OUTLINE: This is a randomized study. Patients are randomized to receive one of two treatments. Arm I: Induction: Patients receive homoharringtonine IV continuously over 24 hours daily for 14 days. Induction continues every 28 days for a maximum of 6 courses or until hematopoietic recovery. Maintenance: Patients receive homoharringtonine IV continuously over 24 hours daily for 5 days. Treatment repeats every 28 days. Arm II: Induction: Patients receive oral hydroxyurea daily for 28 days until acceptable blood counts are achieved. Maintenance: Patients receive oral hydroxyurea daily every 28 days to maintain acceptable blood counts. Treatment in both arms continues for a minimum of 6 courses in the absence of disease progression or unacceptable toxicity. Patients are followed every 6 months for a maximum of 10 years.