Combination of Metformin With Gefitinib to Treat NSCLC

Primary Objectives: To determine the 1 year progression-free survival (PFS) of the combination of metformin and gefitinib in patients who harbors EGFR-mutant with previously untreated advanced or metastatic pulmonary adenocarcinoma. Secondary Objectives: A. To evaluate the response to therapy and overall survival of the combination of metformin with gefitinib in patients who harbors EGFR-mutant with previously untreated advanced or metastatic pulmonary adenocarcinoma. B. To acquire preliminary data regarding the effects of metformin on interleukin-6 (IL-6) levels in tumor and serum. Treatment will be administered on an outpatient basis. Metformin starting at a dose of 500 mg twice a day, orally with meals. After one week, increase the dose of metformin to 1000 mg as the first dose of the day and 500 mg as the second dose. After another week, increase to 1000 mg of metformin two times a day. Metformin treatment will be initiated one week before beginning gefitinib, if possible, but gefitinib administration will not be delayed for metformin loading. Gefitinib will be administered 250mg QD continuously. Metformin will be administered continuously, beginning one week before beginning gefitinib, if possible, but tyrosine kinase inhibitors (TKI) will not be delayed for metformin loading. Maintenance Therapy Patients responding to this therapy will be maintained with metformin (1000 mg twice daily) and gefitinib. Duration of Therapy In the absence of treatment delays due to adverse events, treatment may continue until one of the following criteria applies: 1. Disease progression, 2. Intercurrent illness that prevents further administration of treatment, 3. Unacceptable adverse events(s), 4. Patient decides to withdraw from the study, or 5. General or specific changes in the patient's condition render the patient unacceptable for further treatment in the judgment of the investigator.