Study of Haploidentical Bone Marrow Transplant with Post-Transplant Cyclophosphamide and/or Bendamustine

This is a Phase I/II, single center study to evaluate the safety and efficacy of substituting day +4 cyclophosphamide with post-transplant bendamustine in myeloablative (MAC) or reduced intensity conditioning (RIC) haploidentical hematopoietic cell transplantation (HHCT) for advanced leukemia and lymphoma patients. This study will follow the standard-of-care bone marrow transplant (BMT), with the only exception being to gradually substitute post-transplant cyclophosphamide (on day +4 after BMT) with bendamustine. Three dose levels are planned for the phase I component of the study, consisting of a combination of sequentially reduced doses of cyclophosphamide and increased doses of bendamustine (on day +4 after BMT) with the full dose cyclophosphamide on day +3 after BMT remaining unchanged. The goal of the phase I component of the study is to evaluate the safety of completely substituting the second dose of post-transplant cyclophosphamide (PT-CY) given on day +4 with bendamustine (PT-BEN). The phase II component of the study will continue to evaluate the safety and efficacy of subjects who receive PT-CY on day +3 and PT-BEN on day +4.