OBJECTIVES: Primary * Determine the objective response rate in patients with stage III or IV recurrent non-small cell lung cancer treated with 3-AP (Triapine®) and gemcitabine as second-line therapy. Secondary * Determine the response duration, median time to progression, and overall survival of patients treated with this regimen. * Determine the toxicity of this regimen in these patients. * Determine the effect of 3-AP (Triapine®) on gemcitabine pharmacokinetics and cellular uptake into peripheral mononuclear cells in patients treated with this regimen. OUTLINE: This is an open-label, multicenter study. Patients are stratified according to participating center. Patients receive 3-AP (Triapine®) IV over 4 hours and gemcitabine IV over 30 minutes on days 1, 8, and 15\*. Treatment repeats every 28 days for up to 6 courses in the absence of disease progression or unacceptable toxicity. NOTE: \*For course 1 only, gemcitabine is administered alone on day 1 and in combination with 3-AP (Triapine®) on days 8 and 15. Patients are followed every 3 months for up to 2 years. PROJECTED ACCRUAL: A total of 15-31 patients will be accrued for this study within 7.5-21 months.
DISEASE CHARACTERISTICS: * Histologically or cytologically confirmed\* non-small cell lung cancer (NSCLC) * Stage III or IV disease * One of the following cellular types: * Adenocarcinoma * Non-diffuse bronchoalveolar cell carcinoma * Large cell carcinoma * Squamous cell carcinoma NOTE: \*A repeat biopsy of any accessible tumor site is required if \> 5 years have elapsed since the initial diagnosis * Progressive disease after 1 prior gemcitabine-containing chemotherapy regimen for stage III or IV NSCLC and must have achieved, at least once, a partial response, complete response, or stable disease during therapy * Not a primary non-responder and experienced only progressive disease during gemcitabine-containing chemotherapy * Measurable disease * At least 1 unidimensionally measurable lesion ≥ 20 mm by conventional techniques OR ≥ 10 mm by spiral CT scan * No known brain metastases PATIENT CHARACTERISTICS: Age * 18 and over Performance status * ECOG 0-2 OR * Karnofsky 60-100% Life expectancy * Not specified Hematopoietic * WBC ≥ 3,000/mm\^3 * Absolute neutrophil count ≥ 1,500/mm\^3 * Platelet count ≥ 100,000/mm\^3 * No glucose-6-phosphate dehydrogenase (G6PD) deficiency Hepatic * Bilirubin ≤ 1.5 times upper limit of normal (ULN) * ALT ≤ 2.5 times ULN (5 times ULN if liver metastases are present) Renal * Creatinine ≤ 1.5 times ULN OR * Creatinine clearance ≥ 50 mL/min Cardiovascular * No prior uncontrolled cardiac disease * No myocardial infarction within the past 12 months * No symptomatic congestive heart failure * No coronary artery disease * No cardiac arrhythmia Pulmonary * No uncontrolled symptomatic pulmonary disease * No pulmonary disease that requires oxygen therapy Other * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * No other malignancy within the past 5 years except completely treated carcinoma in situ of the cervix or nonmelanoma skin cancer * No prior allergic reaction attributed to compounds of similar chemical or biological composition to study agents * No other concurrent uncontrolled illness * No psychiatric illness or social situation that would preclude study compliance PRIOR CONCURRENT THERAPY: Biologic therapy * Not specified Chemotherapy * See Disease Characteristics * More than 4 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin) and recovered Endocrine therapy * Not specified Radiotherapy * More than 4 weeks since prior radiotherapy and recovered Surgery * Not specified Other * No concurrent combination antiretroviral therapy for HIV-positive patients * No other concurrent investigational agents * No other concurrent anticancer agents or therapies