CLDN18 and esophageal adenocarcinoma: The MONO study (NCT01197885), a phase II clinical trial, examined the outcome of zolbetuximab (monoclonal antibody against CLDN18.2: IMAB362) monotherapy in a series of patients with recurrent or refractory, locally advanced or metastatic and CLDN18.2‐positive gastric, gastro‐oesophageal junction, or oesophageal adenocarcinoma (Table 3).