Efficacy and safety of first-line osimertinib in Chinese patients with EGFR-mutated advanced non-small cell lung cancer: a prospective, multicenter, non-interventional study (FLOURISH)

Objective: Osimertinib has demonstrated superior efficacy as a first-line treatment for epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (NSCLC) in clinical trials. This study was aimed at providing real-world evidence of osimertinib treatment in Chinese populations. Methods: This prospective, multicenter, non-interventional study was conducted from July 27, 2020, to April 27, 2022. Treatment-naïve adults (≥18 years of age) with locally advanced or metastatic EGFR-mutated NSCLC scheduled to receive first-line osimertinib were included. Of 507 patients screened, 481 were eligible in the full analysis set. The primary endpoint was time to treatment discontinuation (TTD). Secondary endpoints included real-world progression-free survival (rwPFS), overall survival (OS), objective response rate (ORR), disease control rate (DCR), and safety. Results: Among 481 patients (median age 64.1 years; 62.2% women), the median follow-up was 31.3 months. The mTTD was 24.6 months (95% CI, 22.4–26.7), the median rwPFS was 19.4 months (95% CI, 16.2–20.4), and the mOS was 41.0 months [95% CI, 39.7 to not reached (NR)]. The mOS was 43.1 months (95% CI, 39.7 to NR) in FLAURA-eligible patients vs. 33.5 months (95% CI, 26.8 to NR) in FLAURA-ineligible patients. The mOS was 29.3 months (95% CI: 25.4 to NR) in patients with co-mutations vs. NR (95% CI: 32.9 to NR) in the cohort with EGFR-only mutations. Adverse events occurred in 71.7% of patients, and grade ≥3 events occurred in 11.4%. The safety profiles were similar between FLAURA-eligible and ineligible patients. Conclusions: First-line osimertinib demonstrated robust effectiveness and manageable safety in real-world Chinese patients with EGFR-mutated advanced NSCLC, including those ineligible for clinical trials. Patients with co-mutations showed diminished clinical benefit, thus suggesting a potential need for intensified treatment strategies in this population.