[Acquired Drug Resistance Mechanism of Osimertinib in the Targeted Therapy of Non-small Cell Lung Cancer].

While treating cancer, epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) still faces inevitable drug resistance. Investigations into the mechanisms which foster resistance to EGFR-TKI has led to the discovery of novel biomarkers and drug targets, and in turn has enabled the development of third-generation TKIs and proposals for rational therapeutic combinations. The threonine-to-methionine substitution mutation at position 790 (T790M) is clinically validated to engender refractoriness to first- and second-generation TKI, and is a standard-of-care predictive biomarker used in therapeutic stratification. For patients who are T790M-negative, cytotoxic chemotherapy or protracted EGFR-TKI treatment are acceptable treatment standards after disease progression, although combinations of targeted therapies and checkpoint blockade immunotherapy may offer promising alternatives in the future. Among T790M-positive patients, the third-generation EGFR-TKI, osimertinib, has shown superiority over both platinum-doublet chemotherapy and first-generation EGFR-TKI in randomized clinical trials. This article appraises the key literature on the contemporary management of non-small cell lung cancer patients with acquired resistance to EGFR-TKIs, and envisions future directions in translational and clinical research.