CONTINUATION I (WEEKS 20-49): Patients receive vincristine sulfate IV over 1 minute on day 1 in weeks 20, 24, 33, 37, and 46; dexamethasone PO or IV BID on days 1-5 in weeks 20, 24, 33, 37, and 46; triple IT chemotherapy on day 1 in weeks 20, 24, 33, 37, and 46; methotrexate IV on day 1 in weeks 21-23, 25-26 and 37-45; mercaptopurine PO on days 1-7 in weeks 21-23, 25-26 and 37-45; etoposide IV over 2 hours on days 1-5 in week 27; cyclophosphamide IV over 2 hours on days 1-5 in week 27: high-dose cytarabine IV over 3 hours every 12 hours on days 1 and 2 in week 30; pegaspargase or asparaginase IM on day 2 in week 30: and filgrastim SC or IV beginning on day 3 in weeks 30 and continuing until blood counts recover. (Retired as of 7/16/2014)