Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed follicular lymphoma

- Stage III or IV disease OR stage II disease not suitable for radiotherapy

- Grades 1, 2, or 3a disease

- Previously untreated disease

- CD20-positive disease

- Patients in need of systemic therapy, meeting at least 1 of the following criteria:

- Symptomatic enlarged lymph nodes, spleen, or other lymphoma manifestations

- Bulky disease ≥ 6 cm in long diameter

- Clinically significant progression over at least 6 months of any tumor lesion

- Anemia (hemoglobin < 100 g/L) or thrombocytopenia (platelet count < 100 x
10^9/L) due to lymphoma

- Clinically significant progressive decrease in hemoglobin or platelet count due
to lymphoma

- B-symptoms, weight loss > 10% within the past 6 months, drenching night sweats,
or fever > 38°C not due to infection

- At least one two-dimensionally measurable lesion with longest transverse diameter >
10 mm

- Paraffin-embedded tumor tissue available

- No known CNS involvement

PATIENT CHARACTERISTICS:

- WHO performance status 0-2

- EF ≥ 50% for patients with a history of cardiac disease or older than 70 years

- Neutrophil count ≥ 1.5 x 10^9/L

- Platelet count ≥ 100 x 10^9/L

- Bilirubin ≤ 1.5 x upper limit of normal (ULN) (unless due to Gilbert syndrome)

- ALT ≤ 2.5 x ULN

- Alkaline phosphatase ≤ 2.5 x ULN

- Creatinine clearance ≥ 30 mL/min

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception 4 weeks prior to, during, and for
12 months after completion of study therapy

- Must be compliant and geographically proximal to allow for proper staging and
follow-up

- No serious underlying medical condition, at the judgment of the investigator, which
could impair the ability of the patient to participate in the trial (e.g., active
autoimmune disease or uncontrolled diabetes)

- No malignancy within the past 3 years except for adequately treated carcinoma in situ
of the cervix or localized nonmelanoma skin cancer

- No psychiatric disorder precluding understanding information of trial-related topics,
giving informed consent, or interfering with compliance for oral drug intake

- No known hypersensitivity to trial drugs or hypersensitivity to any other components
of the trial drugs

- No known HIV positivity or hepatitis C infection

- No serological evidence of current or past hepatitis B infection, unless the
serological findings are clearly due to vaccination

PRIOR CONCURRENT THERAPY:

- No prior systemic therapy for this disease

- At least 3 months since prior radiotherapy

- At least 30 days since prior treatment in another clinical trial

- At least 4 weeks since prior and no concurrent corticosteroids unless administered as
prophylaxis in at-risk patients for ≤ 3 days or at a dose equivalent to prednisone ≤
15 mg/day, for indications other than lymphoma or lymphoma-related symptoms

- No concomitant drugs contraindicated for use with the trial drugs

- No other concurrent experimental drugs or anticancer therapy

- No other concurrent investigational treatments