Clinical Research Directory

Inclusion Criteria: * Voluntary written informed consent from the participant or their legally authorized representative * At least 18 years of age at the time of signing the consent form * Agreement to use highly effective birth control methods for both male and female patients * WHO-ECOG performance status of 0 or 1 * Histologically proven HER2-positive gastroesophageal, esophageal, or gastric adenocarcinoma * Localized, resectable disease that is fit for perioperative treatment, including surgery * Adequate hepatic function * Adequate renal function with an estimated Glomerular Filtration Rate (GFR) \> 50 mL/min * Adequate hematologic function * Cardiac ejection fraction Exclusion Criteria: * Prior neoadjuvant or definitive chemoradiation * Squamous cell cancer of the esophagus * Metastatic or unresectable gastroesophageal cancer * Active or relapsing autoimmune diseases, with exceptions for controlled Type 1 diabetes, hypothyroidism (hormone replacement only), controlled celiac disease, or certain skin diseases not requiring systemic treatment * Known hypersensitivity to zanidatamab, tislelizumab, or any of their excipients * Known Dihydropyrimidine Dehydrogenase (DPD) deficiency * Active infections requiring systemic treatment * History of significant cardiac disease * Previous malignancy within the last 5 years * Current participation in another interventional Trial involving an investigational medicinal product or device