Phase III Trial to Evaluate the Elortinib vs Gefitinib in Advanced NSCLC With EGFR Exon 19 or 21 Mutations

Inclusion Criteria: * Histologically or cytologically confirmed stage IIIB (wet) or IV NSCLC. * Patients with positive EGFR exon19 or exon21 mutation as confirmed by direct sequencing histologically. * Signing the informed consent form. * The vital organ functions are tolerant to therapy. * Have recovered to CTCAE2 grade below from toxicity of previous chemotherapy and radiotherapy * PS 0-2 scores. * Functional reserve of bone marrow is adequate, e.g. white blood cell count ≥3.0×109/L, planet count ≥90×109/L, and HB≥80×109/L. * Serum bilirubin is 2 times less than the upper limit of normal (ULN), ALT and AST are 3 times less than ULN; for liver metastases, ALT and AST need to be 5 times less than ULN; creatinine should be 2 times less than ULN. Exclusion Criteria: * Informed consent is not provided. * Women of pregnancy or breastfeeding. * Have difficulty in swallowing.