Stem Cell Transplantation for Diamond-Blackfan Anemia. a Retrospective Study on Behalf of Severe Aplastic Anemia Working Party of the European Blood and Marrow Transplantation Group (EBMT)
Authors: Miano Maurizio , Eikema Dirk-Jan , de la Fuente Josu , Bosman Paul , Ghavamzadeh Ardeshir , Smiers Frans , Sengeløv Henrik , Yesilipek Akif , Formankova Renata , Bader Peter , Díaz Pérez Miguel Ángel , Bertrand Yves , Niemeyer Charlotte , Bron Dominique , Ansari Marc , Bykova Tatiana A , Lanino Edoardo , Rovelli Attilio , Gozdzik Jolanta , Satti Tariq Mahmood , Bodova Ivana , Wölfl Matthias , Rocha Vanderson G. , Mellgren Karin , Rascon Jelena , Lange Andrzej , Meisel Roland , Beguin Yves , Mozo Yasmina , Kriván Gergely , Sirvent Anne , Bruno Benedicte , Onofrillo Daniela , Risitano Antonio M. , Peffault de Latour Régis , Dufour Carlo 
Published: February 2020

INTRODUCTION
Diamond-Blackfan Anemia (DBA) is a congenital pure red cell aplasia, secondary to ribosomal protein genetic defects that usually presents within the first year of age and can be associated with congenital abnormalities and increased risk of cancer. Some patients are successfully treated with steroids but most of them remain transfusion-dependent. Stem Cell Transplantation (SCT) represents the only curative option for this disease, however data from literature is scarce and limited to a very small number of cases. In this retrospective study we describe the outcome of SCT in patients with DBA reported in the EBMT data base.
PATIENTS AND METHODS
The study was conducted on behalf of Severe Aplastic Anemia Working Party of the EBMT and was based on data of patients affected with DBA who underwent SCT and registered in the EBMT Data Base. Clinical information of the disease and details on transplant procedures and follow-up were collected by a specific form distributed to Centres participating in the study.
RESULTS
Between 1985-2016, 106 patients (60 males-46 females) aged 6.8 yo (range 1-32) underwent SCT from matched sibling donor (58, 57%), unrelated donor (37, 36%) or from other donors (7, 7%) using bone marrow (73, 69%), peripheral blood (21, 20%) or cord blood (12, 11%) as cell source. 91 patients (86%) received a myeloblative regimen which included Busulfan in 66 cases. 86% (80-93%) of patients engrafted by day 28. Median days to neutrophils and platelets engraftment were 18 and 36, respectively. EFS and OS at 36 months were 81% (74-89%) and 84% (77-91%), respectively. OS was significantly higher (p=0.01) in patients &lt;10 years of age (91% (84-98%)) compared to the older ones (71% (56-86%)). No differences were noted between transplant from sibling vs unrelated donor. Day 100 acute (Grade II-IV) and 36m chronic (extensive) GvHD incidence were 30% (21-39%) and 15% (7-22%), respectively. A higher not statistically significant incidence of extensive cGvHD was present in patients transplanted from unrelated donors (22% (7-38%)) compared to the ones who received stem cells from siblings (11% (3-20%)). All patients died due to transplant related causes. Median follow-up was 68 months (52-89).
CONCLUSION
To the best of our knowledge, this is the largest reported cohort of patients transplanted for DBA and having a long follow-up. The very good OS of patients undergoing transplant from both sibling and unrelated donors and the rather low rate of cGvHD confirms that this procedure can be considered an alternative option for transfusion-dependent patients &lt;10 years of age.

Disclosures
Bader: Riemser, Neovii: Research Funding; Medac: Patents & Royalties, Research Funding; Amgen (Brasil), Novartis: Consultancy, Speakers Bureau; Celgene: Consultancy. Risitano:Alexion: Honoraria, Research Funding, Speakers Bureau; Achillion: Research Funding; Apellis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Apellis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Biocryst: Membership on an entity's Board of Directors or advisory committees; Alexion: Honoraria, Research Funding, Speakers Bureau; Amyndas: Consultancy; Samsung: Membership on an entity's Board of Directors or advisory committees; Samsung: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Amyndas: Consultancy; Biocryst: Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Ra Pharma: Research Funding; Ra Pharma: Research Funding; Alnylam: Research Funding; Alnylam: Research Funding; Achillion: Research Funding. Peffault de Latour:Pfizer: Consultancy, Honoraria, Research Funding; Amgen: Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Alexion: Consultancy, Honoraria, Research Funding.