Cohort 1:~Currently, no PD-1 antibody against gastric cancer have been approved in China, and there are many patients with gastric cancer in China, so effective, low-toxicity and affordable treatment is urgently needed. This study aims to investigate the efficacy of combined application of recombinant human anti-PD-1 monoclonal antibody (HX008) and irinotecan in patients with locally advanced or metastatic gastric cancer (including gastric esophageal junction cancer) ,thus providing a better treatment for Chinese patients with gastric cancer.Advanced gastric adenocarcinoma with failed first-line chemotherapy-line cancer participants, who had failed or were unable to tolerate first line chemotherapy with platinum-based or fluorouracil regimens are needed.~Cohort 2:~Later-line therapies after failure of standard treatments for advanced solid cancer patients are limited. Mismatch repair (MMR) deficiency or microsatellite instability-high (MSI-H) played a role of positive predictive factor, which had been documented after the pembrolizumab and nivolumab trial were reported, for PD-1 blockade monotherapy in patients with advanced solid carcinomas.~In this study, patients with previously-treated locally-advanced or metastatic mismatched repair deficient (dMMR) or microsatellite instability-high (MSI-H) advanced solid tumors will be treated with HX008 monotherapy.Advanced solid tumor participants, who are required to have been previously treated with at least one line of systemic standard of care therapy are needed.
In this study, patients of advanced gastric adenocarcinoma with failed first-line chemotherapy-line or advanced mismatched repair deficient (dMMR) or microsatellite instability-high (MSI-H) advanced solid carcinoma will be treated with HX008 combined with irinotecan and HX008 monotherapy There will be two cohorts in this study: Cohort 1 and Cohort 2. For Cohort 1, advanced gastric adenocarcinoma with failed first-line chemotherapy-line cancer participants, who had failed or were unable to tolerate first line chemotherapy with platinum-based or fluorouracil regimens. For Cohort 2, advanced solid tumor participants, who are required to have been previously treated with at least one line of systemic standard of care therapy.