DISEASE CHARACTERISTICS: Histopathologically proven non-small cell lung cancer that is incurable by surgery or radiotherapy Brain metastases allowed Demonstrated resistance to prior chemotherapy required by 1 of the following: Tumor growth or recurrence while on treatment Failure of tumor to shrink over 3 consecutive courses of treatment Measurable or evaluable disease

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Zubrod 0-2 Life expectancy: Greater than 12 weeks Hematopoietic: ANC at least 1,500 Platelets at least 100,000 Hemoglobin at least 10 g/dL Hepatic: Bilirubin less than 1.5 mg/dL (26 micromoles/L) AST/ALT less than 1.5 times normal Renal: Creatinine less than 1.6 mg/dL (150 micromoles/L) Cardiovascular: No uncontrolled hypertension or other cardiac disease No myocardial infarction within 6 months Other: No uncontrolled diabetes No active abuse of ethanol No allergies to study medication No active infection or other serious medical condition that precludes protocol treatment No dementia or significantly altered mental status that precludes informed consent No prior melanoma or malignancy of the following sites: Breast Kidney Thyroid Salivary glands Endometrium No other second malignancy within 5 years except: Nonmelanomatous skin cancer Carcinoma in situ of cervix No pregnant or nursing women Effective contraception required of fertile women

PRIOR CONCURRENT THERAPY: Recovery from any treatment-limiting toxicity required Biologic therapy: Not specified Chemotherapy: At least 3 weeks since myelosuppressive chemotherapy (6 weeks since nitrosoureas, mitomycin, or high-dose carboplatin) Endocrine therapy: Not specified Radiotherapy: At least 3 weeks since radiotherapy unless to a limb or limited treatment area Surgery: Not specified