- Patients receive ARA-C IV over 2 hours every 12 hours on days 29-34 and mitoxantrone IV on days 33-35. Patients without CNS disease at presentation receive CNS prophylaxis comprising MTX IT on day 29. Patients with CNS disease at presentation receive CNS therapy comprising HC IT and MTX IT alternating with ARA-C weekly for 6 weeks. Patients who achieve complete response (CR) at day 55-60 receive MTX IV on days 64 and 79, leucovorin calcium IV or orally every 6 hours on days 65-67 and 80-82, and asparaginase IV over 1 hour or intramuscularly on days 65 and 80.