Ofatumumab in Treating Patients With Previously Untreated Stage II, Stage III, or Stage IV Follicular Non-Hodgkin Lymphoma

Inclusion criteria

DISEASE CHARACTERISTICS: * Histologically confirmed follicular non-Hodgkin lymphoma (NHL) meeting 1 of the following criteria: * Bulky (i.e., single mass ≥ 7cm in any uni-dimensional measurement) stage II disease * Stage III or IV disease * WHO grade 1, 2, or 3a disease * Bone marrow biopsies allowed provided they are submitted in conjunction with nodal biopsies * No fine-needle aspirates for diagnosis * Tumor tissue must express the CD20-positive antigen by flow cytometry or IHC * At least 1 site of measurable disease that is \> 1 cm in diameter in ≥ 1 dimension present either on physical exam or imaging studies * Non-measurable disease alone not allowed, including the following: * Bone lesions (lesions if present should be noted) * Ascites * Pleural/pericardial effusion * Lymphangitis cutis/pulmonis * Bone marrow (involvement by NHL should be noted) * Low- or intermediate-risk disease by the Follicular Lymphoma International Prognostic Index (FLIPI) * FLIPI score meeting 1 or 2 of the following risk factors: * Age \> 60 years * Involvement of \> 4 nodal sites * Stage III-IV disease * Hemoglobin \< 12.0 g/dL * LDH normal * Risk determined by the following: * Low Risk: 0-1 of the above risk factors * Intermediate Risk: 2 risk factors * Poor Risk: ≥ 3 risk factors * No known CNS involvement PATIENT CHARACTERISTICS: * ECOG performance status 0-2 * ANC ≥ 1,000/μL * Platelet count ≥ 75,000/μL * Creatinine clearance ≥ 30 mL/min * Bilirubin ≤ 2 times upper limit of normal (unless secondary to Gilbert syndrome or hepatic involvement of NHL) * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception during and for 3 months after completion of study treatment * Patients with HIV infection allowed provided the following criteria are met: * No evidence of coinfection with hepatitis B or C * CD4+ cell count ≥ 400/mm³ * No evidence of resistant strains of HIV * HIV viral load \< 10,000 copies HIV RNA/mL if not on anti-HIV therapy OR HIV viral load \< 50 copies if on anti-HIV therapy * No history of AIDS-defining conditions * No evidence of active hepatitis B (HBV) or C (HCV) infection (i.e., no positive serology for anti-HBc or anti-HCV antibodies) * HBV seropositivity allowed (HBsAg+) provided they are closely monitored for evidence of active HBV infection by HBV DNA testing * After completing treatment, HBsAg + patients must be monitored by HBV DNA testing every 2 months for 6 months post-treatment, while continuing lamivudine (required) PRIOR CONCURRENT THERAPY: * No prior chemotherapy or immunotherapy (e.g., monoclonal antibody-based therapy) for NHL * Prior involved-field radiation therapy allowed * More than 2 weeks since prior corticosteroids except for maintenance therapy for a non-malignant disease * No concurrent dexamethasone or other steroids as antiemetics * No live virus vaccination within 6 weeks prior to study entry * No concurrent zidvoudine or stavudine