RATIONALE: Drugs used in chemotherapy, such as pemetrexed disodium and carboplatin, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Giving more than one drug (combination chemotherapy) may kill more tumor cells.

PURPOSE: This phase II trial is studying how well giving pemetrexed disodium together with carboplatin works in treating patients with extensive-stage small cell lung cancer.

OBJECTIVES:

Primary

• Determine the complete and partial response rates in patients with previously untreated, extensive-stage small cell lung cancer treated with pemetrexed disodium and carboplatin.

Secondary

• Determine the toxicity of this regimen in these patients.
• Determine, preliminarily, the survival of patients treated with this regimen.
• Determine, preliminarily, the response rate in patients 70 years and older treated with this regimen.
• Determine, preliminarily, the toxicity of this regimen in patients 70 years and older.

OUTLINE: This is a multicenter study. Patients are stratified according to age (< 70 years vs ≥ 70 years).

Patients receive pemetrexed disodium IV over 10 minutes and carboplatin IV over 30 minutes on day 1. Treatment repeats every 21 days for up to 6 courses in the absence of disease progression or unacceptable toxicity. Patients who develop progressive disease in the CNS only may receive whole-brain radiotherapy and then continue chemotherapy after completion of whole-brain radiotherapy for up to 6 courses.

After completion of study treatment, patients are followed every 3 months for 1 year and then every 6 months for 4 years.

PROJECTED ACCRUAL: Approximately 77 patients at least 46 who are < 70 years of age and at least 24 who are ≥ 70 years of age) will be accrued for this study within 20-26 months.

DISEASE CHARACTERISTICS:

• Histologically or cytologically confirmed small cell lung cancer

  • Previously untreated disease
  • No mixed histology

• Extensive-stage disease

  • Clinically significant effusions (e.g., symptomatic pleural effusion) must be drained prior to treatment

• Measurable disease, defined as ≥ 1 unidimensionally measurable lesion ≥ 20 mm by conventional techniques OR ≥ 10 mm by spiral CT scan

• No symptomatic, untreated, or uncontrolled CNS metastases

  • CNS metastases previously treated with whole-brain radiotherapy allowed

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• ECOG 0-2

Life expectancy

• At least 12 weeks

Hematopoietic

• Absolute neutrophil count ≥ 1,500/mm^3
• Platelet count ≥ 100,000/mm^3
• Hemoglobin ≥ 9.0 g/dL

Hepatic

• Total bilirubin ≤ 1.5 times upper limit of normal (ULN) OR
• Direct bilirubin normal
• ALT and AST ≤ 3 times ULN (5 times ULN if there is liver involvement)

Renal

• Creatinine clearance ≥ 45 mL/min

Cardiovascular

• No angina pectoris
• No congestive heart failure within the past 3 months, unless ejection fraction > 40%
• No cardiac arrhythmia
• No myocardial infarction within the past 3 months
• No hypertension, including labile hypertension

Pulmonary

• No interstitial pneumonia
• No extensive and symptomatic interstitial fibrosis of the lung

Other

• Not pregnant or nursing

• Negative pregnancy test

• Fertile patients must use effective contraception

• No history of poor compliance with antihypertensive medication

• Able to take folic acid, cyanocobalamin (vitamin B_12) supplementation, or dexamethasone

• No uncontrolled diabetes

• No serious condition that would preclude study participation

• No clinically significant infection

• No significant traumatic injury

• No other malignancy within the past 5 years except carcinoma in situ of the cervix or nonmelanoma skin cancer

  • Low-grade (Gleason score ≤ 6), localized prostate cancer allowed even if diagnosed < 5 years prior to study entry

• No seizure disorder

• No other severe and/or uncontrolled medical condition

PRIOR CONCURRENT THERAPY:

Biologic therapy

• No concurrent immunotherapy
• No concurrent immunomodulating agents

Chemotherapy

• No other concurrent chemotherapy

Endocrine therapy

• No concurrent hormonal therapy

Radiotherapy

• See Disease Characteristics

• Prior palliative radiotherapy allowed

  • No prior palliative radiotherapy to the chest except for ≤ 3 fractions for superior vena cava syndrome

• No concurrent radiotherapy

Surgery

• More than 4 weeks since prior major surgery* (i.e., laparotomy) or open biopsy
• More than 2 weeks since prior minor surgery* NOTE: *Insertion of a vascular access device is not considered major or minor surgery

Other

• More than 4 weeks since prior investigational therapy
• No concurrent Hypericum perforatum (St. John's wort)
• No concurrent inducers or inhibitors of CYP3A4
• No concurrent medications that are metabolized by CYP3A4
• No aspirin dose ≥ 1.3 grams per day for ≥ 10 days prior to and after study treatment
• No other concurrent cytostatic or cytotoxic agents