Korea OKs Sanofi’s monoclonal antibody injection against RSV for infants

Sanofi Korea said it received marketing approval from the Ministry of Food and Drug Safety for Beyfortus, a monoclonal antibody injection designed to prevent respiratory syncytial virus (RSV) in infants.

RSV is a major cause of respiratory illness in young children, leading to conditions such as pneumonia and bronchiolitis.

While a Sanofi Korea official said the company views Beyfortus as a vaccine as it has preventive effects, Professor Ruth Karron, an expert in pediatric infectious diseases at Johns Hopkins Medicine in Baltimore, Maryland, the U.S., said monoclonal antibody injections like Beyfortus are different from vaccines, according to Medscape, a U.S. medical news outlet. 

A monoclonal antibody directly fights RSV infection, while a vaccine trains your body to make its own defenses.

Beyfortus, developed jointly by Sanofi and AstraZeneca, marks a significant breakthrough by being available not just for high-risk groups but for all infants facing their first RSV season.

The RSV season, typically spanning from October to March in Korea, poses a significant health threat each year. Beyfortus offers a significant advancement in public health measures against the virus, promising to maintain antibody protection for a minimum of five months, effectively covering the entire RSV season with just a single injection.

The MFDS approved the antibody after reviewing the results from the MELODY clinical trial, which demonstrated that Beyfortus significantly reduces medically attended lower respiratory tract infections caused by RSV by 74.5 percent compared to a placebo. The trials also confirmed the safety of the treatment, with adverse events similar to those observed in the placebo group.

Previously, the only RSV antibody approved in Korea was AstraZeneca's Synagis (ingredient palivizumab, which was limited to very high-risk groups, which included infants born before 35 weeks of gestation and under six months old at the start of the RSV season or those with significant congenital heart disease.

In contrast, Beyfortus can be administered to all infants up to 24 months old who are at high risk of severe RSV disease.

According to Sanofi, the timing of the Beyfortus injection is critical and varies depending on the birth month of the infant.

The company stressed that infants born during the RSV season should receive the injection shortly after birth, whereas those born outside the RSV season should be vaccinated just before the onset of the high-risk period.

"RSV infects 90 percent of infants and children before the age of two, and can lead to lower respiratory tract illnesses such as pneumonia and bronchiolitis," Sanofi Korea Vaccines General Manager Pascal Robin said. "The approval of Beyfortus is significant because it expands previously limited RSV prevention options to include all infants and children during their first RSV season.

Sanofi hopes that Beyfortus, like Sanofi's widely administered DTaP vaccine Pentaxim, will make a significant contribution to the prevention of infectious diseases in Korean infants and young children, Pascal added .