Farag SS, Zaid MA, Schwartz JE, et al. - Researchers performed a two-stage, phase 2 clinical trial to determine if acute graft-versus-host disease (GVHD) following allogeneic stem-cell transplantation may be prevented by inhibition of dipeptidyl peptidase 4 with sitagliptin. They examined if sitagliptin plus tacrolimus and sirolimus would decrease the incidence of grade II to IV acute GVHD from 30% to no more than 15% by day 100. Myeloablative conditioning was received by patients followed by mobilized peripheral-blood stem-cell transplants. At a dose of 600 mg, sitagliptin was administered orally every 12 hours starting the day prior to transplantation until day 14 post-transplantation. Findings of this nonrandomized trial revealed that a low incidence of grade II to IV acute GVHD by day 100 following myeloablative allogeneic hematopoietic stem-cell transplantation was conferred by sitagliptin in combination with tacrolimus and sirolimus.