Prognosis of Immune-related Adverse Events in Patients With Advanced Gastric Cancer Treated With Nivolumab or Pembrolizumab: A Multicenter Retrospective Analysis.

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.