Epratuzumab and Rituximab in Treating Patients With Previously Untreated Follicular Non-Hodgkin Lymphoma

RATIONALE: Monoclonal antibodies, such as epratuzumab and rituximab, can block cancer growth in different ways. Some block the ability of cancer cells to grow and spread. Others find cancer cells and help kill them or carry cancer-killing substances to them. Giving epratuzumab and rituximab together may be more effective in treating follicular non-Hodgkin lymphoma. PURPOSE: This phase II trial is studying how well giving epratuzumab together with rituximab works in treating patients with previously untreated follicular non-Hodgkin lymphoma.

OBJECTIVES: Primary * To determine the response rate (overall and complete) after extended induction therapy comprising epratuzumab and rituximab in patients with previously untreated CD20+ follicular non-Hodgkin lymphoma (NHL). * To determine the time to progression after extended induction therapy comprising epratuzumab and rituximab in patients with previously untreated CD20+ follicular NHL. Secondary * To determine the toxicity profile of epratuzumab and rituximab in patients with previously untreated CD20+ follicular NHL. * To establish whether the therapeutic effects of the combination of epratuzumab and rituximab are sufficiently promising to warrant evaluation in a subsequent randomized trial (in comparison to rituximab alone). * To determine the relationship between the change in fludeoxyglucose F 18 uptake early after epratuzumab and rituximab treatment with response rate and time to progression. OUTLINE: * Induction therapy (month 1): Patients receive epratuzumab IV over 5-30 minutes on days 1, 8, 15, and 22 and rituximab IV on days 3, 8, 15, and 22 in the absence of disease progression or unacceptable toxicity. * Extended induction therapy (months 3, 5, 7, and 9): Patients receive epratuzumab IV over 5-30 minutes followed by rituximab IV in weeks 12, 20, 28, and 36 in the absence of disease progression or unacceptable toxicity. Patients receive fludeoxyglucose F 18 (FDG) subcutaneously and undergo positron emission tomography at baseline and after induction therapy to assess the degree of FDG uptake. After completion of study treatment, patients are followed every 4 months for 2 years then every 6 months for up to 10 years.