FDA to Review Nirsevimab for RSV Prevention in Kids Under 2

AstraZeneca’s Biologics License Application (BLA) for nirsevimab has been accepted for review by the US Food and Drug Administration (FDA) for the prevention of respiratory syncytial virus (RSV) lower respiratory tract disease in newborns and infants entering or during their first RSV season, and for children up to 24 months of age who remain vulnerable to severe RSV disease through their second RSV season.

Nirsevimab is a single dose long-acting antibody, developed and commercialized in partnership by AstraZeneca and Sanofi using AstraZeneca’s YTE technology. It is designed to protect infants entering or during their first RSV season and for children up to 24 months of age who remain vulnerable to severe RSV disease through their second RSV season.

Nirsevimabis being developed and commercialized by AstraZeneca in collaboration with Sanofi and is the first single-dose preventative option for the broad infant population, including those born healthy, at term or preterm, or with specific health conditions. The FDA has indicated it will work to expedite its review.  The Prescription Drug User Fee Act date, the FDA target action date for its decision, is in the third quarter of 2023. If approved at that time, nirsevimab will be available in the US for the 2023/2024 RSV season.

RSV is a very contagious virus that can lead to serious respiratory illness, according to the Centers for Disease Control and Prevention.¹ In the US, RSV is the leading cause of hospitalization for babies under one.² Any infant can be hospitalised in their first RSV season and about 75% of infants hospitalized for RSV in the US were born at term with no underlying conditions.^3-5

Dr William Muller, Associate Professor, Pediatrics, Northwestern University Feinberg School of Medicine and Scientific Director, Clinical and Community Trials, Ann & Robert H. Lurie Children’s Hospital of Chicago, Illinois, US, said: “A substantial burden of disease from RSV affects infants, families, and healthcare providers every year. Effective interventions to prevent RSV are a critical need. This year in the US, we’ve seen first-hand how frightening the impact of this respiratory disease is on our patients and how stressful it is on the healthcare system, highlighting the urgency of addressing this problem.”

Iskra Reic, Executive Vice President, Vaccines and Immune Therapies, AstraZeneca, said: “This decision brings us a step closer to delivering a first-in-class preventative option for a broad infant population in the US. 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.”

The BLA was based on results from the comprehensive nirsevimab clinical development programme, including the MELODY Phase III (primary cohort and all subjects), MEDLEY Phase II/III (first and second RSV season), and Phase IIb trials.^6-11 Data from the MELODY trial was 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<0.001) vs. placebo through day 151 (a typical RSV season) with a single dose.⁶ Nirsevimab also demonstrated a comparable safety and tolerability profile to Synagis (palivizumab) in the MEDLEY Phase II/III trial, with occurrence of treatment emergent adverse events (TEAEs) or treatment emergent serious adverse events (TESAEs) similar between groups.^10-11

In November 2022, nirsevimab was granted marketing authorization in the European Union for the prevention of RSV lower respiratory tract disease in newborns and infants during their first RSV season, under the name Beyfortus.¹² Additional global regulatory submissions are underway.