Perioperative Zanidatamab and Chemotherapy for HER2 Positive Gastroesophageal Cancer

Perioperative Zanidatamab Combined With Chemotherapy in Operable HER2 Positive Locally Advanced Operable Gastroesophageal Adenocarcinoma (GEA): A Phase 1b/2a Single-Arm Trial

The HER-OIC clinical trial is a Phase 1b/2a study investigating a new combination of treatments for patients with HER2-positive gastroesophageal cancer. Standard treatment for localized gastroesophageal cancer usually involves chemotherapy before and after surgery. This study aims to see if adding targeted therapy (zanidatamab) and immunotherapy (tislelizumab) to standard chemotherapy is safe and effectively eliminates the tumor. The goal is to improve the pathological complete response (pCR) rate, which is the percentage of patients who have no visible cancer cells remaining in the tissue removed during surgery.

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