Sirolimus immunosuppression for graft-versus-host disease prophylaxis and therapy: an update

PURPOSE OF REVIEW: Sirolimus is being used increasingly as an immunosuppressant in allogeneic hematopoietic stem cell transplantation. This article reviews recent results in sirolimus-based graft-versus-host disease (GVHD) prophylaxis, as well as outcomes using sirolimus for established acute and chronic GVHD. RECENT FINDINGS: In uncontrolled experiments, sirolimus provides good control of steroid-resistant acute or chronic GVHD. Similarly, the addition of sirolimus to GVHD prophylaxis regimens appears to reduce the rate of acute GVHD in the myeloablative and reduced-intensity settings, when used in matched, related, and unrelated donor transplantation. The use of sirolimus in haploidentical transplantation is now being explored as well. SUMMARY: Sirolimus should be considered for use in steroid-resistant acute and chronic GVHD. Sirolimus appears promising as primary prophylaxis for GVHD prevention. Randomized trials are currently being performed to determine whether sirolimus-based immunosuppression is superior to traditional GVHD prophylaxis.