BLOCK 1 CONSOLIDATION THERAPY: (weeks 6-8) Patients receive etoposide IV over 1 hour and ifosfamide IV over 1 hour on days 1-5, dasatinib PO on days 1-14 OR on days 1-21, and some patients receive methotrexate, hydrocortisone, and cytarabine IT on days 8 and 15. Patients also receive filgrastim (G-CSF) subcutaneously (SC) or IV QD beginning on day 6 and continuing until blood counts recover.