Busulfan, Fludarabine Phosphate, and Post-Transplant Cyclophosphamide in Treating Patients With Blood Cancer Undergoing Donor Stem Cell Transplant

PRIMARY OBJECTIVE: I. To assess safety of timed sequential busulfan and fludarabine conditioning regimen and post transplant cyclophosphamide as determined by day 100 non-relapse mortality in patients undergoing allogeneic transplantation: from matched donors; from mismatched (haploidentical) donors. SECONDARY OBJECTIVE: I. To evaluate efficacy of this therapy and to compare outcomes between recipients of matched and mismatched donors by studying the following endpoints: graft versus host disease (GVHD)-free/relapse free survival; relapse-free survival; overall survival; non-relapse mortality; relapse rate; time to neutrophil and platelet engraftment; incidence of acute and chronic GVHD; grade 3 and 4 adverse events. TERTIARY OBJECTIVE: I. To study impact of timed sequential busulfan therapy and post-transplant cyclophosphamide on immune reconstitution and cytokines levels post-transplant. OUTLINE: Patients are assigned to 1 of 4 groups. GROUP I (FROM HAPLOIDENTICAL DONOR): Patients receive busulfan intravenously (IV) over 3 hours on days -13, -12, and -6 to -3, thiotepa IV over 4 hours on day -7, fludarabine phosphate IV over 1 hour on days -6 to -3. Patients undergo stem cell transplantation IV on day 0. Patients then receive cyclophosphamide IV over 3 hours on days 3 and 4. Beginning on day 5, patients receive tacrolimus IV continuously or orally (PO) twice daily (BID) for up to 3 months and mycophenolate mofetil PO thrice daily (TID). GROUP II (FROM MATCHED DONOR): Patients receive busulfan IV over 3 hours on days -13, -12, and -6 to -3, fludarabine phosphate IV over 1 hour on days -6 to -3. Patients undergo stem cell transplantation IV on day 0. Patients then receive cyclophosphamide IV over 3 hours on days 3 and 4. Beginning on day 5, patients receive tacrolimus IV continuously or PO BID for up to 3 months. GROUP III and GROUP IV: Patients receiving haploidentical related donor transplant, diagnosis of myelofibrosis, \> 60 years old, or patients with comorbidity scores \> 3 will go in Group 3 or 4. If patients with comorbidity score \> 3, then the principal investigator is the final arbiter of eligibility for comorbidity score \> 3. Busulfan is administered at the dose calculated to achieve a total (including first two doses delivered on day -20 and day -13) system exposure of 20,000 +/- 12% uMol-min based on the pharmacokinetic studies. GROUP V and GROUP VI: Patients receive busulfan IV over 3 hours on days -20, -13, and -6 to -3, a lower dose of thiotepa IV over 4 hours on day -7, fludarabine phosphate IV over 1 hour on days -6 to -3. Patients undergo stem cell transplantation IV on day 0. Patients then receive cyclophosphamide IV over 3 hours on days 3 and 4. Beginning on day 5, patients receive tacrolimus IV continuously or PO BID for up to 3 months and mycophenolate mofetil PO TID.