GSK’s vaccine Arexvy is currently undergoing regulatory review with the potential of being approved in Europe for use in adults aged between 50 and 59 who are at an increased risk for respiratory syncytial virus (RSV) infection. The European Medicines Agency (EMA) accepted the company’s regulatory application to expand the use of Arexvy on 29 January and a decision is anticipated in H2 2024. A label expansion for Arexvy would strengthen its position as a competitor against Pfizer’s Abrysvo, says GlobalData, a leading data analytics company.

Arexvy was approved in Europe in June 2023 for use in adults aged 60 and older for the prevention of lower respiratory tract disease (LRTD) caused by RSV. It was first approved in the US in May 2023.

Anaelle Tannen, Infectious Disease Analyst at GlobalData, comments: “GSK is the first company to file for regulatory approval for the label expansion of its RSV vaccine. If accepted, Arexvy would be the first vaccine available to help protect this patient population, which would address an unmet need for high-risk adults in this age group that currently lack protection”.

The application is supported by positive trial results from a Phase III, placebo-controlled, observer-blind, randomized, multi-country immunogenicity clinical trial. Arexvy elicited a non-inferior immune response in adults aged 50 to 59 compared to those aged 60 and older, measured by RSV-A and RSV-B neutralization titers, and also demonstrated an acceptable tolerability profile. In previous Phase III trials, Arexvy has been shown to have a strong efficacy of 82.6% against RSV-LRTD in adults aged 60 years and older.

Tannen adds: “Arexvy clinical trial data has been promising thus far, although the recombinant vaccine displays contraindications in anyone suffering from severe allergies such as anaphylaxis. This means that there is still space for improvement to current prophylaxis.”

Arexvy was the first-to-market adult vaccine, having been launched in Europe only two months prior to its competitor Pfizer’s Abrysvo. Key Opinion Leaders (KOLs) interviewed by GlobalData do not believe there is much of a difference in safety and efficacy between the two drugs, and thus performance will be based on sale price and marketing.

According to GlobalData’s analyst consensus forecast, sales for Arexvy are projected to reach around $504 million in Europe by 2029. This projection is only based on Arexvy’s use in the adult population aged 60 years and older, and thus the label expansion, if approved, is expected to inflate this figure.

Tannen concludes: “Unlike Arexvy, which is only approved for adults, Abrysvo is also approved as a maternal vaccine and is recommended for use in pregnancy in order to prevent RSV infection in infants. The potential label expansion that will enable Arexvy to be administered to a wider adult population will therefore be important for providing a further differentiating factor against Abrysvo.”