Shorter Course Tacro After NMA, Related Donor PBSCT With High-dose Posttransplant Cy for Hard-to-Engraft Malignancies

The main goal is to learn whether a drug called tacrolimus, which is an immune-lowering drug (an immunosuppressant) given after transplant to help prevent certain complications, can be given safely for a shorter period of time than it has been in the past. The experiences with immunosuppression duration with other allogeneic HSCT platforms cannot be directly extrapolated to the high-dose posttransplantation cyclophosphamide platform (another type of immunosuppressant given after transplant to help prevent GVHD). There are presently no published data on the minimum required duration of tacrolimus after nonmyeloablative HSCT that includes high-dose Cy as part of postgrafting immunosuppression. The effectiveness of high-dose posttransplantation Cy in GVHD prevention, however, permits the investigation of this question. At the present time there are few or no cures for diseases studied on this trial outside of a bone marrow or peripheral blood transplant. The peripheral blood for this transplant comes from a relative who is a half-match or "haplo" match to the participant. Possible donors include parents, siblings, and children. In order to help the bone marrow grow, or "take", inside the body, participants will receive chemotherapy and radiation before the transplant. After the transplant participants will receive high doses of cyclophosphamide (Cytoxan®) along with other medications to lower the immune system, such as tacrolimus. These medications may lower the risk of graft versus host disease (GVHD) and of rejection of the peripheral blood graft.