This is a multi-center, open label, proof-of-principle study for patients with previously untreated metastatic or locally advanced esophagogastric cancer. Patients are sequentially treated with standard of care capecitabine and oxaliplatin, and retifanlimab. Patients are treated with 2 cycles of CapOx (1 cycle is 3 weeks) and sequentially with 4-weekly cycles of retifanlimab up to 2 years. The investigators will include 25 patients in this study.~Biopsies, blood and faeces will be collected during treatment for assessment of infiltrating immune cells and IFNy expression, as well as for other translational research purposes. CT scans are made for evaluation of tumor response before and after chemotherapy, and after 2-3 cycles of immunotherapy.
To investigate the effects of the combination of two chemotherapies followed by immunostimulants on the interferon gamma expression and infiltration of cytotoxic T cells in the tumour microenvironment in patients with previously untreated metastatic or locally advanced esophagogastric cancer.