Perioperative Chemo and Pembrolizumab in Gastric Cancer

This is a non-randomized, multi-site, open-label trial of pembrolizumab and chemotherapy in subjects with gastric or gastroesophageal (GE) junction adenocarcinoma. The purpose of this study is to determine and evaluate the efficacy of combination therapy with immune checkpoint blockade and chemotherapy used in the perioperative period in eradicating micrometastatic disease; and to compare paired tissue and serum samples (pre-treatment and post-treatment) from individually treated patients to explore the immune effects of combination therapy and predictors of response.