Impact of T790M Mutation Status on Later-Line Osimertinib Treatment in Non-Small Cell Lung Cancer Patients.

This study confirmed the greater efficacy of later-line osimertinib for NSCLC with acquired T790M mutation than for NSCLC without acquired T790M mutation. Detection of the T790M mutation after frontline treatment (first- and second-generation EGFR-TKI) is crucial for prolonging the survival of NSCLC patients harboring EGFR mutation. Osimertinib may be considered an option for NSCLC with unknown T790M mutations, as a certain subpopulation may benefit from osimertinib.