RSV Injection Approved by FDA for All Infants

Lisa Gillespie

July 17, 2023

The US Food and Drug Administration (FDA) on Monday approved a new drug against respiratory syncytial virus (RSV) for newborns and infants.

The monoclonal antibody Beyfortus (nirsevimab-alip), which already is approved for use in Europe and Canada, is indicated for newborns and infants born during or entering their first RSV season, and for children up to 24 months of age who are vulnerable to severe RSV through their second RSV season.

As many as 80,000 children under age 5 years are hospitalized with an RSV infection annually in the United States. Most cases are mild, but infants under 6 months, those born prematurely, and children with weakened immune systems or neuromuscular disorders are at an increased risk for severe illness, according to the Centers for Disease Control and Prevention.

The highly contagious virus is also a concern for immunocompromised adults and older people with underlying health conditions, who are at increased risk for severe disease.

Sanofi and AstraZeneca, which jointly developed the drug, said in a press release that the companies plan to make the medication available by the fall of 2023. The long-acting antibody is given as a single intramuscular injection.

Beyfortus was approved in part based on data from the phase 3 MELODY trial, which found the injection reduced the incidence of medically attended lower respiratory tract infections associated with RSV by 74.9% versus placebo (95% CI, 50.6 - 87.3; P < .001).

The phase 2/3 MEDLEY trial, conducted between July 2019 and May 2021, compared Beyfortus with palivizumab, another RSV antibody injection with more limited indications. The trial included more than 900 preterm infants less than 35 weeks gestational age and infants with congenital heart disease. Results were similar to the phase 3 MELODY trial, according to the manufacturers.

"Today's approval marks an unprecedented moment for protecting infant health in the US, following an RSV season that took a record toll on infants, their families, and the US healthcare system," said Thomas Triomphe, executive vice president for vaccines at Sanofi, in a press release about the FDA decision. "Beyfortus is the only monoclonal antibody approved for passive immunization to provide safe and effective protection for all infants during their first RSV season."

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