S0016 Combination Chemotherapy With Monoclonal Antibody Therapy in Newly Diagnosed Non-Hodgkin's Lymphoma

OBJECTIVES: * Compare the progression-free survival and overall survival of patients with newly diagnosed follicular non-Hodgkin's lymphoma treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) with or without either rituximab or iodine I 131 tositumomab (monoclonal antibody anti-B1). (CHOP chemotherapy alone arm closed to accrual as of 12/15/02) * Compare the response rate of these patients treated with these regimens. * Compare the toxic effects of these regimens in these patients. * Compare the molecular remission rates of this patient population treated with these regimens. * Determine the incidence and time to development of human anti-mouse antibody positivity. OUTLINE: This is a randomized, multicenter study. Patients are stratified according to whether microglobulin is greater than upper limit of normal (yes vs no). Patients are randomized to 1 of 3 treatment arms. (Arm I closed to accrual as of 12/15/02) * Arm I (CHOP only): Patients receive cyclophosphamide IV over 15 minutes, doxorubicin IV over 5-20 minutes, and vincristine IV over 5-15 minutes on day 1. Patients also receive oral prednisone daily on days 1-5. Treatment continues every 21 days for up to 6 courses in the absence of disease progression or unacceptable toxicity. (Arm I closed to accrual as of 12/15/02) * Arm II (CHOP + rituximab): Patients receive cyclophosphamide IV over 15 minutes, doxorubicin IV over 5-20 minutes, and vincristine IV over 5-15 minutes on days 8, 29, 50, 71, 92, and 113. Patients also receive oral prednisone daily on days 8-12, 29-33, 50-54, 71-75, and 113-117 and rituximab IV over 4-6 hours on days 1, 6, 48, 90, 134, and 141. * Arm III (CHOP + tositumomab): Patients receive chemotherapy as in arm I and tositumomab (monoclonal antibody anti-B1) IV over 1 hour followed by iodine I 131 tositumomab IV over 20 minutes on days 134 and 141. Patients are followed on day 200, at 1 year, every 6 months for 2 years, and then annually thereafter. PROJECTED ACCRUAL: Approximately 500 patients (250 per treatment arm) will be accrued for this study within 5.5 years. (Arm I closed to accrual as of 12/15/02)