Sanofi ramps up RSV shot supply as new rival looms

FRANCE – Sanofi is ramping up production and distribution of its RSV treatment, Beyfortus, just a day before the FDA decides on a potential competitor from Merck & Co.

The company has announced that it will start shipping its AstraZeneca-partnered antibody in early Q3, ensuring ample supply for the upcoming RSV season.

According to Sanofi, current supplies of Beyfortus match the total doses distributed last year, with manufacturing still ongoing.

Since launching Beyfortus in 2023, Sanofi and AstraZeneca have tripled production capacity and doubled manufacturing sites.

“This marks a new era in infant health,” said Thomas Triomphe, head of vaccines at Sanofi. “With data from over 40 studies involving 250,000 immunized infants, Beyfortus has proven its effectiveness.”

This early announcement highlights Sanofi’s awareness of the looming competition. If approved, Merck’s RSV monoclonal antibody, clesrovimab (MK-1654), could challenge Beyfortus’ dominance.

Merck’s recent trial results suggest clesrovimab significantly reduces RSV-related hospitalizations and infections, with a single-dose formula.

While both treatments target RSV, they focus on different antigenic sites, making direct comparisons difficult.

Merck claims its version is less likely to develop resistance and offers a single-dose option, while Sanofi emphasizes Beyfortus’ six-month protection and higher medically attended lower respiratory infection (MALRI) rate.

Regardless of FDA approval for clesrovimab, Sanofi remains confident that Beyfortus will continue growing in 2025, as highlighted by chief financial officer François Roger in the company’s earnings report earlier this year.