Inclusion Criteria

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