FDA approves GSK RSV vaccine for adults ages 50 to 59

The Food and Drug Administration expanded the approval on Friday GSK's respiratory syncytial virus vaccine for adults aged 50 to 59 who are at increased risk of getting it seriously ill of the potentially deadly virus.

The vaccine, called Arexvy, is the first approved by the FDA to protect that population against RSV. The agency first approved GSK's jab for patients in May 2023 60 and abovewho are more vulnerable to severe cases of the virus.

According to figures, RSV causes thousands of hospitalizations and deaths among seniors every year facts from the Centers for Disease Control and Prevention. But the virus can also cause serious illness in adults aged 50 and older – or even younger – with underlying chronic conditions such as asthma, diabetes and congestive heart failure.

About 13 million Americans ages 50 to 59 are at high risk for severe illness from RSV, Phil Dormitzer, GSK's head of vaccine research and development and infectious disease research, said in an interview.

“It's helpful because you can obviously meet the medical needs of that age group,” Dormitzer told CNBC, “but it's also nice for pharmacists to have a single vaccine that they can administer to a broader population, so that provides simplicity. .”

GSK's injection will not yet reach that new patient population. A CDC advisory panel will vote on recommendations for GSK's vaccine, along with a rival vaccine, later in June Pfizer and a newly approved shot of Modern.

The expanded FDA approval could help GSK maintain its dominance in the RSV market later this fall and winter when the virus usually spreads more widely in the U.S. The British drugmaker's shot posted sales of about £1.2 billion last year, up from $890 million (about £699 million) in revenue that Pfizer's vaccine brought in.

GSK Chief Commercial Officer Luke Miels said during an earnings call in May that the company remains “very confident“that Arexvy could rake in peak annual revenues of more than £3 billion over time.

Dormitzer said GSK had a successful season last RSV, but noted that the company will always “take the competition seriously.”

He said Arexvy showed strong efficacy in patients with underlying medical conditions.

In a late-stage study, a single dose of the shot produced an immune response in high-risk adults aged 50 to 59 that was no worse than that seen in people aged 60 and older.

A previous late-stage study in that older age group found the shot was almost 83% effective at preventing lower respiratory illness caused by RSV and about 94% effective at preventing serious illness.

Safety data in adults aged 50 to 59 were also consistent with data in adults aged 60 and over, according to GSK. Side effects included fatigue, headache and muscle pain, which were usually mild to moderate in severity.

A single dose of GSK injection was only slightly less effective in adults aged 60 and over after two seasons of the virus, showing 67.2% efficacy against diseases of the lower respiratory tract. Dormitzer said the company will test the vaccine's efficacy over three RSV seasons to see if it can provide even longer protection.

GSK is also studying Arexvy in other patient groups to expand the injection's reach in the future. The company is expected to release study data later in 2024 on two separate patient groups: people ages 18 to 59 who are at increased risk for severe RSV, and adults with weakened immune systems.

Dormitzer added that the company is also expanding the shot's reach in other countries. Regulators in Europe, Japan and other areas are currently reviewing GSK's application to expand Arexvy's approval to high-risk adults aged 50 to 59.

GSK's shot is approved in nearly 50 countries, a company spokesperson told CNBC.