The U.S. Food and Drug Administration has approved the combination of Tevimbra (tislelizumab) and Ziihera (zanidatamab) with chemotherapy as a first-line treatment for adult patients with locally advanced unresectable or metastatic HER2-positive gastric, gastroesophageal junction, or esophageal adenocarcinoma.
The approval was granted to BeOne Medicines Ltd. (NASDAQ: ONC), based in San Carlos, California, following positive results from the HERIZON-GEA-01 Phase 3 trial. The study enrolled 914 patients across approximately 300 research centers in more than 30 countries, comparing the combination regimen against trastuzumab plus chemotherapy.
Primary endpoints showed statistically significant improvements in both progression-free survival and overall survival. Median overall survival reached 26.4 months for the Tevimbra-Ziihera-chemotherapy group, compared with 19.2 months in the control group. Progression-free survival averaged 12.4 months versus 8.1 months, respectively. In patients with PD-L1-negative tumors, median overall survival extended to 29.7 months with the combination, compared to 15.8 months in the control arm.
The treatment demonstrated efficacy across HER2 IHC 3+ and HER2 IHC 2+ patient populations, with no new safety signals identified beyond the known profiles of the individual components. Approximately 20% of patients with gastroesophageal adenocarcinoma present with HER2-positive disease, and over 31,000 new stomach cancer cases are diagnosed annually in the United States.
Tevimbra, developed by Jazz Pharmaceuticals and BeOne under license agreements with Zymeworks, has already been approved in more than 50 countries and administered to over 2 million patients globally. Less than 40% of U.S. patients with advanced HER2-positive disease survive beyond two years, underscoring the unmet need addressed by the approval.
