Graft-Versus-Host Disease Prophylaxis with Post-Transplantation Cyclophosphamide versus Cyclosporine A and Methotrexate in Matched Sibling Donor Transplantation.

Abstract Cyclosporine A and methotrexate (CSA/MTX) is the standard graft-versus-host disease (GVHD) prophylaxis regimen for matched sibling donor (MSD) allogeneic hematopoietic cell transplantation (allo-HCT). Recently, post-transplant cyclophosphamide (PTCy) has been shown to be effective in GVHD prevention. In this registry-based study, we compared outcomes of 118 patients with PTCy and 1202 patients with CSA/MTX who underwent MSD allo-HCT for acute myeloid leukemia (AML). In a matched-pair analysis, PTCy was associated with a higher incidence of relapse at 2-year (41.1% versus 21.3%, p=0.039) compared to CSA/MTX. The incidence of day 180 grade II-IV acute GVHD (25.2% versus 25.4%, p=0.90) and 2-year chronic GVHD (42.6% versus 42.6%, p=0.84) were comparable between PTCy and CSA/MTX, respectively. Similarly, 2-year leukemia-free survival (LFS, 54.4% versus 74.32%, p=0.052), overall survival (OS, 70.6% versus 79.7%, p=0.15) and GVHD-free-relapse-free survival (GRFS, 38.1% versus 52.5%, p=0.49) were not statistically different between PTCy versus CSA/MTX. In conclusion, GVHD prophylaxis with PTCy is feasible, resulting in similar incidences of GVHD, GRFS, LFS, and OS compared to conventional CSA/MTX in patients undergoing allo-HCT from MSD. The higher relapse observed with PTCy needs further evaluation in a prospective study.