RE-INDUCTION THERAPY: Patients receive clofarabine, cyclophosphamide, and etoposide IV on days 1-5; dexamethasone PO on days 1-6; and pegaspargase and vincristine sulfate IV on days 6, 13, and 20.Patients may also receive triple intrathecal therapy on days 1 and 15. Patients continue on to continuation treatment after count recovery.