A single high dose of idarubicin combined with high-dose ARA-C for treatment of first relapse in childhood 'high-risk' acute lymphoblastic leukaemia: a study of the AIEOP group.

The outcome of children with acute lymphoblastic leukaemia (ALL) and early relapse remains unsatisfactory. In January 1995, the AIEOP (Associazione Italiana di Oncologia ed Ematologia Pediatrica) group opened a trial for children with ALL in first isolated or combined bone marrow relapse defined at high risk according to the length of first remission and the immunophenotype. The treatment plan included the combination of a single high-dose idarubicin and high-dose cytarabine as induction therapy followed by an intensive consolidation and stem cell transplant (SCT). In total, 100 children from 16 Italian centres were enrolled; 80 out of the 99 evaluable patients (81%) achieved second complete remission; eight (8%) died during induction and 11 (11%) failed to respond. A total of 42 out of the 80 responders (52.5%) received a SCT: 19 from an identical sibling, 11 from a matched unrelated donor and 12 from umbilical cord blood cells. The estimated 4-year overall survival and event-free survival were 25% and 21% respectively. Disease-free survival at 4 years was 25.8% for the 80 responders. At 4 years, 39 out of 100 children remain alive, with 27 of them free of leukaemia. This induction therapy has shown antileukaemic efficacy with acceptable toxicity; moreover, all responders proved eligible for intensive consolidation.