Sitagliptin for Prevention of aGVHD After Alternative Donor Transplantation

Primary Objective: It is hypothesized that the efficacy of Sitagliptin would reduce the incidence of grade II-IV acute Graft Versus Host Disease (GVHD) by day +100 post-transplant in patients undergoing alternative donor (related haploid or unrelated donor ) allogeneic Hematopoietic Stem Cell Transplantation (HSCT) and receiving standard GVHD prophylaxis. Secondary Objectives The following descriptive secondary objectives will be studied: 1. Determine the tolerability and potential toxicity of sitagliptin in patients undergoing allogeneic HSCT. 2. Determine the cumulative incidence of grades II-IV acute GVHD by day +100. 3. To investigate the cumulative incidence of grades III-IV acute GVHD. 4. To investigate the engraftment kinetics of absolute neutrophil count and platelets. 5. To evaluate the incidence of Cytomegalovirus (CMV), Epstein-Barr virus (EBV) and other infections occurring during the 100 days post-transplant. 6. To study non-relapse mortality (NRM) at day +100, and 1 year post-transplant. 7. Determine the overall survival at 1 year post-transplant. 8. Determine the incidence of chronic GVHD. 9. Determine the cumulative incidence of relapse of the primary hematological malignancy.