Ziihera® (zanidatamab-hrii) Combinations Achieve Unprecedented Results in First-Line HER2+ Locally Advanced or Metastatic GEA including more than Two Years Median Overall Survival Benefit
01/06/2026 01:34 PM • Zymeworks announced positive Phase 3 HERIZON-GEA-01 results for Ziihera (zanidatamab-hrii) in combination with chemotherapy, with or without tislelizumab, for first-line treatment of HER2-positive gastroesophageal adenocarcinoma. The trial demonstrated statistically significant improvements in progression-free survival (approximately 35% risk reduction) and overall survival (26.4 months median, representing a 7+ month improvement over trastuzumab). Zymeworks is eligible to receive up to $440 million in milestone payments from regulatory approvals across major markets.
ZYME - Positive Phase 3 trial results demonstrating significant clinical benefits (7+ month OS improvement, longest reported in GEA Phase 3 trials), potential to become new standard of care, and substantial near-term milestone payments ($440M) from partners Jazz and BeOne across major markets (US, Europe, Japan, China). Results validate the company's Azymetric platform technology.