Remission induction using alemtuzumab can permit chemotherapy-refractory chronic lymphocytic leukemia (CLL) patients to undergo allogeneic stem cell transplantation.

The outcome of allogeneic stem cell transplantation depends upon the disease status before transplantation. Patients with refractory disease are at high risk for relapse. To improve the curative potential of the transplant procedure, we treated 3 chemotherapy-refractory CLL patients with alemtuzumab before allogeneic stem cell transplantation. Prior to therapy, all patients suffered from B-symptoms, and had massive adenopathy, splenomegaly, thrombocytopenia, and anemia; two patients had hepatomegaly. Alemtuzumab greatly reduced tumor mass in blood and bone marrow, B-symptoms resolved, and organomegaly improved. Two patients became blood product independent. All patients proceeded to transplantation after conditioning with TBI 2 Gy (n=1) or Treosulfan (n=2) in combination with Fludarabine either from an HLA-matched sibling (n=2) or from an HLA-matched unrelated donor (n=1). All patients engrafted, and are alive and well. Two patients reached complete remission (CR); one patient attained stable partial remission (PR). These heavily pre-treated refractory patients gained substantial clinical benefit from alemtuzumab, and received successful allografts.