Jazz Pharmaceuticals to Present Pivotal Phase 3 Results of Ziihera® (zanidatamab-hrii) Combinations in First-Line HER2-Positive Locally Advanced or Metastatic Gastroesophageal Adenocarcinoma at the 2026 ASCO Gastrointestinal Cancers Symposium

Rhea-AI Summary

Jazz Pharmaceuticals (NASDAQ: JAZZ) announced that Phase 3 HERIZON-GEA-01 results for Ziihera (zanidatamab-hrii) combinations in first-line HER2-positive locally advanced or metastatic gastroesophageal adenocarcinoma will be presented as a late-breaking oral abstract at ASCO GI, Jan 8–10, 2026. The release notes highly statistically significant, clinically meaningful improvements in progression-free survival (PFS) for both Ziihera regimens versus trastuzumab plus chemotherapy, and statistically significant overall survival (OS) improvement for Ziihera plus tislelizumab and chemotherapy; Ziihera plus chemotherapy showed a clinically meaningful OS effect with a strong trend toward significance. A post-hoc OS analysis from HERIZON-BTC-01 in previously treated HER2+ biliary tract cancer will also be presented. Jazz will host an investor webcast on Jan 9, 2026 to review the data.

Positive

• Late-breaking Phase 3 HERIZON-GEA-01 oral presentation at ASCO GI Jan 8, 2026
• PFS improvements highly statistically significant for both Ziihera regimens versus control
• OS statistically significant for Ziihera + tislelizumab + chemotherapy
• Investor webcast scheduled Jan 9, 2026 to review trial data

Negative

• OS for Ziihera + chemotherapy only showed a trend, not definitive statistical significance at first analysis

News Market Reaction – JAZZ

+0.23%

1 alert

+0.23% News Effect

On the day this news was published, JAZZ gained 0.23%, reflecting a mild positive market reaction.

Data tracked by StockTitan Argus on the day of publication.

Key Figures

ASCO GI dates: January 8–10, 2026 Investor webcast date: January 9, 2026 Webcast time PT: 6:30 a.m. PT +5 more

8 metrics

ASCO GI dates January 8–10, 2026 2026 ASCO Gastrointestinal Cancers Symposium in San Francisco

Investor webcast date January 9, 2026 Webcast to review Ziihera data from ASCO GI

Webcast time PT 6:30 a.m. PT Scheduled start time for investor webcast

Webcast time ET 9:30 a.m. ET Scheduled start time for investor webcast

HERIZON-GEA-01 phase Phase 3 First-line HER2+ locally advanced or metastatic GEA trial

HERIZON-BTC-01 phase Phase 2b Previously treated HER2+ biliary tract cancer trial

Late-breaking abstract number LBA285 HERIZON-GEA-01 oral presentation at ASCO GI

BTC poster abstract 545 HERIZON-BTC-01 post hoc OS analysis poster

Market Reality Check

Price: $183.63 Vol: Volume 1,063,222 is at 0....

low vol

$183.63 Last Close

Volume Volume 1,063,222 is at 0.66x the 20-day average of 1,608,772, indicating subdued trading relative to recent norms. low

Technical Shares at $164.89 are trading above the 200-day MA of $125.76 and about 9.89% below the 52-week high of $182.99.

Peers on Argus

Peers in Biotechnology show mixed, mostly modest moves (e.g., CORT +2.11%, LEGN ...

Peers in Biotechnology show mixed, mostly modest moves (e.g., CORT +2.11%, LEGN -1.88%), suggesting this Jazz update is more stock-specific than sector-driven.

Historical Context

5 past events · Latest: Dec 09 (Positive)

Pattern 5 events

Date	Event	Sentiment	Move	Catalyst
Dec 09	Sleep disorder data	Positive	-4.0%	Phase 4 DUET data and real-world Xywav sleep outcomes at conferences.
Dec 05	Epilepsy data update	Positive	+2.0%	Multiple Epidiolex abstracts and real-world evidence in treatment‑resistant epilepsies.
Dec 02	HER2 GEA trial data	Positive	+0.2%	Announcement of late‑breaking ASCO GI slot and positive HERIZON‑GEA‑01 results.
Nov 18	Conference participation	Neutral	-2.5%	Citi Global Healthcare Conference fireside chat disclosure and webcast details.
Nov 17	Top-line Phase 3 data	Positive	+20.6%	Positive HERIZON‑GEA‑01 results and stated plans for U.S. sBLA submission.

