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

Inclusion Criteria: * Histologically confirmed recurrent or refractory B-cell non-Hodgkin's lymphoma o CD20 positive * Bidimensionally measurable or evaluable disease * 19 years old and over * ECOG 0-2 or Karnofsky 70-100% * Life expectancy at least 3 months * WBC at least 3,000/mm3 * Granulocyte count at least 1,000/mm3 * Platelet count at least 100,000/mm3 * Bilirubin no greater than 1.5 times upper limit of normal(ULN) * AST or ALT no greater than 2.5 times ULN * Creatinine no greater than 1.5 mg/dL * Fertile patients must use effective contraception * Concurrent non-steroidal hormonal therapy allowed for non-disease related conditions (e.g., insulin for diabetes) Exclusion Criteria: * No myelodysplastic syndrome or chronic myeloid leukemia * Not pregnant or nursing/negative pregnancy test * 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 * No prior bone marrow or peripheral blood stem cell transplantation for non-Hodgkin's lymphoma * No other concurrent chemotherapy * No concurrent corticosteroids except transient administration as antiemetic * No concurrent radiotherapy * No other concurrent investigational therapy * No other concurrent antitumor agents