The FDA has endorsed Pfizer’s respiratory syncytial virus (RSV) vaccine Abrysvo for adults ages 18 to 59 who are at an increased risk of developing lower respiratory tract disease (LRTD). The approval makes the shot the first of its kind for adults who are younger than 50 years old.
While it’s a win for Pfizer over GSK and its RSV vaccine Arexvy, which is approved for those 50 and older, it’s difficult to determine how much advantage will be gained from the nod as the Centers for Disease Control (CDC) will have to sign off on Abvrysvo's use in the wider age group.
Four months ago, the CDC narrowed its recommendation for RSV vaccines to adults age 75 and older and those between the ages of 60 and 74 who are at risk of severe disease. The CDC had previously recommended the shots for all adults 60 and older.
The FDA thumbs up for Abrysvo comes on top of its original approval in May of 2023 for those 60 and older. Three months later, the U.S. regulator also endorsed Abrysvo for women in weeks 32 through 36 of their pregnancy to protect their soon-to-be-born infants.
The most recent nod was backed by the phase 3 MONeT trial, which showed that Abrysvo provided a non-inferior response in people between 18 and 59 years old compared to its performance in a previous study, which evaluated the shot in older adults.
The MONeT study examined Abrysvo’s performance across two subgroups. The trial enrolled 681 adults with chronic medical conditions for substudy A, plus another 200 immunocompromised individuals for substudy B. Patients who got Abrysvo in substudy A received a single dose, while those in substudy B received two doses.
“RSV represents a significant threat to younger adults with certain chronic conditions. After decades of vaccine research by the scientific community and Pfizer, we now have the opportunity to help alleviate the burden of RSV in this high-risk adult population,” Aamir Malik, Pfizer’s chief U.S. commercial officer, said in a release.
Among U.S. adults ages 18 to 49, 9.5% have an underlying chronic condition that increases their risk of developing severe disease, Pfizer said. In the 50 to 64 age group, the prevalence of at-risk individuals rises to 24%.
Among the most common conditions that put people at risk are obesity, diabetes, asthma, heart failure, chronic kidney disease and chronic obstructive pulmonary disease (COPD).
In addition to Abrysvo and Arexvy, there is a new entrant in the RSV adult market as Moderna scored FDA approval for its vaccine mRESVIA five months ago.
Last year, while Abrysvo generated sales of $890 million, GSK reported that revenue from Arexvy reached 1.2 billion pounds sterling ($1.5 billion). After the CDC’s narrowed recommendation, GSK reduced its projection for 2024 sales from a high single- to low double-digit percent growth to a low- to mid-single-digit percent at constant exchange rates.