Sanofi, AstraZeneca advance immunization master plan with US nod for infant RSV drug Beyfortus

Sanofi’s immunization scheme is starting to fall into place thanks to an approval that could propel it and its partner AstraZeneca to the front lines of the respiratory syncytial virus (RSV) scene.

Monday, the U.S. FDA gave a thumbs-up to Sanofi and AstraZeneca’s antibody Beyfortus, also known as nirsevimab, as a preventive for RSV lower respiratory tract disease in babies. The approval covers newborns and infants born during or entering their first RSV season, as well as young kids up to 24 months old who remain at risk of RSV through their second disease season.

The go-ahead thrusts Sanofi and AZ into an indication recently crowded by Pfizer and GSK, which won back-to-back FDA approvals for their adult vaccines this summer. In Pfizer’s case, the company is also working on a vaccination to protect babies through maternal immunization. The FDA is set to make a decision on that application next month. 

Sanofi and AstraZeneca aim to make Beyfortus available in the U.S. ahead of the upcoming 2023-24 RSV season, the partners said in a press release.

According to Sanofi and AZ, RSV is the main culprit behind hospitalizations for infants under the age of 1 in the U.S., averaging 16 times higher than the annual rate for influenza. What’s more, some 590,000 RSV disease cases in newborns require some form of medical care each year.

Sanofi has been banking on a U.S. approval for Beyfortus for months. After the antibody’s world-first approval in Europe back in November, the French pharma recently talked a big game about the role a stateside green light would play in its broader immunization game plan moving forward.

As part of a broader goal to bring home more than 10 billion euros in annual immunization sales by 2030, Sanofi surmised that—first and foremost—it must become a leader in RSV, both with Beyfortus and a pair of experimental shots.

“Our ambition is to lead in RSV across all critical target populations and that ambition starts with Beyfortus in infants,” Kimberly Tutwiler, head of Sanofi’s RSV franchise, said on a conference call last month.

At the time, Tutwiler noted that U.S. manufacturing was already underway, adding that “we expect to fulfill the demand for this first season.” 

She pointed out that Sanofi had already engaged with many physicians and public health experts, who’ve been “waiting for decades for a solution for RSV that they could offer to the broad infant population.”

Regarding Monday’s approval, Thomas Triomphe, executive vice president of vaccines at Sanofi, called the occasion an “unprecedented moment for protecting infant health,” while AZ’s EVP of vaccines and immune therapies, Iskra Reic, said the antibody “represents an opportunity for a paradigm-shift in preventing serious respiratory disease due to RSV across a broad infant population in the U.S.”

The FDA approval was largely expected after Beyfortus cruised through an agency meeting of outside experts early last month. At an advisory committee meeting in June, panelists voted 21 to 0 that Beyfortus boasted a favorable benefit-risk profile to protect against RSV-associated lower respiratory disease in infants born during or entering their first RSV season.

On a separate voting question of whether the antibody had a favorable benefit-risk profile in children up to 24 months of age who remain vulnerable through their second RSV season, the vote was 19 to 2 in favor of Sanofi and AZ’s product.

According to the partners, a single dose of Beyfortus—across all clinical endpoints—demonstrated “high and consistent” efficacy against RSV lower respiratory tract disease through five months, which is the span of a typical RSV season.

Aside from Europe and the U.S., Sanofi and AZ’s drug has also snagged clearance in the U.K. and Canada. The antibody is currently under review in China, Japan and several other countries.