR-T cell exposure in patients (Spearman rank correlation (95% CI) for CD4+: 0.791 (0.27-0.99) and for CD8+: 0.791 (0.28-0.98); n = 11).

Conclusions: The Galapagos PoC manufacturing platform enables a 7-day vein-to-vein infusion. Early phenotype CAR-T cells were enriched in the final product compared to apheresis starting material. GLPG5201 demonstrated robust expansion and durable persistence in CLL and CLL + RT patients post-infusion.

Clinical Trial Registry: CTIS: 2022-501686-47-00

Disclosure: Esmée P. Hoefsmit: Employee of Galapagos BV, Netherlands

Sandra Blum: Employee of Galapagos GmbH, Switzerland

Claire Vennin: Employee of Galapagos BV, Netherlands

Kirsten Van Hoorde: Employee of Open Analytics NV, Belgium

Sergi Betriu: Nothing to declare

Leticia Alserawan: Nothing to declare

Julio Delgado: Nothing to declare

Nadia Verbruggen: Employee of, and shareholder in, Galapagos NV, Belgium

Anna D. D. van Muyden: Employee of Galapagos BV, Netherlands

Henriëtte Rozema: Employee of Galapagos BV, Netherlands

Ruiz Astigarraga: Employee of Galapagos BV, Netherlands

Margot J. Pont: Employee of Galapagos BV, Netherlands

The study was funded by Galapagos NV (Mechelen, Belgium).

4: CAR-based Cellular Therapy – Clinical

P090 INCIDENCES AND FACTORS ASSOCIATED WITH EARLY HEMATOTOXICITY AFTER CAR T-CELL THERAPY ASSESSED BY EHA/EBMT ICAHT CRITERIA

Emily Liang 1,2, Aya Albittar1, Andrew Portuguese1,2, Jennifer Huang1,2, Natalie Wuliji1,2, Qian Wu1, Joseph De Los Reyes1,2, Nikki Pin1, Aiko Torkelson1, Delaney Kirchmeier1, Abigail Chutnik1, Barbara Pender1, Joshua Hill1,2, Noam Kopmar1,2, Rahul Banerjee1,2, Andrew Cowan1,2, Damian Green1,2, Ajay Gopal1,2, Christina Poh1,2, Mazyar Shadman1,2, Alexandre Hirayama1,2, Brian Till1,2, Erik Kimble1,2, Lorenzo Iovino1,2, Aude Chapuis1,2, Folashade Otegbeye1,2, Ryan Cassaday1,2, Filippo Milano1,2, Cameron Turtle3, David Maloney1,2, Jordan Gauthier1,2

1Fred Hutchinson Cancer Center, Seattle, United States, 2University of Washington, Seattle, United States, 3University of Sydney, Sydney, Australia

Background: The observation that distinct patterns of hematologic toxicity are not adequately captured by CTCAE grading led to the recently developed EHA/EBMT immune effector cell-associated hematotoxicity (ICAHT) grading system (Rejeski et al, Blood, 2023). We applied the ICAHT grading system to patients undergoing CAR T-cell therapy at a large institution in the US and assess factors associated with grade ≥3 ICAHT.

Methods: Adults who underwent CAR T-cell therapy for hematologic malignancies with commercial or investigational products at our center between 2013 and 2023 were included (n = 454). Grading of early hematotoxicity (day-0-30 after CAR T-cell cell infusion) was automated using the heatwaveR package in R per ICAHT criteria detailed in Rejeski et al, Blood, 2023. Associations with 50 patient, disease-related, and laboratory factors, and ICAHT grade ≥3 were modeled using univariate and multivariable logistic regression.

Results: The most common disease types were aggressive non-Hodgkin lymphoma (n = 216; 48%), acute lymphoblastic leukemia (n = 82; 18%), and multiple myeloma / plasma cell leukemia (n = 61; 13%) (Table). The most common CAR T-cell products were investigational CD19 CAR T-cell products (n = 180; 40%), axicabtagene ciloleucel (n = 114; 25%), and lisocabtagene maraleucel (n = 58; 13%).

Incidences of early ICAHT grades 1, 2, 3, and 4 were 141 (31%), 177 (39%), 47 (10%), and 30 (7%), respectively. Patients with grades 3-4 ICAHT had worse overall survival compared to those with grade 0-2 ICAHT (median of 6 s. 18 months, p < 0.001).

Baseline patient factors associated with grade 3-4 ICAHT included ALL (reference: aggressive NHL, OR = 3.0, 95% CI, 1.7-5.6, p < 0.001) and age (OR = 0.97, 95% CI, 0.96-0.99, p = 0.003). Pre-lymphodepletion (LD) laboratory factors associated with grade 3-4 ICAHT included ANC (OR = 0.18 per log10, 95% CI, 0.10-0.30, p < 0.001), lactate dehydrogenase (OR = 7.4 per log10U/L, 95% CI, 3.3-17.4, p < 0.001), C-reactive protein (CRP; OR = 5.9 per log10mg/L, 95% CI, 2.8-14.0, p < 0.001), and ferritin (OR = 6.5 per log10mg/L, 95% CI, 3.0-16.0, p < 0.001). Peak CRP (OR = 12.8, 95% CI, 5.3-33.9, p < 0.001) and ferritin (OR = 5.6, 95% CI, 3.7-8.7, p < 0.001) after CAR T-cell infusion were strongly associated with grade 3-4 ICAHT. In a multivariable model including disease type, pre-LD ANC, pre-LD LDH, and peak CRP, pre-LD ANC (OR = 0.22, 95% CI, 0.11-0.42, p < 0.001), pre-LD LDH (OR = 5.0, 95% CI, 1.7-14.6, p = 0.003), and peak CRP (OR = 6.7, 95% CI, 2.7-18.4) remained independently associated with grade 3-4 ICAHT.

Table. Demographic, disease, and treatment characteristics (N = 454)

Age at infusion, median (range)

60 (50, 68)

Male sex

286 (63%)

Prior HCT

186 (41%)

Disease

Aggressive NHL

216 (48%)

ALL

82 (18%)

MM/PCL

61 (13%)

Indolent NHL

53 (12%)

CLL

42 (9%)

CAR T-cell product

Investigational CD19 CAR T-cell product

180 (40%)

Commercial CD19 CAR T-cell product with CD28 costimulatory domain (axi-cel, brexu-cel)

143 (31%)

Commercial CD19 CAR T-cell product with 4-1BB costimulatory domain (liso-cel, tisa-cel)

70 (15%)

Commercial BCMA CAR T-cell product (cilta-cel, ide-cel)

61 (13%)

Conclusions: We found that 17% of patients undergoing CAR T-cell therapy at our center developed grade 3-4 hematotoxicity by EHA/EBMT ICAHT criteria. Grade 3-4 ICAHT was associated with worse OS. Multivariable logistic regression of factors associated with grade 3-4 ICAHT identified pre-LD ANC, pre-LD LDH, and peak CRP as independent predictors of grade 3-4 ICAHT.

Disclosure: Joshua Hill: allovir: Consultancy, Research Funding; moderna: Consultancy; deverra: Research Funding.

Rahul Banerjee: BMS: Consultancy; Janssen: Consultancy; Genentech: Consultancy; SparkCures: Consultancy; Sanofi: Consultancy; Caribou: Consultancy; Pfizer: Consultancy; Pack Health: Research Funding.

Andrew Cowan: BMS, Adaptive: Consultancy; Adaptive Biotechnologies, Harpoon, Nektar, BMS, Janssen, Sanofi, Abbvie: Research Funding.

Damian Green: Cellectar Biosciences: Research Funding; SpringWorks Therapeutics: Research Funding; Celgene: Consultancy; GlaxoSmithKline: Membership on an entity’s Board of Directors or advisory committees; Sanofi: Research Funding; Janssen Biotech: Consultancy, Research Funding; Ensoma: Consultancy; Seattle Genetics: Consultancy, Research Funding; Juno Therapeutics A BMS Company: Patents & Royalties, Research Funding.

Ajay Gopal: Compliment Corporation: Current holder of stock options in a privately-held company; Incyte, Kite, Morphosys/Incyte, ADCT, Acrotech, Merck, Karyopharm, Servier, Beigene, Cellectar, Janssen, SeaGen, Epizyme, I-Mab bio, Gilead, Genentech, Lilly, Caribou, Fresenius-Kabi: Consultancy; Merck, I-Mab bio, IgM Bio, Takeda, Gilead, Astra-Zeneca, Agios, Janssen, BMS, SeaGen, Teva, Genmab: Research Funding.

Christina Poh: BeiGene: Consultancy; Seattle Genetics: Consultancy; Incyte: Research Funding; Acrotech: Consultancy.

Mazyar Shadman: Fate Therapeutics: Consultancy; Genmab: Consultancy, Research Funding; Vincerx: Research Funding; MorphoSys/Incyte: Consultancy, Research Funding; Eli Lilly: Consultancy; Bristol Myers Squibb: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Kite, a Gilead Company: Consultancy; AbbVie: Consultancy, Research Funding; Mustang Bio: Consultancy, Research Funding; ADC therapeutics: Consultancy; BeiGene: Consultancy, Research Funding; AstraZeneca: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding; Janssen: Consultancy; MEI Pharma: Consultancy; Regeneron: Consultancy; TG Therapeutics: Research Funding.

Alexandre Hirayama: Novartis: Honoraria; Bristol Myers Squibb: Honoraria, Research Funding; Nektar Therapeutics: Honoraria, Research Funding; Juno Therapeutics, a Bristol Myers Squibb Company: Research Funding.

Till: Mustang Bio: Consultancy, Patents & Royalties, Research Funding; BMS/Juno Therapeutics: Research Funding; Proteios Technology: Consultancy, Current holder of stock options in a privately-held company.

Kimble: Juno/BMS: Research Funding.

Lorenzo Iovino: Mustang Bio: Current equity holder in publicly-traded company.

Aude Chapuis: Juno Therapeutics: Research Funding.

Ryan Cassaday: Amgen: Consultancy, Honoraria, Research Funding; Merck: Research Funding; Incyte: Research Funding; Autolus: Membership on an entity’s Board of Directors or advisory committees; Pfizer: Consultancy, Honoraria, Research Funding; Servier: Research Funding; Vanda Pharmaceuticals: Research Funding; Jazz: Consultancy, Honoraria; Kite/Gilead: Consultancy, Honoraria, Research Funding; PeproMene Bio: Membership on an entity’s Board of Directors or advisory committees; Seagen: Other: Spouse was employed by and owned stock in Seagen within the last 24 months.

Filippo Milano: ExCellThera Inc.: Research Funding.

