DISEASE CHARACTERISTICS: Pathologically confirmed recurrent or extensive stage small cell lung cancer Received at least one prior chemotherapy regimen Measurable or evaluable disease that has not been irradiated No pleural effusions, bone metastases, brain metastases, elevated serum enzymes, or radionuclide scans as the sole indicator lesion Brain metastases allowed if patients received cranial irradiation and have no clinical evidence of brain metastases

PATIENT CHARACTERISTICS: Age: Not specified Performance status: Karnofsky 60-100% Life expectancy: Not specified Hematopoietic: WBC at least 3,000/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin no greater than 2.0 mg/dL PT and aPTT normal Renal: Creatinine no greater than 1.5 mg/dL OR Creatinine clearance greater than 60 mL/min Cardiovascular: No unstable heart rhythm No unstable angina No clinical evidence of congestive heart failure No prior cerebrovascular accident or stroke No uncontrolled or severe hypertension Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception At least 6 weeks since any signs or symptoms of bleeding No history of bleeding disorder No bacterial endocarditis or other active infection

PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: At least 3 weeks since prior chemotherapy Endocrine therapy: Not specified Radiotherapy: At least 3 weeks since prior radiotherapy Surgery: At least 6 weeks since major surgery, trauma, or needle biopsy of any organ Other: No concurrent anticoagulant or platelet inhibitor therapy