Fludarabine Phosphate, Low-Dose Total-Body Irradiation, and Peripheral Blood Stem Cell Transplant Followed by Donor Lymphocyte Infusion in Treating Older Patients With Chronic Myeloid Leukemia

PRIMARY OBJECTIVES: I. To determine if mixed hematopoietic chimerism can be safely established using a non-myeloablative conditioning regimen in patients \> 65 years of age with chronic myeloid leukemia (CML) in chronic or accelerated phase who have human leukocyte antigen (HLA) identical related donors. II. To determine if mixed chimerism, established with non-myeloablative conditioning regimens, can be converted to full donor hematopoietic chimerism by infusions of donor lymphocytes (DLI), and thereby produce an immunologic cure of the malignancy. OUTLINE: CONDITIONING REGIMEN: Patients receive fludarabine phosphate intravenously (IV) on days -4 to -2 and undergo low-dose total-body irradiation (TBI) on day 0. TRANSPLANTATION: Patients undergo allogeneic peripheral blood stem cell transplantation (PBSCT) on day 0. IMMUNOSUPPRESSION: Patients receive cyclosporine orally (PO) twice daily (BID) or IV BID or thrice daily (TID) on days -3 to 56 with taper to day 77 or 180, and mycophenolate mofetil PO or IV BID on days 0-27. DLI: At least 2 weeks after completion of immunosuppression, patients with \> 5% donor cluster of differentiation (CD)3+ T cells and no evidence of graft-versus-host disease (GVHD) receive donor lymphocytes IV over 30 minutes. Patients may receive up to 3 DLIs at increasing cell doses in the absence of GVHD. After completion of study treatment, patients are followed up periodically for 5 years.