- Maintenance chemotherapy: Patients receive methotrexate IV over 3 hours and IT over 5 minutes on day 1; oral procarbazine on days 1-7; oral lomustine on day 1; oral dexamethasone every 6 hours on days 1-14 followed by a taper (as tolerated); and cytarabine intraventricularly or IT over 5 minutes on day 1. Treatment repeats every 42 days for a total of 5 courses.