Intensive chemotherapy will be given on an inpatient or outpatient basis (depending on what the study doctor thinks is safe) for the 8 intensive cycles of chemotherapy. The maintenance treatments may be given on an outpatient basis. However, under some circumstances (such as intolerance to intensive chemotherapy), you may be moved from the intensive chemotherapy to the maintenance phase before the completion of 8 cycles of intensive chemotherapy or without having received nelarabine.