David Maloney: A2 Biotherapeutics: Consultancy, Current holder of stock options in a privately-held company, Honoraria, Other: Member of the Scientific Advisory Board; Juno Therapeutics: Consultancy, Honoraria, Patents & Royalties: Rights to royalties from Fred Hutch for patents licensed to Juno Therapeutics/BMS, Research Funding; Janssen: Consultancy, Honoraria; Legend Biotech: Consultancy, Honoraria, Research Funding; Mustang Bio: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Lyell Immunopharma: Other: Member, CAR T Steering Committee; Incyte: Consultancy, Honoraria; Gilead Sciences: Consultancy, Honoraria, Other: Member, Scientific Review Committee, Research Scholars Program in Hematologic Malignancies; Kite, a Gilead Sciences: Consultancy, Honoraria, Research Funding; Pharmacyclics: Consultancy, Honoraria; Umoja: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Other: Participation on a Data Safety Monitory Board, Research Funding; Genentech: Consultancy, Honoraria, Other: Chair and Member of the Lymphoma Steering Committee; MorphoSys: Consultancy, Honoraria; Bristol Myers Squibb: Consultancy, Honoraria, Other: Member of the JCAR017 EAP-001 Safety Review Committee and Member, CLL Strategic Council, Member of the JCAR017-BCM-03 Scientific Steering Committee under BMS, Research Funding; Amgen: Consultancy, Honoraria; Navan Technologies: Consultancy, Honoraria, Other: Member of the Scientific Advisory Board; Bioline Rx: Consultancy, Membership on an entity’s Board of Directors or advisory committees, Other: Participation on a Data Safety Monitory Board; Fred Hutch: Other: rights to royalties for patents licensed to Juno; Navan Technologies: Current holder of stock options in a privately-held company; Chimeric Therapeutics: Other: Member of the Scientific Advisory Board; ImmPACT Bio: Other: Member, Clinical Advisory Board, CD19/CD20 bi-specific CAR-T Cell Therapy Program; Interius: Other: Member, Clinical Advisory Board.

Jordan Gauthier: Kite Pharma: Consultancy, Honoraria; MorphoSys: Consultancy, Research Funding; Angiocrine Bioscience: Research Funding; Century Therapeutics: Other: Independent data review committee; Celgene (a Bristol Myers Squibb company): Research Funding; Legend Biotech: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Juno Therapeutics (a Bristol Myers Squibb company): Research Funding; Sobi: Consultancy, Honoraria, Research Funding.

4: CAR-based Cellular Therapy – Clinical

P091 COMPARISON OF IMMUNOPHENOTYPIC AND FUNCTIONAL PROPERTIES OF ANTI-CD19 CAR-T CELL PRODUCTS MANUFACTURED USING CLINIMACS PRODIGY AND G-REX PLATFORMS

Ekaterina Malakhova1, Dmitriy Pershin 1, Viktoria Vedmedskaia1, Mariia Fadeeva1, Elena Kulakovskaya1, Oyuna Lodoeva1, Tatiana Sozonova1, Elvira Musaeva1, Yakov Muzalevskii1, Alexei Kazachenok1, Vladislav Belchikov1, Anastasia Melkova1, Larisa Shelikhova1, Olga Molostova1, Michael Maschan1

1Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology, and Immunology, Moscow, Russian Federation

Background: The use of anti-CD19 CAR-T cell therapy for treating B cell malignancies has shown impressive results in recent years. Today, there are several cell culture platforms that allow the manufacturing of cell products for subsequent clinical use; the issue of choosing a platform for the manufacturing of CAR-T remains relevant. This study compares the immunophenotypic and functional properties of final anti-CD19 cell products manufactured using the CliniMACS Prodigy and G-Rex platforms.

Methods: A total of 73 cell products were obtained, 49 of which were produced according to сGMP using the automated CliniMACS Prodigy® system (Miltenyi Biotec) and 24 using the G-Rex®10M-CS bioreactor (Wilson Wolf). Autologous and haploidentical cell sources were used for the manufacturing (no statistical differences in the cell composition in the start product of the processes). At the start of manufacturing with CliniMACS Prodigy® system, 100 million CD4+ and CD8 + T cells were selected at CliniMACS Prodigy, after which T lymphocytes were activated, transduced, and expanded in an automated closed system. For production in the G-Rex bioreactor, 5 million CD4+ and CD8 + T cells were selected by sorting using MACSQuant Tyto (Miltenyi Biotec). Lentiviral Vector aCD19 CAR was used for T cell transduction in both platforms (without using transduction enhancers and spinoculation). During the stages of manufacturing, the efficiency of transduction, composition, immunophenotypic and functional properties of cell products were determined using flow cytometry. Functional testing included TNFα secretion assay and degranulation assay (CD107a + ) upon incubation with the CD19+ cell line JeKo-1.

Results:

CliniMACS Prodigy

(final product)

G-Rex

(final product)

P value

CliniMACS Prodigy

(start product)

G-Rex

(start product)

P value

CD8+ Naïve

n/a

45.7% (0.7-91.9%), N = 46

38.1% (14.4-80.9%), N = 24

ns

CD4+ Naïve

n/a

37.7% (3.9-75.1%), N = 46

49.3% (16.7-78.7%), N = 24

ns

CD8+ Central memory

86.1% (6.4-99.1%), N = 49

69.0% (22.0-89.0%), N = 19

0.0006

5.5% (0.9-23.8%), N = 46

6.4% (0.6-27.5%), N = 24

ns

CD4+ Central memory

83.4% (3.9-98.8%), N=49

72.0% (39.0-88.0%), N=19

0.0093

32.6% (13.7-64.4%), N=46

31.7% (16.7-53.1%), N=24

ns

CD8+ Effector memory

12.0% (0.7-85.5%), N=49

31.0% (10.0-76.0%), N=19

0.0001

22.6% (0.7-85.3%), N=46

22.7% (4.8-56.1%), N=24

ns

CD4+ Effector memory

16.0% (1.2-89.9%), N=49

28.0% (12.0-58.0%), N=19

0.0032

22.5% (5.0-73.7%), N=46

10.7% (4.0-45.3%), N=24

ns

CD8 + TEMRA

n/a

18.9% (2.4-62.9%), N=46

18.1% (3.7-55.2%), N=24

ns

CD4 + TEMRA

n/a

0.7% (0.2-10.7%), N=46

1.0% (0.1-5.4%), N=24

ns

CD8 + CD279+

7.7% (0.5-20.9%), N=47

7.6% (0.9-30.9%), N=16

ns

24.9% (0.6-67.9%), N=45

23.9% (6.8-46.0%), N=21

ns

CD4 + CD279+

13.6% (1.5-43.6%), N=48

18.3% (0.5-40.7%), N=16

ns

29.2% (4.1-62.2%), N=45

20.0% (7.0-44.8%), N=21

0.0341

CD8 + TIGIT+

7.6% (1.0-33.4%), N=35

7.7% (2.0-20.9%), N=22

ns

22.9 (2.9-63.7%), N=34

32.3% (4.8-59.1%), N=23

ns

CD4 + TIGIT+

4.5% (0.7-16.5%), N=34

2.9% (1.0-9.4%), N=22

0.0348

17.7% (7.1-48.9%), N=35

14.6% (5.4-24.0%), N=23

0.0220

Degranulation assay for CD8 + CAR-T cells

39.4% (22.5-57.0%), N=17

9.6% (2.0-22.9%), N=24

<0.0001

n/a

n/a

n/a

Degranulation assay for CD4 + CAR-T cells

33.4% (16.8-51.5%), N=17

13.5% (2.0-30.8%), N=24

<0.0001

n/a

n/a

n/a

TNFα secretion assay for CD8 + CAR-T cells

33.6% (14.2-100%), N=35

3.1% (0.8-10.9%), N=24

<0.0001

n/a

n/a

n/a

TNFα secretion assay for CD4 + CAR-T cells

68.8% (25.1-87.4%), N=34

10.6% (4.6-24.3%), N=24

<0.0001

n/a

n/a

n/a

A comparison of the immunophenotypic and functional properties of final cell products produced using the CliniMACS Prodigy or G-Rex platforms is presented in Table. Using both platforms, we obtain a stable product with sufficient expansion and transduction of T cells for subsequent CAR-T therapy. There was a tendency for the Tcm population to predominate in the final cell product, as well as low expression of cellular exhaustion markers in products manufactured by both methods. However, transduction efficiency was statistically significantly higher in products manufactured using the CliniMACS Prodigy system (p < 0.0001), and there was a greater predominance of Tcm over Tem in these products compared to products manufactured in bioreactor G -Rex. All products showed functional activity against the target cell line, but in products obtained using CliniMACS Prodigy it was more pronounced.

The 50th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians – Poster Session (P001-P755) (11)

Conclusions: Both CliniMACS Prodigy and G-Rex platforms can be used to produce a high quality CAR-T cell product. Despite lower transduction efficiency and T cell counts in the final cell products in the G-Rex bioreactor, this was sufficient for subsequent CAR-T therapy. Regarding the differences in effector function found as well as the composition of Tcm/Tem, further analysis of the correlation with clinical response and CRS is required.

Clinical Trial Registry: Clinical Trial (NCT03467256)

Disclosure: Nothing to declare.

4: CAR-based Cellular Therapy – Clinical

P092 ALLOGENEIC HSCT AFTER CAR T-CELL THERAPY HAD DELAYED PLATELET ENGRAFTMENT, HIGHER RISK OF CYTOMEGALOVIRUS VIRUS VIREMIA AND THROMBOTIC MICROANGIOPATHY COMPARED TO CHEMOTHERAPY

Luxin Yang 1, Xiaoyu Lai1, Lizhen Liu1, Jimin Shi1, Yanmin Zhao1, Jian Yu1, Huarui Fu1, Yongxian Hu1, Mingming Zhang1, He Huang1, Yi Luo1

1The First Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China

Background: Allogeneic hematopoietic stem cell transplantation (allo-HSCT) after Chimeric antigen receptor-modified T-cell (CAR T-cell) may achieve durable remission and long-term survival for relapsed/refractory acute lymphoblastic leukemia. However, reliable comparison of treatment-related toxicity of allo-HSCT after CAR-T therapy and traditional chemotherapy lacked.

Methods: Consecutive patients who received CAR T-cells therapy then underwent allo-HSCT during June 1st, 2016 and January 1st, 2023 were included. Propensity score matching was conducted between the CAR T-cells and chemotherapy cohort. The matching process incorporated disease, patient age, minimal residual disease (MRD) before HSCT, time interval from diagnosis to HSCT, donor resource, donor age and sex with a 1:1 ratio.

Results: Fifity-five patients with B cell acute lymphoblastic leukemia (ALL) and four patients with T cell ALL were included in the CAR T cohort. Most patients (86.4%) received anti-CD19 CAR T, four patients received anti-CD19/CD22 CAR T and four patients received anti-CD7 CAR T. All the patients achieved complete remission before transplantation. The median time from CAR T infusion to allo-HSCT was 84 (43-512) days. Thirty-four (57.6%) patients experienced grade 1-2 cytokine release syndrome (CRS) and twenty-five (42.4%) patients experienced grade 3-4 CRS. The median age was 28 (12-67) and 17.1(16-60) years in the CAR T and chemotherapy cohort, respectively. The patient age, gender, disease, minimal residual disease at HSCT, donor resource, donor gender and age were quite comparable between the two cohorts. The median time of neutrophil engraftment were 13 (7-20) and 12 (8-19) days in the CAR T and chemotherapy cohort. The CAR-T cohort had longer platelet engraftment time than chemotherapy cohort (15 days versus 13 days, p=0.042). Patients in the CAR T cohort had higher cumulative incidence of hemorrhagic cystitis (37.3% versus 15.3%, p=0.005). The 100-days cumulative incidence of septicemia of two cohorts were low (3.4% versus 5.1%, p=0.47). The 100-days cumulative incidence of EB virus viremia was 50.8% for the CAR T cohort and 40.7% for chemotherapy cohort (p= 0.48). The cumulative incidence of CMV virus viremia was higher for patients who underwent allo-HSCT after previous CAR T than chemotherapy (76.3% versus 62.7%, p=0.01). In the CAR T cohort, transplant-associated thrombotic microangiopathy (TA-TMA) occurred in four patients. No one in the chemotherapy cohort underwent TA-TMA. The incidence of TA-TMA was higher in the CAR T cohort (76.3% versus 62.7%, p=0.01). There is no difference in the cumulative incidence of grades III-IV acute graft-versus-host disease (GVHD) between cohorts (10.2% versus 16.9%, p=0.29). The cumulative incidence of any grades chronic GVHD in the CAR T cohort was 38.2%, which was significantly higher than 15.3% in the chemotherapy cohort (p=0.034). The incidence of moderate to severe chronic GVHD was comparable between cohorts. There was no difference between two cohorts in 2-year overall survival, progression-free survival, incidence of relapse and non-relapse mortality (NRM).

