While recent CDC guidance threatens to shrink the market for a new class of immunizations, GSK continues to build the case for its first-to-market respiratory syncytial virus (RSV) shot Arexvy.
GSK on Tuesday unveiled fresh data from the late-stage AReSVi-006 study of Arexvy in older adults over the span of three full RSV seasons.
In the trial, which looked at Arexvy’s ability to stop RSV-associated lower respiratory tract disease (LRTD) in people 60 and older, a single dose of GSK’s shot yielded a cumulative efficacy of 62.9% against RSV-associated LRTD—and 67.4% against severe RSV-LRTD—compared to placebo over three full RSV seasons.
Looking specifically at the third season, Arexvy was 48% effective against RSV-LRTD, GSK said.
The positive and clinically meaningful readout makes Arexvy the only RSV vaccine with efficacy and safety data spanning three years, including in people at increased risk from RSV, GSK said in a release.
GSK’s study looked at Arexvy’s efficacy against multiple RSV subtypes, as well as in adults with advancing age (70-79 years of age) and those with underlying medical conditions.
The drugmaker figures its cumulative efficacy data could allow healthcare professionals to administer the vaccine year-round.
To date, GSK has tallied more than 9 million doses of Arexvy being administered since its original approval last year. The shot holds the lion’s share of the RSV vaccine market in the U.S.
The British drugmaker’s shot won a landmark approval as the world’s first RSV vaccine last May. Pfizer subsequently snared a green light for its RSV shot Abrysvo in June of 2023, while Moderna scored approval for an mRNA offering, dubbed mRESVIA, in May.
Still, the newly unlocked RSV vaccine market is already facing significant growth hurdles thanks to a recent vote from the Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices (ACIP).
In late June, ACIP unanimously voted to recommend that adults aged 75 years and older and those aged 60 to 74 with a higher risk of severe disease receive a single lifetime dose of an RSV vaccine.
The prior recommendation urged all adults ages 60 and older to get vaccinated.
The ACIP vote was tied to the identification of a potential link between RSV vaccines and the rare neurological disorder Guillain-Barré syndrome (GBS).
A month after the narrowing of the recommendation, London-based healthcare analytics firm Airfinity slashed the U.S. RSV market value for seniors from $4.7 billion to $1.7 billion in 2030. The analysts added that the new recommendations reduce the eligible population in the U.S. by 44% to 46 million.
GSK quickly responded, with CEO Emma Walmsley in late July noting that the company was reducing its 2024 vaccine sales projection.
Despite the hit from the CDC recommendation, Walmsley stood strong in her conviction that Arexvy could eventually achieve peak annual sales of 3 billion pounds sterling (nearly $4 billion).