07:50 AM EST, 11/17/2025 (MT Newswires) -- Zymeworks ( ZYME ) said Monday its phase 3 trial evaluating Ziihera plus chemotherapy as a first-line treatment in gastroesophageal adenocarcinoma showed a statistically significant improvement in progression-free survival compared with trastuzumab and chemotherapy.

Further, Ziihera plus Tevimbra and chemotherapy demonstrated clinically meaningful and statistically significant improvements in overall survival and progression-free survival compared with trastuzumab and chemotherapy, the company said.

The safety profile of Ziihera in combination with chemotherapy, with or without Tevimbra, was generally consistent with the known safety profile of each agent with no new safety signals observed, Zymeworks ( ZYME ) said.

Zymeworks ( ZYME ) said its partner Jazz Pharmaceuticals plans to submit a biologics license application in H1 of 2026 as a first-line treatment for patients with HER2+ locally advanced or metastatic gastroesophageal adenocarcinoma for use as part of a standard chemotherapy regimen.