Histomolecular Resistance Mechanisms to First-Line Osimertinib in EGFR-Mutated Advanced Non-Small Cell Lung Cancer: A Multicentric Retrospective French Study.

Background: Osimertinib is an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) used in first line for the treatment of advanced EGFR-mutated non-small cell lung cancer (NSCLC).

Objective: The identification of related histomolecular resistance mechanisms to first-line osimertinib is a critical step to define the optimal treatment strategy beyond progression.

Patients And Methods: All consecutive patients treated in the first line with osimertinib for advanced EGFR-mutated NSCLC at 10 hospitals in the Greater Paris area between April 2015 and January 2021 were included.