Purging autologous bone marrow with monoclonal antibodies for transplantation in acute myelogenous leukemia

Myeloablative chemotherapy followed by allogeneic bone marrow rescue is considered curative therapy and offers an alternative approach to consolidate patients with acute myelogenous leukemia who achieve a first complete remission after standard induction chemotherapy. In patients transplanted during second or third complete remission, allogeneic transplantation can also be curative, although there is lower relapse-free survival. Despite the success of this treatment modality, only 10-20% of patients will be eligible to receive an allogeneic transplantation due to advanced age or lack of an HLA-matched donor. In this situation, autologous bone marrow transplantation allows therapy of comparable intensity to be administered with less morbidity and mortality due to the lack of graft-versus-host disease. In contrast to allografts, remission autografts may harbor residual occult malignant cells unable to be grossly detected. The infusion of these malignant cells following myeloablative therapy can contribute to leukemia relapse. Various in vitro approaches to 'purge' occult malignant leukemia cells from remission marrows have been developed. The two techniques that have been studied in preclinical and clinical trials include pharmacological and monoclonal antibody-mediated methods. The efficacy of using the latter to purge autografts compared with the use of unpurged autografts in patients with acute myelogenous leukemia undergoing autologous bone marrow transplantation is currently the focus of a prospective multicenter trial.