Outcomes of Allogeneic Hematopoietic Cell Transplantation with Post-Transplant Cyclophosphamide Prophylaxis in Myelodysplastic Syndromes: A Multicenter Study Conducted on Behalf of GETH-TC.

Considering that post-transplant cyclophosphamide (PTCy) has emerged as an effective GVHD prophylaxis across donor types, we conducted a multicenter retrospective study to evaluate outcomes of PTCy-based allo-HCT in patients with MDS. A total of 291 patients undergoing allo-HCT with PTCy between 2014 and 2024 were included. Median age was 61 years (range, 20 to 76), with 28.2% aged >65 years. Reduced-intensity conditioning was used in 73.5% of patients, and donor sources included matched sibling (20.3%), matched unrelated (25.8%), mismatched unrelated (14.4%), and haploidentical donors (39.5%). Median follow-up was 23 months. Neutrophil and platelet engraftment occurred at a median of 18 and 24 days, respectively. Cumulative incidence of grade II-IV acute GVHD at day +100 was 27.8% and grade III-IV was 12.0%; 2-year moderate-to-severe chronic GVHD was 20.0%. At 3 years, OS was 54.6%, CIR was 21.5%, and NRM was 28.4%. Patients aged >65 years had higher 3-year NRM (35.2% versus 25.7%, P = .039) but similar OS, CIR and GRFS compared with younger patients. High-risk cytogenetics, rather than age, was the main predictor of relapse. PTCy-based provided a feasible and effective allo-HCT platform for MDS patients, including selected older adults, with acceptable GVHD rates and encouraging survival outcomes.