- Arm I: Patients receive rituximab IV over 4 hours on days 1, 3, and 5 of week 1 and then on day 1 of weeks 5, 9, 13, 17, and 21. Patients also receive fludarabine phosphate IV over 30 minutes on days 1-5 of weeks 1, 5, 9, 13, 17, and 21. After completion of chemoimmunotherapy, patients are followed every 3 months until disease progression. At the time of disease progression, patients receive retreatment with chemoimmunotherapy as above or another treatment regimen.