On March 18, 2026 Zymeworks Inc. (Nasdaq: ZYME), a biotechnology company managing a portfolio of licensed healthcare assets while developing a diverse pipeline of novel, multifunctional biotherapeutics, reported that the company’s partner, Jazz Pharmaceuticals, will present four abstracts featuring data from clinical trials evaluating Ziihera (zanidatamab-hrii) at the American Association for Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting, being held April 17-22, 2026 in San Diego, CA.
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"We are pleased to see the continued clinical progress of zanidatamab reflected in multiple presentations at AACR (Free AACR Whitepaper)," said Ken Galbraith, Chair, Chief Executive Officer, and Interim Chief Financial Officer of Zymeworks. "These studies highlight emerging data evaluating zanidatamab across tumor types beyond biliary tract cancer and gastroesophageal adenocarcinoma, and contribute to the growing body of evidence supporting its potential across HER2-expressing cancers."
Highlights at the AACR (Free AACR Whitepaper) Annual Meeting include:
An oral presentation with results from the Phase 2 single-arm, open-label NeoZanHER trial (NCT05035836) evaluating zanidatamab for the investigational use as neoadjuvant monotherapy in patients with early-stage HER2+ breast cancer. At six weeks, zanidatamab treatment resulted in a statistically significant decrease in tumor size and volume from baseline, and 30% of patients (n=6) achieved pathologic complete response (pCR). Treatment with zanidatamab was manageable with no new safety signals.
A poster presentation detailing mechanistic and multi-omics analyses characterizing zanidatamab’s differentiated HER2 biology, including dual, domain-specific binding and downstream effects on key cellular signaling pathways, with insights into activity in models following progression on trastuzumab deruxtecan (T-DXd).
Additional presentations further explore zanidatamab’s utility across HER2-expressing solid tumors and within innovative biomarker-driven clinical trial designs, including adaptive organ-preservation strategies in gastroesophageal adenocarcinoma.
Oral Presentation
Title: A Phase 2 Single-Arm Open-Label Trial Evaluating Zanidatamab in Patients with Early Stage HER2 positive Breast Cancer: The NeoZanHER Study
Presentation Number: CT012
Session: Clinical Trials Minisymposium: Aiming for Cure: Perioperative Clinical Trials
Date/Time: Saturday, April 18, 2026 at 12:30 – 2:30 pm Pacific Standard Time (PST)
Poster Presentations
Title: Zanidatamab Modulates Multiple Pathways Involved in Tumor Growth and Survival is Efficacious Post-T-DXd
Abstract: 452
Session: Experimental and Molecular Therapeutics: Next-Generation Targeted Therapies Directed Against Tumor Surface Antigens
Date/Time: Tuesday, April 21, 2026 at 9:00 am – 12:00 pm PST
Title: DiscovHER PAN-206: Phase 2 Tumor-Agnostic Study of Zanidatamab in Patients With Previously Treated Human Epidermal Growth Factor Receptor 2–Overexpressing Solid Tumors
Abstract: CT209
Session: Phase II and Phase III Clinical Trials in Progress
Date/Time: Tuesday, April 21, 2026 at 9:00 am – 12:00 pm PST
Title: AACR (Free AACR Whitepaper) Adaptive Biomarker-Driven Organ Preservation Trial in GE Adenocarcinomas (AACR-ADOPT-GEA)
Abstract: CT223
Session: Phase II and Phase III Clinical Trials in Progress
Date/Time: Tuesday, April 21, 2026 at 9:00 am – 12:00 pm PST
The AACR (Free AACR Whitepaper) abstracts are available at View Source!/21436.
About Ziihera (zanidatamab-hrii)
Ziihera (zanidatamab-hrii) is a bispecific HER2-directed antibody that binds to two extracellular sites on HER2. Binding of zanidatamab-hrii with HER2 results in internalization leading to a reduction in HER2 expression of the receptor on the tumor cell surface. Zanidatamab-hrii induces complement-dependent cytotoxicity (CDC), antibody-dependent cellular cytotoxicity (ADCC), and antibody-dependent cellular phagocytosis (ADCP). These mechanisms result in tumor growth inhibition and cell death in vitro and in vivo. In the United States, Ziihera is indicated for the treatment of adults with previously treated, unresectable or metastatic HER2-positive (IHC 3+) biliary tract cancer (BTC), as detected by an FDA-approved test.1 The FDA granted accelerated approval for this indication based on overall response rate and duration of response. Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial(s).1
Zanidatamab is being developed in multiple clinical trials as a targeted treatment option for patients with solid tumors that express HER2. Zanidatamab is being developed by Jazz and BeOne under license agreements from Zymeworks, which first developed the molecule.
The FDA granted two Breakthrough Therapy designations for zanidatamab’s development: one as a single agent for previously treated HER2 gene-amplified BTC, and one in combination with standard-of-care chemotherapy for first-line HER2+ locally advanced or metastatic GEA. The FDA also granted two Fast Track designations for zanidatamab: one as a single agent for refractory BTC and one in combination with standard-of-care chemotherapy for first-line GEA. Additionally, zanidatamab has received Orphan Drug designations from the FDA for the treatment of BTC, gastric (including gastroesophageal junction) cancer, and esophageal cancer, as well as Orphan Drug designations from the European Medicines Agency for the treatment of BTC, gastric/gastroesophageal junction cancer and oesophageal cancer.
The full U.S. Prescribing Information for Ziihera, including BOXED Warning, is available at: View Source
(Press release, Zymeworks, MAR 18, 2026, View Source [SID1234663730])