Pattern Detected

Jazz has generally seen positive alignment between strong clinical data and share price, though some scientific/medical data presentations have coincided with short-term pullbacks.

Recent Company History

Over the last several months, Jazz has highlighted multiple R&D and medical meeting milestones. Positive Phase 3 HERIZON-GEA-01 top-line results on Nov 17, 2025 drove a 20.57% gain, contrasting with a -3.95% move after Phase 4 Xywav data at World Sleep 2025. Epilepsy data for Epidiolex on Dec 5, 2025 was followed by a 1.99% rise. Today’s ASCO GI late-breaking presentation fits into this pattern of leveraging HER2+ oncology data and prior HERIZON-GEA-01 disclosures to reinforce the Ziihera clinical narrative.

Market Pulse Summary

This announcement highlights detailed Phase 3 HERIZON‑GEA‑01 and Phase 2b HERIZON‑BTC‑01 results for...

Analysis

This announcement highlights detailed Phase 3 HERIZON‑GEA‑01 and Phase 2b HERIZON‑BTC‑01 results for Ziihera combinations in HER2‑driven gastrointestinal cancers, including a late‑breaking ASCO GI oral slot and a post‑hoc overall survival analysis. It builds on prior disclosures that showed statistically significant PFS and OS benefits versus trastuzumab‑based therapy. Investors following Jazz may focus on the depth of efficacy and survival data, safety profile, and upcoming regulatory milestones around these regimens.

Key Terms

her2-positive, progression-free survival (pfs), overall survival (os), phase 3, +4 more

8 terms

her2-positive medical

"first-line HER2-positive (HER2+) locally advanced or metastatic gastroesophageal"

HER2-positive describes cancer cells that have too many copies of the HER2 gene or make too much of the HER2 protein, which acts like an overactive growth switch that drives tumor growth. For investors, HER2 status matters because it determines whether patients can receive specific, often expensive targeted therapies and diagnostic tests, so trial results, approvals, or competing drugs tied to HER2 can strongly affect drug sales and company value.

progression-free survival (pfs) medical

"improvements in progression-free survival (PFS) compared to the control arm"

Progression-free survival (PFS) measures the length of time in a clinical trial or treatment period during which a patient’s disease does not get worse. Investors watch PFS because longer PFS in trials can signal a drug’s effectiveness, influence regulatory approval and reimbursement decisions, and affect commercial value—think of it as how long a product keeps a problem from returning, which helps estimate future sales and competitive advantage.

overall survival (os) medical

"also demonstrated clinically meaningful and statistically significant improvements in overall survival (OS)"

Overall survival (OS) is the length of time from the start of a treatment or clinical study until death from any cause, essentially measuring how long patients live after a therapy begins. Investors watch OS because it is the most direct evidence a treatment extends life; stronger OS results can drive regulatory approvals, wider use and higher revenue expectations, much like sales figures proving a product actually works.

phase 3 medical

"The Phase 3 HERIZON-GEA-01 trial, conducted jointly with BeOne Medicines, is"

Phase 3 is the late-stage clinical testing step for a new drug or medical treatment, where the product is given to large groups of patients to confirm effectiveness, monitor side effects, and compare it to standard care. Successful Phase 3 results are often the final scientific hurdle before regulators decide on approval and market launch—like passing a final exam before graduation—and can sharply change a company's valuation and future revenue prospects.

phase 2b medical

"HERIZON-BTC-01 Phase 2b trial in previously treated HER2+ biliary tract cancer"

Phase 2b is a stage in the development of a new medicine or treatment where researchers test its effectiveness and safety in a larger group of people. This step helps determine whether the treatment works well enough to move forward and if it has manageable side effects, which is important for investors because successful results can lead to potential approval and market opportunity.

pd-1 inhibitor medical

"with or without the PD-1 inhibitor Tevimbra® (tislelizumab), as first-line treatment"

