Treatment of childhood acute myeloblastic leukemia: dose intensification improves outcome and maintenance therapy is of no benefit--multicenter studies of the French LAME (Leucémie Aiguë Myéloblastique Enfant) Cooperative Group.

ABSTRACT

From 1989 to 1998, 341 children were included in the French multicentric LAME (Leucémie Aiguë Myéloblastique Enfant) trials. A total of 309 children were registered in the LAME 89/91 protocol. This intensive regimen included an induction phase (mitoxantrone plus cytarabine), two consolidation courses, one containing timed-sequential high-dose cytarabine, asparaginase and amsacrine; 276 (90%) achieved a CR. The 5-year overall survival (OS) and event-free survival (EFS) were 60+/-4 and 48+/-4%, respectively. From 1997, timed-sequencing of the LAME SP induction chemotherapy led to an unacceptable frequency of consolidation delay; future improvements are unlikely to come from further increases in intensity. The role of allogenic bone-marrow transplantation from an HLA-identical sibling in CR1 was examined. The disease-free survival (DFS) was 52+/-4% for non-allografted patients and 57+/-7% for allografted patients (P=NS); a better OS for allografted patients was shown and could be related either to allo-BMT early in CR1 or to a second allo-BMT in CR2. For the complete responders after consolidation therapy, the 5-year OS was significantly better in patients randomized for no maintenance therapy (MT-) than in patients randomized for MT (77.6+/-8 vs 59+/-8%; P=0.05), while the 5-year DFS was not significantly different. Exposure to low-dose MT might contribute to clinical drug resistance and treatment failure in relapsing patients.