Zymeworks Rallies On Positive Phase 3 Results For Ziihera In Gastroesophageal Cancer

(RTTNews) - Shares of Zymeworks Inc. (ZYME) are up over 38.82% at $27.51 in premarket trading on Monday, following positive Phase 3 results from its HERIZON-GEA-01 trial.

HERIZON-GEA-01 is a phase 3 trial evaluating Ziihera (zanidatamab-hrii) in combination with chemotherapy, with or without the PD-1 inhibitor Tevimbra (tislelizumab), as a first-line treatment option for patients with HER2- positive cancers of the stomach, gastroesophageal junction, and esophagus.

Results show that Ziihera plus chemotherapy delivered a meaningful and statistically significant improvement in progression-free survival (PFS) compared to Tevimbra plus chemotherapy.

In addition, Ziihera plus Tevimbra and chemotherapy demonstrated statistically significant improvement in both overall survival (OS) and PFS, reinforcing the drug's potential as a new standard of care in this indication.

Ziihera has received accelerated approval in the U.S., conditional approval in China, and conditional marketing authorization from the European Commission for the treatment of adults with previously treated, unresectable or metastatic HER2-positive (IHC 3+) biliary tract cancer.

Jazz Pharmaceuticals and BeOne Medicines serve as Zymeworks' commercialization partners for Ziihera.

Based on the results, Jazz intends to submit a supplemental Biologics License Application (sBLA) in the first half of 2026 to support Ziihera's use in first-line gastroesophageal adenocarcinoma.

ZYME has traded in the range of $9.03 to $20.17 over the past year.