ERBB2 and gastroesophageal junction adenocarcinoma: Zolbetuximab is a “first-in-class” chimeric lgG1 monoclonal antibody targeting CLDN 18.2 (16, 17), which is currently being developed for first-line treatment with HER2-negative CLDN 18.2 strongly positive locally advanced unresectable or metastatic G/GEJ adenocarcinoma.