Abstract
BACKGROUND: Immune-checkpoint inhibitors (ICI), including nivolumab and pembrolizumab, are among the standard treatments for previously treated advanced gastric cancer (AGC). This study aimed to evaluate the frequency of immune-related adverse events (irAEs) and the correlation between irAEs and their efficacy in AGC cases. PATIENTS AND METHODS: Patients were divided into two groups according to irAE occurrence. The frequency of irAEs and the treatment outcome (response rate [RR], progression-free survival [PFS], and overall survival [OS]) were evaluated. The survival rates were evaluated by landmark analysis considering lead-time bias. RESULTS: Among 108 patients who received nivolumab or pembrolizumab, 17 (15.7%) had irAEs. In a 4-week landmark analysis, the RR, median PFS, and median OS were 28.5%, 3.9 months (95% CI=2.8-9.3), and 12.2 months (95% CI=3.8-NA) in patients with irAEs, while 3.0% (2/65), 1.8 months (95% CI=1.4-2.1), and 3.5 months (95% CI, 2.9-5.1) in patients without irAEs, respectively. In multivariate analysis, irAEs were associated with better PFS (HR=2.08, 95% CI=1.34-3.21). CONCLUSION: The occurrence of irAEs was associated with a better clinical outcome of ICIs in patients with AGC.