A PD-1 inhibitor is a type of medicine that helps the immune system recognize and attack cancer cells by blocking the PD-1 checkpoint—a molecular “off switch” that cancer can use to hide from immune defenses. For investors, these drugs matter because they can transform treatment options, drive sales or partnerships, and affect a company’s valuation if clinical trials, approvals, or competitive positioning change; think of them as unlocking a locked door to let the body’s defenses work.

post hoc analysis medical

"biliary tract cancer (BTC): post hoc analysis of the HERIZON-BTC-01 trial"

Post hoc analysis is an exploratory look at data carried out after a study or trial is finished to search for patterns or effects that were not specified beforehand. Because it’s done after seeing the results, findings can arise by chance and are less reliable than preplanned tests; investors should treat post hoc claims as hypothesis-generating signals that may need confirmatory studies or regulatory review before they meaningfully affect a company’s value.

late-breaking abstract technical

"were accepted as a late-breaking presentation. Additionally, a new post-hoc"

A late-breaking abstract is a short summary of new clinical or scientific data submitted and accepted for presentation at a medical or scientific conference after the usual submission deadline. Investors watch these because they often contain fresh, potentially market-moving results—like seeing the final score of a game released just before kickoff—so they can change expectations about a drug’s safety, effectiveness, or commercial prospects.

AI-generated analysis. Not financial advice.

Late-breaking HERIZON-GEA-01 presentation highlights the expanding clinical profile of Ziihera across HER2-driven gastrointestinal cancers

Jazz to host investor webcast on Friday, January 9, 2026, to review data

For U.S. media and investors only

DUBLIN, Dec. 2, 2025 /PRNewswire/ -- Jazz Pharmaceuticals plc (Nasdaq: JAZZ) today announced two abstracts featuring key data for Ziihera^® (zanidatamab-hrii) have been accepted for presentation at the American Society of Clinical Oncology Gastrointestinal Cancers Symposium (ASCO GI) from January 8-10, 2026, in San Francisco. The Phase 3 HERIZON-GEA-01 trial results in first-line HER2-positive (HER2+) locally advanced or metastatic gastroesophageal adenocarcinoma (GEA) were accepted as a late-breaking presentation. Additionally, a new post-hoc overall survival (OS) analysis from the HERIZON-BTC-01 Phase 2b trial in previously treated HER2+ biliary tract cancer (BTC) will be presented, providing further information for this approved indication.

"We look forward to sharing the clinically meaningful results from the Phase 3 HERIZON-GEA-01 trial with the oncology community at ASCO GI," said Rob Iannone, M.D., M.S.C.E., executive vice president, global head of research and development, and chief medical officer of Jazz Pharmaceuticals. "Advanced HER2+ GEA, which includes cancers of the stomach, gastroesophageal junction and esophagus, remains an aggressive cancer with a poor prognosis and continues to be an area with limited progress for patients. This trial was designed to evaluate whether Ziihera plus chemotherapy, with or without tislelizumab, could improve on the current standard of care in first-line therapy. We believe these positive results support Ziihera as the HER2-targeted agent-of-choice and the Ziihera combinations to become the new standard of care for patients with HER2+ first-line metastatic GEA regardless of PD-L1 status. Alongside new analyses from the HERIZON-BTC-01 Phase 2b trial, these presentations highlight the continued impact of our broad zanidatamab clinical program and our commitment to advancing innovation across HER2-targeted cancers."

The Phase 3 HERIZON-GEA-01 trial, conducted jointly with BeOne Medicines, is evaluating Ziihera in combination with chemotherapy, with or without the PD-1 inhibitor Tevimbra^® (tislelizumab), as first-line treatment for HER2+ locally advanced or metastatic GEA. As previously announced, both Ziihera plus chemotherapy and Ziihera plus tislelizumab and chemotherapy demonstrated highly statistically significant and clinically meaningful improvements in progression-free survival (PFS) compared to the control arm, trastuzumab plus chemotherapy. Ziihera plus tislelizumab and chemotherapy also demonstrated clinically meaningful and statistically significant improvements in overall survival (OS), and Ziihera plus chemotherapy demonstrated a clinically meaningful effect with a strong trend toward statistical significance for OS compared to the control arm at the time of this first analysis.

