Osimertinib as first-line treatment for advanced epidermal growth factor receptor mutation–positive non–small-cell lung cancer in a real-world setting (OSI-FACT)

Abstract

BackgroundOsimertinib is the standard of care in the initial treatment for advanced epidermal growth factor receptor (EGFR) mutation–positive lung cancer. However, clinical data and reliable prognostic biomarkers are insufficient. MethodsWe performed a retrospective multicentre cohort study for 538 EGFR mutation–positive patients, who received osimertinib as the initial treatment between August 2018 and December 2019. The main outcome was progression-free survival (PFS). ResultsThe median observation period was 14.7 months (interquartile range 11.4–20.0). The median PFS was 20.5 months (95% confidence interval [CI] 18.6−not reached). Multivariate analysis showed that sex (male) (hazard ratio [HR] 1.99, 95% CI 1.35–2.93, P = 0.001), malignant effusions (HR 1.51, 95% CI 1.11–2.04, P = 0.008), liver metastasis (HR 1.55, 95% CI 1.03–2.33, P = 0.037), advanced unresectable cases (HR 1.71, 95% CI, 1.04–2.82, P = 0.036), mutation type and programmed cell death-ligand 1 (PD-L1) expression were associated with PFS. The L858R (HR 1.55, 95% CI 1.01–2.38, P = 0.043) and uncommon mutations (HR 3.15, 95% CI 1.70–5.83, P < 0.001) were associated with PFS. PD-L1 expression of 1–49% (HR 1.66, 95% CI 1.05–2.63, P = 0.029), ≥50% (HR 2.24, 95% CI 1.17–4.30, P = 0.015) and unknown (HR 1.53, 95% CI 1.05–2.22, P = 0.026) was associated with PFS. The main reasons for treatment discontinuation among 219 patients were disease progression (44.3%), pneumonitis (25.5%) and other adverse events (16.0%). ConclusionDuring initial treatment with osimertinib, PD-L1 expression is significantly related to PFS. Adverse events are a noteworthy reason for discontinuation.