FDA Approves Nirsevimab-alip to Prevent RSV in Infants, Toddlers

Officials with the FDA have approved nirsevimab-alip (Beyfortus; Sanofi and AstraZeneca) for the prevention of respiratory syncytial virus (RSV)-associated lower respiratory tract disease in neonates and infants born during or entering the first RSV season, and in children up to 2 years of age who remain vulnerable to severe RSV disease through their second RSV season.¹

In most parts of the United States, circulation of RSV begins during the fall and peaks in the winter. It is transmitted through close contact with someone who is infected. Although most infants and young children experience mild, cold-like symptoms, some infants can develop lower respiratory tract disease, such as pneumonia and bronchiolitis, particularly during their first infection. This often leads to a visit to the emergency department or physician.¹

Premature infants, particularly those with chronic lung disease related to prematurity or significant congenital heart disease, are at the highest risk for severe RSV disease. Approximately 1% to 3% of children under 12 months of age are hospitalized each year due to RSV, according to data from the American Academy of Pediatrics.¹

“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, MD, MPH, director of the Office of Infectious Diseases in the FDA’s Center for Drug Evaluation and Research, in a press release. “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.”¹

Nirsevimab-alip is a monoclonal antibody with activity against RSV. A single dose, administered as a single intramuscular injection prior to or during RSV season, may provide protection.¹

“Beyfortus represents an opportunity for a paradigm-shift in preventing serious respiratory disease due to RSV across a broad infant population in the US,” said Iskra Reic, DMD, MBA, executive vice president of Vaccines and Immune Therapies at AstraZeneca, in a press release.²

The safety and efficacy of nirsevimab-alip were supported by 3 clinical trials (Trials 03, 04, and 05). Medically attended RSV lower respiratory tract infection (MA RSV LRTI) was evaluated during the 150 days after administration of nirsevimab-alip and included all health care provider visits for lower respiratory tract disease with worsening clinical severity and a positive RSV test.¹

Trial 03 included 1453 preterm infants, 969 of whom received a single dose of nirsevimab-alip and 484 received placebo. Among those who were treated with nirsevimab-alip, 25 (2.6%) experienced MA RSV LRTI compared with 46 (9.5%) who received the placebo. Immunization with nirsevimab-alip reduced the risk of MA RSV LRTI by approximately 70% relative to placebo.¹

In trial 04, the primary analysis group included 1490 term and late preterm infants, 994 of whom received a single dose of nirsevimab-alip and 496 of whom received placebo. Among those who were treated with nirsevimab-alip, 12 (1.2%) experienced MA RSV LRTI compared with 25 (5%) who received placebo. Nirsevimab-alip reduced the risk of MA RSV LRTI by approximately 75% relative to placebo.¹

Finally, trial 05 supported the use of nirsevimab-alip in children up to 24 months of age who remain vulnerable to severe RSV disease through their second RSV season. The trial enrolled 925 preterm infants as well as infants with chronic lung disease of prematurity or congenital heart disease.¹

Potential adverse effects include rash and injection site reactions.¹

“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 health care system,” said Thomas Triomphe, MSc, MBA, executive vice president of Vaccines at Sanofi, in a press release. “Beyfortus is the only monoclonal antibody approved for passive immunization to provide safe and effective protection for all infants during their first RSV season.”²

References

1. FDA Approves New Drug to Prevent RSV in Babies and Toddlers. News release. FDA. July 17, 2023. Accessed July 17, 2023. https://www.fda.gov/news-events/press-announcements/fda-approves-new-drug-prevent-rsv-babies-and-toddlers
2. FDA approves Beyfortus (nirsevimab-alip) to protect infants against RSV disease. News release. Sanofi. July 17, 2023. Accessed July 17, 2023. https://www.sanofi.com/en/media-room/press-releases/2023/2023-07-17-17-00-00-2705911