Conclusions: Allo-HSCT after CAR-T therapy had higher risk of transplant related toxicity compared to traditional chemotherapy. The incidence of survival, NRM, acute GVHD and moderate to severe chronic GVHD was comparable.

Disclosure: The authors declare that they have no competing interests.

4: CAR-based Cellular Therapy – Clinical

P093 AUTOMATED GRADING OF IMMUNE EFFECTOR CELL-ASSOCIATED HEMATOTOXICITY

Emily Liang 1,2, Kai Rejeski3, Sandeep Raj3, Aya Albittar1, Jennifer Huang1,2, Andrew Portuguese1,2, Natalie Wuliji1,2, Qian Wu1, Aiko Torkelson1,2, Delaney Kirchmeier1,2, Abigail Chutnik1, Barbara Pender1, Joshua Hill1,2,2, Noam Kopmar1,2, Rahul Banerjee1,2, Andrew Cowan1,2, Christina Poh1,2, Mazyar Shadman1,2, Alexandre Hirayama1,2, Erik Kimble1,2, Lorenzo Iovino1,2, Roni Shouval3, Jordan Gauthier1,2

1Fred Hutchinson Cancer Center, Seattle, United States, 2University of Washington, Seattle, United States, 3Memorial Sloan Kettering Cancer Center, New York, United States

Background: Following CAR T-cell therapy, hematologic toxicity has emerged as a substantial limitation due to associated infections and increased morbidity. Recognizing unique patterns of hematologic toxicity beyond the scope of CTCAE criteria prompted the development of the EHA/EBMT immune effector cell-associated hematotoxicity (ICAHT) grading system (Rejeski et al, Blood, 2023). Manually assessing longitudinal data is prone to subjectivity and demands extensive labor. Here we use a computational approach to automate the process of ICAHT grading to improve efficacy and accuracy of grading CAR T-cell-associated hematotoxicity.

Methods: The heatwaveR package (Schlegel and Smit, Journal of Open Source Software, 2023; https://robwschlegel.github.io/heatwaveR/), implemented through the R programming language, was originally created to identify marine heatwaves and coldspells. Utilizing this package requires a data table with the following columns: subject IDs, dates (multiple rows per patient), the laboratory value of interest (in this case, ANC) for each date, and the threshold above or below which events should be detected (e.g., 500 or 100 cells/μL).

Using the detect_event() function in heatwaveR, we can expediently identify instances where ANC decreases below the threshold and the duration of each instance, defined as the number of consecutive days during which the ANC is below the threshold (neutropenia “streak”). We also can set the minimum duration of streaks and whether to join streaks across a pre-specified number of days. We set the minimum streak duration to 1 day and required streaks to be joined if ANC did not recover above 500 or 100 for ≥3 consecutive days between streaks, based on the CIBMTR criteria for neutrophil engraftment.

Results: We applied heatwaveR to our longitudinal ANC dataset of patients undergoing CAR T-cell therapy at our center (Table). In this dataset, the most common disease types were aggressive non-Hodgkin lymphoma (n= 216; 48%), acute lymphoblastic leukemia (n= 82; 18%), and multiple myeloma / plasma cell leukemia (n= 61; 13%). The most common CAR T-cell products were investigational CD19 CAR T-cell products (n= 180; 40%), axicabtagene ciloleucel (n= 114; 25%), and lisocabtagene maraleucel (n= 58; 13%). We set thresholds of 500 and 100 to represent the cutoffs for ICAHT grading. For each patient, we extracted the maximum “streak” where ANC ≤ 500 and ≤ 100 cells/μL, then applied the ICAHT guidelines for duration and depth of neutropenia.

Thirteen percent of patients did not meet ICAHT criteria. In the remaining patients, the majority displayed grade 1 (31%) or grade 2 (39%) ICAHT. We noted grade 3 and grade 4 ICAHT in 10% and 7% of cases, respectively.

Table. Demographic, disease, and treatment characteristics (N= 454)

Age at infusion, median (range)

60 (50, 68)

Male sex

286 (63%)

Prior HCT

186 (41%)

Disease

Aggressive NHL

216 (48%)

ALL

82 (18%)

MM/PCL

61 (13%)

Indolent NHL

53 (12%)

CLL

42 (9%)

CAR T-cell product

Investigational CD19 CAR T-cell product

180 (40%)

Commercial CD19 CAR T-cell product with CD28 costimulatory domain (axi-cel, brexu-cel)

143 (31%)

Commercial CD19 CAR T-cell product with 4-1BB costimulatory domain (liso-cel, tisa-cel)

70 (15%)

Commercial BCMA CAR T-cell product (cilta-cel, ide-cel)

61 (13%)

Conclusions: This is a novel application of the heatwaveR package to automate ICAHT grading, eliminating subjectivity and labor. This approach allows rapid and automated ICAHT grading in large datasets. External validation of heatwaveR in a separate dataset from Memorial Sloan Kettering Cancer Center is ongoing. We plan to develop an online tool to help clinicians easily apply this approach to grade the severity of hematotoxicity per ICAHT criteria.

Disclosure: Kai Rejeski: BMS/Celgene: Consultancy, Honoraria; Novartis: Honoraria; Kite/Gilead: Other: Travel Support, Research Funding; Pierre-Fabre: Other: Travel Support.

Joshua Hill: allovir: Consultancy, Research Funding; moderna: Consultancy; deverra: Research Funding.

Rahul Banerjee: BMS: Consultancy; Janssen: Consultancy; Genentech: Consultancy; SparkCures: Consultancy; Sanofi: Consultancy; Caribou: Consultancy; Pfizer: Consultancy; Pack Health: Research Funding.

Andrew Cowan: BMS, Adaptive: Consultancy; Adaptive Biotechnologies, Harpoon, Nektar, BMS, Janssen, Sanofi, Abbvie: Research Funding.

Damian Green: Cellectar Biosciences: Research Funding; SpringWorks Therapeutics: Research Funding; Celgene: Consultancy; GlaxoSmithKline: Membership on an entity’s Board of Directors or advisory committees; Sanofi: Research Funding; Janssen Biotech: Consultancy, Research Funding; Ensoma: Consultancy; Seattle Genetics: Consultancy, Research Funding; Juno Therapeutics A BMS Company: Patents & Royalties, Research Funding.

Ajay Gopal: Compliment Corporation: Current holder of stock options in a privately-held company; Incyte, Kite, Morphosys/Incyte, ADCT, Acrotech, Merck, Karyopharm, Servier, Beigene, Cellectar, Janssen, SeaGen, Epizyme, I-Mab bio, Gilead, Genentech, Lilly, Caribou, Fresenius-Kabi: Consultancy; Merck, I-Mab bio, IgM Bio, Takeda, Gilead, Astra-Zeneca, Agios, Janssen, BMS, SeaGen, Teva, Genmab: Research Funding.

Christina Poh: BeiGene: Consultancy; Seattle Genetics: Consultancy; Incyte: Research Funding; Acrotech: Consultancy.

Mazyar Shadman: Fate Therapeutics: Consultancy; Genmab: Consultancy, Research Funding; Vincerx: Research Funding; MorphoSys/Incyte: Consultancy, Research Funding; Eli Lilly: Consultancy; Bristol Myers Squibb: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Kite, a Gilead Company: Consultancy; AbbVie: Consultancy, Research Funding; Mustang Bio: Consultancy, Research Funding; ADC therapeutics: Consultancy; BeiGene: Consultancy, Research Funding; AstraZeneca: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding; Janssen: Consultancy; MEI Pharma: Consultancy; Regeneron: Consultancy; TG Therapeutics: Research Funding.

Alexandre Hirayama: Novartis: Honoraria; Bristol Myers Squibb: Honoraria, Research Funding; Nektar Therapeutics: Honoraria, Research Funding; Juno Therapeutics, a Bristol Myers Squibb Company: Research Funding.

Till: Mustang Bio: Consultancy, Patents & Royalties, Research Funding; BMS/Juno Therapeutics: Research Funding; Proteios Technology: Consultancy, Current holder of stock options in a privately-held company.

Kimble: Juno/BMS: Research Funding.

Lorenzo Iovino: Mustang Bio: Current equity holder in publicly-traded company.

Aude Chapuis: Juno Therapeutics: Research Funding.

Ryan Cassaday: Amgen: Consultancy, Honoraria, Research Funding; Merck: Research Funding; Incyte: Research Funding; Autolus: Membership on an entity’s Board of Directors or advisory committees; Pfizer: Consultancy, Honoraria, Research Funding; Servier: Research Funding; Vanda Pharmaceuticals: Research Funding; Jazz: Consultancy, Honoraria; Kite/Gilead: Consultancy, Honoraria, Research Funding; PeproMene Bio: Membership on an entity’s Board of Directors or advisory committees; Seagen: Other: Spouse was employed by and owned stock in Seagen within the last 24 months.

Filippo Milano: ExCellThera Inc.: Research Funding.

David Maloney: A2 Biotherapeutics: Consultancy, Current holder of stock options in a privately-held company, Honoraria, Other: Member of the Scientific Advisory Board; Juno Therapeutics: Consultancy, Honoraria, Patents & Royalties: Rights to royalties from Fred Hutch for patents licensed to Juno Therapeutics/BMS, Research Funding; Janssen: Consultancy, Honoraria; Legend Biotech: Consultancy, Honoraria, Research Funding; Mustang Bio: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Lyell Immunopharma: Other: Member, CAR T Steering Committee; Incyte: Consultancy, Honoraria; Gilead Sciences: Consultancy, Honoraria, Other: Member, Scientific Review Committee, Research Scholars Program in Hematologic Malignancies; Kite, a Gilead Sciences: Consultancy, Honoraria, Research Funding; Pharmacyclics: Consultancy, Honoraria; Umoja: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Other: Participation on a Data Safety Monitory Board, Research Funding; Genentech: Consultancy, Honoraria, Other: Chair and Member of the Lymphoma Steering Committee; MorphoSys: Consultancy, Honoraria; Bristol Myers Squibb: Consultancy, Honoraria, Other: Member of the JCAR017 EAP-001 Safety Review Committee and Member, CLL Strategic Council, Member of the JCAR017-BCM-03 Scientific Steering Committee under BMS, Research Funding; Amgen: Consultancy, Honoraria; Navan Technologies: Consultancy, Honoraria, Other: Member of the Scientific Advisory Board; Bioline Rx: Consultancy, Membership on an entity’s Board of Directors or advisory committees, Other: Participation on a Data Safety Monitory Board; Fred Hutch: Other: rights to royalties for patents licensed to Juno; Navan Technologies: Current holder of stock options in a privately-held company; Chimeric Therapeutics: Other: Member of the Scientific Advisory Board; ImmPACT Bio: Other: Member, Clinical Advisory Board, CD19/CD20 bi-specific CAR-T Cell Therapy Program; Interius: Other: Member, Clinical Advisory Board.

