Get ready for a groundbreaking development in the world of oncology! Jazz Pharmaceuticals is set to unveil pivotal phase 3 results for Ziihera® (zanidatamab-hrii) combinations at the 2026 ASCO Gastrointestinal Cancers Symposium. This presentation will showcase the expanding clinical profile of Ziihera across HER2-driven gastrointestinal cancers, offering a glimmer of hope for patients battling these aggressive diseases. But here's where it gets controversial: Jazz believes these results could establish Ziihera as the new standard of care for HER2+ first-line metastatic gastroesophageal adenocarcinoma (GEA).
The HERIZON-GEA-01 trial, conducted with BeOne Medicines, evaluated Ziihera in combination with chemotherapy, with or without the PD-1 inhibitor Tevimbra® (tislelizumab), as a first-line treatment for HER2+ locally advanced or metastatic GEA. The results demonstrated highly statistically significant improvements in progression-free survival (PFS) compared to the control arm, trastuzumab plus chemotherapy. Additionally, Ziihera plus tislelizumab and chemotherapy showed clinically meaningful improvements in overall survival (OS), with a strong trend towards statistical significance for OS compared to the control arm.
Jazz Pharmaceuticals will host an investor webcast on Friday, January 9, 2026, to review these exciting data. The webcast will feature commentary from senior management and Dr. Geoffrey Ku, an associate attending physician at Memorial Sloan Kettering Cancer Center. Access the webcast via the Investors section of the Jazz Pharmaceuticals website at www.jazzpharmaceuticals.com.
The presentation details for the symposium can be found online and include:
- Zanidatamab (zani) + chemotherapy (chemo) ± tislelizumab (tisle) for first-line (1L) HER2-positive (HER2+) advanced/metastatic gastroesophageal adenocarcinoma (mGEA): first results from the phase 3 HERIZON-GEA-01 study
- Landmark analysis of overall survival (OS) by objective response in patients (pts) with previously treated, advanced HER2-positive biliary tract cancer (BTC): post hoc analysis of the HERIZON-BTC-01 trial
GEA, including cancers of the stomach, gastroesophageal junction, and esophagus, is a prevalent and aggressive cancer with a poor prognosis. Approximately 20% of patients have HER2+ disease, and the overall survival rate for GEA remains dismally low at less than 30% for gastric cancer and about 19% for GEA. Biliary tract cancer (BTC), which includes gallbladder cancer and cholangiocarcinoma, is also rare and aggressive, often associated with a poor prognosis. BTCs are typically diagnosed at an advanced stage, limiting treatment options to chemotherapy and, more recently, immunotherapy-based combinations.
HER2 overexpression or amplification defines a distinct molecular subtype of BTC, observed in approximately 26% of patients globally. HER2-positive BTC is associated with a worse prognosis than HER2-negative disease. Ziihera® (zanidatamab-hrii) is a bispecific HER2-directed antibody that binds to two extracellular sites on HER2, leading to a reduction in HER2 expression on the tumor cell surface. In the United States, Ziihera is indicated for the treatment of adults with previously treated, unresectable or metastatic HER2-positive (IHC 3+) BTC. The FDA granted accelerated approval for this indication based on overall response rate and duration of response.
However, it's important to note the safety information for ZIIHERA. Exposure to ZIIHERA during pregnancy can cause embryo-fetal harm, and left ventricular dysfunction can occur. Infusion-related reactions and severe diarrhea are also potential adverse reactions. The full U.S. Prescribing Information for ZIIHERA is available at https://pp.jazzpharma.com/pi/ziihera.en.USPI.pdf.
Jazz Pharmaceuticals is dedicated to developing life-changing medicines for patients with serious diseases. With a diverse portfolio of marketed medicines and a growing portfolio of cancer treatments, Jazz is committed to advancing innovative therapeutics in oncology and neuroscience. For more information, visit www.jazzpharmaceuticals.com.
This press release contains forward-looking statements, including statements related to the potential therapeutic benefits of Ziihera and its potential as a new standard of care. These statements are subject to risks and uncertainties, which could cause actual results to differ materially. Please refer to Jazz Pharmaceuticals' Securities and Exchange Commission filings and reports for more information on these risks and uncertainties.
For media inquiries, please contact Kristin Bhavnani, Head of Global Corporate Communications, at CorporateAffairsMediaInfo@jazzpharma.com or +353 1 637 2141 (Ireland) or +1 215 867 4948 (U.S.). For investor inquiries, please contact Jack Spinks, Executive Director of Investor Relations, at InvestorInfo@jazzpharma.com or +353 1 634 3211 (Ireland) or +1 650 496 2717 (U.S.).
