Randomized trial to compare LSA2L2-type maintenance therapy to daily 6-mercaptopurine and weekly methotrexate with vincristine and dexamethasone pulse for children with acute lymphoblastic leukemia.

Background A total of 201 pediatric cases of acute lymphoblastic leukemia were treated with the ALL-96 protocol by the Kyushu-Yamaguchi Children's Cancer Study Group. Procedure Risk stratification was based on white cell counts, immunophenotype, the presence of central nervous system disease at diagnosis, organomegaly, and early treatment response (day 14 bone marrow status). All of the patients were classified into standard-risk (SR) or high-risk (HR) groups and were randomly assigned to receive maintenance therapy with either LSA2L2-type or 6-mercaptopurine (6-MP)/methotrexate (MTX) with vincristine (VCR) and dexamethasone (DEX) pulse in both risk groups. Results The 7-year event-free survival (EFS) and overall survival (OS) rates in the entire study population were 72.1% (95% CI: 68.0–76.2%) and 84.8% (95% CI: 79.7–89.9%), respectively, and the EFS of the SR patients (85.3% [95% CI: 78.2–92.4%]) was significantly better than HR patients (62.4% [95% CI: 52.2–72.6%]) (P = 0.0007). Conclusions There were no differences in the EFS between the different maintenance therapies in each risk group; however, grade IV liver toxicity occurred more often in the patients receiving 6-MP/MTX with VCR and DEX therapy than in patients receiving LSA2L2. Pediatr Blood Cancer. © 2010 Wiley-Liss, Inc.