LEUKEMIA - MANAGEMENT OF RELAPSE AFTER ALLOGENEIC BONE-MARROW TRANSPLANTATION

Purpose: To review the current state of knowledge regarding the management of leukemic relapse after allogeneic bone marrow transplantation (BMT). Patients and Methods: The literature was analyzed using MEDLINE (National Library of Medicine, Bethesda, MD) and reports were identified through review of report bibliographies. Pertinent studies were selected and data synthesized into a review format. Results: Leukemic relapse after allogeneic BMT is an important cause of treatment failure. The risk of leukemic relapse varies from 20% to 60% depending on the diagnosis and phase of disease. Reinduction chemotherapy (CT), second BMT, interferon (IFN) alfa, and donor leukocyte infusions are various options, but none of the approaches is clearly optimal. Approximately 50% of acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) patients achieve remission after standard induction CT. However, most patients finally relapse and die of uncontrolled leukemia. Second BMT is successful in 20% to 25% patients and is a reasonable option in patients who relapse more than 6 months after the initial transplant. Young patients with a good performance status and those in remission from initial transplant relapse have a better outcome after second BMT. Venoocclusive disease (VOD), interstitial pneumonitis (IP), and acute graft-versus-host disease (GVHD) are the main complications. Therapy with IFN alfa results in cytogenetic complete remission (CR) in 10% to 25% patients with chronic myeloid leukemia (CML). The initial results of leukocyte infusions from the original donor are promising. However, acute GVHD and bone marrow aplasia are associated complications. The correct dose and schedule of donor leukocyte infusions need to be determined in future studies to minimize GVHD while maintaining the graft-versus-leukemia (GVL) effect. Conclusion: Identification of patients at increased risk for relapse and use of biologic response modifiers posttransplant to augment the GVL effect in such patients are possible areas of improvement for future studies.