What Was Approved?
On August 25, 2026, the FDA approved zanidatamab-hrii (Ziihera) in combination with chemotherapy as a first-line treatment for certain adults with HER2-positive advanced gastric, gastroesophageal junction, or esophageal adenocarcinoma.
For some patients, Ziihera is also approved in combination with tislelizumab-jsgr (Tevimbra) and chemotherapy.
Who Is This Treatment For?
The approval applies to adults with:
- HER2-positive disease
- Unresectable locally advanced or metastatic cancer
- Gastric, gastroesophageal junction, or esophageal adenocarcinoma
HER2 status must be confirmed with an FDA-approved test.
Why Is This Important?
This approval gives patients with HER2-positive advanced gastrointestinal cancer another first-line treatment option.
In the HERIZON-GEA-01 trial, the combination of Ziihera, Tevimbra, and chemotherapy improved both progression-free survival and overall survival compared with the control treatment.
What Are the Main Safety Concerns?
Ziihera has important safety warnings, including risks related to:
- Diarrhea
- Embryo-fetal toxicity
- Heart function
- Infusion-related reactions
Tevimbra also carries warnings for immune-related adverse reactions and infusion reactions.
What Should Patients Know?
This treatment is not appropriate for every patient with gastric or esophageal cancer.
Treatment depends on factors such as:
- HER2 test results
- Cancer type and stage
- Previous treatment
- Overall health
- Other medications
Patients should discuss treatment options with their oncology team.
Bottom Line
The FDA’s August 25, 2026 approval expands first-line treatment options for certain adults with HER2-positive advanced gastric, gastroesophageal junction, or esophageal adenocarcinoma.
Source
U.S. Food and Drug Administration — FDA approval announcement, August 25, 2026.