• Phase 1/2 H5 avian flu vaccine study shows positive interim results
• Company has been notified that HHS will terminate Moderna's award for late-stage development of pre-pandemic influenza vaccines

CAMBRIDGE, MA / ACCESS Newswire / May 28, 2025 / Moderna, Inc. (NASDAQ:MRNA) today announced positive interim data from a Phase 1/2 clinical study (NCT05972174) evaluating the safety and immunogenicity of its investigational pandemic influenza vaccine, mRNA-1018, in approximately 300 healthy adults aged 18 years and older. The interim results focus on a vaccine candidate targeting the H5 avian influenza virus subtype.

The Company had previously expected to advance the program to late-stage development with the U.S. Department of Health and Human Services (HHS); however, today Moderna received notice that HHS will terminate the award for the late-stage development and right to purchase pre-pandemic influenza vaccines.

"While the termination of funding from HHS adds uncertainty, we are pleased by the robust immune response and safety profile observed in this interim analysis of the Phase 1/2 study of our H5 avian flu vaccine and we will explore alternative paths forward for the program," said Stéphane Bancel, Chief Executive Officer of Moderna. "These clinical data in pandemic influenza underscore the critical role mRNA technology has played as a countermeasure to emerging health threats."

The Phase 1/2 study evaluated a two-dose regimen of Moderna's investigational avian influenza vaccine. mRNA-1018 demonstrated a rapid, potent and durable immune response. At baseline, pre-existing immunity was minimal, with only 2.1% of participants showing hemagglutination inhibition (HAI) antibody titers ≥1:40, an HAI titer considered to correlate with protection. At Day 43, three weeks after the second vaccination, 97.8% of participants achieved titers ≥1:40 with a 44.5-fold increase of titers from baseline.

The investigational vaccine was generally well-tolerated, with no dose-limiting tolerability concerns observed. Most solicited adverse reactions were Grade 1 or 2 and did not increase significantly with number of doses or between first and second doses. Further data is expected to be submitted for presentation at an upcoming scientific meeting.

Moderna will explore alternatives for late-stage development and manufacturing of the H5 program consistent with the Company's strategic commitment to pandemic preparedness.

About Moderna

Moderna is a leader in the creation of the field of mRNA medicine. Through the advancement of mRNA technology, Moderna is reimagining how medicines are made and transforming how we treat and prevent disease for everyone. By working at the intersection of science, technology and health for more than a decade, the company has developed medicines at unprecedented speed and efficiency, including one of the earliest and most effective COVID-19 vaccines.

Moderna's mRNA platform has enabled the development of therapeutics and vaccines for infectious diseases, immuno-oncology, rare diseases and autoimmune diseases. With a unique culture and a global team driven by the Moderna values and mindsets to responsibly change the future of human health, Moderna strives to deliver the greatest possible impact to people through mRNA medicines. For more information about Moderna, please visit modernatx.com and connect with us on X (formerly Twitter), Facebook, Instagram, YouTube and LinkedIn.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including statements regarding: the clinical development of mRNA-1018, the safety and immunogenicity data from the Phase 1/2 study; the cancellation of the development contract for Moderna's pandemic flu program by the U.S. Department of Health and Human Services; and the exploration of alternative paths for development of the vaccine program. The forward-looking statements in this press release are neither promises nor guarantees, and you should not place undue reliance on these forward-looking statements because they involve known and unknown risks, uncertainties, and other factors, many of which are beyond Moderna's control and which could cause actual results to differ materially from those expressed or implied by these forward-looking statements. These risks, uncertainties, and other factors include, among others, those risks and uncertainties described under the heading "Risk Factors" in Moderna's Annual Report on Form 10-K for the fiscal year ended December 31, 2024, and in subsequent filings made by Moderna with the U.S. Securities and Exchange Commission, which are available on the SEC's website at www.sec.gov. Except as required by law, Moderna disclaims any intention or responsibility for updating or revising any forward-looking statements contained in this press release in the event of new information, future developments or otherwise. These forward-looking statements are based on Moderna's current expectations and speak only as of the date of this press release.

Moderna Contacts

Media:
Chris Ridley
Global Head of Media Relations
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Investors:
Lavina Talukdar
Senior Vice President & Head of Investor Relations
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