DISEASE CHARACTERISTICS:

• Histologically confirmed mantle cell lymphoma OR indolent B-cell lymphoproliferative disorders of any of the following types:

  • Chronic lymphocytic leukemia
  • Small lymphocytic lymphoma
  • Follicular center cell non-Hodgkin's lymphoma (grade I or II)
  • Marginal zone lymphoma
  • Waldenstrom's macroglobulinemia
  • Hairy cell leukemia
• Previously untreated or relapsed/refractory disease
• No evidence of histological transformation to an intermediate-grade or aggressive lymphoma
• CD20 positive by immunoperoxidase or flow cytometry

• Evaluable disease with presence of 1 of the following criteria:

  • Absolute lymphocyte count greater than 5,000/mm^3
  • At least 1 measurable node greater than 2 cm by CT scan OR measurable disease in a lymphoid structure (spleen)
  • Bone marrow involvement (greater than 20% of marrow cellularity)

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• ECOG 0-2

Life expectancy

• Not specified

Hematopoietic

• See Disease Characteristics
• Absolute neutrophil count at least 1,500/mm^3*
• Platelet count at least 100,000/mm^3*
• Hemoglobin at least 9.0 g/dL* NOTE: *Unless due to hematologic malignancy

Hepatic

• Bilirubin no greater than 2 times normal
• AST no greater than 2 times normal

Renal

• Creatinine no greater than 2.0 mg/dL OR
• Creatinine clearance at least 50 mL/min
• No renal dysfunction that would impair tolerance or compliance with study therapy

Cardiovascular

• No cardiac dysfunction that would impair tolerance or compliance with study therapy

Pulmonary

• No pulmonary dysfunction that would impair tolerance or compliance with study therapy

Other

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception
• No chronic gastrointestinal disease (e.g., Crohn's disease, ulcerative colitis, short gut syndrome) that would impair tolerability of compliance with therapy
• No neurological or psychiatric dysfunction that would impair tolerability of or compliance with study therapy

PRIOR CONCURRENT THERAPY:

Biologic therapy

• Not specified

Chemotherapy

• At least 6 weeks since prior nitrosourea or mitomycin
• No more than 6 prior courses of fludarabine

Endocrine therapy

• No concurrent corticosteroids as antiemetics

Radiotherapy

• Not specified

Surgery

• Not specified

Other

• At least 4 weeks since prior therapy for disease
• No more than 3 prior treatments for disease (not including steroids alone)