Moderna gets FDA okay for RSV vaccine mResvia

Moderna has secured FDA approval for its respiratory syncytial virus (RSV) vaccine, giving it a chance to generate revenue from a second product as sales of its Spikevax COVID-19 shot have slumped.

The mRNA vaccine – called mResvia (formerly mRNA-1345) – has been cleared to protect older adults aged 60 and over from lower respiratory tract disease caused by RSV infection. It will compete in the US market with GSK’s Arexvy and Pfizer’s Abrysvo, both based on conventional protein-based vaccine technologies.

mResvia’s prescribing information indicates that the vaccine was 78.7% effective at preventing RSV that presents with two or more symptoms at 3.7 months of follow-up – a little lower than highlighted by Moderna in the New England Journal of Medicine paper on its pivotal trial – falling to 62.5% at 8.6 months.

Moderna’s shares dipped slightly on the approval announcement, likely due to that revised efficacy, according to analysts at William Blair.

mResvia’s top-line score comes in slightly lower than Arexvy and slightly above Abrysvo, they note – notwithstanding differences in study design – and will be weighed up against the convenience of mResvia’s prefilled syringe formulation and no reported cases of Guillain-Barré syndrome (GBS), a rare side effect seen with both GSK and Pfizer’s products.

There’s still one more step before Moderna’s vaccine can take on Arexvy and Abrysvo in the market. It will need to get endorsement from the Centers for Disease Control and Prevention (CDC) Advisory Committee on Immunisation Practices (ACIP) at a meeting due to be held 26th to 28th June.

At the moment, Arexvy is out in front in the market, having made around $1.6 billion in sales last year, compared to $890 million for Abrysvo, which is also approved for maternal use to prevent RSV in newborns and infants.

William Blair estimates that mResvia could eventually capture around 27% of the US market, which would translate to $1.5 billion in revenue in 2033.

“While mResvia may not have a best-in-class efficacy profile, we still see a significant market opportunity with the ability to differentiate on convenience of administration and no known GBS risk,” they wrote in a research note.

“The focus now shifts to the expected ACIP recommendation and potential for commercial contracting, which will be critical to Moderna’s return to top-line revenue growth in 2025 and breakeven in 2026.”

Spikevax generated $6.7 billion in sales for Moderna last year, down from $18.4 billion in the prior year, and fell to $167 million in the first quarter of 2024. The company has said it expects total revenues this year to reach $4 billion from sales of its updated version of Spikevax and mResvia.