Nintedanib Plus EGFR TKI In EGFR-mutated Non-small Cell Lung Cancer Patients

The efficacy of the regimen is evaluated by participants' progression-free survival and overall survival. Nintedanib is a medication that blocks endothelial cells in tumor microenvironments and is effective in delaying tumor progression. Nintedanib is also a drug approved for idiopathic pulmonary fibrosis in the clinic. The participants will take 1 nintedanib tablet after a meal twice per day with a twelve-hour interval. EGFR TKI-gefitinib, erlotinib, afatinib, or osimertinib will be taken 1 tablet once per day during each treatment cycle. The treatment cycle in this study is 30 days. In this study, the participants will have a physical exam in 6 weeks and 12 weeks after the initiation of the treatment. In the 6 weeks of the study, the participants will have blood tests and a CT scan. About 5cc of blood will be collected each time. In addition, the participant's tumor will be measured by a CT scan every 12 weeks. If the participants develop any unacceptable symptoms or changes in liver function tests, the participants' treatment may be delayed and/or the dose decreased until the symptoms are disappeared. It may even be necessary to stop your treatment. The doctor will inform the participant of any changes in the participants' treatment schedule or in the doses of medication after he/she evaluates the participants in the clinic. After treatment ends, the participants will have a follow-up visit at the clinic. At this visit, the participants will have a complete physical exam, including blood (about 5cc) tests and CT scan to measure the size of the tumors. This is an investigational study. Up to 20 participants will take part in this study.