Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically proven advanced (extensive stage) small cell lung cancer with
progressive or recurrent disease after 1 first line chemotherapy regimen

- Sensitive disease, defined as a response to prior chemotherapy lasting at least
3 months from the end of all prior treatment, including radiotherapy, until the
time of progression OR

- Refractory disease, defined as no response to prior chemotherapy, or a response
to prior chemotherapy followed by progression within 3 months after completion
of all prior therapy, including radiotherapy

- Minimum of 1 target lesion that can be accurately measured in at least 1 dimension

- 20 mm or more with conventional techniques OR

- 10 mm or more with spiral CT scans

- No symptomatic brain metastases

PATIENT CHARACTERISTICS:

Age:

- 18 and over

Performance status:

- ECOG 0-2

Life expectancy:

- At least 3 months

Hematopoietic:

- Neutrophil count at least 2,000/mm^3

- Platelet count at least 100,000/mm^3

Hepatic:

- Bilirubin less than 1.5 times upper limit of normal (ULN)

- Alkaline phosphatase, SGOT, and SGPT no greater than 2.5 time ULN (no greater than 5
times ULN if hepatic metastases present)

Renal:

- Creatinine no greater than 1.7 mg/dL

Cardiovascular:

- No ischemic heart disease within the past 6 months

- Normal 12 lead electrocardiogram

Other:

- Not pregnant or nursing

- Fertile patients must use effective contraception

- No other prior or concurrent malignancy except cone biopsied carcinoma of the cervix
or adequately treated basal cell or squamous cell skin cancer

- No unstable systemic disease or active uncontrolled infection

- No psychological, familial, sociological, or geographical condition that may preclude
compliance

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- Prior maintenance therapy with biologic agents following first line chemotherapy
allowed

- No concurrent filgrastim (G-CSF) with nitrocamptothecin

Chemotherapy:

- See Disease Characteristics

- Greater than 4 weeks since prior chemotherapy

- No more than 1 prior chemotherapy regimen for extensive disease

- Alternate or sequential use of different regimens without interruption in first line
treatment is considered 1 first line therapy

Endocrine therapy:

- Not specified

Radiotherapy:

- See Disease Characteristics

- Greater than 4 weeks since prior radiotherapy

Surgery:

- Greater than 2 weeks since prior major surgery

Other:

- No other concurrent anticancer therapy

- No other concurrent investigational therapy