OUTLINE: This is a multicenter study. Patients are stratified according to cellular type of disease (B cell vs T cell). Patients receive 506U78 IV over 2 hours on days 1, 3, and 5. Treatment repeats every 28 days for a maximum of 8 courses in the absence of disease progression or unacceptable toxicity. Patients are followed at 28 days and then every 2 months for 2 years until disease progression. After disease progression, patients are followed every 3 months for 2 years.