- Induction therapy: Patients receive methotrexate IV over 2-3 hours and vincristine IV on day 1 and rituximab IV over 5 hours and MGd IV over 30-60 minutes on day 8. Patients also receive oral procarbazine hydrochloride on days 1-7 of courses 1, 3, and 5. Treatment repeats every 14 days for 5 courses in the absence of disease progression or unacceptable toxicity. Patients with partial response receive an additional 2 courses of induction therapy.