Impact of Specific Epidermal Growth Factor Receptor (EGFR) Mutations and Clinical Characteristics on Outcomes After Treatment With EGFR Tyrosine Kinase Inhibitors Versus Chemotherapy in EGFR-Mutant Lung Cancer: A Meta-Analysis

PURPOSE: We examined the impact of different epidermal growth factor receptor (EGFR) mutations and clinical characteristics on progression-free survival (PFS) in patients with advanced EGFR-mutated non-small-cell lung cancer treated with EGFR tyrosine kinase inhibitors (TKIs) as first-line therapy. PATIENTS AND METHODS: This meta-analysis included randomized trials comparing EGFR TKIs with chemotherapy. We calculated hazard ratios (HRs) and 95% CIs for PFS for the trial population and prespecified subgroups and calculated pooled estimates of treatment efficacy using the fixed-effects inverse-variance-weighted method. All statistical tests were two sided. RESULTS: In seven eligible trials (1,649 patients), EGFR TKIs, compared with chemotherapy, significantly prolonged PFS overall (HR, 0.37; 95% CI, 0.32 to 0.42) and in all subgroups. For tumors with exon 19 deletions, the benefit was 50% greater (HR, 0.24; 95% CI, 0.20 to 0.29) than for tumors with exon 21 L858R substitution (HR, 0.48; 95% CI, 0.39 to 0.58; Pinteraction < .001). Never-smokers had a 36% greater benefit (HR, 0.32; 95% CI, 0.27 to 0.37) than current or former smokers (HR, 0.50; 95% CI, 0.40 to 0.63; Pinteraction < .001). Women had a 27% greater benefit (HR, 0.33; 95% CI, 0.28 to 0.38) than men (HR, 0.45; 95% CI, 0.36 to 0.55; treatment-sex interaction P = .02). Performance status, age, ethnicity, and tumor histology did not significantly predict additional benefit from EGFR TKIs. CONCLUSION: Although EGFR TKIs significantly prolonged PFS overall and in all subgroups, compared with chemotherapy, greater benefits were observed in those with exon 19 deletions, never-smokers, and women. These findings should enhance drug development and economic analyses, as well as the design and interpretation of clinical trials.