Zymeworks (ZYME) Soars on Positive Phase 3 Ziihera Data in Gastric Cancer – What Today’s Breakthrough Means for the Stock and Patients
What Zymeworks Announced Today Before the U.S. market open on November 17, 2025, Vancouver‑based Zymeworks Inc. (ZYME) released topline Phase 3 data from its pivotal HERIZON‑GEA‑01 study, evaluating Ziihera (zanidatamab‑hrii) in first‑line treatment of HER2‑positive locally advanced or metastatic gastroesophageal adenocarcinoma, a group that includes cancers of the stomach, gastroesophageal junction, and esophagus. GlobeNewswire+1 The trial compared three regimens: According to Zymeworks and its partners Jazz Pharmaceuticals and BeOne Medicines, HERIZON‑GEA‑01 delivered several key findings: GlobeNewswire+2GlobeNewswire+2 On the back of these data, Jazz plans to: GlobeNewswire+1 For Zymeworks, which originally discovered Ziihera using its Azymetric™ bispecific antibody platform, the company