- Arm II: Patients receive fludarabine IV on days -6 to -2 and cyclophosphamide IV on days -3 to -2. Patients undergo PBSCT on day 0. Patients receive GVHD prophylaxis comprising methotrexate IV on days 1, 3, 6, and 11 and tacrolimus IV continuously and then orally on days -2 to 90 followed by a taper on days 90-150.