Tacrolimus versus Cyclosporine after Hematopoietic Cell Transplantation for Acquired Aplastic Anemia

• We compared outcomes with tacrolimus plus methotrexate versus cyclosporine plus methotrexate as graft-versus-host disease prophylaxis after hematopoietic cell transplantation for severe aplastic anemia
• Tacrolimus plus methotrexate was associated with a lower risk of mortality in unrelated donor recipients
• Tacrolimus plus methotrexate was associated with slightly earlier absolute neutrophil count recovery in HLA-identical sibling recipients
• Other outcomes did not differ statistically between the 2 regimens
• No firm conclusions were reached regarding the relative merits of the 2 regimens

Combinations of cyclosporine (CSP) with methotrexate (MTX) have been widely used for immunosuppression after allogeneic transplantation for acquired aplastic anemia. We compared outcomes with tacrolimus (TAC)+MTX versus CSP+MTX after transplantation from HLA-identical siblings (SIB) or unrelated donors (URD) in a retrospective cohort of 949 patients with severe aplastic anemia. Study endpoints included hematopoietic recovery, graft failure, acute graft-versus-host disease (GVHD), chronic GVHD, and mortality. TAC+MTX was used more frequently in older patients and, in recent years, in both SIB and URD groups. In multivariate analysis, TAC+MTX was associated with a lower risk of mortality in URD recipients and with slightly earlier absolute neutrophil count recovery in SIB recipients. Other outcomes did not differ statistically between the 2 regimens. No firm conclusions were reached regarding the relative merits of TAC+MTX versus CSP+MTX after hematopoietic cell transplantation for acquired aplastic anemia. Prospective studies would be needed to determine whether the use of TAC+MTX is associated with lower risk of mortality in URD recipients with acquired aplastic anemia.