Regimen A: Patients receive low-dose vincristine intravenously (IV) on days 1, 8, 15, and 22; prednisone orally (PO) 3 times daily (TID) on days 1-28; doxorubicin hydrochloride IV over 15 minutes on day 1; pegaspargase intramuscularly (IM) on days 2, 8, 15, and 22; cytarabine intrathecally (IT) on day 1; and methotrexate IT* on days 15 and 29.