Pemetrexed Combined With Synchronous Gefitinib as Adjuvent Therapy in Patient With EGFR Mutant Lung Adenocarcinoma

Inclusion Criteria:

* Written informed consent provided.
* Males or females aged ≥18 years, \< 70 years.
* Able to comply with the required protocol and follow-up procedures, and able to receive oral medications.
* Target population is completely resected pathological stage II-IIIA(N1-N2) NSCLC with EGFR exon 19 deletions and exon 21 L858R activating mutation.
* Patient who can start the investigational therapy within 3-6 weeks after the complete resection
* ECOG performance status 0-1.
* Life expectancy ≥12 weeks.
* Adequate hematological function: Absolute neutrophil count (ANC) ≥2.0 x 109/L, and Platelet count ≥100 x 109/L, and Hemoglobin ≥9 g/dL (may be transfused to maintain or exceed this level).
* Adequate liver function: Total bilirubin ≤ 1.5 x upper limit of normal (ULN), Aspartate aminotransferase (AST), alanine aminotransferase (ALT) ≤ 2.5 x ULN in subjects without liver metastases; ≤ 5 x ULN in subjects with liver metastases.
* Adequate renal function: Serum creatinine ≤ 1.25 x ULN, or ≥ 60 ml/min.
* Female subjects should not be pregnant or breast-feeding.

Exclusion Criteria:

* Known severe hypersensitivity to gefitinib or any of the excipients of this product.
* Known severe hypersensitivity to pre-medications required for treatment with cisplatin / vinorelbine doublet chemotherapy.
* Inability to comply with protocol or study procedures.
* A serious concomitant systemic disorder that, in the opinion of the investigator, would compromise the patient's ability to complete the study.
* A serious cardiac condition, such as myocardial infarction within 6 months, angina, or heart disease.
* Interstitial pneumonia.
* Patients with prior exposure to agents directed at the HER axis (e.g. erlotinib, gefitinib, cetuximab, trastuzumab).
* Patients with prior chemotherapy or therapy with systemic anti-tumour therapy (e.g. monoclonal antibody therapy).
* Patients with prior radiotherapy
* History of another malignancy in the last 5 years with the exception of the following:Other malignancies cured by surgery alone and having a continuous disease-free interval of 5 years are permitted. Cured basal cell carcinoma of the skin and cured in situ carcinoma of the uterine cervix are permitted.
* Any unstable systemic disease (including active infection, uncontrolled hypertension, unstable angina, congestive heart failure, myocardial infarction within the previous year, serious cardiac arrhythmia requiring medication, hepatic, renal, or metabolic disease).
* Eye inflammation or eye infection not fully treated or conditions predisposing the subject to this.
* Evidence of any other disease, neurological or metabolic dysfunction, physical examination or laboratory finding giving reasonable suspicion of a disease or condition that contraindicated the use of an investigational drug or puts the subject at high risk for treatment-related complications.
* Patient who has active serious infection (e.g. pyrexia of or 38.0℃ over)
* Patients who harbouring exon 20 T790M mutation.