OUTLINE: Patients receive arsenic trioxide IV over 1-4 hours daily for up to 60 days, or until bone marrow blasts are less than 5%, followed by 4-6 weeks of rest. After the first course, additional courses of arsenic trioxide last 25 days. Treatment continues for a maximum of 6 courses in the absence of unacceptable toxicity or disease progression. Patients with a complete response (CR) receive 1 additional 25 day course after achieving CR. Patients are followed monthly for 6 months, every 2 months for 6 months, every 3 months for 12 months, and then every 6 months thereafter.