Thanks to respiratory syncytial virus (RSV) shot Arexvy’s new label expansion into a slightly younger pool of adults, GSK is more confident than ever that its vaccine will be able to conquer the competition.

June 7, the FDA approved Arexvy for RSV prevention in adults ages 50 to 59 who are at increased risk of developing RSV disease. The green light marks Arexvy’s first new approval since the vaccine’s original nod to prevent lower respiratory tract disease (LRTD) caused by RSV in adults ages 60 and older last May.

According to GSK’s research, there are about 13 million people between the ages of 50 and 59 in the U.S. with underlying conditions that place them at higher risk of RSV disease, Len Friedland, M.D., vice president and director, scientific affairs and public health, vaccines at GSK, said in an interview.

Those chronic conditions include congestive heart disease, asthma and chronic obstructive pulmonary disease as well as diabetes and chronic kidney disease, the executive explained.

Increasing age puts people at greater risk of developing severe outcomes from RSV, including hospitalizations and trips to the intensive care unit, Friedland said.

“We estimate there are about 42,000 hospitalizations each year in adults 50 to 64 due to RSV, so there’s tremendous opportunity to prevent morbidity and perhaps even mortality from RSV,” Friedland said of the latest Arexvy approval.

With Arexvy’s label expansion locked down, the next milestone ahead for GSK is its meeting with the Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices scheduled for June 26, at which point the government's vaccine advisers will decide whether to widely endorse the company’s vaccine in the new age range.

“We see it as so important to build on what’s happened in the pediatric space where vaccination has become part of routine practice,” Friedland explained. “To have that translate into the adult arena is really important.”

GSK’s Arexvy became the world’s first approved RSV vaccine last May, backed up by data showing the immunization was 82.6% effective at preventing RSV-related LRTD in older adults. Shortly thereafter, in June 2023, Pfizer won its own RSV nod in older adults with its vaccine Abrysvo, kicking off a fierce competition between the two companies.

Meanwhile, just last week, Moderna snagged a green light for the first FDA-approved mRNA shot in RSV, dubbed mRESVIA. The biotech’s vaccine is also cleared to protect adults ages 60 and older from LRTD caused by RSV.

To hear Friedland tell it, Arexvy’s rollout has gone “extremely well” so far thanks to the high unmet medical need for an RSV vaccine at the time the shot debuted last summer.

More than 8 million people 60 years of age and older in the U.S. received a dose of Arexvy during the first RSV season after launch, the executive said.  

Between Arexvy—which currently controls more than 60% of the market—and Pfizer’s rival RSV shot Abrysvo, roughly 22% of U.S. adults ages 60 and over received an RSV vaccine last year, which Friedland hailed as a “great start.”

Looking ahead, GSK will continue to attempt to expand Arexvy’s reach: The company is currently studying the shot in people 18 and older at increased risk of RSV—both those who are immunocompromised with solid organ transplants as well as those who have any of the underlying comorbidities covered in today’s approval—Friedland pointed out.

GSK expects to have data on those populations in the second half of 2024, at which point the company will follow up with the FDA, he said.

As for the recent approval of Moderna’s RSV vaccine mRESVIA, “I think it’s great,” Friedland said.

“We want there to be innovation, and we want there to be options, and we want there to be choices,” he said. “Now, it’s our job to gather and continue to generate the evidence that speaks to the value of Arexvy.”

“We believe that we have the market-leading vaccine, and our goal is to keep it that way,” Friedland stressed.

Over the first three months of 2023, Arexvy maintained its market lead against rival Abrysvo. In the first quarter, Arexvy generated 182 million pounds sterling ($227 million) versus Abrysvo's sales of $145 million.

Cumulatively since launch, Arexvy has generated 1.2 billion pounds ($1.5 billion) while Abrysvo has managed to take home $1.03 billion.