- Courses 3, 5, and 7: Patients receive cyclophosphamide IV over 5-15 minutes daily on days 1-5; vincristine IV over 10 minutes and methotrexate IV over 24 hours on day 1; leucovorin calcium IV every 6 hours on day 2; doxorubicin IV daily on days 4 and 5; oral dexamethasone daily on days 1-5; methotrexate and cytarabine IT on day 1; and rituximab IV over 1 hour on day 8. Patients also receive G-CSF as in courses 2, 4, and 6. After course 3, treatment continues in the absence of disease progression or unacceptable toxicity.