Tacrolimus Versus Cyclosporine for Graft-Versus-Host Disease Prophylaxis in Pediatric Patients Undergoing Matched Unrelated Donor Hematopoietic Stem Cell Transplants. A Pediatric Blood and Marrow Transplant Consortium Study..

Calcineurin inhibitors form the backbone of graft versus host disease (GVHD) prophylaxis in hematopoietic stem cell transplantation. In the adult literature tacrolimus was demonstrated superior to cyclosporine in preventing grade II–IV acute GVHD in both related and unrelated donor transplants; however, there is no data comparing their efficacy in the pediatric population. In a multi-institutional trial, we prospectively evaluated the clinical data on 102 patients receiving either cyclosporine/methotrexate or tacrolimus/methotrexate based prophylactic regimens for 6/6 matched unrelated donor, transplant. Conditioning regimens were fully ablative; no T-cell depletion was permitted; cord blood donors were excluded. Patients were required to receive either cyclosporine or tacrolimus, but the choice was per investigator preference. The two arms were reasonably balanced: 59.8% of patients received cyclosporine and 40.2% of patients received tacrolimus. Rates for maximum grade II–IV acute GVHD were 37.7% for cyclosporine and 39% for tacrolimus (p = 0.89). Rates for maximum grade III–IV acute GVHD were 19.6% for cyclosporine and 24.4% for tacrolimus (p = 0.57). Incidence of chronic GVHD in 97 evaluable patients was 37.9% in 58 patients who received cyclosporine and 35.8% in 39 patients who received tacrolimus (p = 0.84). Survival at 1 year post-transplant was similar in both groups: 59.2% for cyclosporine and 51.2% for tacrolimus (p= 0.31). Toxicity analysis is ongoing. In pediatric matched unrelated donor transplantation, the efficacy of tacrolimus/methotrexate and cyclosporine/methotrexate based regimens for prophylaxis of GVHD are not significantly different.