Jordan Gauthier: Kite Pharma: Consultancy, Honoraria; MorphoSys: Consultancy, Research Funding; Angiocrine Bioscience: Research Funding; Century Therapeutics: Other: Independent data review committee; Celgene (a Bristol Myers Squibb company): Research Funding; Legend Biotech: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Juno Therapeutics (a Bristol Myers Squibb company): Research Funding; Sobi: Consultancy, Honoraria, Research Funding.

4: CAR-based Cellular Therapy – Clinical

P094 RELEVANT STUDIES ON CYTOKINES LEVEL AND CAR-T EXPANSION ASSOCIATED TO CD7 CAR-T THERAPY

Dongchu Wang1, Hui Wang1, Man Chen 1

1Hebei Yanda Lu Daopei Hospital, Langfang, China

Background: In the past few years, CD7 became a highly reliable marker of CAR-T therapy treating T cell acute lymphocytic leukemia(T-ALL). In this case, better understanding of CD7 CAR-T therapy on cellular level became meaningful.

Methods: PB samples were collected from 70 patients treated with CD7 CAR-T from Dec. 2020 to Nov. 2022 in Hebei Yanda Ludaopei Hospital. There were 56 males and 14 females, 2-60 with median age 19. Based on criteria of CRS and assessment results, 70 patients were split in different groups. According to CRS level, two groups were set as low (CRS0-1, 56 of 70) group and high group (CRS2-4, 14 of 70). 55 of 70 were classified as CR/CRi group, 15 of 70 were Non-CR group.

IL-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12p70, IL-17A, IL-17F, IL-22, TNFα, TNFβ, IFN-γ, IL-2RA/sCD25, MIP-1α, MCP-1, GM-CSF, IL-15, REG3a, Elafin, ST-2, Granzyme B, TNFRI were measure with microbeads with Calibur flow cytometer, CAR-T cells, target cells(CD7+ cells), T cells subsets(CD3 + , CD4 + , CD8 + , CD8 + TCM, CD8 + TEM, Treg) were tested with Canto flow cytometer. All the cellular variations were calculated by comparing value of peak-time to value of D0 which was used as baseline. Time points day0, 4, 7, 11, 14, 21, 30 were monitored after CAR-T infusion.

Results: Patients in all 4 groups had similar median age and transfection efficiency. Based on criteria of CRS level, patients were split into low group and high group. CAR-T peak time was appeared significantly later in high group. In high group, CD8 + TEM cells was amplified significantly more than that in low group at peak time point. Clearance rates of target cells in low group were significantly higher. The level of IL-4, IL-6, IL-8, IL-10, IL-22, IFN-γ, sCD25, MCP-1, IL-15, GranzymeB were significant higher in high group. All median peak time of those 10 cytokines in high group were calculated, from day 10 up to day 15 after CAR-T infusion. MCP-1 had the largest time gap, which means MCP-1 reached peak time 9 days earlier than that of CAR-T cells. The median peak-time gap between cytokines level with CAR-T cells expansion was 6 days.70 patients were classified as CR/CRi group and Non-CR group. CAR-T expansion, T cell subsets variation showed no statistical difference between two groups, and only target cells clearance rate was significantly higher in CR group. For all 24 cytokines measured in this study showed no significant differences between both groups.

Conclusions: 10 cytokines were correlated to severity of CRS after CD7 CAR-T therapy. 10 cytokines showed positive correlation to the level of CRS, and reached peak time earlier than that of CAR-T expansion, which means all these 10 cytokines could be used as indicators to predict occurrence and severity of CRS. Concurrence time of peak expansion of CD7 CAR-T cells, and amplification of CD8 + TEM cells were significantly related to CRS. For all the patients who reached complete remission or CRi, CD7+ clearance rates were higher with statistical significance. Our results proved potential indicators for CRS prediction and prognosis.

Disclosure: Nothing to declare

4: CAR-based Cellular Therapy – Clinical

P095 AUTOLOGOUS HEMATOPOIETIC STEM CELL TRANSPLANTATION COMBINED WITH CAR-T CELL THERAPY SIGNIFICANTLY IMPROVES PROGRESSION-FREE SURVIVAL IN RELAPSED REFRACTORY CENTRAL NERVOUS SYSTEM LYMPHOMA

Rui Liu 1, Fan Yang1, Fei Xue1, Zhonghua Fu1, Yuelu Guo1, Shaomei Feng1, Peihao Zheng1, Lixia Ma1, Hui Shi1, Biping Deng1, Xiaoyan Ke1, Kai Hu1

1Bejing Gobroad boren hospital, Beijing, China

Background: Relapsed or refractory Central nervous system lymphoma(R/R CNSL) is challenging to manage clinically. CAR-T therapy has demonstrated efficacy in relapsed and refractory large B-cell lymphoma, with some studies indicating a favourable response rate for R/R CNSL. Nevertheless, disease-free survival and long-term outcomes are suboptimal. Our study aims to explore the efficacy of CAR-T and the factors affecting its long-term survival in R/R CNSL. Additionally, we analysed the safety and effectiveness of ASCT combined with CAR-T therapy.

Methods: This single-centre, retrospective study analysed patients with R/R CNSL who received CAR-T therapy at the Beijing GoBroad Boren Hospital between 2019/03 and 2023/08. 69 patients were included. 46% were male, the median age is 51 (range19-79); 33% (23/69) is PCNSL, 67% (46/69) is SCNSL. The common histology in SCNSL was DLBCL(n=32), followed by HGBL(n=4), PMBL(n=3), BL (n=2), MCL (n=2) and others. Median number of previous treatment lines is 4 (range2-8). 70% (48/69) were IPI≥3.74% (51/69) were resistant to HD-MTX. 52% (36/69) were resistant to BTK inhibitors. 17% (12/69) patients had failed previous autologous hematopoietic stem cell transplantation. 68%(47/69) were parenchymal involved, 17%(12/69) were CNS involved, 14%(10/69) were both. The patients underwent a median of 1 (range 0-5) cycle of bridging therapy. 65.2%(45/69) achieve objective response (CR=33;PR=12) after bridging therapy. According to the response to bridging treatment, patients were divided into two groups: Bridging Effective (BE) group, comprising patients with CR/PR, and Bridging Ineffective (BI) group, comprising patients with SD/PD. In the BE group, 53.3% (24/45) received ASCT combined with CAR-T therapy.

Results: The 3-month ORR was 70% (48/69), and CRR is 61% (42/69). Incidences of any-grade CRS and ICANS were 70% (48/69) and 12% (8/69), with severe (≥3) CRS and ICANS at 12.5% (6/48) and 62.5% (5/8), respectively. BE group exhibited significantly higher 3-month ORR (84.4% vs. 41.6%) and CRR (82.2% vs. 20.8%) compared to BI group. Median follow-up time was 22.65 months. Median Progression-Free Survival (PFS) for BE group was 43.07 months, significantly longer than BI group’s 6.08 months (P<0.0001). Median Overall Survival (OS) was not reached for BE group, while it was 12.79 months for BI group (P<0.0001). 1-year OS rates were 100% vs. 51.4% (P<0.0001), and 1-year PFS rates were 74.7% vs. 9.9% (P<0.0001) for BE and BI groups, respectively. Among the 45 BE group patients, ASCT combined with CAR-T therapy showed more patients with ECOG performance status ≥ 2, more prior therapy lines, and all were HD-MTX-resistant (Table 1). Median PFS in ASCT combined with CAR-T cohort was significantly prolonged (not reached vs. 14.76 months, p=0.0008). Median OS was not reached in this cohort, whereas in CAR-T cohort, it was 27.48 months. However, there was no statistically significant difference. No statistical difference was observed in CRS and ICANS between the two cohorts.

Variable

CAR-T (n=21)

ASCT + CAR-T(n=24)

p-value

age (>60)

8/21(38%)

2/24(8%)

0.018

sex(male)

6/21(29%)

12/24(50%)

0.148

IPI≥3

11/21(52%)

17/24(71%)

0.208

ECOG≥2

7/21(33%)

17/24(71%)

0.013

Histology

-PCNSL

9/21(43%)

11/24(46%)

0.843

-SCNSL

12/21(57%)

13/24(54%)

Previous HD-MTX_resistance

15/21(71%)

24/24(100%)

0.005

Previous BTK inhibitors_resistance

14/21(67%)

13/24(54%)

0.398

Previous auto-HCT

5/21(24%)

3/24(12.5%)

0.328

Previous_regimen_lines≥3

11/21(52%)

20/24(83%)

0.027

Conclusions: Effective bridging therapy can significantly improve the efficacy of CART in the treatment of R/R CNSL. After bridging therapy is effective, the treatment model of ASCT combined with CAR-T can significantly improve disease-free survival.

Clinical Trial Registry: ChiCTR2200058972/https://www.chictr.org.cn/index.html

Disclosure: Nothing to declare

4: CAR-based Cellular Therapy – Clinical

P096 SAFETY AND EFFICACY OF BENDAMUSTINE VERSUS FLUDARABINE-CYCLOPHOSPHAMIDE LYMPHODEPLETION PRIOR TO CAR-T CELL THERAPY WITH AXICABTAGENE CILOLEUCEL FOR NON-HODGKIN LYMPHOMA: A SINGLE-INSTITUTION STUDY

Anthony Stack 1, Yuliya Shestovska1, Rachel Thomas2, Matthew Hamby1, Asya Varshavsky-Yanovsky1, Peter Abdelmessieh1, Michael Styler1, Henry Fung1, Rashmi Khanal1

1Fox Chase Cancer Center/Temple University Health System, Philadelphia, United States, 2Temple University Hospital, Philadelphia, United States

Background: Previously, bendamustine (Benda) lymphodepletion (LD) was shown prospectively to yield similar efficacy, with lower rates of Cytokine Release Syndrome (CRS), neurotoxicity (ICANS) and hematologic toxicity compared to fludarabine-cyclophosphamide (FluCy) prior to tisagenlecleucel, a 4-1BB-costimulated CAR-T cell product; however, the safety and efficacy of bendamustine lymphodepletion prior to axicabtagene ciloleucel (axi-cel), a CD28-costimulated CAR-T cell product, is largely unknown.

Methods: We performed a retrospective analysis to compare safety and efficacy outcomes of patients treated for non-Hodgkin lymphoma with axi-cel at Fox Chase Cancer Center from 10/1/2018 to 7/14/2023. All patients received lymphodepletion with Benda (90 mg/m2/day x 2 days) or FluCy (Flu 30 mg/m2/day and Cy 500 mg/m2/day x 3 days) based on availability, physician preference and institutional practice. P values were calculated using Mann-Whitney test for continuous variables and Fisher’s exact test for categorical variables. Grading of hematologic toxicities is based on the Common Terminology Criteria for Adverse Events Version 5.0.

