OBJECTIVES:

• Compare the efficacy (event-free survival) and toxicity of tretinoin, cytarabine, and daunorubicin with or without arsenic trioxide as induction/consolidation therapy in patients with previously untreated acute promyelocytic leukemia.
• Evaluate the efficacy (disease-free survival) and toxicity of intermittent tretinoin with or without mercaptopurine and methotrexate as maintenance therapy in these patients who achieve a complete response after induction/consolidation therapy.
• Determine the relationship between CD56 expression at diagnosis and clinical outcomes in these patients treated with this regimen.
• Evaluate the cardiac toxicity of intensive daunorubicin therapy in pediatric patients.

OUTLINE: This is a randomized, multicenter study. Patients are stratified according to age (under 15 vs 15 to 60 vs over 60) for the induction phase. Patients are stratified according to age, as in the induction phase, and the consolidation arm (with vs without arsenic trioxide) for the consolidation phase. Patients under age 5 do not receive arsenic trioxide.

• Induction: All patients receive oral tretinoin every 12 hours beginning on day 1 until complete response or for a maximum of 90 days. Patients also receive daunorubicin IV on days 3-6 and cytarabine IV continuously on days 3-9.

• Consolidation: All patients achieving complete response (CR), or partial response (PR) after completion of tretinoin, proceed to consolidation within 2 weeks of achieving CR or PR, but not prior to 30 days from the start of induction. Patients are randomized to 1 of 2 treatment arms.

  • Arm I: Patients receive oral tretinoin every 12 hours on days 1-7 and daunorubicin IV on days 1-2 or days 1-3, depending on age. Patients may receive an additional course. Treatment begins no earlier than 2 weeks and no later than 4 weeks after hematopoietic recovery.
  • Arm II: Patients receive arsenic trioxide IV over 2 hours daily 5 days a week for 5 weeks. After a 2-week rest, patients receive a second course of arsenic trioxide. Patients then receive tretinoin and daunorubicin as in arm I.

• Maintenance: Patients maintaining CR or PR after consolidation therapy proceed to maintenance therapy, beginning no earlier than 2 weeks and no later than 4 weeks after hematopoietic recovery. Patients are randomized to 1 of 2 treatment arms.

  • Arm I: Patients receive oral tretinoin every 12 hours for 7 days every other week for 1 year.
  • Arm II: Patients receive oral tretinoin as in arm I above. Patients also receive oral mercaptopurine once a day and oral methotrexate once weekly for up to 1 year.

Maintenance therapy continues for up to 1 year in the absence of unacceptable toxicity.

Patients are followed every 2 months for 2 years, every 3 months for 1 year, every 6 months for 2 years, and then annually for 5 years.

PROJECTED ACCRUAL: A total of 522 patients (456 adults and 66 pediatric) will be accrued for this study within 4.75 years.