Beginning on day 56 of interim maintenance I chemotherapy, patients receive delayed intensification chemotherapy comprising oral DM twice daily on days 0-6 and 14-20; VCR IV and doxorubicin (DOX) IV over 15 minutes to 2 hours on days 0, 7, and 14; PEG-ASP IM on day 3; cyclophosphamide (CTX) IV over 20-30 minutes on day 28; oral thioguanine (TG) on days 28-41; ARA-C IV or subcutaneously (SC) daily on days 28-31 and 35-38; and MTX IT on days 0 and 28.