Jazz Pharmaceuticals will host an investor webcast on Friday, January 9, at 6:30 a.m. PT/ 9:30 a.m. ET to review the Ziihera data presented at the meeting. The webcast will include commentary from the company's senior management and Dr. Geoffrey Ku, Associate Attending physician on the Gastrointestinal Oncology Service in the Department of Medicine at Memorial Sloan Kettering Cancer Center. The webcast may be accessed from the Investors section of the Jazz Pharmaceuticals website at www.jazzpharmaceuticals.com. To ensure a timely connection, it is recommended that participants register at least 15 minutes prior to the scheduled webcast.

A replay of the webcast will be available via the Investors section of the Jazz Pharmaceuticals website.

Details for both presentations can be found online and below:

Presentation Title	Authors	Presentation Details
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	Elena Elimova, Sun Young Rha, Kohei Shitara, Tianshu Liu, Josep Tabernero, Keun-Wook Lee, Michael Schenker, Niall Tebbutt, Jaffer Ajani, Norhidayu Bt Salimin, Geoffrey Ku, Jong Gwang Kim, Inmaculada Ales Diaz, Jingdong Zhang,  Filippo Pietrantonio, Li-Yuan Bai, Samuel Le Sourd, Ye Chen, Jonathan Grim, Lin Shen, on behalf of the HERIZON-GEA-01 study group	Type: Late-Breaking Abstract Oral Presentation Session: Oral Abstract Session A: Cancers of the Esophagus and Stomach Date: Thursday, Jan. 8, 8:57- 9:07 a.m. PST Abstract number: LBA285
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	James J Harding, Jia Fan, Do-Youn Oh, Hye Jin Choi, Jin Won Kim, Heung-Moon Chang, Lequn Bao, Hui-Chuan Sun, Teresa Macarulla, Feng Xie, Jean- Philippe Metges, Jie'er Ying, John Bridgewater, Harpreet Singh Wasan, Michel Pierre Ducreux, Zinan Bao, Phillip M Garfin, Douglas S Fuller, Parveen Jayia, Shubham Pant	Type: Poster Session Session: Poster Session B: Cancers of the Pancreas, Small Bowel, and Hepatobiliary Tract Date: Friday, Jan. 9, 11:30 a.m.-1:00  p.m. PST Abstract number: 545

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

About Gastroesophageal Adenocarcinoma  
GEA, including cancers of the stomach, gastroesophageal junction, and esophagus, is the fifth most common cancer worldwide, and approximately 20% of patients have HER2+ disease.^1,2,3 HER2+ GEA has high morbidity and mortality, and patients are urgently in need of new treatment options. The overall prognosis for patients with GEA remains poor, with a global five-year survival rate of less than 30% for gastric cancer and about 19% for GEA.⁴

About Biliary Tract Cancer
BTC, which includes gallbladder cancer and intrahepatic and extrahepatic cholangiocarcinoma, are rare and aggressive epithelial tumors often associated with poor prognosis.^5,6 Although they account for less than 1% of all human cancers, cholangiocarcinoma is the second most common primary liver cancer after hepatocellular carcinoma and comprises approximately 10–15% of all primary liver cancers. Global mortality from BTC has risen in recent decades.⁷

Because early symptoms are often vague or nonspecific, most BTCs are diagnosed at an advanced stage,⁸ when curative surgery is not an option.^6,9,10 While chemotherapy and, more recently, immunotherapy-based combinations are used in the first-line setting, disease progression is common. In the absence of molecular profiling, treatment options following first-line therapy are largely limited to chemotherapy.^7,9,11

HER2 overexpression or amplification defines a distinct molecular subtype of BTC¹² and is observed in approximately 26% of patients globally.¹³ HER2-positive BTC is associated with worse prognosis than HER2-negative disease.¹⁴ Across the U.S., Europe, and Japan, an estimated 12,000 people are diagnosed with HER2-positive BTC each year.¹⁵

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.¹⁶ In the United States, Ziihera is indicated for the treatment of adults with previously treated, unresectable or metastatic HER2-positive (IHC 3+) BTC, as detected by an FDA-approved test.16 The U.S. 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).¹⁶ 

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 Pharmaceuticals and BeOne Medicines under license agreements from Zymeworks Inc., which first developed the molecule.   

The FDA granted Breakthrough Therapy designation for zanidatamab's development in patients with previously treated HER2 gene-amplified BTC, and 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 and GEA, as well as Orphan Drug designation from the European Medicines Agency for the treatment of BTC and gastric cancer.   

