Combination Chemotherapy Plus Peripheral Stem Cell Transplantation in Treating Patients With Refractory Chronic Lymphocytic Leukemia

OBJECTIVES: I. Determine the feasibility and toxicity of using allogeneic peripheral blood stem cell transplantation after intensive, but non-myeloablative chemotherapy with fludarabine/cyclophosphamide in patients with advanced chronic lymphocytic leukemia. II. Determine the engraftment kinetics and degree of chimerism available with this strategy. OUTLINE: This is a nonrandomized, dose-seeking study. Stem cell donors receive G-CSF for 4 days prior to and throughout stem cell harvest. Patients receive intensive chemotherapy with fludarabine and cyclophosphamide for 3 days, with patients entered at increasing doses of both drugs until the dose allowing engraftment is determined. Three days after intensive chemotherapy, allogeneic stem cells are infused. Responding patients who do not experience worse than grade 1 acute graft-vs.-host disease receive additional stem cell infusions after 60 and 120 days. Patients are followed monthly for 4 months, at 6 and 12 months, then yearly for 5 years. PROJECTED ACCRUAL: Up to 25 patients will be entered.