A Prospective Study of Post-transplantation Cyclophosphamide in Allogeneic Hematopoietic Cell Transplantation for Higher-risk MDS: A Comparative Analysis with ATG

Abstract Post-transplantation cyclophosphamide (PTCy) has been increasingly used to prevent graft-versus-host disease (GVHD). This prospective study aimed to assess the efficacy and safety of PTCy-based GVHD prophylaxis in allogeneic hematopoietic cell transplantation (HCT) for patients with higher-risk myelodysplastic syndrome (MDS) and compare post-transplantation outcomes between PTCy and anti-thymocyte globulin (ATG)-based regimen, as a historical control. The PTCy group (N = 152) showed a significantly lower incidence of grade II-IV acute GVHD (9.2 vs. 26.2%) and grade III-IV acute GVHD (2.6 vs. 15.9%) than the ATG group (N = 145), which was consistently observed across donor types. The incidence of moderate-to-severe chronic GVHD (22.7 vs. 23.1%), overall survival (2-years, 64.0 vs. 56.6%), and event-free survival (2-years, 52.6 vs. 51.7%) did not differ between the two groups. Neutrophil (15 vs. 11 d) and platelet engraftment times (25 vs. 15 d) were longer in the PTCy group. A trend towards lower non-relapse mortality (NRM, 2-years rate of 19.1 vs. 29.0%) and higher cumulative incidence of relapse (2-years rate of 27.8 vs. 17.2%) was observed in the PTCy group. In conclusion, allogeneic HCT using PTCy for higher-risk MDS demonstrated a significantly lower acute GVHD incidence with a favorable NRM and acceptable relapse rate.