FDA approves Beyfortus ahead of 2023-24 RSV season


The U.S. Food and Drug Administration (FDA) has approved Sanofi and AstraZeneca’s Beyfortus (nirsevimab-alip) for the prevention of respiratory syncytial virus (RSV) lower respiratory tract disease (LRTD) in newborns and infants born during or entering their first RSV season. 

The approval also covers children up to 24 months of age who remain vulnerable to severe RSV disease through their second RSV season. 

The companies plan to make Beyfortus, a single-use long-acting antibody, available in the U.S. ahead of the upcoming 2023-2024 RSV season.

RSV is the leading cause of hospitalization for infants under the age of one in the U.S., averaging 16 times higher than the annual rate for influenza. Each year, an estimated 590,000 RSV disease cases in infants under one require medical care, including physician office, urgent care, emergency room visits and hospitalizations.

Thomas Triomphe, executive vice president, vaccines, Sanofi, said: “Today’s approval marks an unprecedented moment for protecting infant health in the U.S., following an RSV season that took a record toll on infants, their families, and the U.S. healthcare system. Beyfortus is the only monoclonal antibody approved for passive immunization to provide safe and effective protection for all infants during their first RSV season. I am proud that, by prioritizing this potential game-changer, we are now about to bring Beyfortus to American families.”

Beyfortus: an opportunity for a paradigm shift in RSV treatment

Iskra Reic, executive vice president, vaccines and immune therapies, AstraZeneca, added: “Beyfortus 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 science that Beyfortus is built on demonstrates AstraZeneca’s continued leadership in addressing the needs of the most vulnerable populations and reducing the burden on healthcare systems.”

The FDA decision follows the positive recommendation of the FDA Antimicrobial Drugs Advisory Committee and was based on the extensive Beyfortus clinical development program spanning three pivotal late-stage clinical trials. Across all clinical endpoints, a single dose of Beyfortus demonstrated high and consistent efficacy against RSV LRTD extending through five months, a typical RSV season.

Beyfortus was well tolerated with a favorable safety profile that was consistent across all clinical trials. The overall rates of adverse events were comparable between Beyfortus and placebo and the majority of adverse events were mild or moderate in severity. The most common adverse events were rash and injection site reactions.

The single administration of Beyfortus was developed to correspond with the beginning of the RSV season for babies born prior to the season or at birth for those born during the RSV season. In clinical trials, Beyfortus helped prevent RSV LRTD requiring medical care in all infant populations studied, including those born healthy at term, late preterm or preterm, or with specific health conditions that make them vulnerable to severe RSV disease. RSV disease requiring medical care included physician office, urgent care, emergency room visits and hospitalizations.

Beyfortus, jointly developed by Sanofi and AstraZeneca, was approved in the European Union in October 2022, in Great Britain in November 2022, and recently received approval in Canada in April 2023. Regulatory applications are also currently under review in China, Japan and several other countries.

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