Wednesday, February 04, 2026 Exciting results for the use of Zanidatamab in first line treatment for GEA has been presented at the 2026 ASCO GI Symposium. HERIZON-GEA-01 was a global, randomized phase 3 study evaluating zanidatamab plus chemotherapy (with or without PD-1 inhibition) versus trastuzumab plus chemotherapy as first-line treatment for HER2-positive locally advanced unresectable or metastatic GEA. The study results establish zanidatamab as a high-activity HER2-targeted agent in mGEA and support its role as a key component of HER2-directed therapy.Publication: Elimova E, Rha SY, Shitara K, et al. Zanidatamab + chemotherapy (CT) ± tislelizumab for first-line (1L) HER2-positive (HER2+) locally advanced, unresectable, or metastatic gastroesophageal adenocarcinoma (mGEA): primary analysis from HERIZON-GEA-01. J Clin Oncol. 2026, 44(suppl4): LBA285. doi:10.1200/JCO.2026.44.2_suppl.LBA285Impact for CCTG GA.4The positive first-line results from HERIZON-GEA-01 further strengthen the scientific and clinical rationale for evaluating zanidatamab in previously treated mGEA. These findings reinforce the relevance of the GA.4 study A Randomized Phase II Study of Paclitaxel and Ramucirumab +/- Zanidatamab in HER2 Positive Advanced Gastroesophageal Adenocarcinoma — highlighting the opportunity for investigators to offer zanidatamab to patients with mGEA who have already completed first or second-line therapy that does not yet contain zanidatamab. Investigators are encouraged to continue screening patients with mGEA during first-line treatment (until zanidatamab is integrated into routine clinical practice) or during second-line therapy, where trastuzumab deruxtecan remains an available option. Early consenting and screening of potential candidates is strongly encouraged as it allows sufficient time for central HER2 testing and facilitates proactive planning for subsequent lines of therapy based on confirmed HER2 status.
