 MINIMAL RESIDUAL DISEASE MRD CONSOLIDATION THERAPY: Patients who have APL in the bone marrow after 2 courses of consolidation therapy receive MRD consolidation therapy prior to continuing onto consolidation course 3. Patients receive cytarabine IV over 1-3 hours every 12 hours on days 1-4; mitoxantrone hydrochloride IV over 15-30 minutes on days 3-6; and tretinoin PO BID on days 1-14. If there are no APL cells in the bone marrow after completion of MRD consolidation therapy, patients continue on to consolidation course 3. 