Short-term methotrexate plus cyclosporine for graft-versus-host disease prophylaxis after single-unit cord blood transplantation following reduced-intensity conditioning

Background: Cord blood is an alternative donor source for patients without HLA-matched donors. Calcineurin inhibitors (CNIs) alone, as prophylaxis for graft-versus-host disease (GVHD) in cord blood transplantation (CBT) patients, reportedly increase the incidence of severe pre-engraftment immune reaction (PIR), leading to transplant-related mortality (TRM) with primary engraft failure and multiple organ dysfunctions. Therefore, additional immunosuppressive agents are needed. Reportedly, short-term methotrexate (sMTX) plus CNIs improved outcomes in patients receiving CBT with full-intensity conditioning (FIC) regimens; however, safety and efficacy of sMTX plus cyclosporine have not been assessed in patients receiving CBT with reduced-intensity conditioning (RIC) regimens. Methods: We retrospectively analyzed 43 patients who received single-unit CBT and were treated with sMTX plus cyclosporine (RIC group, 15; FIC group, 28). Results: Neutrophil engraftment rate was significantly lower in RIC group (53.3%) than in FIC group (78.6%, P=0.04). Cumulative incidence of TRM tended to be higher in the RIC group than in the FIC group (P=0.12); the leading cause of death in the RIC group was bacterial infections. Conclusions: sMTX plus cyclosporine does not seem feasible for treating patients receiving single-unit CBT following RIC. MTX dose optimization or alternative immunosuppressive agent application should be considered in such patients.