 Important Safety Information for ZIIHERA   

WARNING: EMBRYO-FETAL TOXICITY  Exposure to ZIIHERA during pregnancy can cause embryo-fetal harm. Advise patients  of the risk and need for effective contraception.

WARNINGS AND PRECAUTIONS 

Embryo-Fetal Toxicity
ZIIHERA can cause fetal harm when administered to a pregnant woman. In literature reports, use of a HER2-directed antibody during pregnancy resulted in cases of oligohydramnios and oligohydramnios sequence manifesting as pulmonary hypoplasia, skeletal abnormalities, and neonatal death. 

Verify the pregnancy status of females of reproductive potential prior to the initiation of ZIIHERA. Advise pregnant women and females of reproductive potential that exposure to ZIIHERA during pregnancy or within 4 months prior to conception can result in fetal harm. Advise females of reproductive potential to use effective contraception during treatment with ZIIHERA and for 4 months following the last dose of ZIIHERA. 

Left Ventricular Dysfunction
ZIIHERA can cause decreases in left ventricular ejection fraction (LVEF). LVEF declined by >10% and decreased to <50% in 4.3% of 233 patients. Left ventricular dysfunction (LVD) leading to permanent discontinuation of ZIIHERA was reported in 0.9% of patients. The median time to first occurrence of LVD was 5.6 months (range: 1.6 to 18.7). LVD resolved in 70% of patients. 

Assess LVEF prior to initiation of ZIIHERA and at regular intervals during treatment. Withhold dose or permanently discontinue ZIIHERA based on severity of adverse reactions. 

The safety of ZIIHERA has not been established in patients with a baseline ejection fraction that is below 50%. 

Infusion-Related Reactions
ZIIHERA can cause infusion-related reactions (IRRs). An IRR was reported in 31% of 233 patients treated with ZIIHERA as a single agent in clinical studies, including Grade 3 (0.4%), and Grade 2 (25%). IRRs leading to permanent discontinuation of ZIIHERA were reported in 0.4% of patients. IRRs occurred on the first day of dosing in 28% of patients; 97% of IRRs resolved within one day. 

Prior to each dose of ZIIHERA, administer premedications to prevent potential IRRs. Monitor patients for signs and symptoms of IRR during ZIIHERA administration and as clinically indicated after completion of infusion. Have medications and emergency equipment to treat IRRs available for immediate use. 

If an IRR occurs, slow, or stop the infusion, and administer appropriate medical management. Monitor patients until complete resolution of signs and symptoms before resuming. Permanently discontinue ZIIHERA in patients with recurrent severe or life-threatening IRRs. 

Diarrhea
ZIIHERA can cause severe diarrhea. 

Diarrhea was reported in 48% of 233 patients treated in clinical studies, including Grade 3 (6%) and Grade 2 (17%). If diarrhea occurs, administer antidiarrheal treatment as clinically indicated. Perform diagnostic tests as clinically indicated to exclude other causes of diarrhea. Withhold or permanently discontinue ZIIHERA based on severity. 

ADVERSE REACTIONS
Serious adverse reactions occurred in 53% of 80 patients with unresectable or metastatic HER2-positive BTC who received ZIIHERA. Serious adverse reactions in >2% of patients included biliary obstruction (15%), biliary tract infection (8%), sepsis (8%), pneumonia (5%), diarrhea (3.8%), gastric obstruction (3.8%), and fatigue (2.5%). A fatal adverse reaction of hepatic failure occurred in one patient who received ZIIHERA. 

The most common adverse reactions in 80 patients with unresectable or metastatic HER2-positive BTC who received ZIIHERA (≥20%) were diarrhea (50%), infusion-related reaction (35%), abdominal pain (29%), and fatigue (24%). 

USE IN SPECIFIC POPULATIONS 

Pediatric Use
Safety and efficacy of ZIIHERA have not been established in pediatric patients. 

Geriatric Use
Of the 80 patients who received ZIIHERA for unresectable or metastatic HER2-positive BTC, there were 39 (49%) patients 65 years of age and older. Thirty-seven (46%) were aged 65-74 years old and 2 (3%) were aged 75 years or older. 

No overall differences in safety or efficacy were observed between these patients and younger adult patients. 

