Haploidentical BMT With Post-Transplant Cyclophosphamide and Bendamustine

This study will follow the standard-of-care bone marrow transplant (BMT), with the only exception being to progressively substitute post-transplant cyclophosphamide (on Days +3 and +4 after BMT) with bendamustine. Six dose levels were planned for the Phase I component of the study, consisting of a combination of sequentially reduced doses of cyclophosphamide (PT-CY) and increased doses of bendamustine (PT-BEN) initially on Day +4 after BMT, followed by the same sequential reduction and increase on Day +3. An interim analysis was performed after cohort 3 was completed in Phase I and included a preliminary comparison between treatment and control groups. Phase Ib will evaluate patients treated with PT-CY on day +3 and PT-BEN on day +4. Control patients will be patients that have declined to participate in the main trial but will receive haploidentical BMT with the current standard of two days of PT-CY (and no PT-BEN) and will be consented for the immune monitoring studies only.