RATIONALE: Monoclonal antibodies such as rituximab can locate cancer cells and either kill them or deliver cancer-killing substances to them without harming normal cells. It is not yet known which treatment regimen is more effective for lymphoma.

PURPOSE: Randomized phase III trial to compare the effectiveness of different regimens of rituximab in treating patients who have follicular or mantle cell lymphoma.

OBJECTIVES:

• Assess the clinical efficacy of consolidation treatment with rituximab in terms of response rate in patients with follicular (closed to accrual 9/18/00) or mantle cell lymphoma.
• Compare the event free survival of patients after induction with or without consolidation.
• Compare the tolerability of these two treatment regimens by these patients.

OUTLINE: This is a randomized, open label, multicenter study. Patients are stratified according to participating center, histology (follicular (closed to accrual 9/18/00) vs mantle cell), status of disease (de novo vs relapsed vs resistant), response after induction (stable disease vs partial or complete response), and treatment status (treated vs untreated).

All patients receive induction therapy consisting of rituximab IV over 3-5 hours once a week during weeks 1-4. Patients are then randomized to one of two treatment arms.

• Arm I: Patients are observed.
• Arm II: Patients receive rituximab IV over 3-5 hours once a week during weeks 12, 20, 28, and 36.

Patients are followed weekly for the first month; every 8 weeks for the next 8 months; then at 12, 18, and 24 months; and then annually for the next 3 years.

PROJECTED ACCRUAL: A total of 240 patients (120 per arm) will be accrued for this study within 3-4 years.

DISEASE CHARACTERISTICS:

• Histologically proven CD20 positive follicular (closed to accrual 9/18/00) or mantle cell lymphoma

  • Untreated "de novo" disease OR
  • Chemotherapy resistant disease OR
  • Relapsing disease

• Bidimensionally measurable disease

• No symptomatic CNS disease

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• ECOG 0-2

Life expectancy:

• At least 3 months

Hematopoietic:

• Not specified

Hepatic:

• Bilirubin no greater than 2 times upper limit of normal (ULN)
• No hepatitis B or C

Renal:

• Creatinine no greater than 2 times ULN

Cardiovascular:

• Ejection fraction at least 50%

Other:

• Not pregnant or nursing
• Fertile patients must use effective contraception
• No active opportunistic infections
• HIV negative
• No prior malignancy within 5 years except adequately treated carcinoma in situ of the cervix or localized nonmelanoma skin cancer

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• No prior antibody based therapy

Chemotherapy:

• At least 4 weeks since prior chemotherapy (at least 6 weeks since nitrosoureas) and recovered
• No concurrent chemotherapy

Endocrine therapy:

• At least 4 weeks since prior corticosteroids, unless chronic dose no greater than 20 mg/day for nonlymphoma related condition
• No other concurrent corticosteroids

Radiotherapy:

• Not specified

Surgery:

• Not specified