Maria Babak, Associate Professor at City University of Hong Kong, shared The Babak Lab’s post on LinkedIn, adding:
“Isn’t it wonderful how bispecific antibodies are expanding the oncology toolbox?”
The Babak Lab shared:
“A new first-line option for HER2-positive gastroesophageal cancer.
The FDA has approved zanidatamab-hrii (Ziihera) in combination with tislelizumab-jsgr and chemotherapy for adults with HER2-positive, unresectable locally advanced or metastatic gastric, gastroesophageal junction (GEJ), or esophageal adenocarcinoma.
Key Insights
- Zanidatamab is a bispecific HER2 antibody that binds two different sites on the HER2 protein, offering a different approach from single-target HER2 antibodies such as trastuzumab.
- The approval is based on the Phase 3 HERIZON-GEA-01 trial, which compared zanidatamab-based regimens with the trastuzumab + chemotherapy standard.
- In the arm combining zanidatamab + tislelizumab + chemotherapy, median overall survival reached 26.4 months vs 19.2 months with trastuzumab + chemotherapy (HR 0.72).
- Median progression-free survival was 12.4 vs 8.1 months (HR 0.63).
- The regimen is intended for HER2-positive gastric, GEJ, and esophageal adenocarcinoma, making this an important development across several upper GI cancers.
Conclusion
Rather than simply adding another HER2-targeted antibody, this approval introduces a dual-epitope HER2 strategy combined with immunotherapy and chemotherapy, with improved overall and progression-free survival compared with the trastuzumab-based control arm.
You can also read:
10 Gastroesophageal Cancer Trials to Watch at ESMO 2026
