Tretinoin, Cytarabine, and Daunorubicin Hydrochloride With or Without Arsenic Trioxide Followed by Tretinoin With or Without Mercaptopurine and Methotrexate in Treating Patients With Acute Promyelocytic Leukemia

Inclusion Criteria:

* Patients must have a clinical diagnosis of acute promyelocytic leukemia (APL) with proof of APL morphology (FAB-M3) confirmed by RT-PCR assay; a patient may be entered prior to completion of RT-PCR studies, but a patient who is subsequently found to be PML-RARα negative and RARα-PML negative will be removed from protocol treatment
* FAB clasification: the aspirate smear must show M3 characteristics and at least 30% of cells must be abnormal promyelocytes with heavy granulation; the overall marrow cellularity must be normocellular or hypercellular; patients with the microgranular variant (M3V) are eligible, and the diagnosis will be based on characteristic morphologic findings (e.g., reniform or bilobed nuclei)
* RT-PCR assay: submission of samples for RT-PCR assays for PML-RARα/RARα-PML transcripts is mandatory; the results do not have to be known prior to initiation of therapy; if the assay is subsequently found to be negative, the patient will be removed from protocol treatment and treated at the discretion of the responsible physician
* Prior treatment: the patient must not have received any systemic definitive treatment for APL, including cytotoxic chemotherapy or retinoids; prior therapy with corticosteroids, hydroxyurea or leukapheresis will not exclude the patient
* Non-pregnant, non-nursing: treatment under this protocol would expose an unborn child to significant risks; patients should not be pregnant or plan to become pregnant while on treatment; women and men of reproductive potential should agree to use an effective means of birth control; there is an extremely high risk of fetal malformation if pregnancy occurs while on ATRA in any amount even for short periods