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

This study is testing a two-step anti-thymocyte globulin (ATG) dosing strategy to prevent a serious complication called graft-versus-host disease (GvHD) after an allogeneic (donor) stem cell transplant. GvHD happens when the donor's immune cells attack the patient's body, and ATG is a drug that suppresses this immune response. **You may be eligible if...** - You are between 18 and 60 years old - You have a blood cancer or other condition requiring a myeloablative (high-intensity) stem cell transplant - You have a matched related (sibling, 6/6 HLA match) or matched unrelated (8/8 HLA match) donor who is willing and medically able to donate peripheral blood stem cells - Your overall health and treatment history make you a suitable candidate for myeloablative conditioning (high-dose chemotherapy/radiation before transplant) **You may NOT be eligible if...** - You do not have a suitably matched donor - You are over 60 years old or have significant health problems that make intensive conditioning unsafe - You have had a prior allogeneic transplant Talk to your doctor to see if this trial is right for you.