FDA Grants BLA Review for Nirsevimab for RSV Prevention in Broad Infant Population

The US Food and Drug Administration will review the biologics license application (BLA) for nirsevimab for the prevention of respiratory syncytial virus (RSV) in infants and children up to age 24 months. The announcement, made jointly by codevelopers Sanofi and AstraZeneca (AZ), says the FDA will work to expedite its review, setting the PDUFA date in the third quarter of 2023.

If approved, the long-acting monoclonal antibody will be the first single-dose preventive option for the broad infant population, including those who are born healthy, at term or preterm, or with specific health conditions, according to the companies. The FDA will consider nirsevimab protection for infants entering or during their first RSV season and for those aged up to 24 months who remain vulnerable to the infection through their second RSV season, according to the companies.

An early and significant surge of RSV this year sorely stretched hospital capacity in the US and is blamed, in part, on the decline in COVID-19 mitigation precautions heading into the respiratory virus season as well as potentially reduced immunity tied to those precautions.

Data from the nirsevimab clinical program formed the foundation for the BLA, including results of the MELODY phase 3 trial in all subjects and the MEDLEY phase 2/3 trial in participants’ first and second RSV season, the companies state. MELODY findings were published in the New England Journal of Medicine in March 2022 and demonstrated a reduction in the incidence of medically attended lower respiratory tract infections (LRTI) caused by RSV by 74.5% (95% CI 49.6-87.1; P<.001) vs placebo through day 151 with a single dose. The drug’s safely and tolerability were assessed as similar to the profile for palivizumab (Synagis, Medimmune) with incidence of treatment emergent adverse or serious events similar between groups.

Calling the BLA a “landmark file acceptance in the US,” Sanofi Executive Vice President, Vaccines, Thomas Triomphe said in a statement that it “brings us one step closer to offering the first and only broadly protective option against RSV disease designed for all infants.

“Given the unprecedented number of otherwise healthy infants who have been hospitalized with RSV this year in the US and the recurrent pattern of RSV epidemics year after year, it is our intention to make nirsevimab available, if approved in time, for the 2023/2024 season to help alleviate the burden of RSV on families and the healthcare system.”

“Given the unprecedented number of otherwise healthy infants who have been hospitalized with RSV this year in the US and the recurrent pattern of RSV epidemics year after year, it is our intention to make nirsevimab available, if approved in time, for the 2023/2024 season to help alleviate the burden of RSV on families and the healthcare system.”

“This decision brings us a step closer to delivering a first-in-class preventative option for a broad infant population in the US,” said Iskra Reic, AstraZeneca executive vice president, vaccines and immune therapies in the AZ announcement. “If approved, we believe nirsevimab may transform the medical community’s approach to respiratory syncytial virus prevention in infants and we are committed to working with the FDA to support completion of the review as quickly as possible.”

Nirsevimab was granted marketing authorization in the European Union in November 2022 for the prevention of RSV LRTI in newborns and infants during their first RSV season. Additional global regulatory submissions also are underway, according to AZ.