Don Tracy, Associate Editor

Arexvy receives expanded indication to include adults aged 59 years and younger to prevent RSV lower respiratory tract disease.
GSK’s Arexvy (RSV Vaccine, Adjuvanted) has been approved by the FDA for an expanded indication to prevent respiratory syncytial virus (RSV) lower respiratory tract disease (LRTD) in adults aged 50-59 years with an increased risk. The approval for this age group was based on encouraging results from a Phase III trial (NCT05590403) that evaluated the immune response and safety of Arexvy in adults aged 50-59, including those with underlying medical conditions. Arexvy was previously approved for adults aged 60 years and older for the same purpose in May 2023. Additionally, the Advisory Committee on Immunization Practices (ACIP) recommended its use through shared clinical decision-making.1
“[This] approval reflects the importance of broadening the benefits of RSV immunization to adults aged 50-59 who are at increased risk. For those with underlying medical conditions, RSV can have serious consequences, so we are proud to be the first to help protect them from RSV-LRTD,” said Tony Wood, chief scientific officer, GSK, in a press release.
NCT05590403 is a phase III, placebo-controlled, observer-blind, randomized, multi-country immunogenicity trial that evaluated non-inferiority of the immune response and safety of Arexvy in participants aged 50 to 59 years, including those at increased risk for RSV-LRTD compared to older adults aged 60 years and above after a single dose of GSK’s RSV vaccine, with enrollment totaling 1544 participants. The primary endpoints of the trial were RSV-A and RSV-B neutralization of both groups at one month after the vaccine administration compared to adults aged 60 years and older. Secondary endpoints included safety and immunogenicity.1,2
Safety data of the trial were consistent with findings from previous clinical trials. The most commonly reported adverse event (AE) of the trial was injection site pain, with other AEs including myalgia, fatigue and headache, which GSK stated were mostly temporary and mild to moderate.1
According to the National Foundation for Infectious Diseases, RSV is considered to be a major cause of respiratory illness in adults in the US, with approximately 60,000-160,000 hospitalizations, and 6,000-10,000 deaths in adults aged 65 years and older annually. It is also the most common cause of bronchiolitis and pneumonia in children under 1 year of age. While people of all ages are at risk for RSV, it is most common in premature infants, infants under the age of six months, people with chronic heart or lung disease, people with compromised immune systems, and older adults.3 Overall, it is estimated that RSV causes around 42,000 hospitalizations in the United States annually for adults aged 50-64.1
Results were previously presented at ACIP’s October 2023 meeting during ReSVinet in February. Additionally, GSK submitted the data for peer-reviewed publication and potential label expansions. Regulatory submissions have also been submitted in Japan, Europe, and other locations.1
“I am thrilled that GSK’s RSV vaccine is now approved for adults aged 50-59 at increased risk of RSV-LRTD. When it comes to the risks associated with RSV, age is just a number, an important number, but not the only factor to consider. Many adults in this age group have underlying health conditions that place them at increased risk for serious illness with RSV infection compared with those without these conditions. Now there is a vaccine approved that can help protect them,” said Ann R. Falsey, professor, University of Rochester School of Medicine, in the press release.