HERIZON-GEA-01: Evaluating Zanidatamab ± Tislelizumab Compared with Trastuzumab + Chemotherapy in HER2-Positive Gastric/GEJ Cancer

This discussion reviews the ongoing HERIZON-GEA-01 trial, a global, randomized Phase 3 study evaluating zanidatamab as a potential first-line treatment for HER2-positive gastric and gastroesophageal junction (GEJ) adenocarcinoma. The trial includes two investigational arms, zanidatamab plus chemotherapy, and zanidatamab combined with tislelizumab and chemotherapy, and compares them with a control regimen of trastuzumab plus chemotherapy. Its primary endpoints are overall survival and progression-free survival, designed to determine whether zanidatamab-based regimens can improve outcomes beyond currently used HER2-directed approaches. The segment also outlines the scientific rationale for zanidatamab’s bispecific HER2 targeting and notes that early clinical studies in other HER2-expressing cancers have shown antitumor activity and a manageable safety profile. With final results still pending, HERIZON-GEA-01 represents an important investigation that may help define future first-line treatment strategies for HER2-positive advanced gastric and GEJ cancers.