The respiratory syncytial virus (RSV) vaccine showdown already saw a shake-up last month with a new competitor in Moderna’s mRESVIA. Now, all three vaccine offerings face a potentially shrunken market.
In an unconventional move, the Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices (ACIP) revised recommendations for RSV vaccinations in what could be viewed as a smaller population.
For what will be only the second RSV season with available vaccines, the panel unanimously voted to recommend that adults aged 75 years and older and those aged 60 to 74 with a higher risk of severe disease due to underlying medical conditions receive a single lifetime dose.
Previously, RSV vaccination was recommended for all adults aged 60 and older, upon consultation with their healthcare providers. Now, for the 75-and-above age group, a person is automatically recommended to receive an RSV shot without the need for evaluation. But the higher-risk restriction in the 60-to-74 group marks a clear setback for the vaccine developers.
With a recent potential link identified between the shots and the rare neurological disorder Guillain-Barré syndrome (GBS), the committee changed its tune on the lower-risk RSV population.
Earlier this year, health officials flagged a preliminary statistical analysis that discovered 23 of the some 9.5 million older adults who received an RSV vaccine developed GBS. The link is still being studied, including by GSK, which pledged to start a controlled epidemiological study in March.
Share prices sank for each RSV vaccine maker following the vote, with GSK’s dipping 3.57%, Pfizer’s falling 2.04% and Moderna’s dropping 11%, all by market close on Wednesday.
Moderna already faces an uphill battle to catch up with the two established offerings, GSK’s Arexvy and Pfizer’s Abrysvo. Arexvy specifically was the first to score approval last year and has since led its Pfizer rival in sales and market share, with some two-thirds of the market and 182 million pounds sterling ($227 million) in revenue over this year’s first quarter. Pfizer, meanwhile, collected quarterly Abrysvo sales of $145 million.
The ACIP meeting was key to gauging the potential impact of Moderna’s entry, GSK’s Luke Miels said on a call earlier this year. The decision would kick off a “race to lock down contracts” ahead of the next RSV season, which typically begins in the fall.
While Moderna’s vaccine has not yet launched, the longer-term data the company presented at ACIP could suggest a tougher battle against the two rivals. At 18.8 months of follow-up, mRESVIA’s vaccine efficacy rate stood at 50%, according to the mRNA drugmaker. Previously, a phase 3 study touted an 81% efficacy rate against RSV after 3.7 months of post-vaccination follow-up.
Meanwhile, Abrysvo’s efficacy rate was 78% at 16.4 months, and Arexvy’s stood at 68% after 23 months.
Arexvy’s latest data, which demonstrate what “appears” to be “the most impressive” vaccine efficacy of the group, should help it keep up its majority market share, analysts at Evercore ISI wrote in a note to clients.
However, the GSK preference isn’t unanimous globally. Earlier this week, the U.K. government chose Pfizer to supply 5 million doses of its Abrysvo over the next two years. That vaccine is also approved as a maternal vaccination to protect newborns.