Trial of 2 Step ATG for Prevention of Acute GVHD Post Allogeneic Stem Cell Transplant

On Day -8, you will be admitted to the hospital and receive a dose of prednisone at 1 mg/kg (ATG premedication). You will receive a steroids 3 hours before every ATG infusion. On day -7, you will receive a small dose of ATG as an intravenous (IV) infusion. ATG will be repeated on days -6, -5 and -1. Routine transplant chemotherapy agent fludarabine will be given on days -7 to -3 as daily IV infusions. Melphalan, another routine transplant chemotherapy will be given on day -4 as IV infusion. Tacrolimus (standard immune suppression agent) will start on day -3 as continuous IV infusion and switched to oral after engraftment. Methotrexate is another standard immune suppression medication which is given IV on day +1, +3, +6, and +11 post-transplant. We plan to draw blood on days -4,, -1, +3, +7, and +14 to measure ATG levels.