Sanofi, AstraZeneca Report Positive Nirsevimab Results in RSV Trial

Sanofi and AstraZeneca announced positive topline results from the Phase 2/3 MEDLEY trial for Respiratory Syncytial Virus (RSV) in June 2021. The trial evaluated nirsevimab in preterm infants and those with chronic lung disease or congenital heart disease. Nirsevimab demonstrated a similar safety and tolerability profile to palivizumab, the current standard of care.

RSV is a common seasonal virus that causes lower respiratory tract infections and is the leading cause of hospitalization in infants. Nirsevimab is being developed as a potential first-in-class single-dose immunization aimed at providing protection for all infants throughout their first RSV season.

The MEDLEY trial results are the third pivotal trial to report positive data for nirsevimab. This follows positive results from the Phase 3 MELODY trial, where nirsevimab met its primary endpoint for reducing RSV-related lower respiratory tract infections in healthy preterm and term infants.

These findings, alongside data from a Phase 2b trial, are intended to form the basis for global regulatory submissions planned for the first half of 2022, aiming to offer a new preventative option for all infants against severe RSV disease.