Combination Chemotherapy Plus Rituximab in Treating Patients With Recurrent or Refractory Non-Hodgkin's Lymphoma

DISEASE CHARACTERISTICS: Histologically confirmed recurrent or refractory B-cell non-Hodgkin's lymphoma CD20 positive Bidimensionally measurable or evaluable disease No myelodysplastic syndrome or chronic myeloid leukemia PATIENT CHARACTERISTICS: Age: 19 and over Performance status: ECOG 0-2 OR Karnofsky 70-100% Life expectancy: At least 3 months Hematopoietic: WBC at least 3,000/mm3 Granulocyte count at least 1,000/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin no greater than 1.5 times upper limit of normal (ULN) AST or ALT no greater than 2.5 times ULN Renal: Creatinine no greater than 1.5 mg/dL Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No other prior malignancy except curatively treated basal cell carcinoma, squamous cell carcinoma, or carcinoma in situ of the cervix No active serious infection No other concurrent serious medical condition that would preclude study PRIOR CONCURRENT THERAPY: Biologic therapy: No prior bone marrow or peripheral blood stem cell transplantation for non-Hodgkin's lymphoma Chemotherapy: No other concurrent chemotherapy Endocrine therapy: No concurrent corticosteroids except transient administration as antiemetic Concurrent non-steroidal hormonal therapy allowed for non-disease related conditions (e.g., insulin for diabetes) Radiotherapy: No concurrent radiotherapy Surgery: Not specified Other: No other concurrent investigational therapy No other concurrent antitumor agents