Results of treatment with an intensive combination induction regimen containing idarubicin in children with acute myeloblastic leukemia: preliminary report of the Argentine Group for Treatment of Acute Leukemia.

In April 1990, the Argentine Group for Treatment of Acute Leukemia began a multicenter trial for the treatment of previously untreated acute myeloblastic leukemia patients who were under 21 years of age. Initial treatment consisted of an 8-day induction phase with cytarabine together with idarubicin on days 3 to 5 and etoposide on days 6 to 8. A multidrug consolidation phase was subsequently administered and, after a treatment-free interval of 2 to 4 weeks, two 5-day intensification courses with high-dose cytarabine and etoposide were delivered with a 4-week interval between each course. Continuation therapy was started 2 to 4 weeks after the second course, with 6-thioguanine daily and cytarabine daily for 4 days every 4 weeks. Treatment was stopped after 18 months in children in continuous complete remission. A preliminary evaluation of this ongoing study included 36 patients with a mean age of 7.5 years (age range, 5 months to 16 years). The majority of patients had a French-American-British classification of M2 (n = 13) or M4 (n = 8). Complete remission was achieved by 91.7% of patients, while one died from sepsis in bone marrow hypoplasia and two were regarded as treatment failures. At a median follow-up of 12 months (range, 2 to 23 months) there were 12 adverse events: six bone marrow relapses, one bone marrow/skin relapse, and five deaths in complete remission (all deaths occurred during the consolidation phase). During the induction phase most of the patients experienced prolonged myelosuppression, and grade 3 to 4 toxicity (according to the Children's Cancer Group criteria) was frequently seen. Alopecia was universal. However, toxicity was manageable. We conclude that idarubicin in combination with cytarabine and etoposide is a highly effective regimen for induction in children with acute myeloblastic leukemia.