Results: In total, 20 patients received Benda and 17 patients received FluCy LD prior to axi-cel and were included in our analysis. The ratio of high-grade/low grade lymphoma in the Benda vs FluCy groups was 2.3 and 3.3, respectively. In both groups, ≥90% had Eastern Cooperative Oncology Group performance scores ≤1, an identical median age of 63 and similar rates of bridging therapy utilization (75% vs 76%, respectively). Of note, 95% of patients in the Benda group received CRS/ICANS prophylaxis (all dexamethasone), compared to only 12% in the FluCy group (1 dexamethasone and 1 tocilizumab).

Overall (ORR) and complete response rates (CR) were [ORR 90%, CR 75%] and [ORR 65%, CR 53%] in the Benda and FluCy groups, respectively, and were not statistically different (p>.05). Likewise, 3-month progression-free and overall survival did not differ between groups. CRS rate was identical in both arms, occurring in 70%, while ICANS occurred in 15% after Benda vs 47% after FluCy (p=.069).

In the first 30 days post-CAR-T infusion, patients receiving Benda vs FluCy experienced significantly lower rates of grade 3-4 anemia (10% vs 58%, p=.004), neutropenia (30% vs 100%, p<.001), and thrombocytopenia (25% vs 65%, p=.022), respectively. Additionally, Benda vs FluCy patients experienced significantly higher median nadirs in hemoglobin (10.5 vs 7.4 g/dL, p=.008), absolute neutrophils (ANC) (1.35 vs 0 K/mm3, p<.001) and platelets (117 vs 34 K/mm3, p=.003), required fewer transfusions of red blood cells (10% vs 41%, p=.052) and platelets (5% vs 35%, p=.034), and had numerically lower requirement for G-CSF (15% vs 47%, p=.069), respectively.

In the first 30 days, patients receiving Benda vs FluCy LD experienced fewer days with platelets <50 k/mm3 (mean 2.6 vs 9.4 days, p=.010), and with ANC <1000 K/mm3 (mean 1.8 vs 12 days, p<.001), respectively. Persistent grade ≥3 anemia, thrombocytopenia and neutropenia beyond 30 days were uncommon and did not significantly differ between groups.

Conclusions: In this retrospective study comparing Benda to FluCy lymphodepletion prior to axi-cel, Benda yielded similar efficacy with significantly less early hematologic toxicity. Although CRS and ICANS rates were similar, this is confounded by increased utilization of prophylaxis in the Benda group.

Disclosure: Henry Fung has received honoraria from Incyte, AstraZeneca, Janssen Oncology, and Kite. Asya Varshavsky-Yanovsky has participated on advisory boards and/or has provided consultancy for Pfizer, Janssen and BMS. Peter Abdelmessieh has participated on advisory boards for AbbVie and Sobi. Anthony Stack, Yuliya Shestovska, Rachel Thomas, Matthew Hamby, Michael Styler and Rashmi Khanal have no conflicts of interest to declare.

4: CAR-based Cellular Therapy – Clinical

P097 PSEUDOPROGRESSION: A FREQUENT AND CLINICALLY RELEVANT ADVERSE EVENT OF CHIMERIC ANTIGEN RECEPTOR T CELL THERAPY

Torsten Schroeder 1, Tjark Martens1, Guranda Chitadze1, Fatih Yalcin1, Heiko Trautmann1, Britta Kehden1, Monika Brüggemann1, Christine Heinen1, Philipp Nakov,1, Nicolas Spath1, Lukas Sprenger1, Anca-Maria Albici1, Laura-Jane Kramp1, Matthias Ritgen1, Dominique Wellnitz1, Sebastian Lippross1, Maciej Simon1, Ingram Iaccarino Idelson1, Nico Gagelmann2, Wolfram Klapper1, Lars Fransecky1, Thomas Valerius1, Natalie Schub1, Christiane Pott1, Katja Weisel2, Winfried Alsdorf2, Fabian Müller3, Claudia Baldus1, Friedrich Stölzel1

1University Hospital Schleswig-Holstein, Kiel, Germany, 2University Medical Center Hamburg-Eppendorf, Hamburg, Germany, 3University Hospital of Erlangen, Erlangen, Germany

Background: CAR-T-cell therapy (CARTCT) expands the range of therapeutic options for patients with hematologic malignancies. While complications such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) are well known and consensus grading classifications for documentation and treatment of these adverse events are used, pseudoprogression (PP) is mainly described after checkpoint inhibition. Some reports on CARTCT induced PP (CARTiPP) exist distinguishing it from progressive disease, while only few reports focus on acute local complications. Considering the paucity of data about CARTiPP, we aimed to assess patients treated in our clinical routine. We defined CARTiPP as initial volume increase of malignant manifestations within ten days of CARTCT followed by tumor regression without another cause being more probable. Distinction from true progression of malignancy can be achieved either retrospectively or by histopathological findings. Another special CARTiPP presentation may be severe bone pain in patients suffering from malignant bone lesions which was repeatedly observed after anti-BCMA CAR-T cells.

Methods: Here, we characterize a retrospective multicentric patient cohort with the occurrence of CARTiPP. Evaluation of clinical, laboratory, radiological, and/or histopathological data was carried out. We rated all events in a proposed grading scale for CARTiPP severity.

Results: A total of n=22 patients were identified with CARTiPP throughout a treatment period of 57 months with n=176 patients receiving 180 CAR-T-cell therapies. Thus, we observed a total CARTiPP frequency of 12 %.

Patients with CARTiPP had different B-cell non-Hodgkin lymphoma subtypes (n=10/114) or multiple myeloma (n=12/56) and were treated with commercial anti-CD19 or anti-BCMA CAR-T-cells. The median age of patients was 59 years (range 39-76 years). Staging before CARTCT assessed n=5 patients in very good partial remission (VGPR), n=3 in partial remission, n=6 with stable disease (SD) and n=8 with progressive disease (PD). The rate of CARTiPP was notably higher in multiple myeloma than in B-cell lymphoma patients (21 vs. 9 %) - findings that need to be confirmed by additional studies.

We observed variable complications, e.g. superior vena cava syndrome, severe bone pain, soft tissue swelling with airway compression and postrenal kidney injury. Concomitant CRS occurred in n=21, ICANS in n=5 patients. Complication management ranged accordingly from intensified monitoring to treatment with glucocorticoids/tocilizumab to invasive ventilation and once limb amputation due to compartment syndrome. There was no CARTiPP-associated mortality. In four affected cases intensive care treatment was required.

Conclusions: CARTiPP may be still underreported and lacks classification and prospective reporting in clinical trials and registries investigating CARTCT. Frequency and sometimes severity underline the need for raising awareness of treating physicians. Laboratory analyses and imaging may supplement clinical assessment and should be further examined. Establishment of risk assessment, preventive measures and early treatment to reduce therapy-induced morbidity/mortality as well as a systematic documentation analogous to CRS and ICANS is required for CARTiPP. The increasing availability of CAR-T-cell therapies for a steadily expanding number of disease entities with variable manifestations and different disease stages makes an increasing frequency of CARTiPP plausible.

Disclosure: - Friedrich Stölzel:

Travel Support: Janssen, medac

Honoraria: medac, GWT, Abbvie, Servier, Pierre Fabre

Research funding: medac, Servier

- Claudia Baldus:

advisory and speakers honoraria for Astrazeneca, BMS, Janssen, Kite, Novartis, Jazz, Astellas, Amgen

- Winfried Alsdorf:

Honoraria: GSK, Janssen

Travel/accomodations/expenses: Biontech, Janssen, Immatics

Research funding (institution): Affimed, Biontech

- Fabian Müller:

Advisory and speakers honoraria for Astrazeneca, BMS, Jansen, Kite, kyverna, Miltenyi, Novartis,

Research support from Astrazeneca, Kite.

4: CAR-based Cellular Therapy – Clinical

P098 CAR-T CELL TREATMENT OF LARGE B-CELL LYMPHOMA (LBCL): DO PROGRAM DURATION AND TREATMENT LINE MATTER?

Maria-Luisa Schubert 1, Michael Schmitt1, Andrea Bondong1, Mandy Wegner1, Simon Renders1, Isabelle Krämer1, Carsten Müller-Tidow1, Peter Dreger1

1University Hospital Heidelberg, Heidelberg, Germany

Background: At our institution, CD19-directed CARTs for treatment of multiply relapsed/refractory LBCL were introduced in November 2018 and extended to 2nd line (2L) application in September 2022. The aim of this study was to analyze development of patient characteristics and outcomes over time.

Methods: Eligible for this retrospective analysis were all adult patients who received commercial or experimental CD19 CARTs at the University of Heidelberg. Patients were grouped into 3 cohorts: cohort A >2L 2018-2020; cohort B >2L 2021-2023; cohort C intent-to 2L treatment. Primary endpoint was relapse/progression-free survival (PFS). Descriptive statistics were applied.

Results: Altogether 93 patients (cohort A: n=43, cohort B: n=35, cohort C: n=15) met the eligibility criteria. Of note, introduction of 2L CARTs was associated with a 67% decrease of >2L indications in 2023. Axicabtagene ciloleucel (axicel), tisagenelecleucel (tisacel), lisocabtagen maraleucel (lisocel), and experimental CARTs were used in 73%, 18%, 6%, and 3% of patients, respectively. Cohorts A and B were comparable in terms of underlying diagnosis with DLBCL as the predominant indication, and in terms of the proportion of patients who had received a prior autoHCT. Compared to cohort A, patients from cohort B were significantly older (median age 57 (20-76) vs 67 (25-82) years; p 0.049), but contained fewer patients who received CARTs beyond the 3rd (49% vs 70%; p 0.067) and 4th line (6% vs 30%; p 0.0083), respectively. More patients in cohort B had received holding/bridging therapies (89% vs 70%; p 0.057), with a smaller proportion of patients with refractory disease at lymphodepletion (46% vs 81%; p 0.0058). In cohort C, median age was 63 (26-82) years, holding/bridging was administered to 87%, and 67% of the patients had active disease at lymphodepletion. Because of progression through bridging therapy, 27% of the patients intended to receive 2L CARTs actually underwent CART infusion as 3rd-line therapy.

The 50th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians – Poster Session (P001-P755) (12)

With an overall response rate of 74%, 74%, and 78%, response was comparable across all cohorts. However, CR was more frequently reached in cohort C (57% vs 36% (A) and 40% (B)). Crude non-relapse mortality (NRM) was 12%, 6%, and 7% across the cohorts A, B, and C, respectively, with infections being the predominant cause of death. All NRM events except one occurred with axicel. 12-month PFS was 30%, 43%, and 56% across cohorts A, B, and C, respectively (Logrank for trend p=0.052; HR 1.72 (0.96-2.72) for comparison of cohort A with cohort B) (Figure).

Conclusions: Despite constant response rates, PFS and NRM of >2L CARTs seem to improve with longer CART program duration. This might be partly explained with better patient selection, earlier use of CARTs, and more effective bridging strategies. The advent of 2L CARTs associates with a strong reduction, but not a complete abrogation of >2L indications. Whether 2L CART applications are indeed associated with superior outcomes compared to delaying CART administration beyond 2L needs to be confirmed by further studies.

Disclosure: MLS: honoraria Kite/Gilead. MS: honoraria BMS, Kite/Gilead, Novartis. RS: honoraria Kite/Gilead. PD: honoraria Novartis, Kite/Gilead, BMS, Miltenyi.

