Aim: Nivolumab has survival benefit in patients with previously treated advanced gastric cancer; however, about 60% of the patients did not respond to nivolumab, raising the necessity of its predictive biomarkers. Gut microbiome has been shown to be associated with efficacy of anti-PD-1 antibody in various types of cancers, but little is known about gastric cancer. Design: This is an observational/translational study to evaluate clinical outcomes of nivolumab and to discover novel immune-related biomarkers (gut microbiome, genetic polymorphism, gene expression and metabolome in plasma) in gastric cancer, using fecal and blood samples at two points before and after treatment. Candidate factors will be explored in first 200 patients and then validated in last 300 patients. Trial registration: UMIN000030850.
Keywords: gastric cancer; gut microbiome; nivolumab; predictive marker.