MS1-4 - A Biomarker Analysis of Nivolumab in Previously Treated Advanced Gastric Cancer (WJOG10417GTR).

Nivolumab (anti-PD-1 mAb) is a promising drug that survival benefit has been proven in a phase III trial for advanced gastric cancer in third- or later line treatment. In Japan, nivolumab was approved for unresectable advanced gastric cancer in 2017, and its monotherapy is recommended as the standard treatment in the third or later line treatment in the Gastric Cancer Treatment Guidelines 2018. However, the response rate of the nivolumab monotherapy is only about 10%, and no therapeutic efficacy has been seen in about a half of the treated patients. In addition, pembrolizumab (also anti-PD-1 mAb) failed to show superiority to the weekly-paclitaxel in the Keynote-061 trial for PD-L1-positive (CPS > 1%) advanced gastric cancer. Thus, since the treatment efficacy of blocking PD-1 in gastric cancer is limited, it is urgently necessary for the treatment selection to establish more useful biomarkers. The WJOG10417GTR is a translational research using fresh and unfrozen specimens harvested from gastric cancer patients treated with nivolumab monotherapy. Peripheral blood, endoscopic biopsy samples are collected at 3 time points (before initiating treatment, about 1 month after treatment, and at disease progression), and systems oncoimmunology is being conducted by analyzing gene expression, pathological features of tumor tissues, soluble molecules in plasma, and phenotypes of immune cells by flow cytometry. Then, the relationship between these data and the clinicopathological characteristics including the response to nivolumab will be statistically evaluated. Eleven hospitals are collaborating in this study toward the goal of 100 patient's enrollment in July 2018. Thirty-three patients have been registered until May 2019. [ABSTRACT FROM AUTHOR]