3-AP and Gemcitabine in Treating Patients With Metastatic Non-Small Cell Lung Cancer

DISEASE CHARACTERISTICS: * Histologically or cytologically confirmed non-small cell lung cancer * Metastatic disease * Progressive disease after no more than 2 prior cytotoxic regimens containing at least 1 of the following drugs: * Cisplatin * Carboplatin * Taxane * Vinorelbine * Measurable disease * No CNS metastases PATIENT CHARACTERISTICS: Age * 18 and over Performance status * ECOG 0-1 Life expectancy * More than 3 months Hematopoietic * Absolute neutrophil count at least 1,500/mm\^3 * Platelet count at least 100,000/mm\^3 * Hemoglobin at least 9 g/dL (transfusion allowed) Hepatic * Bilirubin no greater than 2.0 mg/dL * ALT and AST no greater than 3 times upper limit of normal (ULN) (5 times ULN if liver metastases present) * Chronic viral hepatitis allowed Renal * Creatinine no greater than 2.0 mg/dL Cardiovascular * No myocardial infarction within the past 3 months * No uncontrolled congestive heart failure * No uncontrolled coronary artery disease * No uncontrolled cardiac arrhythmias Pulmonary * No dyspnea at rest * No supplemental oxygen dependence Other * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception during and for 3 months after study participation * No active infection * No other prior or concurrent malignancy except carcinoma in situ of the cervix previously treated by cone biopsy and/or resection, nonmetastatic basal cell or squamous cell skin cancer, or any stage I malignancy curatively resected more than 5 years ago * No other concurrent life-threatening illness PRIOR CONCURRENT THERAPY: Biologic therapy * Prior non-cytotoxic biologic regimens allowed (e.g., vaccines, antibodies, cytokines, or small molecule cell signaling inhibitors) Chemotherapy * See Disease Characteristics * More than 3 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin) and recovered * No prior gemcitabine * No prior 3-AP Endocrine therapy * Not specified Radiotherapy * More than 4 weeks since prior radiotherapy and recovered Surgery * More than 3 weeks since prior surgery and recovered Other * More than 3 weeks since prior non-cytotoxic regimens