Rituximab Plus Cyclophosphamide in Treating Patients With Indolent Stage III or Stage IV Non-Hodgkin's Lymphoma

RATIONALE: Monoclonal antibodies can locate cancer cells and either kill them or deliver cancer-killing substances to them without harming normal cells. Drugs used in chemotherapy use different ways to stop cancer cells from dividing so they stop growing or die. Combining chemotherapy and monoclonal antibody therapy may kill more cancer cells. PURPOSE: Phase II trial to study the effectiveness of rituximab plus cyclophosphamide in treating patients who have indolent stage III or stage IV non-Hodgkin's lymphoma.

OBJECTIVES: I. Determine the toxicity associated with cyclophosphamide and rituximab (IDEC-C2B8 monoclonal antibody) as first line treatment in patients with stage III or IV indolent B-cell lymphoma. II. Determine the objective tumor response rate and duration of response associated with this first line treatment in these patients. III. Determine the failure-free and overall survival for these patients. IV. Compare the response rate and survival rates for patients with indolent lymphoma who were treated with this treatment as the first systemic therapy for their disease with response rates and survival observed for similar patients treated in published trials. V. Determine the quality of life associated with this treatment in this patient population. OUTLINE: This is an open label study. Patients receive oral cyclophosphamide daily and rituximab (IDEC-C2B8 monoclonal antibody) IV on days 1, 8, 15, and 22 for the first 4-week course. Patients then receive oral cyclophosphamide daily and rituximab IV monthly until 2 months beyond maximum response. Patients are treated for at least 6 months but no more than 18 months in the absence of disease progression. Patients are followed every 3 months for 2 years, then every 6 months for the next 2 years, and then annually for up to 10 years. PROJECTED ACCRUAL: There will be 20-40 patients accrued into this study.