GSK's Arexvy Wins Expanded FDA Approval for High-Risk Adults Under 50

GSK's respiratory syncytial virus shot gained an expanded approval on Friday from the Food and Drug Administration, a decision that represents a victory in what's been a difficult regulatory climate for vaccine makers of late.

The vaccine, Arexvy, was first approved for use in adults aged 60 and older, and then those 50 to 59 years of age and at higher risk of severe RSV-related disease. The new approval expands its potential use significantly, opening it up to what GSK estimates to be 21 million Americans who are under 50 and have at least one risk factor for severe disease. It also heightens Arexvy's competition with Pfizer's Abrysvo and Moderna's mResvia, which are approved for the same population.

RSV is a leading cause of respiratory illness and can cause severe health complications in infants, the elderly and people with weakened immune systems. In a statement, GSK noted that RSV also causes about 17,000 hospitalizations, 277,000 emergency department admissions and 1.97 million outpatient visits each year in younger adults. Most of those hospital stays involve people with chronic medical conditions that put them at higher risk of severe disease, according to GSK. And some studies have indicated that cases for people with underlying medical problems may be underreported.

GSK's head of vaccines and infectious research and development stated in the announcement that 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.

GSK was the first company to win approval of an RSV vaccine and has since held a commanding market share. But after an initially strong launch, sales have been slipping amid falling demand, particularly in the U.S. The Centers for Disease Control and Prevention has yet to endorse RSV booster shots, limiting Arexvy's sales potential.

Like other vaccine developers, GSK faces slowing sales in the U.S., where the federal government has taken a more combative stance against immunizations under the leadership of Health and Human Services Secretary Robert F. Kennedy Jr. The CDC rolled back what had been universal endorsements for the childhood vaccine schedule, while the Food and Drug Administration set stricter guidelines for vaccine approvals.

Still, there are signs of a potentially friendlier stance in the months ahead. The FDA recently announced that its top vaccine official, Vinay Prasad, will leave the agency at the end of April. And of late, multiple published reports suggested the Trump administration is shying away from more vaccine policy changes amid polling suggesting it could damage Republicans in the midterms.

GSK said the approval was based on study data showing the immune response generated by Arexvy in younger adults was as good as what was observed in testing in older individuals. Safety was also consistent with what was previously seen in testing.