 CONSOLIDATION BLOCK 2: Patients receive imatinib mesylate PO QD on days 1-21, methotrexate IT, cytarabine IT, and therapeutic hydrocortisone IT on day 1, high dose methotrexate IV over 24 hours on day 1, dexamethasone PO BID or IV on days 1-5, vincristine sulfate IV over 1 minute on days 1 and 6, ifosfamide IV over 1 hour and mesna IV on days 2-4, leucovorin calcium PO or IV on days 3 and 4, dexrazoxane hydrochloride IV over 5-15 minutes and daunorubicin hydrochloride IV over 1-15 minutes on day 5, pegaspargase IV over 1-2 hours on day 6, and filgrastim SC on days 7-11 in the absence of disease progression or unexpected toxicity. 