Patients aged 15-50 are enrolled and randomly assigned to receive GM-CSF or no GM-CSF during all remission-induction and consolidation courses of chemotherapy. Induction chemotherapy consists of a timed-sequential chemotherapy including a first sequence of chemotherapy combining daunorubicin, 80 mg/m2 per day, administered IV as a short infusion over 3 days (days 1-3), and cytarabine, 500 mg/m2 per day IV as a continuous infusion over the same period. The second sequence, administered after 4-day free interval, consists of mitoxantrone, 12 mg/m2 per day, administered IV as a short infusion over 2 days (days 8 and 9), and cytarabine, 500 mg/m2/12h, administered as a 3-hour infusion for 3 days (days 8-10). Salvage therapy consists of cytarabine, 3 g/m2/12h on days 1,3,5,7, combined with amsacrine, 100mg/m2 per day on days 1 to 3. GM-CSF (Leucomax, recombinant human GM-CSF from Escherichia Coli, Schering Plough, Kenilworth,N.J., USA) is given at a dose of 5µg/kg per day, intravenously beginning at day 1 of each chemotherapy course and continuing until the last day of chemotherapy of each course.
Patients who achieve CR after induction chemotherapy or salvage therapy are randomly assigned to consolidation courses consisting of either a timed sequential chemotherapy similar to that of the ALFA-9000 trial (P2 arm) or the CALGB postremission chemotherapy (P1 arm), which includes 4 cycles of high-dose cytarabine, followed by 4 additional maintenance courses.