Inclusion Criteria

DISEASE CHARACTERISTICS: Histologically or cytologically confirmed recurrent or refractory
small cell lung cancer Measurable disease At least 20 mm with conventional techniques OR
At least 10 mm with spiral CT scan The following are not considered measurable: Bone
lesions Leptomeningeal disease Ascites Pleural/pericardial effusion Abdominal masses not
confirmed and followed by imaging techniques Cystic lesions Tumor lesions situated in a
previously irradiated area Known CNS metastases allowed

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: CTC 0-2 Life expectancy: Not
specified Hematopoietic: Granulocyte count at least 1,500/mm3 Platelet count at least
100,000/mm3 Hepatic: Bilirubin no greater than 1.5 mg/dL Renal: Creatinine no greater than
2.0 mg/dL Other: Not pregnant or nursing Fertile patients must use effective contraception
No prior or concurrent malignancy in past 5 years except curatively treated carcinoma in
situ of the cervix, breast, or basal cell or squamous cell carcinoma of the skin

PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: No more than 1
prior chemotherapy or chemoradiotherapy regimen No prior gemcitabine or irinotecan
Endocrine therapy: Not specified Radiotherapy: No more than 1 prior chemoradiotherapy
regimen At least 2 weeks since prior cranial radiotherapy for CNS metastases No concurrent
cranial radiotherapy Surgery: Not specified