High-dose melphalan and autotransplantation followed by post transplant maintenance chemotherapy for acute lymphobastic leukemia in first remission

A total of 65 adults with acute lymphoblastic leukemia (ALL) received 200 mg/m² melphalan and an autograft in first remission, with a plan to receive 6-mercaptopurine (6MP), methotrexate (MTX), and vincristine-prednisone (VP) for 2 years afterwards. There was no transplant-related mortality. In all, 69% of patients received 6MP, 54% received MTX, and 49% received VP. The cumulative incidence of relapse at 5 years was 52%. The 5-year probabilities of disease-free (DFS) and overall (OS) survival were 48 and 55%. Age >30 years, >4 weeks to attain remission, and t(9;22) or t(4;11) karyotypes were adverse prognostic features. Patients with 0 (standard risk), 1 (intermediate risk), and 2-3 (high risk) adverse features had 5-year cumulative incidences of relapse of 19, 59, and 100% (P<0.0001), and 5-year probabilities of DFS of 80, 41, and 0% (P<0.0001). The 5-year probabilities of DFS for patients receiving 0, 1, 2, and 3 maintenance therapy agents were 19, 40, 51, and 70% (P=0.0097). Maintenance therapy intensity was an independent determinant of outcome in Cox analysis. These data show that a high-dose melphalan-based autograft is safe and could be widely applicable in ALL in first remission, and that maintenance chemotherapy very likely contributes to improved outcome of auto-grafted ALL patients.