'Practice-Changing' Data Expand Zanidatamab's Approval to Gastroesophageal Cancer

On 25 August 2026 the FDA approved zanidatamab (Ziihera) in the first-line treatment of unresectable locally advanced or metastatic HER2-positive gastric, gastro-oesophageal junction and oesophageal adenocarcinoma. In the registration trial HERIZON-GEA-01 (NCT05152147) the zanidatamab plus tislelizumab regimen extended median overall survival to 26.4 versus 19.2 months (HR 0.72; 95% CI 0.57-0.90; p=0.0043) and median progression-free survival to 12.4 versus 8.1 months (HR 0.63; 95% CI 0.51-0.78; p<0.0001). The approval covers two regimens: with tislelizumab for HER2 IHC 3+ or IHC 2+/ISH+, and without tislelizumab for IHC 3+.