Arm II: Patients receive fludarabine IV over 24 hours on days 0 and 1, cytarabine IV over 72 hours on days 2-4, and idarubicin IV over 15 minutes on days 0-2. G-CSF begins on day 6 and continues until blood counts recover. Patients also receive TIT on days -1 and 7, if CSF is not clear on day 10 of induction. Patients on both arms are reassessed on day 35. Those patients with M1 marrow proceed to intensification; all others are removed from the study.