Allogeneic STEM Cell Transplantation in 45 Patients with Myelodysplastic Syndrome: Single-Center Analysis
Authors: Pomares Helena , Parody Porras Rocio , Mussetti Alberto , Galiano Mercedes , Maluquer Clara , Sureda Anna , Arnan Montserrat 
Published: November 2021

Abstract
Background: Myelodysplastic syndromes (MDS) includes a group of clonal myeloid neoplasms characterized by cytopenias due to ineffective hematopoiesis, abnormal blood and marrow cell morphology, and an increased risk of transformation to acute myelogenous leukemia (AML). Allogeneic hematopoietic cell transplantation (HCT) is the only potentially curative therapeutic option for patients with MDS.
Aim: To analyze the clinical features and evolution of the MDS patients who underwent to HCT in our institution.
Methods: Between July 2006 to January 2021, forty-five patients with MDS underwent allogeneic HCT at the Institut Català d'Oncologia, Hospital Duran i Reynals in Barcelona. Median age at HCT was 56 years (range 35 - 69 years). Thirty-two patients (64%) were male. The diagnosis of patients according to the 2016 WHO classification was: 22% MDS-MLD, 29% MDS-EB-1, 18% MDS-EB-2, 20% CMML, 4% MDS with isolated del(5q) and 7% unclassifiable MDS. Seven patients (15%) underwent allogeneic HCT after progression to AML. Treatments received before the transplant were: chemotherapy AML-like 11 patients (24%) and Azacitidine 24 patients (53%). Ten patients (23%) underwent HCT upfront.
Results: Median time from diagnosis to allogeneic HCT was 5 months (range 2 - 12 months). Donors were: matched related (MRD) 17 (38%), matched unrelated (MUD) 12 (27%) and haploidentical 16 (35%). For HLA-MRD transplants, 12 patients received busulfan and fludarabine, 2 patients received TBI and cyclophosphamide, and 3 received busulfan, cyclophosphamide and thiotepa. All of them received tacrolimus or cyclosporine with methotrexate. For HLA-MUD transplants, 7 patients received busulfan and fludarabine, 1 received busulfan and cyclophosphamide, 2 received fludarabine and melphalan, and 2 received busulfan, cyclophosphamide and thiotepa. Six patients received tacrolimus or cyclosporine with methotrexate, 3 patients received tacrolimus with sirolimus and 3 patients received posttransplant cyclophosphamide . For recipients of haploidentical transplants, 6 patients received fludarabine, busulfan and cyclophosphamide, 4 patients received busulfan, thiotepa and fludarabine, 5 patients received fludarabine, cyclophosphamide and TBI and 1 patient received TBI and cyclophosphamide. All patients received tacrolimus or cyclosporine with mycophenolate and posttransplant cyclophosphamide. Five patients (11%) received myeloablative conditioning and 40 patients (89%) received a reduced intensity conditioning regimen. According to graft soure,5 patients (11%) received bone marrow grafts and 40 patients (89%) received peripheral blood grafts. Grade II-IV acute GVHD at day +100 was observed in 19/41 patients (39%) and chronic GVHD in 15/35 patients (42%). Four patients (8%) presented veno occlusive disease. Cytomegalovirus reactivation was reported in 19/38 (50%), and possible/probable invasive fungal infection was reported in 4/49 (8.2%) patients. Median follow-up from MDS diagnosis was 47 months (range 9 - 252 months). At the time of last follow up, 23 patients (51%) are still alive. Median overall survival (OS) was 20 months (range 2 - 180 months). Median progression-free survival (PFS) after transplant was 17 months (range 3 - 180 months). No significant differences were found in OS between the donor types (P = .234) (Figure 1). However, there was a trend for improved PFS in the MRD group, with 2-year PFS of 88%, 58% and 66% for MRD, MUD, and haploidentical recipients, respectively (P = .084) (Figure 2).
Summary/Conclusion: Although statistical power is limited, these data suggests that MRD should be the first choice as donor transplant. MUD and haploidentical donors are an acceptable approach for patients without an HLA-matched donor.
Figure 1 Figure 1.

Disclosures
Mussetti: GILEAD: Other: Clinical trials participation, Research Funding; TAKEDA: Honoraria; NOVARTIS: Honoraria, Other: Clinical trials participation. Sureda: Roche: Other: Support for attending meetings and/or travel; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Bluebird: Membership on an entity's Board of Directors or advisory committees; Mundipharma: Consultancy; GSK: Consultancy, Honoraria, Speakers Bureau; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; MSD: Consultancy, Honoraria, Speakers Bureau; BMS/Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel, Research Funding, Speakers Bureau; Kite, a Gilead Company: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Arnan: Jazz: Other: Participation in clinical trials; Takeda: Other: Participation in clinical trials; BMS/Celgene: Consultancy, Other: Participation in clinical trials; Novartis: Consultancy, Other: Participation in clinical trials; Astellas: Consultancy.