Lenalidomide in Combination With Rituximab in Treating Participants With Stage III/IV Indolent Non-Hodgkin Lymphoma

PRIMARY OBJECTIVES: I. To evaluate the overall response rate of lenalidomide in combination with rituximab in previously untreated indolent non-Hodgkin's lymphoma (NHL). SECONDARY OBJECTIVES: I. To evaluate the toxicity of lenalidomide in combination with rituximab in previously untreated indolent non-Hodgkin's lymphoma. OUTLINE: Participants are assigned to 1 of 2 drug schedules. SCHEDULE A: Participants receive lenalidomide orally (PO) on days 1-21 and rituximab intravenously (IV) over 4-8 hours on day 1 of courses 1-12. Courses repeat every 28 days for up to 12 courses in the absence of disease progression or unacceptable toxicity. SCHEDULE B: Participants receive lenalidomide PO on days 2-22 and rituximab IV over 4-8 hours on days 1, 8, 15, and 22 of course 1 and on day 1 of all subsequent courses. Courses repeat every 28 days for up to 12 courses in the absence of disease progression or unacceptable toxicity. After completion of study treatment, participants are followed up every 6 months.