Phase III Trial in Acute Promyelocytic Leukemia Patients

* Arm I: * Induction therapy: Patients receive oral tretinoin twice daily and arsenic trioxide IV over 2 hours on days 1-60. Patients achieving hematological complete remission go on to receive consolidation therapy. * Consolidation therapy: Patients receive oral tretinoin twice daily on days 1-14. Treatment with tretinoin repeats every 4 weeks for up to 7 courses. Patients also receive arsenic trioxide IV over 2 hours on days 1-5 in weeks 1-4. Treatment with arsenic trioxide repeats every 8 weeks for up to 4 courses. * Arm II: * Induction therapy: Patients receive tretinoin as in arm I induction therapy and idarubicin IV over 20 minutes on days 2, 4, 6, and 8. Patients achieving hematological complete remission go on to receive consolidation therapy. * Consolidation therapy: Patients receive oral tretinoin twice daily on days 1-45, idarubicin IV over 20 minutes on days 1-4 and day 31, and mitoxantrone hydrochloride IV over 30 minutes on days 16-20. Marrow samples are collected after completion of consolidation therapy and analyzed by reverse transcriptase-PCR for molecular remission. Patients achieving molecular remission (PML-RARa negative) go on to receive maintenance therapy. * Maintenance therapy: Patients receive oral mercaptopurine once daily and methotrexate intramuscularly once weekly for 3 months. Treatment with mercaptopurine and methotrexate repeats every 3 months for 7 courses. After completion of course 1 of mercaptopurine and methotrexate, patients receive oral tretinoin once daily on days 1-15\*. Treatment with tretinoin repeats every 3 months for 6 courses. NOTE: \*Patients do not receive mercaptopurine and methotrexate during tretinoin administration. After completion of study therapy, patients are followed periodically for 5 years. As of 14th September 2010, all patients needed to evaluate the primary endpoint (162 patients) have been recruited but the trial accrual continued in order to assess one secondary outcome (QoL)."