Inclusion Criteria:

- Ability to understand and the willingness to sign a written informed consent form;
the consent form must be signed by the patient prior to any study-specific
procedures.

- Patients age ≥ 18 years with histologically confirmed wet Stage IIIB (with malignant
pleural effusion) or Stage IV non-small cell lung cancer (metastatic or recurrent).

- Pathologic confirmation of non-small cell lung cancer at Memorial Sloan-Kettering
Cancer Center.

- Presence of exon 19 or exon 21 EGFR activating mutation.

- No prior EGFR tyrosine kinase therapy.

- No prior systemic therapy for advanced NSCLC (Stage IIIB with malignant effusion or
Stage IV)

- Karnofsky performance status > or = to 70% OR ECOG performance status ≤ 2.

- Measurable disease defined as greater than or equal to one known/suspected malignant
lesion > or = to 1 cm measurable in two dimensions.

- Adequate hematologic, renal, and/or hepatic function: WBC > or = to 3,000/ul,
hemoglobin > or = to 9.0 g/dl, platelet count > or = to 100,000/ul, total bilirubin ≤
1.5 X UNL, AST ≤ 2.5 X UNL, and serum creatinine within 1.5 x the upper limit of
normal (<1.95 at MSKCC) or calculated creatinine clearance > or = to 60 ml/min.

- Able to swallow and retain oral medication.

- Willingness and ability to comply with study procedures and follow-up examination.

- Four weeks since any major surgery, completion of radiation, or completion of all
prior chemotherapy.

- Acute toxicities of any prior therapy must have resolved to < Grade 1 or baseline
prior to starting study therapy.

- Effective contraception.

Exclusion Criteria:

- Prior treatment with gefitinib, erlotinib, or other EGFR tyrosine kinase inhibitor
therapy.

- Concurrent cytotoxic or biological therapy.

- Known KRAS mutation.

- History within the past 6 months of myocardial infarction, cardiac stent placement,
or intermittent ischemia with troponin leak.

- Active secondary malignancy or history of other malignancy within the last 3 years
except non-melanoma skin cancer and in-situ carcinoma of the cervix.

- Active, serious comorbid medical conditions including severe infection, malnutrition,
unstable angina, congestive heart failure (New York Heart Association Class III or
IV), pulmonary fibrosis, or condition that would be felt by treating physician to
preclude safe participation in the clinical trial.

- Patients with malabsorption syndrome or diseases significantly affecting the
gastrointestinal tract including prior gastric resection or small bowel resection,
inflammatory bowel disease, or partial or complete small bowel obstruction.

- Unstable brain or leptomeningeal metastases including patients who continue to
require glucocorticoids for brain or leptomeningeal metastases.

- Women who are pregnant or breast-feeding.

- Inability/unwillingness to comply with protocol treatment or follow-up.