Study to Evaluate Sutetinib Maleate Capsule in Locally Advanced or Metastatic Non-small Cell Lung Cancer

Inclusion Criteria: 1. Age 18 years old and above, male or female. 2. Histopathological and/or cytopathological confirmation of locally advanced or metastatic NSCLC patients with ≤ 1 prior line of chemotherapy. 3. Confirmation that the tumor harbors a non-resistant uncommon EGFR mutation (tumor tissue biopsy), including one or more of L861Q, G719X and S768I mutations, excluding any other EGFR sensitive mutations and/or oncogenes.. 4. At least one measurable lesion. 5. ECOG score of 0, 1, or 2. 6. A minimum life expectancy of \> 3 months. 7. Adequate bone marrow reserve, hepatic, renal and coagulation function. 8. Willingness of all subjects of childbearing potential to use acceptable methods of birth control. Exclusion Criteria: 1. Ever used the epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) for anti-tumor therapy prior to enrollment. 2. Any systemic anti-tumor therapy such as chemotherapy, immunotherapy and radiation therapy used within 4 weeks prior to enrollment; any palliative radiotherapy for non-target lesions used to relieve symptoms and traditional Chinese medicines indicated for tumor within 2 weeks prior to enrollment. 3. Use or intake of drugs or foods containing potent inhibitor or inducer of cytochrome P450 isozyme 3A4 (CYP3A4) within 14 days or 5 half-lives, whichever was the longer, prior to enrollment. 4. Surgical operation (excluding aspiration biopsy) of main organs or a significant injury within 4 weeks prior to enrollment. 5. Any unresolved toxicities from prior therapy greater than Grade 1 at the time of screening except alopecia. 6. Inability to swallow the study medication, any seriously chronic gastrointestinal disorder, malabsorption syndrome or any other conditions with influence on gastrointestinal absorption. 7. Active central nervous system metastases 8. Previous or current interstitial lung disease, radiation pneumonitis which requires hormone therapy, or drug-related pneumonia, idiopathic interstitial pulmonary fibrosis identified in a baseline CT scan; uncontrolled massive pleural or pericardial effusion. 9. Any active infection which has not been controlled at screening. 10. Any serious cardiovascular disease. 11. History of other serious systemic disease not suitable for clinical trial. 12. Participation in other interventional clinical trial 4 weeks prior to enrollment or within 5 half-lives from the last dose of investigational product (whichever is longer). 13. Known alcohol or drug dependence. 14. Mental disorders or poor compliance. 15. Previously received solid organ transplantation or hematopoietic stem cell transplantation. 16. Females who are pregnant or breastfeeding. 17. Known hypersensitivity to the active ingredients or excipients of the investigational product. 18. Have any other primary malignant tumors within 3 years (except some low- risk cancers).