A view shows the headquarters of GlaxoSmithKline in London, Britain, on January 17, 2022.
Hannah Mckay | Reuters
The Food and Drug Administration on Friday expanded approval of GSK's respiratory syncytial virus vaccine to adults ages 50 to 59 who are at increased risk of becoming severely ill from the potentially deadly virus.
The shot, called Arexvy, is the first vaccine approved by the FDA to protect that population from RSV. The agency first approved GSK's vaccine in May 2023 for patients age 60 and older, who are more vulnerable to severe cases of the virus.
RSV causes thousands of hospitalizations and deaths among older people each year, according to data 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 of becoming seriously ill from RSV, Phil Dormitzer, head of vaccine research and development and infectious disease research at GSK, said in an interview.
“It's helpful because of course you can meet the medical needs of that age group,” Dormitzer told CNBC, “but it's also good for pharmacists to have a single vaccine that they can give to a broader population, which provides simplicity”. “.
GSK's vaccine will not yet reach that new patient population. A CDC advisory panel will vote in late June on recommendations for the GSK vaccine, along with a rival vaccine from Pfizer and a recently approved jab from modern.
The expanded FDA approval could help GSK maintain its dominance in the RSV market later this fall and winter, when the virus typically spreads more widely in the U.S. The British manufacturer's vaccine clocked in at around £ 1.2 billion in sales last year, topping $890 million (£699 million) in revenue generated by the Pfizer vaccine.
GSK chief commercial officer Luke Miels said on an earnings conference call in May that the company remains “very confident” that Arexvy can generate more than £3 billion in peak annual sales over time.
Dormitzer said GSK had a successful final season of RSV, but noted that the company will always “take the competition seriously.”
He said Arexvy demonstrated great effectiveness in patients with underlying medical conditions.
In a late-stage trial, a single dose of the shot elicited an immune response in high-risk adults aged 50 to 59 that was no worse than that seen in people aged 60 and older.
An earlier late-stage trial in that older age group found the shot was nearly 83% effective in preventing lower respiratory tract disease caused by RSV and about 94% effective in preventing serious illness.
Safety data in adults ages 50 to 59 also matched data in adults ages 60 and older, according to GSK. Side effects included fatigue, headache, and muscle pain, among others, which were mostly mild to moderate in severity.
A single dose of GSK injection was only slightly less effective in adults aged 60 and older after two virus seasons, showing 67.2% efficacy against lower respiratory tract diseases. Dormitzer said the company will test the vaccine's effectiveness 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 reach of the injection in the future. The company is expected to announce trial data later in 2024 in two different patient groups: people ages 18 to 59 who are at higher risk for severe RSV and adults with weakened immune systems.
Dormitzer added that the company is also expanding the reach of the vaccine in other countries. Regulatory agencies in Europe, Japan and other areas are currently reviewing GSK's request to expand approval of Arexvy to high-risk adults aged 50 to 59.
GSK's vaccine is approved in nearly 50 countries, a company spokesperson told CNBC.
