Analysts tip Arexvy label expansion to strengthen GSK's hand in RSV fight with Pfizer

GSK’s push to expand the label for its blockbuster respiratory syncytial virus (RSV) vaccine will strengthen its position against Pfizer, according to analysts at GlobalData.

Late last month, the European Medicines Agency accepted an application to expand the label of GSK’s Arexvy to cover the prevention of RSV disease in adults aged 50 to 59 years at increased risk. GlobalData made a statement about the news, framing the possible expansion as a boost to GSK’s positioning and a chance to exceed the $504 million in European sales analysts expect to see by 2029. 

The day after GlobalData released its statement, GSK said the FDA has accepted an application to expand the label in the U.S. under its priority review pathway. Both applications are supported by clinical data GSK presented in October. 

GSK studied Arexvy in people aged 50 to 59 years who had stable chronic diseases, such as diabetes and cardiovascular conditions, that put them at increased risk of RSV. People with immunosuppressive or immunodeficient conditions were excluded from the trial.

Talking to investors on a quarterly results conference call late last month, Luke Miels, chief commercial officer at GSK, called (PDF) the anticipated label expansion “a major opportunity” that could make the vaccine available to “around 15 million people.”

The filings position GSK to be the first RSV vaccine manufacturer to access those people, but its monopoly may be short-lived, as it was in the over-60 market. Pfizer is closing in on data from a phase 3 trial that is testing its rival vaccine, Abrysvo, in around 675 people who are aged 18 to 60 years and at high risk of severe RSV because of long-term medical conditions, plus a further 200 immunocompromised people.

A 2017 survey, which the Advisory Committee on Immunization Practices cited in its initial assessment of Arexvy, suggests some physicians are receptive to the idea of vaccinating younger, high-risk people. One third of the surveyed physicians said RSV is a very important pathogen in adults aged 50 to 64 years with cardiopulmonary disease.

Expansion into younger, high-risk people will open a new front in what looks set to be a three-way fight for the adult RSV market, with Moderna working to join GSK and Pfizer in the space. GSK made the best start, but Pfizer gained ground in the fourth quarter when sales of Arexvy and Abrysvo came in at 529 million pounds sterling ($668 million) and $515 million, respectively.