- Regimen A (courses A1, A2, and A3): Patients receive DM IV or orally every 12 hours on days 1-5; MTX IV over 24 hours on day 1; MTX IT, DOX IV and HC IT (beginning 2-4 hours after initiation of MTX infusion) on day 1; leucovorin calcium (CF) IV rescue at 42, 48, and 54 hours after initiation of MTX infusion; ifosfamide (IFF) IV over 1 hour on days 1-5 (before initiation of MTX infusion); cytarabine (ARA-C) IV over 1 hour every 12 hours and etoposide (VP-16) IV over 2 hours once (beginning after completion of ARA-C infusion) on days 4 and 5. Each course lasts 3 weeks.