The full U.S. Prescribing Information for ZIIHERA, including BOXED Warning, is available at: https://pp.jazzpharma.com/pi/ziihera.en.USPI.pdf 

® TEVIMBRA (tislelizumab) is a registered trademark of BeOne Medicines.

About Jazz Pharmaceuticals
Jazz Pharmaceuticals plc (Nasdaq: JAZZ) is a global biopharma company whose purpose is to innovate to transform the lives of patients and their families. We are dedicated to developing potentially life-changing medicines for people with serious diseases — often with limited or no therapeutic options. We have a diverse portfolio of marketed medicines, including leading therapies for sleep disorders and epilepsy, and a growing portfolio of cancer treatments. Our patient-focused and science-driven approach powers pioneering research and development advancements across our robust pipeline of innovative therapeutics in oncology and neuroscience. Jazz is headquartered in Dublin, Ireland with research and development laboratories, manufacturing facilities and employees in multiple countries committed to serving patients worldwide. Please visit www.jazzpharmaceuticals.com for more information. 

Cautionary Note Concerning Forward-Looking Statements 
This press release contains forward-looking statements, including, but not limited to, statements related to the potential therapeutic benefits of Ziihera, Ziihera's potential as a new standard of care in HER2+ first-line GEA and other HER2-expressing cancers,  and other statements that are not historical facts. These forward-looking statements are based on Jazz Pharmaceuticals' current plans, objectives, estimates, expectations and intentions and inherently involve significant risks and uncertainties. Actual results and the timing of events could differ materially from those anticipated in such forward-looking statements as a result of these risks and uncertainties, which include, without limitation, risks and uncertainties associated with the successful completion of regulatory activities and uncertain regulatory approval, risks related to failure or delays in successfully initiating or completing clinical trials and assessing patients and other risks and uncertainties affecting Jazz Pharmaceuticals and its development programs, including those described from time to time under the caption "Risk Factors" and elsewhere in Jazz Pharmaceuticals's Securities and Exchange Commission filings and reports (Commission File No. 001-33500), including Jazz Pharmaceuticals' Annual Report on Form 10-K for the year ended December 31, 2024, as supplemented by Jazz Pharmaceuticals' Quarterly Report on Form 10-Q for the quarter ended September 30, 2025, and future filings and reports by Jazz Pharmaceuticals. Other risks and uncertainties of which Jazz Pharmaceuticals is not currently aware may also affect Jazz Pharmaceuticals' forward-looking statements and may cause actual results and the timing of events to differ materially from those anticipated. The forward-looking statements herein are made only as of the date hereof or as of the dates indicated in the forward-looking statements, even if they are subsequently made available by Jazz Pharmaceuticals on its website or otherwise. Jazz Pharmaceuticals undertakes no obligation to update or supplement any forward-looking statements to reflect actual results, new information, future events, changes in its expectations or other circumstances that exist after the date as of which the forward-looking statements were made. 

Contacts:
Media Contact: 
Kristin Bhavnani
Head of Global Corporate Communications
Jazz Pharmaceuticals plc
CorporateAffairsMediaInfo@jazzpharma.com
Ireland +353 1 637 2141
U.S. +1 215 867 4948

Jazz Investor Contact: 
Jack Spinks 
Executive Director, Investor Relations 
Jazz Pharmaceuticals plc
InvestorInfo@jazzpharma.com
Ireland +353 1 634 3211
U.S. +1 650 496 2717

