I. To reduce the incidence of relapse at 18 months after reduced-intensity conditioning (RIC) and allogeneic hematopoietic cell transplantation (HCT) for acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), and chronic myeloid leukemia (CML) in blast crisis from a historical baseline of 45% to 25%, using ibrutinib maintenance therapy.