Immune Checkpoint Inhibitors in Locally Advanced, Unresectable, and Metastatic Upper Gastrointestinal Malignancies.

Abstract

Upper gastrointestinal (UGI) malignancies including esophageal, gastroesophageal junction (GEJ), and gastric cancers have a poor prognosis in the metastatic setting. Treatment with cytotoxic chemotherapy remains the treatment of choice in the first-line setting with the addition of trastuzumab, a monoclonal antibody against HER-2, if the tumor is HER2-positive. Before the era of checkpoint inhibitors, there were only few treatment options after failure of the first-line systemic therapy. We extensively searched the English written literature for peer-reviewed manuscripts regarding the use of checkpoint inhibitors in advanced stage and metastatic UGI cancer. We also searched and reviewed ongoing clinical trials from Clinicaltrials.gov. Checkpoint inhibition is a promising therapeutic option in UGI cancers, which have overexpression of PD-L1, high mutation burden, or microsatellite instability. Checkpoint inhibitors that are being investigated or are approved in advanced UGI malignancies include PD-1 antibodies, nivolumab and pembrolizumab, PD-L1 antibody, avelumab, and CTLA-4 inhibitors, ipilimumab and tremelimumab. Based on recent and ongoing studies, eligible patients who have progressed beyond the first-line cytotoxic chemotherapy may benefit from immunotherapy. This review outlines the checkpoint inhibitors that are currently or previously being investigated for patients with metastatic UGI cancers.