[8-K] Jazz Pharmaceuticals plc Reports Material Event

Rhea-AI Filing Summary

Jazz Pharmaceuticals plc reported positive top-line results from its Phase 3 HERIZON-GEA-01 trial. The study evaluated Ziihera® (zanidatamab-hrii) with chemotherapy, and with or without the checkpoint inhibitor tislelizumab, as a first-line treatment for patients with HER2-positive locally advanced or metastatic gastroesophageal adenocarcinoma. These initial results suggest that Ziihera-based combinations may offer a new treatment option in this hard-to-treat cancer setting, pending full data and any future regulatory decisions. Details of the results are provided in a press release attached as an exhibit.

Positive

• Positive Phase 3 clinical results for Ziihera® (zanidatamab-hrii) in the HERIZON-GEA-01 trial as a first-line treatment for HER2-positive locally advanced or metastatic gastroesophageal adenocarcinoma.

Negative

• None.

Insights

Biopharma clinical-stage analyst

Positive Phase 3 top-line data for Ziihera in HER2+ gastric cancer.

Jazz Pharmaceuticals announced positive top-line results from the Phase 3 HERIZON-GEA-01 trial of Ziihera® (zanidatamab-hrii) in combination with chemotherapy, with or without tislelizumab, in first-line HER2-positive locally advanced or metastatic gastroesophageal adenocarcinoma. A positive Phase 3 outcome in this indication can be an important clinical milestone because it typically precedes full data disclosure and potential regulatory submissions.

The regimen design, combining a HER2-targeted antibody with chemotherapy and optionally a checkpoint inhibitor, aligns with current oncology practice for aggressive gastrointestinal cancers. However, the announcement in this excerpt does not specify the exact endpoints, magnitude of benefit, or safety profile, which will shape the eventual clinical value and competitive positioning.

Investors and clinicians will likely focus on the detailed Phase 3 data once released, including efficacy measures such as progression-free and overall survival, as well as tolerability. The attached press release, referenced as Exhibit 99.1, is expected to provide more granular results that will clarify how Ziihera might fit into the treatment landscape for HER2-positive gastroesophageal adenocarcinoma.

Jazz Pharmaceuticals plc false 0001232524 0001232524 2025-11-17 2025-11-17

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported) November 17, 2025

JAZZ PHARMACEUTICALS PUBLIC LIMITED COMPANY

(Exact name of registrant as specified in its charter)

Ireland		001-33500		98-1032470
(State or Other Jurisdiction of Incorporation)		(Commission File No.)		(IRS Employer Identification No.)

Fifth Floor, Waterloo Exchange, Waterloo Road, Dublin 4, Ireland D04 E5W7

(Address of principal executive offices, including zip code)

011-353-1-634-7800

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class		Trading Symbol(s)		Name of each exchange on which registered
Ordinary shares, nominal value $0.0001 per share		JAZZ		The Nasdaq Stock Market LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 8.01. Other Events.

On November 17, 2025, Jazz Pharmaceuticals plc issued a press release announcing positive top-line results from the Phase 3 HERIZON-GEA-01 trial evaluating Ziihera^® (zanidatamab-hrii) in combination with chemotherapy, and with or without the checkpoint inhibitor tislelizumab, as a first-line treatment for HER2-positive locally advanced or metastatic gastroesophageal adenocarcinoma. A copy of the press release is filed herewith as Exhibit 99.1 and incorporated herein by reference.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits

Exhibit Number		Description
99.1		Press Release dated November 17, 2025.
104		104 Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

JAZZ PHARMACEUTICALS PUBLIC LIMITED COMPANY
By:		/s/ Neena M. Patil
Name:		Neena M. Patil
Title:		Executive Vice President and Chief Legal Officer
Date:		November 17, 2025

FAQ

What did Jazz Pharmaceuticals (JAZZ) announce in this 8-K filing?

Jazz Pharmaceuticals announced positive top-line results from the Phase 3 HERIZON-GEA-01 clinical trial of Ziihera® (zanidatamab-hrii) in HER2-positive gastroesophageal adenocarcinoma.

Which drug is involved in the Phase 3 HERIZON-GEA-01 trial reported by JAZZ?

The trial involves Ziihera® (zanidatamab-hrii), evaluated in combination with chemotherapy and with or without the checkpoint inhibitor tislelizumab.

What patient population is targeted in Jazz Pharmaceuticals' HERIZON-GEA-01 trial?

The Phase 3 trial targets patients with HER2-positive locally advanced or metastatic gastroesophageal adenocarcinoma receiving first-line treatment.

How were the HERIZON-GEA-01 trial results for Jazz Pharmaceuticals described?

The results were described as positive top-line results, indicating favorable initial findings from the Phase 3 study, with more detail available in the attached press release.

Where can investors find more detailed information on the HERIZON-GEA-01 trial results?

More details are provided in the press release filed as Exhibit 99.1, which is incorporated by reference in the report.

Does this filing indicate any regulatory decision for Ziihera®?

The filing only reports positive top-line Phase 3 results; it does not mention any regulatory submissions or approvals for Ziihera®.