The FDA has granted approval for a new manufacturing line for Beyfortus (nirsevimab), the respiratory syncytial virus (RSV) antibody developed by Sanofi and AstraZeneca. This approval aims to significantly increase the supply of the antibody in the United States, ensuring broader access for newborns and infants during the 2024/2025 RSV season.
Beyfortus is a long-acting monoclonal antibody designed to provide passive immunity against RSV, a common virus that can cause severe respiratory illness in infants. The antibody targets and binds to the virus, preventing it from entering host cells and thus blocking infection at a cellular level. Approved in July 2023, Beyfortus is indicated for infants entering their first RSV season and for children up to 24 months old who remain at high risk of severe RSV infection during their second season.
Impact on RSV Prevention
According to Sanofi, the approval of the new filling line will enable the delivery of both 50-mg and 100-mg doses of Beyfortus to private healthcare providers and the Centers for Disease Control and Prevention (CDC) for its Vaccines for Children program. This expanded capacity is expected to ensure that every eligible baby, whether born during or outside the RSV season, can receive immunization either at birth or during regular checkups.
Thomas Grenier, head of vaccines, North America at Sanofi, emphasized the importance of this accomplishment, stating that it was made possible through close partnership with the White House, CDC, FDA, and healthcare providers. He noted that the newly approved filling line will help make Beyfortus widely available to patients who need it.
Clinical Efficacy and Real-World Data
Clinical data supports the effectiveness of Beyfortus in preventing RSV-related hospitalizations. A CDC analysis from March 2024 demonstrated that Beyfortus has 90% efficacy in preventing RSV hospitalization in infants. These findings reinforce the CDC's recommendation that all infants should be protected by either maternal RSV vaccination or infant receipt of nirsevimab.
New data presented at the Infectious Disease Society of America’s IDWeek 2024 annual meeting further reinforces the real-world effectiveness of Beyfortus. According to Thomas Triomphe, Executive Vice President, Vaccines, Sanofi, data from several national immunization programs consistently show that Beyfortus exceeds 80% effectiveness against RSV disease and hospitalization in infants. Triomphe also highlighted that Beyfortus delivers protection in the right dose for the right baby, regardless of whether they are born before or during the RSV season, at term or preterm, healthy or with underlying conditions.
Addressing RSV Burden
RSV is a highly contagious virus, with two out of three infants infected during their first year of life. It is the most common cause of lower respiratory tract disease in infants, including bronchiolitis and pneumonia, and a leading cause of hospitalization worldwide. In 2019, there were approximately 33 million cases of acute lower respiratory infections due to RSV, leading to over 3 million hospitalizations in children younger than 5 years. The estimated global direct medical costs related to RSV, including hospital, outpatient, and follow-up care, were €4.82 billion in 2017.
With the increased manufacturing capacity and proven efficacy of Beyfortus, Sanofi and AstraZeneca aim to significantly reduce the burden of RSV in infants, setting a new standard for RSV protection.
