Irinotecan in Treating Patients With Recurrent or Refractory Non-Hodgkin's Lymphoma

DISEASE CHARACTERISTICS: Histologically confirmed recurrent or refractory non-Hodgkin's lymphoma First relapse requires histologic confirmation of relapse No CNS metastases No lymphomatous meningitis Measurable disease PATIENT CHARACTERISTICS: Age: 15-75 Performance status: Zubrod 0-2 Life expectancy: At least 12 weeks Hematopoietic: Unless due to lymphoma: Platelet count at least 100,000/mm^3 Absolute granulocyte count at least 1,500/mm^3 Hemoglobin at least 9 g/dL Hepatic: Bilirubin no greater than 1.5 mg/dL SGOT no greater than 3 times upper limit of normal (ULN) (no greater than 5 times ULN if liver involvement) Renal: Creatinine no greater than 2.0 mg/dL Baseline calcium less than 12 mg/dL Cardiovascular: No myocardial infarction within 6 months No congestive heart failure requiring therapy Other: No history of seizures No uncontrolled diabetes mellitus (i.e., random blood sugar of at least 250 mg) No other concurrent severe disease No uncontrolled infection HIV negative No psychoses No prior malignancy except for adequately treated basal cell or squamous cell skin cancer or in situ cancer of the cervix unless surgically treated and disease free for at least 5 years Not pregnant or lactating Effective contraception required of fertile patients PRIOR CONCURRENT THERAPY: Biologic therapy: No prior bone marrow transplantation Chemotherapy: No more than 2 prior chemotherapy regimens for treatment of lymphoma No prior irinotecan, topotecan or aminocamptothecin At least 3 weeks since prior chemotherapy Endocrine therapy: Not specified Radiotherapy: At least 3 weeks since prior radiotherapy Radiotherapy that is not a part of a combined-modality therapy is counted as a regimen (see Chemotherapy) Surgery: Not specified Other: No phenytoin, phenobarbital, or other antiepileptic prophylaxis