Pharma giant Pfizer said on Tuesday that it plans to seek regulatory approval to expand the allowed use of its RSV vaccine, Abrysvo, for adults 18-59, following positive results from a last-stage clinical trial. There is currently no approved vaccine for adults under 59 years old who have an increased risk for the respiratory virus.
“We are excited to address a significant unmet need, pending regulatory authority approval, as ABRYSVO has the potential to become the first and only RSV vaccine for adults 18 years and older,” Pfizer Senior Vice President and Head of Vaccine Research and Development Annaliesa Anderson said in a press release.
RSV, or respiratory syncytial virus, is a common cause of respiratory illness among young infants and older adults. In the U.S., RSV is responsible for 60,000-160,000 hospitalizations and 6,000-13,000 deaths among older adults each year, according to Pfizer.
The pharmaceutical company launched its RSV vaccine last year, which the U.S. Food and Drug Administration approved for adults older than 60 and pregnant woman as a way to protect their infants. The FDA also last year approved AstraZeneca’s RSV vax for infants.
In this new study, Pfizer tested its vaccine on 681 individuals between 18 and 59 years old who have chronic conditions that make them vulnerable to RSV. About 10% of that demographic lives with such a condition.
The trial found that the vaccine resulted in a similar immune response to its previous phase 3 trial of the drug for older adults. One month after taking the vaccine, participants developed at least four times increase in levels of neutralizing antibodies for the two primary types of RSV.
Pfizer vs. GSK — the race for market dominance
The news comes as Pfizer is trying to catch up with U.K.-based GlaxoSmithKline (GSK). Its RSV vaccine for adults was approved by the FDA in May. The company is already undergoing priority review with the FDA to expand the approved use of its jab for adults 50-59 years old. The agency is expected to make a decision by June 7.
GSK’s vaccine, Arexvy, generated 1.2 billion pounds ($1.6 billion) in revenue for the company in 2023.
For comparison, Pfizer’s Abrysvo generated $515 million in revenue in 2023.