4: CAR-based Cellular Therapy – Clinical

P099 REAL-WORLD EXPERIENCE OF CAR T-CELL THERAPY: A SINGLE CENTRE EXPERIENCE

Francys Lopez Llanos1, Inês Rocha2, Gilda Teixeira1, Isabelina Ferreira1, Pedro Sousa1, Maria João Gutierrez1, Susana Pereira 1, Ana Carolina Freitas1, Carla Espadinha1, Nuno Miranda1

1IPOFG, Lisboa, Portugal, 2Centro Hospitalar Universitário Lisboa Central, Lisboa, Portugal

Background: Chimeric antigen receptor (CAR) T-cell therapy has changed the landscape of treatment for relapsed/refractory B cell lymphomas. We present real world patient characteristics and outcomes from a Portuguese center.

Methods: This is a single-center, retrospective study of consecutive patients receiving CAR-T cell therapy between October 2019 and December 2023. Data were retrieved by reviewing individual electronic health records at the Instituto Português de Oncologia Francisco Gentil, Lisbon, Portugal.

Results: 50 patients were accepted for CAR-T therapy. Median age was 60 [26- 74] years, 94% (N=47) had ECOG PS1 and male-to-female ratio was 2:1. Regarding diagnosis, 78% (N=39) had histologically diffuse large B-cell lymphoma (DLBCL), 4% (N=2) follicular lymphoma and 18% (N=9) mantle cell lymphoma (MCL). 36% (N=18) had ≥ 3 lines of therapy prior CAR-T49 patients (98%) underwent leukapheresis and 42 (84%) received CAR-T therapy (3 DLBCL and 3 LCM did not undergo lymphodepletion to medical complications or rapidely progressive disease, 1 is awaiting infusion). 81% (N=34) received Axicabtagene, 14.3% (N=6) with Bretuxabtagene and 4.8% (N=2) with Tisagenlecleucel. Median delay (Md) between leukapheresis and infusion was 64 days [30 - 141]. CRS occurred in 35 patients (83.3%), with grade 3 in 11,9% (N=5). ICANS occurred in 10 patients (23.8%), with grade 3 in12% (N=5). Infections were documented in 10 and pancytopenia in 9. Two second neoplasms were diagnosed 1 AML and 1 MDS.

PET-CT was used to evaluate post-CAR-T response. At D + 100, 33 patients (78.6%) had completed evaluation, 63.6% (N=21) in complete response (CR), 15.2% (N=5) partial response (PR) and 21.2% (N=7) disease progression (DP). At D + 180, of 22 patients (66.7%) with complete evaluation, 63.6% (N=14) in CR, 31.8% (N=7) in DP and 4.6% (N= 1) in PR. There are patients who have not yet reached assessment time intervals.

Post-CAR-T DP occurred in 16 patients (38.0%), in whom Md time between infusion and DP was 3 months [1-16]. Death occurred in 14 patients (33.3%), mostly due to DP (11 patients, 78.6%); the Md time between infusion and death was 6 months [1-29]. Two fatalities were infection related: 1 HHV6 encephalitis and 1 COVID19.

With a median OS of infused patients was estimated at 29.7 months [95% CI: 23.3-36.1] and PFS was 9.0 months [95% CI: 1.9-16.0].

There was a trend to higher mortality in older than 65 vs younger (p=0.19).

There was no difference between PFS with a vein-to-vein time below or over median.

We observed a significant difference in PFS when making cohorts for year of infusion: before 2021 PFS=24,6 months vs 2022 11.4 vs 2023 5.4 p=0.041.

Conclusions: Relapsed and refractory NHL, in anti-CD20 era, constitute a large patient population in need of new solutions. CAR-T therapy provides an answer for some, with acceptable toxicity. Our real-world data shows that over the years, with broader selection criteria, inclusion of older patients, and those with higher disease burden, worse outcomes are observed. Accessment of disease burden prior to CAR-T may help selecting more adequate candidates,. Better patient selection is necessary also due to economic burden of this therapy.

Disclosure: The authors declare no conflit of interests

4: CAR-based Cellular Therapy – Clinical

P100 IMPACT OF ACUTE KIDNEY INJURY IN LYMPHOMA PATIENTS TREATED WITH AXICABTAGENE CILOLEUCEL

Cristina Soler1, Rafael Hernani 1, Ariadna Pérez1, Jose Luis Piñana1, Juan Carlos Hernández-Boluda1, Ana Benzaquen1, Rosa Goterris1, Montse Gómez1, Paula Amat1, Blanca Ferrer1, Francesc Moncho1, Isidro Torregrosa1, Jose Luis Górriz1, María José Terol1, Carlos Solano1

1Hospital Clínico Universitario, INCLIVA Research Institute, Valencia, Spain

Background: Chimeric antigen receptor T-cell (CAR-T) therapy has improved outcomes in patients with relapsed/refractory (R/R) hematological malignancies. However, there is limiting data regarding the impact of acute kidney injury (AKI) on outcomes following CAR-T infusion.

Methods: Adult patients with R/R large B-cell lymphoma (LBCL) receiving commercial axicabtagene ciloleucel were consecutively enrolled at Hospital Clínico Universitario de Valencia from December 2019 to August 2023. Data regarding patient and disease characteristics, treatment course, and clinical outcomes were prospectively collected. Cytokine-release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) were graded following CARTOX scale. Chronic kidney disease (CKD) was defined by Kidney Disease Improving Global Outcomes (KDIGO) staging using estimated glomerular filtration rate (eGRF). Acute kidney injury (AKI) was defined by Common Terminology Criteria for Adverse Events version 5. The renal function was monitored from the onset of lymphodepleting chemotherapy (LDC) until one month after infusion. Subsequently, monitoring continued until day 90, unless death or R/R, whichever occurred first. All patients received allopurinol or rasburicase as tumor lysis syndrome prophylaxis.

Results: A total of 48 adult patients with R/R LBCL were included in this study (diffuse large B-cell lymphoma, n=44; primary mediastinal large B-cell lymphoma, n=4). Briefly, the median age was 56 years (range, 22–75). Three (6%), 7 (15%) and 9 (19%) patients had prior history of CKD, diabetes, or high blood pressure, respectively. Baseline eGRF was graded as follows: 1 (n=28), 2 (n=17) and 3a (n=3). Most patients were primary refractory (53%) and had progressive disease (63%) at LDC. Myc was rearranged in 11 (23%) patients. Baseline EASIX score was 2.47 (range, 0.49–552).

Sixteen (33%) patients developed AKI (grade 1, n=10; grade 2, n=6) at a median time of 14 days (-4 – 57) after CAR-T infusion. Of them, five (31%), 6 (38%) and 5 (31%) patients developed AKI between LDC and CAR-T infusion, within the first month following CAR-T infusion or beyond, respectively. AKI showed no association with any baseline characteristics. Only age (>65 years) correlated with abnormal baseline eGFR in univariate analysis (71% vs 29%, P 0.018). Neither CKD, abnormal baseline eGFR (>= G2 KDIGO) or AKI had an impact on toxicity (CRS/ICANS), overall response rate (ORR), or survival (Table 1). Six (13%) patients required nephrologist support due to the following causes: AKI (n=4), electrolyte imbalances (n=1), adjustment of nephrotoxic medications owing to a prior kidney transplant (n=1). None of the patients required renal replacement therapy. Twenty-six (54%) patients remained alive with a median follow-up of 384 days (range, 63–1323).

Conclusions: In this study, we found no correlation between CKD, baseline eGFR, or AKI and outcomes post-CAR-T therapy for R/R LBCL. Notably, one-third of patients experienced mild AKI throughout three distinct time periods: i) from LDC and CAR-T infusion; ii) from CAR-T infusion to day 30; iii) from day 30 to day 90.

Disclosure: Nothing to declare

4: CAR-based Cellular Therapy – Clinical

P101 CHARACTERISTICS OF CENTRAL NERVOUS SYSTEM RELAPSE AFTER CD19 CAR-T CELL THERAPY IN R/R NHL

Mengyu Zhao 1, Tingting Yang1, YeTian Dong1, Jiazhen Cui1, Delin Kong1, Wenfa Huang2, Lei Wang2, Lixin Wang2, He Huang1, Yongxian Hu1

1Bone Marrow Transplantation Center, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China, 2lnternational Cancer Center, Shenzhen University General Hospital, Shenzhen, China

Background: CD19-targeted chimeric antigen receptor T (CAR-T) cell therapy has shown remarkable antitumor activity against relapsed/refractory (R/R) non-Hodgkin lymphoma (NHL). However, NHL with central nervous system (CNS) relapse carries a poor prognosis and high mortality. We reported an analysis of 80 patients with NHL who underwent CAR-T cell therapy, and described the characteristics including the international prognostic index (IPI) and other clinical variables to evaluate the outcomes of CNS relapse in NHL patients treated with CAR-T cell therapy.

Methods: A total of 80 patients with NHL treated with CD19 CAR-T cell therapy in our center between April 2017 and November 2022 was retrospectively analyzed. Patient characteristics, laboratory parameters, and clinical outcomes were collected. CNS relapse was diagnosed by cerebrospinal fluid cytology, MRI or PET-CT.

Results: Baseline characteristics of all 80 patients are summarized. The median age was 58.5 (range, 10 to 79) years, and 57.5% of patients were male. Overall, 67 (83.8%) patients achieved complete remission (CR) or partial remission (PR) after CD19 CAR-T therapy. Seven (8.43%) patients developed isolated CNS relapse after CAR-T cell therapy, all of which were heavily pre-treated with multiple lines of chemotherapy prior to CAR-T cell therapy, and one of them had received autologous stem cell transplant before infusion of CAR-T cells. Only 4 of 7 patients with isolated CNS relapse achieved CR (n=4), and the median time to isolated CNS relapse from CAR-T cell infusion was 6.3(range, 1.53 to 25.8) months. Thirty-seven patients (46.2%) developed systemic recurrence without CNS involvement, with the median time from CAR-T to relapse of 3.2 (range, 0.467-30.8) months. The other 36 patients remained in remission at the last follow-up. During the median follow-up of 13.5 months of the whole cohort, the number of recorded deaths in isolated CNS relapse, systemic only recurrence, and no relapse patients was 5 (71.4%), 22 (59.4%), 1(2.78%), respectively. The 1-year OS and 1-year PFS of patients with isolated CNS recurrence was significantly lower compared to the no relapse group (OS, 35.7% [95%CI 12.1–100] vs 97.22% [95%CI 92–100], P<0.001; PFS, 28.6% [95%CI 8.86–92.2] vs 100% [95%CI 100–100], P<0.001), but showed no difference compared to the systemic only recurrence group (OS: 53.3% [95%CI 39.3–72.4], P=0.79; PFS: 13.0% [95%CI 5.53-30.5], P=0.17).

Conclusions: In conclusion, patients with CNS relapse showed significant difference in 1-year outcomes with no relapse group but not systemic relapse group in our study, which suggested the importance of effective prophylaxis against CNS relapse. Further investigation is necessary to better define the characteristics of patients who will benefit from prophylaxis.

