The role of maintenance chemotherapy after autotransplantation for acute lymphoblastic leukemia in first remission: Single-center experience of 100 patients

A total of 100 adults with ALL in first CR received melphalan (110mg/ m²) with TBI followed by autologous marrow (n=35) or single-agent melphalan (200mg/m²) followed by autologous blood stem cells (n=65). After adequate hematologic recovery, maintenance chemotherapy with 6-mercaptopurine, methotrexate and vincristine-prednisone was administered for 2 years. Six patients, all TBI recipients (P=0.001), died of toxicity. In total 70 patients received 6-mercaptopurine, 53 received methotrexate and 40 received vincristine-prednisone. The cumulative incidence of relapse at 7 years was 45%. The 7-year probabilities of disease-free survival (DFS) and overall survival were 45 and 48%. Age 30 years, >4 weeks to attain remission, and karyotypes t(4;11) and t(9;22) were associated with adverse outcome. Patients with 0 (standard risk), 1 (intermediate risk), and 2-3 (high risk) adverse features had 7-year cumulative incidences of relapse of 19, 53 and 82% (P<0.0001), and 7-year DFS probabilities of 73, 36 and 7% (P<0.0001). The 7-year probabilities of DFS for patients receiving 0, 1, 2 and 3 maintenance chemotherapy agents were 15, 29, 58 and 61% (P<0.0001). Maintenance chemotherapy intensity was an independent determinant of outcome in Cox analysis. Maintenance chemotherapy after autotransplantation reduces relapse and improves outcome in adult patients with ALL.