Overview
Metastatic esophagogastric cancer (mEGC) is a lethal disease with poor long-term survival. Recent studies have established anti-PD-1 therapy in combination with chemotherapy as the standard of care for first-line therapy for mEGC. KeyLargo (NCT03342937 [1]) was a single-arm phase II study of pembrolizumab in combination with oxaliplatin and capecitabine in the first-line treatment of patients with HER2 negative mEGC. While high response rates were noted, not all patients received benefits, emphasizing the need for better biomarkers. Paired tumor biopsies and plasma were longitudinally collected, processed, and stored for optimal biomarker testing. In this retrospective study, we employed a novel, tumor-informed ctDNA approach for longitudinal disease monitoring and dynamic tumor evolution.
