The Food and Drug Administration on Monday approved a monoclonal antibody treatment to protect infants and young children from illness caused by respiratory syncytial virus, or RSV.
The drug, called Beyfortus and developed by partners AstraZeneca and Sanofi, is intended to prevent lower respiratory tract disease in newborns and infants who are entering their first RSV season. It’s also cleared for use in children up to two years old who remain vulnerable to severe disease.
“RSV can cause serious disease in infants and some children and results in a large number of emergency department and physician office visits each year,” said John Farley, head of the FDA’s office of infectious diseases, in a statement. “Today’s approval addresses the great need for products to help reduce the impact of RSV disease on children, families and the health care system.”
Beyfortus is the first RSV treatment to be approved for all infants. An older antibody drug, called Synagis, is available in the U.S., but its use is limited to specific high-risk infants or those with certain underlying medical conditions.
The FDA’s decision follows recent clearances of two RSV vaccines for older adults, who can also be at risk of serious illness from infection by the virus. Others, including one from Moderna, are in late-stage development — part of a flurry of research activity into the virus and how to attack it.
In June, a panel of FDA advisers backed use of Beyfortus in infants and toddlers, judging its benefits outweighed any risks to treatment. The drug, which is given via a single intramuscular injection, won regulatory clearance in Europe last year.
Typically, infections with RSV cause mild symptoms similar to those of a cold. They are common, too; the Centers for Disease Control and Prevention estimates that almost all infants will be infected before age 2.
In some, infection leads to pneumonia and swelling of airway passages in the lungs, which can be serious. Between 1% and 3% of children under 1 year old are hospitalized in the U.S. each year due to RSV, according to an estimate cited by the FDA.
The usual RSV season in the U.S. overlaps with when influenza and COVID-19 infections are also most prevalent, putting pressure on the healthcare system that Beyfortus could help ease. Sanofi, which will sell the drug in the U.S., said it and AstraZeneca plan to make treatment available ahead of the 2023-2024 season.
In clinical testing, Beyfortus reduced the risk of medically attended lower respiratory tract disease by 70% in one study, and by 75% in another. A third, larger study showed treatment was 83% effective in preventing hospitalization from RSV-related disease in infants under 1 year of age.
AstraZeneca and Sanofi also gathered data supporting the drug’s safety. Possible side effects to treatment include rash and injection site reactions. Two cases of low platelet counts were reported in one safety trial, but were judged not to be linked to the vaccine.
Beyfortus is currently under review in other countries including Japan and China.