Webinar to Highlight Unmet Needs in Hypothyroidism, Market Opportunity, and Planned Phase 3 Program for XP-8121

Xeris Biopharma Holdings, Inc. (NASDAQ:XERS), a fast-growing biopharmaceutical company committed to improving patient lives by developing and commercializing innovative products across a range of therapies, today announced details for a dedicated Program Overview webinar for XP-8121, the Company’s Phase 3-ready, once-weekly subcutaneous levothyroxine injection in development for the treatment of hypothyroidism.

The XP-8121 webinar will take place on Wednesday, September 9, 2026, at 10 a.m. ET and will feature a leading endocrinologist, alongside members of the Xeris program team. The speakers will discuss the significant unmet medical need in hypothyroidism, the potential market opportunity for XP-8121, and the Company’s planned Phase 3 development program, including:

Trial design and objectives,
Primary and secondary endpoints,
Target patient population,
Expected development milestones, and
Anticipated regulatory timelines.

"We believe XP-8121 has the potential to address important and persistent challenges faced by patients failing to achieve biochemical control with the current oral therapy due to GI absorption issues," said John Shannon, Chairman and Chief Executive Officer, Xeris. "We are excited to share our vision for XP-8121, the science supporting its development, and additional details around our Phase 3 registrational clinical trial."

How to Register and Access the Event

The XP-8121 Program Overview will be held on Wednesday, September 9, 2026, at 10 a.m. ET.

Investors and other interested participants are encouraged to register for the webinar in advance. A replay of the event will also be made available following the live presentation. For registration and access, please click here.

About XP-8121

XP-8121 is a Phase 3-ready, once-weekly subcutaneous injection in development for the treatment of hypothyroidism. The program is designed to address persistent challenges associated with existing thyroid hormone replacement therapy and has the potential to provide a differentiated treatment option for people living with hypothyroidism and physicians.

About Xeris

Xeris (NASDAQ:XERS) is a fast-growing biopharmaceutical company committed to improving patient lives by developing and commercializing innovative products across a range of therapies. Xeris has three commercially available products: Recorlev^®, for the treatment of endogenous Cushing’s syndrome; Gvoke^®, a ready-to-use liquid glucagon for the treatment of severe hypoglycemia; and Keveyis^®, a proven therapy for primary periodic paralysis. Xeris also has a pipeline of development programs led by XP-8121, a Phase 3-ready, once-weekly subcutaneous injection for hypothyroidism, as well as multiple early-stage programs leveraging Xeris’ technology platforms, XeriSol^® and XeriJect^®, for its partners.

Xeris Biopharma Holdings is headquartered in Chicago, IL.

Forward-Looking Statements

Any statements in this press release other than statements of historical fact are forward-looking statements. Forward-looking statements include, but are not limited to, statements about future expectations, plans, opportunities, and prospects for the Company, including statements, among other things, including an opportunity to share deeper insights into the Company’s comprehensive clinical development program for XP-8121, the Company’s commercial opportunity for XP-8121, the market and therapeutic and commercial potential of its products and product candidates, including its expectations regarding the timely execution of XP-8121's ongoing development leading into the initiation of its Phase 3 clinical trial and the expected timing of the XP-8121 Phase 3 clinical, the timing, duration, and expected results of clinical trials, expected regulatory approval of its product candidates, the potential utility of its formulation platforms, the advancement of its pipeline, and other statements containing the words "achieve," "anticipate," "believe," "continue," "expect," "potential," "should," "will," "would," and similar expressions, constitute forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995. These forward-looking statements are based on numerous assumptions and assessments made in light of Xeris’ experience and perception of historical trends, current conditions, business strategies, operating environment, future developments, geopolitical factors, and other factors it believes appropriate. By their nature, forward-looking statements involve known and unknown risks and uncertainties because they relate to events and depend on circumstances that will occur in the future. The various factors that could cause Xeris’ actual results (including revenue and sales in the near- and long-term), performance or achievements, industry results, market opportunity and developments to differ materially from those expressed in or implied by such forward-looking statements (including its 2026 guidance), include, but are not limited to, its financial position and need for financing, including to fund its product development programs or commercialization efforts, whether its products will achieve and maintain market acceptance in a competitive business environment, its reliance on third-party suppliers, including single-source suppliers, its reliance on third parties to conduct clinical trials, the ability of its product candidates to compete successfully with existing and new drugs, its and collaborators’ ability to protect its intellectual property and proprietary technology, the accuracy and completeness of its assumptions and its ability to accurately estimate future financial results and market opportunities, and general macroeconomic and geopolitical conditions, including the possibility of an economic downturn, political unrest, trade disputes, changes in U.S. governmental priorities and resources, announced or implemented tariffs or export controls and market volatility. No assurance can be given that such expectations will be realized and persons reading this communication are, therefore, cautioned not to place undue reliance on these forward-looking statements. Additional risks and information about potential impacts of financial, operational, economic, competitive, regulatory, governmental, technological, and other factors that may affect Xeris can be found in Xeris’ filings, including its most recently filed Annual Report on Form 10-K and subsequent filings with the U.S. Securities and Exchange Commission, the contents of which are not incorporated by reference into, nor do they form part of, this communication. The risks described herein and in Xeris’ U.S. Securities and Exchange Commission filings are not the only risks the Company faces. Additional risks and uncertainties not currently known to it or that it currently deems immaterial may also impact its business operations or financial results. Forward-looking statements in this communication are based on information available to management, as of the date of this communication and, while the Company believes its assumptions are reasonable, actual results may differ materially. Subject to any obligations under applicable law, the Company does not undertake any obligation to update any forward-looking statement whether as a result of new information, future developments or otherwise, or to conform any forward-looking statement to actual results, future events, or to changes in expectations.

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Investor Contact

Allison Wey

Senior Vice President, Investor Relations and Corporate Communications

awey@xerispharma.com