PR104 in Treating Patients With Previously Untreated or Relapsed Small Cell Lung Cancer

DISEASE CHARACTERISTICS: Inclusion criteria: * Histologically or cytologically confirmed small cell lung cancer (SCLC) * If patient is treatment-naive, then they must have extensive disease * If patients are not treatment-naive, then they must be classified as sensitive-relapse with either extensive disease or limited disease * Sensitive-relapse defined as disease that responded to first-line chemotherapy and relapsed more than 90 days following the last dose of first-line chemotherapy * Limited disease SCLC defined as disease confined to the hemithorax of origin, mediastinum, and/or ipsilateral supraclavicular lymph nodes, which could be encompassed within a tolerable radiotherapy port * Extensive disease defined as disease that does not fit the definition of limited disease as defined above * Measurable or evaluable disease Exclusion criteria: * Active central nervous system (CNS) metastases, defined as metastases to the CNS (symptomatic or non-symptomatic) that requires immediate treatment or that are likely to require treatment in the following 6 weeks * Medical conditions requiring urgent intervention, including any of the following: * Superior vena cava syndrome * Lobar obstruction * Spinal cord compression * Liver metastases involving greater than one-third of the liver PATIENT CHARACTERISTICS: Inclusion criteria: * Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 * Absolute neutrophil count ≥ 1,500/mm\^3 * Platelet count ≥ 100,000/mm\^3 * Hemoglobin ≥ 9 g/dL (no red blood cell transfusions allowed) * Serum bilirubin ≤ 1.5 x upper limit of normal (ULN) * Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 5 x ULN (if liver metastases are present) or ≤ 2 x ULN (if liver metastases are absent) * Serum creatinine ≤ 1.5 x ULN * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception during and for at least 30 days after completion of study treatment Exclusion criteria: * Prior or concurrent malignancies, except for adequately treated basal cell or squamous cell carcinoma of the skin, carcinoma in situ of the cervix, or localized low-grade prostate cancer * Hyponatremia (\< 130 mmol/L) * Evidence of a significant medical disorder or laboratory finding that, in the opinion of the investigator, compromises the patient's safety during study participation, including any of the following: * Uncontrolled infection or infection requiring a concurrent parenteral antibiotic * Uncontrolled diabetes * Congestive heart failure * Myocardial infarction within the past 6 months * Chronic renal disease * Coagulopathy (excluding prophylactic anticoagulation) * Known human immunodeficiency virus (HIV) positivity, hepatitis B surface antigen-positivity, or hepatitis C positivity with abnormal liver function tests PRIOR CONCURRENT THERAPY: Inclusion criteria: * See Disease Characteristics * No concurrent prophylactic growth factors (filgrastim \[G-CSF\] or sargramostim \[GM-CSF\]) during course 1 of study treatment Exclusion criteria: * More than one prior chemotherapy regimen for SCLC * Less than 24 hours from any prior radiotherapy or the likelihood of toxicity from prior radiotherapy * Radiotherapy to \> 25% of the bone marrow within the past 4 weeks * Less than four weeks since major surgery