Inclusion Criteria:

• Signed informed consent
• Age >=18 years
• Histologically documented, unresectable, inoperable, locally advanced, recurrent or metastatic Stage IIIB or Stage IV Non-Small Cell Lung Cancer (NSCLC)
• A cytologic diagnosis is acceptable (i.e., FNA or pleural fluid cytology)
• Measurable or non-measurable disease
• ECOG performance status of 0 or 1
• Life expectancy of >=3 months
• >= 3 weeks since any prior surgery or radiotherapy (>=2 weeks for patients who receive <=30 Gy of radiotherapy involving <25% of the marrow reserve)
• Use of an effective means of contraception (women of childbearing potential)
• Able to comply with study and follow-up procedures

Exclusion Criteria:

• Evidence of small cell, carcinoid, or mixed small cell/non-small cell histology
• Malignancies within 3 years except for adequately treated carcinoma in situ of the cervix or basal or squamous cell skin cancer
• Symptomatic or untreated brain metastases
• Prior systemic chemotherapy for NSCLC
• Prior exposure to agents directed at the HER axis (e.g., ZD1839 [Iressa], C225 [Cetuximab], Trastuzumab [Herceptin])
• Unstable systemic disease, including active infection, uncontrolled hypertension, unstable angina, congestive heart failure, or myocardial infarction within 6 months prior to Day 1, or serious cardiac arrhythmia requiring medication (patients with chronic atrial arrhythmia, i.e., atrial fibrillation or paroxysmal supraventricular tachycardia, are eligible)
• History of other diseases, metabolic dysfunction, physical examination finding, or clinical laboratory finding giving reasonable suspicion of a disease or condition that contraindicates the use of an investigational drug or that might affect the interpretation of the results of the study or render the patient at high risk from treatment complications
• Gastrointestinal tract disease resulting in an inability to take oral medication or a requirement for intravenous (IV) alimentation, or prior surgical procedures affecting absorption
• Pregnancy or lactation

Any of the following abnormal baseline hematologic values:

• Granulocytes count <=1500/uL
• Platelet count <100,000/uL

Any of the following abnormal baseline liver function tests:

• Serum bilirubin >1.5× upper limit of normal (ULN)
• Serum ALT and AST >=2.5× ULN (>5× ULN if due to liver metastases)
• Alkaline phosphatase >=2.5× ULN

Other baseline laboratory values:

• Serum creatinine >1.5× ULN or creatinine clearance <60 mL/min
• Uncontrolled hypercalcemia (>11.5 mg/dL)