DISEASE CHARACTERISTICS: Histologically confirmed oat cell or intermediate type small cell lung cancer Patients must have received prior therapy, with the following: Documented disease progression (new lesions or increased lesion size) after first line therapy No more than 1 prior chemotherapy regimen Complete or partial response to initial chemotherapy (must have lasted more than 60 days after end of therapy before relapse occurred) Bidimensionally measurable disease At least one lesion outside of irradiation field Pleural effusions are not measurable No brain or bone metastases as only measurable site No uncontrolled brain or other CNS metastases (surgical excision and/or radiotherapy)

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: Not specified Hematopoietic: Absolute neutrophil count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hepatic: AST no greater than 2 times upper limit of normal Bilirubin no greater than 1.5 mg/dL Renal: Creatinine less than 1.3 mg/dL OR Creatinine clearance greater than 60 mL/min Cardiovascular: Cardiac ejection fraction greater than 45% by MUGA or echocardiogram No uncontrolled ventricular arrhythmias Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No senile dementia or psychiatric disorders Not concurrent serious infection No major seizure disorder No grade 3 neuropathies No spinal cord compression

No other concurrent unstable medical condition No other prior malignancies within past 5 years, except:

Adequately treated basal or squamous cell skin cancer Any carcinoma in situ

PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: See Disease Characteristics No prior doxorubicin or vincristine as first line treatment for small cell lung cancer Endocrine therapy: Not specified Radiotherapy: No prior radiotherapy to greater than 50% of bone marrow At least 30 days since prior radiotherapy Surgery: Not specified Other: No concurrent experimental drugs or anticancer therapies Concurrent medication for chronic medical conditions allowed (e.g., hypertension) No concurrent cimetidine, phenothiazines, phenobarbital, carbamazepine, trolandeomycin, sulfinpyrazone, rifampin, Dilantin, and cyclosporine-A (or other P-gp inhibitors)