- Induction therapy: Patients receive rituximab IV weekly in weeks 1-4 and undergo restaging between weeks 11-13. Patients with stable disease or progressive disease are taken off study. Patients achieving partial or complete response are stratified according to prior treatment status (untreated* vs treated with or without anti-CD20 therapy), presence of bulky disease** at study entry (yes vs no), and participating center. Patients are then randomized to 1 of 2 maintenance treatment arms.