Zymeworks Announces Participation in Upcoming Conferences

• Late-breaking HERIZON-GEA-01 presentation at ASCO GI highlights the expanding clinical profile of Ziihera® across HER2-driven gastrointestinal cancers by partner Jazz

• Zymeworks to present a Trial-in-Progress poster for ZW251, a GPC3-targeting antibody-drug conjugate for hepatocellular carcinoma at ASCO GI

• Management will present at J.P. Morgan Healthcare Conference on January 14 at 3:00 pm Pacific Time (PT)

VANCOUVER, British Columbia, Dec. 02, 2025 (GLOBE NEWSWIRE) -- Zymeworks Inc. (Nasdaq: ZYME) a biotechnology company managing a portfolio of licensed healthcare assets, while developing a diverse pipeline of novel, multifunctional biotherapeutics, today announced participation in the following upcoming conferences.

ASCO Gastrointestinal Cancers Symposium

January 8-10, 2026

San Francisco, CA

Zymeworks Presentation

Partner Presentations

The majority of abstracts accepted to ASCO GI will be released at 2:00 pm PT/ 5:00 pm Eastern Time (ET) on January 5, 2026. Late-breaking abstracts will be released at 7:00 am PT / 10:00 am ET on their day of presentation at the Symposium and made publicly available online at that time.

J.P. Morgan Annual Healthcare Conference

January 12-16, 2026

San Francisco, CA

Zymeworks’ management will participate in one-on-one meetings and a corporate presentation on January 14, 2026, at 3:00 pm PT.

About Zymeworks Inc.

Zymeworks is a global biotechnology company managing a portfolio of licensed healthcare assets and developing a diverse pipeline of novel, multifunctional biotherapeutics to improve the standard of care for difficult-to-treat diseases, including cancer, inflammation, and autoimmune disease. The Company’s asset and royalty aggregation strategy focuses on optimizing positive future cash flows from an emerging portfolio of licensed products such as Ziihera® (zanidatamab-hrii) and other licensed products and product candidates, such as pasritamig. In addition, Zymeworks is also building a portfolio of healthcare assets that can generate strong cash flows, while supporting the early-stage development of innovative medicines. Zymeworks engineered and developed Ziihera® (zanidatamab-hrii), a HER2-targeted bispecific antibody using the Company’s proprietary Azymetric™ technology and has entered into separate agreements with BeOne Medicines Ltd. (formerly BeiGene, Ltd.) and Jazz Pharmaceuticals Ireland Limited granting each exclusive rights to develop and commercialize zanidatamab in different territories. Zymeworks is rapidly advancing a robust pipeline of product candidates, leveraging its expertise in both antibody drug conjugates and multispecific antibody therapeutics targeting novel pathways in areas of significant unmet medical need. The Company’s complementary therapeutic platforms and fully integrated drug development engine provide the flexibility and compatibility to precisely engineer and develop highly differentiated antibody-based therapeutics. These capabilities have been further leveraged through strategic partnerships with global biopharmaceutical companies. For information about Zymeworks, visit www.zymeworks.com and follow @ZymeworksInc on X.

Investor inquiries:

Shrinal Inamdar

Senior Director, Investor Relations

(604) 678-1388

ir@zymeworks.com

Media inquiries:

Diana Papove

Senior Director, Corporate Communications

(604) 678-1388

media@zymeworks.com