Clinical Trial Registry: ChiCTR1800015575; NCT03118180; NCT04532281; NCT04532268; NCT04213469

Disclosure: Nothing to declare

4: CAR-based Cellular Therapy – Clinical

P102 DAY7-CART COUNT ENHANCES PREDICTIVE POWER OF PET30 AND POSSIBLY ANTICIPATES CD19 LOSS IN RELAPSE AFTER CART

Fabian Müller 1,2, Viktoria Blumenberg3,2, Veit L. Bücklein3,2, Ralph A. Bundschuh4,2, Dennis Harrer5,2, Klaus Hirschbühl4,2, Johannes Jung6,2, Wolfgang Kunz3,2, Igor Yakushev7,2, Anna Lena Illert6,2, Simon Völkl1,2, Rainer Claus4,2, Leo Hansmann5,2, Judith Hecker6,2, Dirk Hellwig8,2, Andreas Mackensen1,2, Marion Subklewe3,2, Michael Beck1,2

1University Hospital of Erlangen, Erlangen, Germany, 2Bavarian Cancer Research Center, Resp. Site, Germany, 3LMU University Hospital, LMU Munich, Munich, Germany, 4University Hospital of Augsburg, Augsburg, Germany, 5Clinic III Internal Medicine, University Hospital Regensburg, Regensburg, Germany, 6Klinikum Rechts der Isar, Technische Universität München, München, Germany, 7Klinikum Rechts der Isar, Technische Universität München, Munich, Germany, 8University Hospital of Regensburg, Regensburg, Germany

Background: CD19. CAR T cell therapy (CAR-T) has revolutionized current treatment practice in relapsed/refractory diffuse-large B cell Lymphoma (DLBCL) and transformed follicular lymphoma (tFL) by achieving cure in previously palliative situation. Despite this progress, predicting patients benefitting from CAR-T remains challenging. Independently, higher cell numbers at day 7 of CAR-T cell expansion (CAR-peak, at least 20/µl), as well as a negative PET scan as early as day 30 (PET30) have shown to be individually of high predictive power for lasting responses.

Here, we aimed to combine PET30 and d7-CAR-T-count to test whether they support each other’s predictive power.

Methods: DLBCL patients were treated with Tisa-cel, Axi-cel, or Liso-cel at 5 university hospitals of the Bavarian center of cancer research (BZKF) where clinical data was collected. CAR T cell numbers were assessed by flow cytometry. PET-CT scans were analyzed in a standardized manner among the five individual sites. The more recently implemented PET30 and the PET90 were analyzed.

Results: Overall 67 patients with DLBCL-NOS and four with tFL, together with a median age of 64.4 years were treated with CAR-T. 64 patients received bridging therapy to which 33 patients responded (PR/CR) and 30 did not (SD/PD, 8 missing data). 5 patients had an ECOG of 2 + , and 36 an IPI of 3+ at lymphodepletion when mean of LDH was 352 U/L, of CRP was 8.8 mg/L, and of ferritin was 808.6 ng/mL. By ROC analyses, response to bridging and the metabolic-IPI before CAR-T as well as PET30 and CAR-peak after infusion strongly predicted durable response. For 30 of the 71 patients, both, PET30 and day7-CAR-T-count were available. Among those, best long-term outcome was observed in patients with >20 CAR-T cells/µl and negative PET30 (8 patients). Only one/eight patients relapsed at month 5 and was CD19-negative. In contrast, none of the patients with positive PET30 and low Day7-CAR-T-count showed long-term remission. Of the 12 patients with positive PET30 and high CARs, one converted to CR, two died of unknown cause (NRM), one died of CAR-toxicity, and 8 relapsed. 6 of those 8 relapses were biopsied of which 3 presented with CD19 loss. Lastly, of 4 patients with negative PET30 and low Day7-CAR-count, one is in lasting remission, the others relapsed CD19 positive, where assessed.

Conclusions: In this small, retrospective cohort, PET30 and Day7-CAR-T-count greatly support each other in predicting lasting remission vs. relapse. In addition, relapse after high-CAR peak was associated with CD19 loss in 4 of 7 cases, whereas relapse after low CAR-peak was not possibly suggesting distinct resistance mechanisms.

Clinical Trial Registry: N/A

Disclosure: This research was funded by the Bavarian Cancer Research Center.

FM received honoraria and served on advisory boards for BMS, Janssen, Kite, Kyverny, Miltenyi, and Novartis and receied research support from AstraZeneca and Kite.

VBlu received research funding from Bristol Myers Squibb (BMS)/Celgene, Kite/Gilead, Janssen, Novartis, Roche, and Takeda and research funding and honoraria/consultancy fee from Kite/Gilead, Janssen, and Novartis.

VBue received research funding and/or honoraria from Amgen, Celgene/BMS, Kite/Gilead, Novartis, and Pfizer.

AM received honorarai and served on advisory boards for BMS, Janssen, Kite, Kyverny, Miltenyi, and Novartis and receied research support from Kyverna and Miltenyi.

MS received research funding, speaker’s bureau fee, and/or consultancy fee from Amgen, AstraZeneca, Aven Cell, BMS/Celgene, CDR-Life, Kite/Gilead, GlaxoSmithKline, Ichnos Sciences, Incyte Biosciences, Janssen, Miltenyi Biotec, Molecular Partners, Novartis, Pfizer, Roche, Seattle Genetics, and Takeda.

RB, DH, KH, JJ, WK, IY, ALI, SV, RC, LH, DH, and MB have no relevant conflict of interest.

4: CAR-based Cellular Therapy – Clinical

P103 EXCELLENT OUTCOME OF CAR-T CELL THERAPY IN CHILDREN WITH PB-ALL RELAPSING POST HSCT, WHO HAD VERY LOW MRD AT LYMPHODEPLETING CHEMOTHERAPY – POLISH CENTRES’ EXPERIENCE

Karolina Liszka 1, Paweł Marschollek1, Iwona Dachowska - Kałwak1, Monika Mielcarek-Siedziuk1, Jowita Frączkiewicz1, Anna Panasiuk1, Igor Olejnik1, Natalia Haze1, Monika Richert-Przygońska2, Krzysztof Czyżewski2, Robert Dębski2, Jan Styczyński2, Krzysztof Kalwak1

1Wroclaw Medical University, Wrocław, Poland, 2Nicolaus Copernicus University in Torun, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Bydgoszcz, Poland

Background: CAR-T cell therapy brought about a revolution in pB-ALL treatment, improving the survival chances of children in whom the conventional options of therapy failed. Although the outcome is impressive (the newest ELIANA trial update results show 3-year EFS of 44% and OS of 63%, respectively), there’s still a question how to use the whole potential of CAR-T cells. CAR-T cell therapy is effective in treatment of pB-ALL relapse post HSCT, however acc. to Bader et al., outcome in patients with very early relapse (<6 months post HSCT) is significantly worse. In our series it was aimed to achieve the lowest possible MRD before lymphodepleting chemotherapy (LDC) independently from interval between HSCT and relapse.

Methods: We included 18 patients (10 boys, 8 girls, aged 2-17 yrs) with pB-ALL who relapsed post HSCT and were treated with tisagenlecleucel in Polish centres in Wroclaw and Bydgoszcz in years 2020-2023. All patients were severely pretreated, 3 children underwent two HSCT procedures. In 8 patients it was the first relapse, in 7 patients the second, in 2 children the third relapse and 1 patient relapsed four times before CAR-T cells infusion. Median time range between HSCT and relapse prior to CAR-T cell therapy was 9.3 months (range 2-132 months). Negative MRD before LDC was achieved in 5 patients, in others it ranged from below 10-4 to 1x10-2. Different strategies were used as bridging therapy – conventional chemotherapeutics and/or immunotherapeutic drugs.

Results: In the analysed cohort, 16 out of 18 (88%) children remain alive and well with negative MRD. In this group, median time between HSCT and relapse was 10.3 months. Three patients relapsed earlier than 6 months post HSCT. Two CD19-negative relapses were observed – both children died. Median observation time in presented patients is 12 months, 2-year OS is 82.5% and 2-year EFS is 83.6%. No CRS/ICANS ≥ grade III were observed.

The 50th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians – Poster Session (P001-P755) (13)

Conclusions: Very low disease burden before LDC, stated as CR with negative or low MRD, ensured excellent 2-year OS and EFS. CAR-T cell therapy increases the chance for cure in high-risk patients, in whom HSCT had not guaranteed long-lasting remission. To enhance the probability of optimal outcome, the goal should be to obtain as low disease burden before LDC as possible, ideally with negative MRD. Every patient requires an individualized approach to bridging therapy but our results highlight the need for maximal possible reduction in MRD before LDC in patients relapsing post HSCT, especially when they relapse early. CR before CAR-T cells infusion not only lowers the risk of relapse but also minimizes the occurrence of post infusion complications such as CRS, ICANS or HLH.

Disclosure: Karolina Liszka – no conflict of interest

Paweł Marschollek – no conflict of interest

Iwona Dachowska – Kałwak – no conflict of interest

Monika Mielcarek-Siedziuk – speaker’s bureau: Novartis, medac, Amgen

Jowita Frączkiewicz – speaker’s bureau: Gilead

Anna Panasiuk – no conflict of interest

Igor Olejnik – no conflict of interest

Natalia Haze – no conflict of interest

Monika Richert-Przygońska - Lecture fees: Novartis, Gilead. Conference participation: Gilead

Krysztof Czyżewski – Lecture fees: Novartis, Gilead. Conference participation: MSD.

Robert Dębski - Lecture fees: Novartis

Jan Styczyński – lecture fees: Novartis, Gilead, MSD, AstraZeneca. Advisory Board: MSD, AstraZeneca, Pfizer, Moderna. Conference participation: medac, Roche

Krzysztof Kałwak – speaker’s bureau: medac, Novartis, Pierre Fabre, Neovii. Advisory Board: Pfizer, MSD

4: CAR-based Cellular Therapy – Clinical

P104 THE DARK SIDE OF CORTICOSTEROIDS IN CD19. CAR-T CELL THERAPY

Marcello Roberto 1,2, Francesco Iannotta1, Francesco De Felice1,2, Beatrice Casadei1, Gianluca Storci1, Serena De Matteis1, Noemi Laprovitera1, Francesca Vaglio1, Barbara Sinigaglia1, Enrica Tomassini1, Enrico Maffini1, Mario Arpinati1, Francesco Barbato1,2, Margherita Ursi1,2, Salvatore Nicola Bertuccio1, Daria Messelodi1, Irene Salamon1, Maria Naddeo1, Elisa Dan1, Luca Zazzeroni1, Cinzia Pellegrini1, Matteo Carella1,2, Marianna Gentilini2,1, Pier Luigi Zinzani1,2, Massimiliano Bonafè1,2, Francesca Bonifazi1

1IRCCS-Azienda Ospedaliero Universitaria di Bologna, Bologna, Italy, 2University of Bologna, Bologna, Italy

Background: Chimeric antigen receptors (CAR)-T cells represent an advanced therapy targeting the CD19 antigen on B cells, with consistent efficacy and relative safety in patients diagnosed with relapsed or refractory (r/r) B‐cell lymphomas. Corticosteroids are often used for the management of CAR-T cell toxicities. However, conflicting data are described about their harmful impact on CAR-T cell therapy and patient’s outcome. This study aimed to explore the role of corticosteroids after infusion in overall survival (OS) and progression-free survival (PFS).

