INDs for multispecific programs, ZW209 and ZW1528, remain on track for submission in 2026, as we continue evaluating partnership opportunities before the commencement of clinical studies; and,
Development of wholly-owned preclinical candidates from our multispecific antibody portfolio to provide for one planned IND filing per annum commencing in 2028.
Ziihera® (zanidatamab-hrii)
Late-breaking HERIZON-GEA-01 clinical data presented at ASCO GI by partner Jazz Pharmaceuticals on January 8, 2026. The study found:
Both investigational arms, Ziihera plus tislelizumab and chemotherapy and Ziihera plus chemotherapy, led to a statistically significant and clinically meaningful prolongation of progression-free survival (PFS) with approximately 35% reduction in the risk of disease progression or death versus trastuzumab plus chemotherapy. This resulted in a median PFS of more than one year, representing a greater than four month improvement compared to the control arm.
Ziihera plus tislelizumab and chemotherapy demonstrated a statistically significant and clinically meaningful overall survival (OS) benefit with a median OS of more than two years (26.4 months), the longest reported in a Phase 3 trial in GEA, representing a greater than seven-month improvement in median OS and a 28% reduction in the risk of death versus trastuzumab plus chemotherapy.
At this first interim analysis, Ziihera plus chemotherapy showed a median OS of more than two years, with a strong trend toward statistical significance, favoring Ziihera plus chemotherapy versus trastuzumab plus chemotherapy. An additional planned OS interim analysis for Ziihera plus chemotherapy is currently expected in mid-2026.
The OS and PFS benefits were generally consistent across major prespecified subgroups including geographic region and PD-L1 status for both investigational arms.
Based on the topline results from HERIZON-GEA-01, Jazz plans to submit a supplemental Biologics License Application in 1H-2026 for zanidatamab in the U.S. as first-line treatment for HER2+ locally advanced or metastatic GEA; and,
Zymeworks has the potential to receive substantial near-term milestone payments related to future anticipated regulatory approvals in GEA totaling $440.0 million, as follows: U.S. - $250.0 million; EU - $100.0 million; Japan - $75.0 million; China - $15.0 million.
Authorized Share Repurchase Program
In November 2025, the Board of Directors authorized a new share repurchase program providing the ability to repurchase up to $125.0 million in common stock. The program underscores our confidence in Zymeworks’ long-term growth prospects and helps enhance shareholder value by reducing share count, while maintaining cash resources for operations and growth investments and preserving financial flexibility for strategic opportunities.
To date, the Company has utilized approximately $19.0 million of this approved repurchase program to acquire 727,271 shares of the Company’s common stock at an average price of $26.07 (exclusive of commission expense and estimated excise tax).