Pembrolizumab (Mk-3475) For Previously Treated Metastatic Adenocarcinoma Or Squamous Cell Carcinoma Of The Esophagus: Phase Ii Keynote-180 Study.

TPS189 Background: PD-L1 is frequently overexpressed in esophageal cancer. Pembrolizumab is a humanized monoclonal antibody that targets the PD-1 receptor and blocks interaction with PD-L1 and PD-L2. In the multicohort, phase Ib KEYNOTE-028 trial, pembrolizumab showed manageable toxicity, a 30.4% ORR, and median duration of response of 40 wk in 23 patients (pts) with PD-L1+ advanced esophageal cancer. The single-arm, multicenter phase II KEYNOTE-180 trial is designed to further evaluate pembrolizumab as a monotherapy in pts with previously treated advanced/metastatic esophageal cancer. Methods: Key eligibility criteria include age ≥ 18 y, advanced/metastatic adenocarcinoma or squamous cell carcinoma of the esophagus or advanced/metastatic Siewert type I adenocarcinoma of the esophagogastric junction (EGJ), measurable disease, documented progression during or after 2 prior lines of therapy, ECOG PS 0-1, no active autoimmune disease or brain metastases, and provision of a tumor sample for retrospective biom...