Haploidentical BMT With Post-Transplant Cyclophosphamide and Bendamustine

The purpose of this study is to evaluate the safety of progressively substituting day +3 and +4 post-transplant cyclophosphamide (PT-CY) with post-transplant bendamustine (PT-BEN) in myeloablative (MAC) haploidentical hematopoietic cell transplantation (HHCT) for patients with hematological malignancies. The goal of the Phase 1 component of the study is to evaluate the safety of progressively substituting post-transplant cyclophosphamide (PT-CY) given on Days +3 and +4 with bendamustine (PT-BEN). The Phase I component of the study has been completed. The Phase Ib component of the study will continue to evaluate the safety and efficacy of subjects who receive PT-BEN on Days +3 and +4 at the maximum tolerated dose determined by Phase I. The Phase Ib component of the study has been completed. Approximately, 18-36 subjects will be treated as part of Phase I and 15 as part of Phase Ib. Approximately 18 subjects will be used as controls, subjects that receive no PET-BEN, for direct comparison. Total, approximately 38-56 treatment and control patients and 38-56 donor subjects will be enrolled.