Reduced-Intensity Conditioning Before Donor Stem Cell Transplant in With High-Risk Hematologic Malignancies

PRIMARY OBJECTIVES: I. To compare the rate of disease-free survival (DFS) at 1 year post hematopoietic stem cell transplant (HSCT) in patients undergoing HSCT treated on this successor Thomas Jefferson University (TJU) 2 Step reduced intensity conditioning (RIC) haploidentical regimen and compare it with that of the initial 2 Step RIC regimen. SECONDARY OBJECTIVES: I. To assess the 100 day regimen-related mortality (RRM) in patients undergoing HSCT on this treatment protocol. II. To determine the incidence and severity of graft-versus-host disease (GVHD) in patients undergoing treatment on this regimen. III. To evaluate engraftment rates and lymphoid reconstitution in patients treated on this trial. IV. To assess overall survival at 1 and 3 years past HSCT in patients treated on this trial. OUTLINE: REDUCED INTENSITY CONDITIONING: Patients receive fludarabine phosphate intravenously (IV) on days -15 to -12, busulfan IV on days -14 to -13, donor lymphocyte infusion (DLI) on day -6, and cyclophosphamide IV on days -3 and -2. Patients also undergo total-body irradiation (TBI) on day -10. TRANSPLANT: Patients undergo allogeneic peripheral blood stem cell transplant (PBSCT) on day 0. GVHD PROPHYLAXIS: Patients receive tacrolimus IV on days -1 to 42 followed by taper and mycophenolate mofetil IV twice daily (BID) on days -1 to 28. After completion of study treatment, patients are followed up periodically.