This open label two-step phase II study is designed to determine the safety and efficacy of epigenetic priming with 5-Azacytidine immediately prior to reduced intensity conditioning for an in vivo T-cell depleted hematopoietic stem cell transplantation for high risk myeloid malignancies in complete remission (CR).~Subjects will be given a five day course of subcutaneous 5-azacytidine, followed by a reduced intensity conditioning regimen of fludarabine, melphalan and total body irradiation (TBI) prior to an allogeneic hematopoietic stem cell transplantation from a related or unrelated Human Leukocyte Antigen (HLA) matched donor.~The effect of 5-azacytidine on global gene methylation will be assessed. Evaluations for safety, in particular for graft failure, transplant related mortality and acute graft versus host disease will be made on a weekly basis. Efficacy, as defined by disease free survival, will be evaluated with a bone marrow biopsy at the standard time points, which are one-, three-, six-, and twelve-months after transplant and upon clinical suspicion within regular follow-up visits - weekly for the first 3 months, then biweekly for 3 months, then monthly until one-year post-stem cell transplant. Thereafter, unless otherwise dictated by the clinical scenario, the follow up visits will be every 3 months.
The purpose of this study is to determine whether 5-Azacytidine priming before the conditioning regimen for subjects receiving a hematopoietic stem cell transplant is an effective treatment for high risk myeloid malignancies in complete remission (CR).