Comparative Outcome of Myeloablative and Reduced Intensity Allogeneic Stem Cell Transplantation for Chronic Lymphocytic Leukemia.

Allogeneic stem cell transplantation (SCT) remains the only potentially curative modality for patients with CLL. Reduced intensity conditioning (RIC) approaches are commonly used because of lower initial toxicity and the belief that cure is primarily mediated by a GVL effect. However, the role of dose intensity in these patients has not been fully explored. We analyzed the outcomes of 88 CLL patients undergoing a first allogeneic SCT from a HLA-matched (6/6) donor at DFCI between 1998 and 2007. 26 patients receiving ablative transplants were conditioned either with standard doses of cyclophosphamide and total body irradiation (96%), or cyclophosphamide and oral busulfan (4%). 62 patients receiving RIC were conditioned with fludarabine 30 mg/m 2 and intravenous busulfan 0.8 mg/kg/d, both for 4 days. GVHD prophylaxis regimens consisted mostly of tacrolimus/ sirolimus +/− MTX (35% ablative, 63% RIC), cyclosporine with prednisone or MTX (15% ablative, 23% RIC) and T cell depletion (31% ablative, 0% RIC). 50% of the ablative SCTs were performed after 2002, compared to 90% of the RICs (p