References

¹ Abrahao-Machado I.F., et al. HER2 testing in gastric cancer: An update WorldJGastroenterol. 2016;22(19):4619-4625.
² Van Custem E., et al. HER2 screening data from ToGA: targeting HER2 in gastric and gastroesophageal junction cancer. Gastric Cancer. 2015;18(3):476-484.
³ Stroes, C.I., et al. A systematic review of HER2 blockade for the curative treatment of gastroesophageal adenocarcinoma: Successes achieved and opportunities ahead. CancerTreatRev. 2021;99:102249.
⁴ Battaglin F, et al. Molecular biomarkers in gastro-esophageal cancer: recent developments, current trends and future directions. Cancer Cell International. 2018;18(99).
⁵ Mirallas O, López-Valbuena D, García-Illescas D, et al. Advances in the systemic treatment of therapeutic approaches in biliary tract cancer. ESMO Open. 2022;7(3):100503. doi:10.1016/j.esmoop.2022.100503.
⁶ Kam A, et al. Current and emerging therapies for advanced biliary tract cancers. Lancet Gastroenterol Hepatol. 2021;6(11):956-69. doi:10.1016/S2468-1253(21)00171-0.
⁷ Vogel A, Bridgewater J, Edeline J, et al. Biliary tract cancer: ESMO Clinical Practice Guideline for diagnosis, treatment, and follow-up. Ann Oncol. 2023;34(2):127-40. doi:10.1016/j.annonc.2022.10.506.
⁸ Rimassa, L., Khan, S., Koerkamp, B. G., Roessler, S.,et al. Mapping the landscape of biliary tract cancer in Europe: challenges and controversies. The Lancet Regional Health–Europe. 2025;  50, 101171. doi.org/10.1016/j.lanepe.2024.101171.
⁹ Chakrabarti, S., Kamgar, M., Mahipal, A. Targeted therapies in advanced biliary tract cancer: an evolving paradigm. Cancers. 2020;12(8), 2039. doi.org/10.3390/cancers12082039.
¹⁰ Valle JW, Kelley RK, et al. Biliary tract cancer. Lancet. 2021;397(10272):428-44. doi:10.1016/S0140-6736(21)00153-7.
¹¹ Lamarca, A., Hubner, R. A., Ryder, W. D., et al. Second-line chemotherapy in advanced biliary cancer: a systematic review. Annals of Oncology. 2025; 25(12), 2328-2338. doi.org/10.1093/annonc/mdu162.
¹² Hechtman, J. F., Liu, W., Sadowska, J.,et al. Sequencing of 279 cancer genes in ampullary carcinoma reveals trends relating to histologic subtypes and frequent amplification and overexpression of ERBB2 (HER2). Modern Pathology. 2015;28(8), 1123-1129.  doi: 10.1038/modpathol.2015.57.
¹³ Galdy S, Lamarca A, et al. HER2/HER3 pathway in biliary tract malignancies; systematic review and meta-analysis: a potential therapeutic target? Cancer Metastas Rev. 2017; doi: 10.1007/s10555-016-9645-x.
¹⁴ Vivaldi, C. HER2 overexpression as a poor prognostic determinant in resected biliary tract cancer. Oncologist. 2020;25(10):886-893. doi:10.1634/theoncologist.2019-0922.
¹⁵ Jazz Pharmaceuticals, Inc, Data on file.
¹⁶ ZIIHERA (zanidatamab-hrii) Prescribing Information. Palo Alto, CA: Jazz Pharmaceuticals, Inc.)

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FAQ

What did Jazz Pharmaceuticals (JAZZ) present about Ziihera at ASCO GI 2026?

Jazz presented late-breaking Phase 3 HERIZON-GEA-01 results showing highly significant PFS gains for Ziihera regimens and a statistically significant OS benefit for Ziihera + tislelizumab + chemotherapy.

When and how can investors review Jazz (JAZZ) Ziihera data from ASCO GI 2026?

Jazz will host an investor webcast on Jan 9, 2026 at 6:30 a.m. PT / 9:30 a.m. ET; a replay will be available on the company's investor website.

Which HERIZON-GEA-01 Ziihera regimen showed an overall survival benefit in the Phase 3 readout?

The combination of Ziihera + tislelizumab + chemotherapy demonstrated clinically meaningful and statistically significant overall survival improvement.

Did Ziihera plus chemotherapy improve overall survival in HERIZON-GEA-01?

Ziihera plus chemotherapy produced a clinically meaningful OS effect with a strong trend toward statistical significance at the first analysis.

Will Jazz present additional Ziihera data beyond HERIZON-GEA-01 at ASCO GI 2026?

Yes; a post-hoc overall survival analysis from the Phase 2b HERIZON-BTC-01 trial in previously treated HER2+ biliary tract cancer will be presented on Jan 9, 2026.

When are ASCO GI abstracts for Jazz (JAZZ) being released publicly?

Most abstracts will be released at 2:00 p.m. PT / 5:00 p.m. ET on Jan 5, 2026; late-breaking abstracts are released at their presentation time.