Methods: The study cohort included seventy-five patients with r/r B-cell lymphomas admitted to the “advanced cell therapy unit of IRCCS_AOU of Bologna” for CD19. CAR-T cell therapy. The median age was 60 years (19-71). The cell product was axi-cel (n=45, 60%) or tisa-cel (n=30, 40%). After infusion, 63 (84%) developed cytokine release syndrome (CRS) of any grade: 40 (53%) developed grade 1; 18 (24%) grade 2; 5 (7%) grade ≥3. Twenty-two (29%) patients developed immune effector cell-associated neurotoxicity syndrome (ICANS) of any grade: 6 (8%) developed grade 1, 7 (9%) grade 2, 9 (12%) grade ≥3. Thirty-eight (51%) patients received corticosteroids within 30 days after infusion for CRS and/or ICANS management (not for any other indications). Cumulative corticosteroid doses were reported as methylprednisolone-equivalent (median 1120 mg, range 380-13035). Available blood samples after CAR-T cell infusion were analyzed by FACS for CAR+T cell tracking.

Results: As expected, we found a strong association between corticosteroid administration after infusion and severe toxicities (grade ≥2 CRS and/or any grade ICANS occurrence). Thus, in order to determine the contribution of these variables on the time-dependent outcomes (OS and PFS), their distributions were marginalized. At first, we selected a subgroup of patients without severe toxicities (n=45) experiencing at most persistent grade 1 CRS. When comparing patients who received steroid (n=12; median methylprednisolone-equivalent dose was 1002.5 mg) with those who did not receive it (n=33), no significant differences in OS (p=0.80) and PFS (p=0.08) were found. Next, to address the impact of severe toxicities we focused on patients receiving corticosteroid (n=38) verifying that only grade ≥2 CRS impacted on OS (p=0.04) but not on PFS (p=0.08). Noteworthy, in a multiple Cox regression model (also including age, disease histotype, stage and bulky, CAR-T cell product, bridging therapy response, pre-lymphodepletion LDH levels) grade ≥2 CRS did not retain its significativity, while cumulative corticosteroid dose was associated with OS (p=0.002) and PFS (p=0.018). Finally we found no correlation between cumulative corticosteroid dose and CAR+T cell peak and area under curve (AUC0-30) levels as measured by MFC.

Conclusions: This evidence suggests that a higher cumulative corticosteroid dose after CAR-T cell infusion may have a harmful effect in OS and PFS, without compromising CAR+T cell expansion. Further analyses in larger cohorts are needed to confirm this result and to investigate the detrimental effect of steroids on CAR-T cell activity rather than quantity.

Disclosure: FB: scientific advisory boards and speaker fees: NEOVII, NOVARTIS, KITE, GILEAD, PFIZER, CELGENE, MSD.

PLZ: scientific advisory boards: Secura Bio BIO, Celltrion, Gilead, Janssen-Cilag, BS, Servier, Sandoz, MSD, TG Therap., Takeda, Roche, EUSA Pharma, Kiowa Kirin, Novartis, ADC Therap., Incyte, Beigene; consultancy: EUSA Pharma, MSD, Novartis; speaker’s bureau: Celltrion, Gilead, Janssen-Cilag, BMS, Servier, MSD, TG Therap., Takeda, Roche, EUSA Pharma, Kiowa Kirin, Novartis, Incyte, Beigene.

The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

4: CAR-based Cellular Therapy – Clinical

P105 MATCHING-ADJUSTED INDIRECT COMPARISON OF EFFECTIVE CHARACTERISTICS AMONG DIFFERENT BCMA TARGETING CAR-T IN TREATMENT OF RELAPSED OR REFRACTORY MULTIPLE MYELOMAS

Chunrui Li 1, Lu-Gui Qiu2, Di Wang1, Yongping Song3, He Huang4, Jianyong Li5, Bing Chen6, Jing Liu7, Xi Zhang8, Yu-Jun Dong9, Kai Hu10, Peng Liu11, Jian-Qing Mi12, Kaiyang Ding13, Zhenyu Li14, Qie Dong15, Fuyuan Zhang15, Guang Hu15, Wen Wang15

1Institute of Hematology; Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China, 2Chinese Academy of Medical Sciences and Peking Union Medical College, State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Tianjin, China, 3The Affiliated Cancer Hospital of Zhengzhou University, Henan Cancer Hospital, Zhengzhou, China, 4The First Affiliated Hospital, Zhejiang University, Hangzhou, China, 5The First Affiliated Hospital of Nanjing Medical University, Nanjing, China, 6Nanjing Drum Tower Hospital, Affiliated Hospital of Nanjing University Medical School, Nanjing, China, 7Third Xiangya Hospital of Central South University, Changsha, China, 8Medical Center of Hematology, Xinqiao Hospital, State Key Laboratory of Trauma, Burn and Combined Injury, Army Medical University, Chongqing, China, 9Peking University First Hospital, Beijing, China, 10Beijing Boren Hospital, Beijing, China, 11Zhongshan Hospital, Fudan University, Shanghai, China, 12State Key Laboratory of Medical Genomics, National Research Center for Translational Medicine at Shanghai, Shanghai Institute of Hematology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China, 13The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China, 14Affiliated Hospital of Xuzhou Medical University, Xuzhou, China, 15Nanjing IASO Biotechnology Co., Ltd., Nanjing, China

Background: Several studies on BCMA targeting CAR-T cell therapies have disclosed their results, each with different characteristics in efficacy. These BCMA CAR-T cell therapies have been used in different marketing and clinical settings. However, there are no controlled studies directly comparing different CAR-T cell therapies. This analysis used matching-adjusted indirect comparisons (MAIC) to evaluate the comparative efficacy of Equecabtagene Autoleucel (Eque-cel) versus Ciltacabtagene Autoleucel (Cilta-cel), Idecabtagene vicleucel (ide-cel), zevorcabtagene autoleucel (zevor-cel, CT053) in patients with relapsed or refractory multiple myeloma.

Methods: Primary data sources included individual patient data from the FUMANBA-1 study (NCT05066646; N=103 for efficacy set) for Eque-cel and summary-level data from the CARTITUDE-1 study (NCT03548207; N=97 for efficacy set) for cilta-cel; data from CARTIFAN-1 study (NCT03758417; N=48 for efficacy set) for cilta-cel; data from KARMMA study (NCT03361748; N=128 for efficacy set) for ide-cel; data from LUMMICAR STUDY (NCT03975907 N=102 for efficacy set) for zevor-cel. Inter-study differences in design, eligibility criteria, baseline characteristics, and outcomes were assessed and aligned to the extent feasible. Clinically relevant prognostic factors were adjusted in a stepwise fashion by ranked order.

Results: This analysis revealed many different characteristics of these BCMA CAR-T therapies in RRMM, with eque-cel showing a better trend in MAIC-weighted efficacy outcomes.

The MAIC of the response rates, including overall and complete response rates and MRD negativity rate, were compared by odds ratio (OR) and 95% confidence intervals (CI). In FUMANBA-1 study versus CARTIFAN study, eque-cel showed a better trend than cilta-cel for overall response rate. When FUMANBA-1 study was compared to LUMMICAR study, eque-cel showed a better trend than zevor-cel for overall response rate and significantly better for complete response rate. In FUMANBA-1 study versus CARTITUDE-1 study, due to very limited effective sample size resulting from different patient characteristics, no clear trend was detected. When FUMANBA-1 study was compared to KARMMA study, eque-cel showed a better trend than ide-cel in overall response rate, complete response rate, and particularly MRD negativity rate, even with a limited effective sample size. The specific data is shown in the following table.

Because the median PFS was not reached in FUMANBA-1 study, 12-month PFS rate and 12-month MRD negativity maintaining rate were calculated by MAIC-weighted methods. Eque-cel showed higher 12-month PFS rate and MRD negativity maintaining rate after such adjustments. The specific data is also shown in the following table.

Table Summary of ORR,≥CR rate, MRD negativity rate,12 month PFS rate, and 12 month MRD negativity maintaining rate

FUMANBA-1(eque-cel)

versus

CARTIFAN(cilta-cel)

FUMANBA-1(eque-cel)

versus

LUMMICAR (zevor-cel)

FUMANBA-1(eque-cel)

versus

KARMMA(ide-cel)

FUMANBA-1(eque-cel)

versus

CARTITUDE1(cilta-cel)

MAIC(ESS*=75)

MAIC(ESS=49.4)

MAIC(ESS=10.7)

MAIC(ESS=7.2)

OR (95%CI)

OR (95%CI)

OR (95%CI)

OR (95%CI)

ORR

5.65 (0.94,33.9)

5.17(0.69,38.82)

11.57 (0, inf)

0.19 (0, inf)

≥CR rate

1.15(0.49,2.71)

6.08 (2.88, 12.83)

3.20 (0, inf)

0.29 (0, inf)

MRD negativity rate

0.8(0.08,8.36)

/

28.59 (0, inf)

/

12-month PFS rate

82.3%

93.2%

75.8%

94.2%

12-month sustained MRD negativity

77.8%

76.4%

84%

100%

  1. *ESS: effective sample size

Conclusions: After matching and adjusting for clinically relevant prognostic factors, eque-cel demonstrated a better trend of short-term efficacy when compared to cilta-cel of CARTIFAN study, ide-cel of KARMMA study and zevor-cel of LUMMICAR study. Eque-cel also showed a favorable long-term efficacy in patients with heavily pretreated relapsed or refractory MM.

Disclosure: Nothing to declare. Professor Lu-Gui Qiu is the corresponding author of this study.

4: CAR-based Cellular Therapy – Clinical

P106 IMPACT OF EARLY CAR CD4+ T-LYMPHOCYTES RECOVERY FOLLOWING CAR-T CELL INFUSION FOR RELAPSED OR REFRACTORY B CELL LYMPHOMAS

Massimiliano Gambella 1,2, Simona Carlomagno2, Rosa Mangerini1, Nicoletta Colombo1, Alessia Parodi1, Chiara Ghiggi1, Livia Giannoni1, Elisa Coviello1, Chiara Setti2, Silvia Luchetti1, Alberto Serio1, Antonella Laudisi1, Monica Passannante1, Alessandra Bo1, Elisabetta Tedone1, Simona Sivori2, Emanuele Angelucci1, Anna Maria Raiola1

1IRCCS Ospedale Policlinico San Martino, Genova, Italy, 2University of Genoa, Genova, Italy

Background: CAR CD4+ T cell lymphopenia is an emerging issue following CAR-T infusion. We focused on potential determinants of CD4+ T cell recovery and investigated a possible association with survival. We also described the kinetics of CAR CD8+ T, NK, and NKT cell recovery following CAR-T therapy for aggressive B-cell lymphomas.

Methods: We investigated a cohort of patients affected by Diffuse Large B-cell Lymphoma or Mantle Cell Lymphoma, treated at IRCCS Ospedale Policlinico San Martino, Genova, with commercially available CAR-T products. Peripheral blood immune cell subpopulations were characterized before lymphodepletion and following CAR-T infusion through multiparametric-flow cytometry, primarily focusing on CAR lymphoid subpopulations. Infectious complications were analyzed according to CD4 T cell recovery.

Results: Thirty-one consecutive patients were selected for the analysis. Six-month cumulative incidence of CAR CD4+ T cell recovery (i.e., ≥ 200cells/μl) was 0.43 (95% CI: 0.28-0.65). Among possible determinants of CD4+ T cell recovery, we recognized infusion of a 4-1BB product (tisagenlecleucel, TSA) in comparison with CD28-based ones (axicabtagene/brexucabtagene, AXI/BRX) (hazard ratio [95% CI]: 5.79 [1.16-24.12] p= 0.016). Higher CD4+ T cell counts resulted with TSA at month-1, -2, and- 3 following infusion. Moderate to severe infectious complications were registered in patients with pro