Pfizer's Abrysvo maintains strong efficacy through 2nd RSV season, study finds

Pfizer’s respiratory syncytial virus (RSV) vaccine Abrysvo has shown its staying power in older adults who received a single dose before the previous virus season.

In season two, Abrysvo was 78% effective against RSV-associated lower respiratory tract disease with at least three symptoms in people 60 and older, according to trial results released Thursday. After the first season of the RENOIR phase 3 study, Abrysvo’s efficacy was 89%. 

The bivalent shot maintained its efficacy for both strains of the virus—the more common RSV A and RSV B, with efficacy for both strains exceeding 80%.

Abrysvo was approved in May of last year for adults 60 and older. Three months later, Pfizer tacked on an FDA nod for Abrysvo for pregnant women to protect their newborns.

While Abrysvo generated $890 million in sales in its first year on the market, it trailed GSK’s RSV vaccine Arexvy, which achieved sales of 1.2 billion pounds sterling ($1.5 billion).

The silver lining for Pfizer was that it made up ground on GSK in the fourth quarter with $515 million in sales versus 529 million pounds ($671 million) for Arexvy. Another positive, according to Pfizer's fourth-quarter earnings presentation, was the sales of Abrysvo for expectant mothers. They are eligible for the shot in weeks 32 through 36 of their pregnancy.

Sanofi and AstraZeneca compete with Pfizer in protecting infants from RSV. Their partnered antibody Beyfortus, which can be given to children up to 24 months old, raked in 547 million euros ($592 million) last year.