Tretinoin and Arsenic Trioxide in Treating Patients With Untreated Acute Promyelocytic Leukemia

This phase III trial studies tretinoin and arsenic trioxide in treating patients with newly diagnosed acute promyelocytic leukemia. Standard treatment for acute promyelocytic leukemia involves high doses of a common class of chemotherapy drugs called anthracyclines, which are known to cause long-term side effects, especially to the heart. Tretinoin may stop the growth of cancer cells by blocking some of the enzymes needed for cell growth. Arsenic trioxide may stop the growth of cancer cells by either killing the cells, by stopping them from dividing, or by stopping them from spreading. Completely removing or reducing the amount of anthracycline chemotherapy and giving tretinoin together with arsenic trioxide may be an effective treatment for acute promyelocytic leukemia and may reduce some of the long-term side effects.

PRIMARY OBJECTIVES:

1. To eliminate exposure to conventional chemotherapy (including anthracyclines), for patients with standard risk acute promyelocytic leukemia (APL), through use of arsenic trioxide (ATO) and all-trans retinoic acid (ATRA) (tretinoin) based therapy while achieving an event free survival (EFS) that is not inferior compared to historical controls.

II. To significantly reduce exposure to conventional chemotherapy, and in particular, anthracycline exposure, for patients with high risk APL, through use of ATO and ATRA based therapy while achieving an event free survival that is not inferior compared to historical controls.

EXPLORATORY OBJECTIVES:

1. To analyze the clinical impact of FMS-like tyrosine kinase 3 (FLT3) mutations in pediatric APL.

II. To correlate clinical outcomes with the kinetics of reduction in promyelocytic leukemia (PML)/retinoic acid receptor alpha (RARalpha) transcript level by quantitative real-time (RT)-polymerase chain reaction (PCR) (RQ-PCR) in bone marrow and peripheral blood samples from diagnosis to time points during therapy.

III. To monitor incidence of coagulopathy complications, utilizing standardized conventional supportive care, and correlate with a battery of coagulation testing.

IV. To evaluate the neurocognitive outcomes of patients treated on this protocol using patient-completed, performance-based measures of neuropsychological functioning and parent questionnaire report.

OUTLINE:

INDUCTION THERAPY: Patients with standard and high risk APL receive tretinoin orally (PO) twice daily (BID) and arsenic trioxide intravenously (IV) over 2-4 hours on days 1-28. High risk APL patients also receive dexamethasone PO or IV BID on days 1-14 and idarubicin IV over 15 minutes on days 1, 3, 5, and 7. Patients achieving hematologic complete remission (hCR)/hematologic complete remission with incomplete blood count recovery (hCRi) may go on to consolidation therapy. Patients who do not achieve hCR/hCRi may continue treatment with tretinoin and arsenic trioxide for up to 70 days.

CONSOLIDATION THERAPY: Patients receive tretinoin PO BID on days 1-14 and 29-42 and arsenic trioxide IV over 2-4 hours on days 1-5, 8-12, 15-19, and 22-26. Treatment repeats every 56 days for up to 3 courses in the absence of disease progression or unacceptable toxicity. Patients then receive tretinoin PO BID on days 1-14 and arsenic trioxide IV over 2-4 hours on days 1-5, 8-12, 15-19, and 22-26.

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.

After completion of study treatment, patients are followed up monthly for 12 months, every 3 months for 36 months, every 6 months for 48 months, and then annually for 2 years.