 CONSOLIDATION BLOCK 2: Patients receive imatinib mesylate, methotrexate, cytarabine, therapeutic hydrocortisone, high dose methotrexate, dexamethasone, vincristine sulfate, ifosfamide, leucovorin calcium, dexrazoxane hydrochloride, daunorubicin hydrochloride, pegaspargase, and filgrastim as Arm A Consolidation Block 2 in the absence of disease progression or unexpected toxicity. 