- Regimen AM (courses AM1, AM2, and AM3): Patients receive DM IV or orally every 12 hours on days 1-5; MTX IV over 3 hours on day 1; and CF IV rescue every 6 hours for a total of 12 doses beginning 24 hours after initiation of MTX infusion. Patients also receive IFF, ARA-C, and VP-16 as in regimen A. Each course lasts 3 weeks.