Results of alemtuzumab-based reduced-intensity allogeneic transplantation for chronic lymphocytic leukemia: a British Society of Blood and Marrow Transplantation Study

We report results in 41 consecutive patients with chronic lymphocytic leukemia (CLL) who underwent allogeneic hematopoietic cell transplantation (HCT) after fludarabine, melphalan, and alemtuzumab conditioning. Donors were 24 HLA-matched siblings and 17 unrelated volunteers, 4 of them mismatched with recipients. All but 3 patients had initial hematologic recovery, but 5 more patients had secondary graft failure. Median intervals to neutrophil (greater than 0.5 × 109/L) and platelet (greater than 20 × 109/L) recovery were 14 days (range, 9-30 days) and 11 days (range, 8-45 days), respectively. Eleven (27%) patients had relapses and received escalated donor lymphocyte infusions, but only 3 of them had sustained responses. Acute and chronic graft-versus-host disease (GVHD) was observed in 17 (41%) and 13 (33%) patients, respectively. Seventeen (41%) patients have died, 5 of progressive disease. The 2-year overall survival and transplantation-related mortality (TRM) rates were 51% (95% confidence interval [CI], 33%-69%) and 26% (95% CI, 14%-46%), respectively. The alemtuzumabbased regimen was feasible and effective in patients with CLL with a relatively low rate of GVHD. However, TRM remains relatively high as a result of a variety of viral and fungal infections. Studies are ongoing to address the efficacy of reduced doses of alemtuzumab in this group of immunosuppressed patients.