514MO Acquired mechanisms of resistance to first-line (1L) osimertinib with or without platinum-based chemotherapy (CT) in EGFR-mutated (EGFRm) advanced NSCLC: Preliminary data from FLAURA2

Osimertinib (osi) is the preferred 1L treatment (tx) for patients (pts) with EGFRm advanced NSCLC; however, most pts will develop progressive disease (PD) due to tx resistance. The phase III, open-label, randomised FLAURA2 (NCT04035486) study demonstrated a significant PFS benefit with 1L osi + CT vs osi monotherapy in EGFRm advanced NSCLC. A safety run-in (SRI) assessed safety of the combination prior to the randomised phase. We report preliminary results for the pre-specified, exploratory analysis of acquired mechanisms of resistance to osi ± CT in pts.