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17 January 2023

Investigational mRNA Vaccines & Respiratory Syncytial Virus

Stéphane Bancel
Chief Executive Officer
 Investigational mRNA Vaccines & Respiratory Syncytial Virus

Today we announced positive top-line data from our pivotal Phase 3 study of mRNA-1345, our investigational vaccine candidate against respiratory syncytial virus (RSV), in older adults. RSV is a common seasonal virus that can cause serious illness in certain vulnerable groups. Our Phase 3 study met its primary endpoints and based on the positive results from this interim analysis, we expect to submit for regulatory approval early this year. mRNA-1345 is an investigational asset and has not been determined to be safe or effective by the U.S. FDA. From the first older adult participant in the Phase 1 study of mRNA-1345 dosed in January 2021 to announcing positive Phase 3 data today, we have accelerated this program, spending approximately 2 years in development.

Moderna’s Commitment to Advancing Vaccines Against Respiratory Viruses

Since our founding, we have worked to study whether it is possible to instruct a patient’s own cells to produce proteins that may have the potential to treat a wide range of conditions with mRNA. We have continued to scale, now with 48 programs in development, including 36 programs in clinical trials encompassing investigational mRNA infectious disease vaccine candidates and mRNA therapeutic candidates spanning seven different modalities.

Our late-stage respiratory vaccine pipeline continues to progress. Today’s data announcement is our second mRNA vaccine showing positive data in a Phase 3 study. Applying our experience and using our mRNA platform, we are developing vaccine candidates that we believe could one day help prevent hospitalizations and deaths from some of the most prevalent respiratory viruses.

We are also progressing several respiratory vaccine candidates, including combination vaccines against multiple respiratory viruses, and are committed to building our respiratory franchise. By pursuing combination products to protect against a range of diseases, we believe that we can potentially help decrease morbidity and mortality from respiratory disease, lower healthcare costs and increase health security globally.

Global RSV Data (2019)

RSV is a common seasonal virus. For some, RSV causes mild cold-like symptoms, yet it can cause serious illness in certain vulnerable groups like infants and older adults. RSV is very contagious and can cause coughing, nasal congestion, and sore throat. RSV can also lead to more serious complications like respiratory distress, pneumonia, and bronchitis. Severe cases of RSV can cause hospitalization and even death. RSV can cause severe disease with an estimated 5.2 million cases and nearly half a million hospitalizations in adults 60 years or older reported across high-income countries in 2019. Each year in the US, approximately 60,000–120,000 older adults are hospitalized, and 6,000–10,000 of them die due to RSV infection. In the U.S., the burden of illness caused by RSV in older adults (60 years or older) results in approximately $3 billion in direct medical costs per year.

Positive Pivotal Phase 3 Results

The pivotal ConquerRSV Phase 3 efficacy trial is a randomized, double-blind, placebo-controlled study, which enrolled approximately 37,000 adults 60 years or older in 22 countries, including the US. Today, we announced results from a pre-specified interim efficacy analysis of the study.

The study met the pre-defined statistical criteria for efficacy, with a vaccine efficacy of 83.7% (95.88% CI: 66.1%, 92.2%; p<0.0001) against RSV-associated lower respiratory tract disease defined by 2 or more symptoms, and 82.4% (96.36% CI: 34.8%, 95.3%; p=0.0078) against RSV-associated lower respiratory tract disease defined by 3 or more symptoms.

In this interim analysis, 64 cases of RSV-associated lower respiratory tract disease defined by 2 or more symptoms were reported, of which 55 cases were observed in the placebo group compared with 9 cases observed in the mRNA-1345 group. 20 cases of RSV-associated lower respiratory tract disease defined by 3 or more symptoms were reported, of which 17 cases were observed in the placebo group compared with 3 cases observed in the mRNA-1345 group.

mRNA-1345 was well tolerated with no safety concerns identified. Solicited adverse reactions were mostly mild or moderate, the most commonly reported in the mRNA-1345 group were injection site pain, fatigue, headache, myalgia, and arthralgia. The overall rate of Grade 3 (severe) or above solicited systemic adverse reactions was 4.0% for mRNA-1345 and 2.8% for placebo.

Additional data analysis is ongoing, and the final study results may differ. We will submit these data for peer-reviewed publication and present it at an upcoming scientific meeting.

Working to Deliver the Greatest Possible Impact Through mRNA Medicines

This research could not be done without the participants and investigators involved in our clinical trial and we are grateful for their contribution. Looking ahead, we will submit these Phase 3 data for regulatory approval early this year. Since RSV also has a significant disease burden on children, we are studying our investigational RSV vaccine candidate in an ongoing Phase 1 trial in pediatric populations. We will continue to advance vaccines against respiratory viruses as we work toward our mission to deliver the greatest possible impact to people through mRNA medicines.

Moderna Forward-Looking Statements

This post contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including statements regarding: the Company’s development of a vaccine against RSV (mRNA-1345); the vaccine efficacy of mRNA-1345; the development of additional respiratory vaccines by the Company; the potential benefits of combination respiratory vaccines; the potential for mRNA-1345 to reduce disease burden from RSV; future data analysis from the Phase 3 trial of mRNA-1345; the safety profile and tolerability of mRNA-1345; the mechanism of action for mRNA-1345; the conduct of additional trials targeting RSV; and the anticipated timing for submissions for regulatory approval of mRNA-1345.  In some cases, forward-looking statements can be identified by terminology such as “will,” “may,” “should,” “could,” “expects,” “intends,” “plans,” “aims,” “anticipates,” “believes,” “estimates,” “predicts,” “potential,” “continue,” or the negative of these terms or other comparable terminology, although not all forward-looking statements contain these words. The forward-looking statements in this post 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, 2021 and Quarterly Report on Form 10-Q for the quarterly period ended March 31, 2022, each filed with the U.S. Securities and Exchange Commission (SEC), and in subsequent filings made by Moderna with the SEC, which are available on the SEC's website at Except as required by law, Moderna disclaims any intention or responsibility for updating or revising any forward-looking statements contained in this post 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 post.


²Savic M, Penders Y, Shi T, Branche A, Pirçon JY. Respiratory syncytial virus disease burden in adults aged 60 years and older in high-income countries: A systematic literature review and meta-analysis. Influenza Other Respir Viruses. 2022 Nov 11. doi: 10.1111/irv.13031.
⁴Herring WL, et al. Clinical and economic outcomes associated with respiratory syncytial virus vaccination in older adults in the United States. Vaccine. 2022;40(3):483-493.
⁵Clinical Trials identifier: NCT05127434