Comparison of first-generation EGFR-TKIs (gefitinib, erlotinib, and icotinib) as adjuvant therapy in resected NSCLC patients with sensitive EGFR mutations

Background: Several randomized controlled trials have suggested that adjuvant epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) were associated with prolonged disease-free survival (DFS) in EGFR-mutated NSCLC patients after radical resection, comparing with chemotherapy or placebo. We aimed to compare the effectiveness of different first-generation EGFR-TKIs as adjuvant treatment in real-world setting. Methods: Early-stage EGFR mutated NSCLC patients who underwent radical resection and treated with first-generation EGFR-TKIs (gefitinib, erlotinib, icotinib) as adjuvant therapy between Feb 2010 and Jan 2019 were retrieved from a prospectively-maintained database in our center. The primary endpoint was DFS in stage II/III (TNM 8th) patients with exploratory endpoint regarding DFS in stage I patients. Sensitivity analyses were based on propensity score matched (PSM) cohorts. Treatment failure patterns among different TKIs were also compared. Results: Of 588 eligible patients, 198 patients (33.7%) received gefitinib, 106 patients (17.9%) received erlotinib, and 284 patients (48.2%) received icotinib. The median DFS of stage II/III patients in the gefitinib, erlotinib and icotinib group were 36.1 months (95% CI, 23.9-49.4), 42.8 months (95% CI, 29.6-97.8), and 32.5 months (95% CI, 23.9-49.4), respectively, with no significant difference (log-rank test P=0.22). There was also no significant difference in DFS among stage I patients receiving different TKIs (P=0.12). PSM adjustments and multivariate analyses adjusting for other confounders revealed similar results. In addition, there were no significant differences in treatment failure pattens in different EGFR-TKI arms, especially in terms of brain metastases (6.1% in gefitinb, 7.5% in erlotinib, 3.9% in icotinib) and bone metastases (8.6% in gefitinb, 9.4% in erlotinib, 7.0% in icotinib). Conclusions: This first and largest real-world study showed that gefitinib, erlotinib, and icotinib demonstrated comparable clinical effectiveness as adjuvant therapy for patients with early-stage EGFR mutated NSCLC.