Regorafenib plus nivolumab in patients with advanced colorectal or gastric cancer: an open-label, dose-finding, and dose-expansion phase 1b trial (REGONIVO, EPOC1603)

2Division of Cancer Immunology, Exploratory Oncology Research and Clinical Trial Center, National Cancer Center Hospital East, Kashiwa, Japan 3Department of Gastroenterology, Saitama Cancer Center, Kitaadachi, Japan 4National Cancer Center Hospital East, Kashiwa, Japan 5National Cancer Center Hospital East, Kashiwa-shi, Japan 6Saitama Cancer Center, Saitama, Japan 7Department of Gastroenterology and Gastrointestinal Oncology, National Cancer Center Hospital East, Kashiwa, Japan 8National Cancer Center, Kashiwa, Japan 9Clinical Research Support Office, National Cancer Center Hospital East, Kashiwa, Japan 10Clinical Research Support Office, National Cancer Center Hospital East, Kashiwa-city, Japan 11National Cancer Center, Kashiwa, Japan