RESUMEN
Until 1990, the survival of children with acute lymphoblastic leukaemia (ALL) in Russia was below 10%. To establish a protocol feasible under conditions there, ALL-MB 91 was designed to avoid prolonged bone marrow aplasia, thereby reducing needs for extensive supportive care, blood transfusions, long-lasting hospitalization and costs. High-dose therapies were avoided, anthracycline use was limited and CNS radiation therapy only foreseen in high-risk patients (about 30%). This was randomized against a modified BFM protocol. From 1995 to 2002, 834 patients of age up to 18 years were registered in 10 centres and 713 received after central randomization the allocated risk-stratified treatment. After a median follow-up of 7 years, the event-free survival (EFS) was 67+/-3% on ALL-MB 91 (N=358) vs 68+/-3% on ALL-BFM 90m (N=355). The overall survival (OS) was 71+/-3% vs 74+/-2%, respectively. Anaemia, thrombocytopenia, agranulocytosis >10 days and hospitalization (median 35 vs 68 days) were lower on ALL-MB 91 (P<0.01, N=197). While EFS and OS were similar with both protocols, ALL-MB 91 significantly incurred fewer toxicity and resource requirements and, therefore, has been increasingly used across Russia.