- Chemoimmunotherapy: Patients receive rituximab IV on day 1 and fludarabine IV over 30 minutes and cyclophosphamide IV over 60 minutes on days 1-3. Treatment repeats every 4 weeks for up to 3 courses in the absence of disease progression. Four weeks after the first day of the last chemoimmunotherapy course, patients receive 1 dose of rituximab IV alone. Patients with disease progression are removed from the study. Patients with stable disease proceed to radioimmunotherapy 8-12 weeks after the first day of the last chemoimmunotherapy course.