FDA Expands Approval of GSK’s RSV Vaccine to At-Risk Adults Aged 18- 49

The U.S. Food and Drug Administration has expanded the approved use of Arexvy, an RSV vaccine developed by GSK, to include adults aged 18 to 49 who are at increased risk of lower respiratory tract disease caused by Respiratory Syncytial Virus Infection. The vaccine was previously approved for all adults aged 60 and older and for adults aged 50 to 59 who are at increased risk of RSV-related complications.

This vaccine is not for use in pregnant individuals.

Sanjay Gurunathan, GSK Head of Vaccines and Infectious Diseases Research and Development, said: “This age expansion can help address a significant medical need for adults in the United States at higher risk of severe RSV disease due to certain underlying conditions, and help ease pressure on the healthcare system. We are proud of this latest step in our strategy to bring RSV prevention to broader adult populations.”

The annual RSV burden among US adults aged 18-49 years is about 17,000 hospitalisations, 277,000 emergency department admissions, and 1.97 million outpatient visits. Most hospitalisations in younger adults occur in those with chronic medical conditions which place them at increased risk for severe RSV disease (e.g. chronic cardiopulmonary, kidney or renal disease, obesity and diabetes).

The FDA’s decision was supported by data from a Phase IIIb trial (NCT06389487) demonstrating a non-inferior immune response compared to adults aged 60 years and above. Vaccine efficacy was demonstrated in the earlier Phase III trial (NCT04886596). The safety profile was consistent with findings from the broader Phase III programme that supported the initial US approval, with the most common adverse events being injection site pain, fatigue, myalgia, headache, and arthralgia within four days of vaccination.

GSK continues to advance regulatory submissions for its RSV vaccine across multiple geographies to expand availability and support long-term growth objectives.

About GSK’s RSV vaccine

Respiratory Syncytial Virus vaccine (adjuvanted) contains recombinant RSV glycoprotein F stabilised in the prefusion conformation (RSVPreF3). This antigen is combined with GSK’s proprietary AS01E adjuvant before administration.

The use of this vaccine should be in accordance with official recommendations. As with any vaccine, a protective immune response may not be elicited in all vaccinees.

The vaccine has been approved for the prevention of RSV-LRTD in individuals 60 years of age and older in 70 countries. In addition, it is approved for use in individuals aged 50–59 who are at increased risk due to certain underlying medical conditions in more than 60 countries. In the European Economic Area it is approved for adults aged 18 years and older.

The GSK proprietary AS01 adjuvant system contains STIMULON QS-21 adjuvant licensed from Antigenics LLC, a wholly owned subsidiary of Agenus Inc. STIMULON is a trademark of SaponiQx Inc., a subsidiary of Agenus.

About the NCT06389487 trial

NCT06389487 is a Phase IIIb, open-label multi-country immunogenicity trial to evaluate the non-inferiority of the immune response and evaluate safety in participants aged 18–49 at increased risk for lower respiratory tract disease (LRTD) caused by RSV (n=426), compared to participants aged 60 years and above (n=429) after a single dose of GSK’s RSV vaccine. An additional cohort, of 603 participants aged 18-49, was followed up for adverse events separate to safety follow up of the initial cohort. A total of 1,458 participants were enrolled across 52 locations in six countries, including 16 US sites.

The study assessed the immune response in participants aged 18-49 with pre-defined stable chronic diseases leading to an increased risk for RSV disease, compared to those aged 60 years and above. The trial’s primary endpoints were RSV-A and RSV-B neutralisation titres of adults aged 18 – 49 years at one month after the vaccine administration compared to adults aged 60 and older. There were also safety and immunogenicity secondary and tertiary endpoints. Safety and reactogenicity data were consistent with results from the initial data read out in NCT04886596. The most common local adverse event was pain. The most common systemic adverse events were myalgia, fatigue and headache, which were largely transient and mild to moderate in intensity.

About RSV in adults

RSV is a common contagious virus affecting the lungs and breathing passages and impacts an estimated 64 million people of all ages globally every year.5 Adults can be at increased risk for RSV disease due to certain comorbidities, immune compromised status, or advanced age.6 RSV can exacerbate certain conditions, including COPD, asthma, and chronic heart failure and can lead to severe outcomes, such as pneumonia, hospitalisation, and death.6 Compared to children, adults hospitalised for RSV are at a higher risk of severe complications, require more costly treatments, have a higher fatality rate, and the true number of RSV-related cases is likely underestimated due to lack of routine testing.