CD6-DEPLETED ALLOGENEIC BONE-MARROW TRANSPLANTATION FOR ACUTE-LEUKEMIA IN FIRST COMPLETE REMISSION

The appropriate timing of bone marrow transplantation (BMT) for adults with acute myelogenous leukemia (AML) and acute lymphoblastic leukemi a (ALL) is controversial. Although allogeneic transplantation results in a lower risk of disease recurrence than intensive chemotherapy alon e, overall outcome following BMT may not be improved due to the higher incidence of therapy-related fatal complications, frequently as a res ult of the development of graft-versus-host disease (GVHD). Selective T-cell depletion of donor marrow can reduce the incidence of GVHD and thereby limit transplant-related toxicity. Herein we report the risk o f GVHD, incidence of transplant related mortality (TRM), likelihood of disease relapse, and overall survival in adult patients undergoing BM T with CD6 depleted allogeneic marrow for acute leukemia in first remi ssion. Forty-one consecutive allogeneic transplants were performed on patients with acute leukemia and high-risk features (28 AML, 13 ALL) u sing T12 monoclonal antibody and complement to remove CD6+ T cells fro m donor marrow. No pre- or posttransplant immune suppressive medicatio ns for GVHD prophylaxis were administered. The actuarial estimated ris k of grade 2 to 4 acute GVHD was 15% in patients receiving HLA identic al grafts. Chronic GVHD developed in five patients. The estimated risk of TRM for patients in first complete remission was 5% at Day + 100 a nd 16% at 2 years. Fatalities attributable to infection with cytomegal ovirus or Epstein-Barr virus occurred in only three patients. Estimate d probabilities of relapse, overall survival, and event-free survival at 4 years were 25%, 71%, and 63%, respectively. No significant differ ences in GVHD, TRM, relapse rate, or survival was observed for patient s with AML compared with those with ALL. Allogeneic transplantation wi th CD6 depleted bone marrow is effective in consolidating remissions o f high-risk patients with acute leukemia in first remission without ex cessive toxicity. (C) 1997 by The American Society of Hematology.