Comparison of chemotherapy with immunotherapy for maintenance of acute lymphoblastic leukemia in children and adults

Two hundred and seventeen patients, 1–50 yr old, with acute lymphoblastic leukemia in complete remission were randomized to receive a 1-yr consolidation chemotherapy of either type P, comprising 7 different drugs, or type M, consisting of methotrexate interspersed with prednisone and vincristine. Thereafter, they were randomized a second time to receive a 4-yr maintenance of either chemotherapy or immunotherapy, comprised of allogeneic blasts and bacillus Calmette- Guerin (BCG). Consolidation P caused more toxicity than consolidation M. However, comparison between the consolidation therapies P and M showed no significant difference, neither for disease-free interval nor for duration of survival. Chemotherapy showed more lethal toxicity in adults than in children. Comparison between chemotherapy (C) and immunotherapy (I) as maintenance treatment showed a significant (p = 0.016) superiority of C for disease-free interval (DFI). The difference was even more pronounced (p = 0.009) in the group with less than 8 g/dl of hemoglobin (Hb) at diagnosis before therapy. On the other hand, for patients with more than 8 g/dl Hb at diagnosis, presumably those with T- ALL, no difference in DFI was seen. No difference has been seen so far between maintenance therapies I and C concerning the duration of survival. The patients who were receiving maintenance I when they relapsed and who were consequently retreated by chemotherapy, survived longer from relapse than those patients retreated for relapse while receiving maintenance C.