1 Dose of Nirsevimab Reduced Infant RSV Hospitalizations by Over 83%

Today, the global health care company Sanofi announced new trial data demonstrating a single dose of nirsevimab had an 83.21% reduction in infant hospitalizations due to respiratory syncytial virus (RSV).

RSV is the most common cause of lower respiratory tract disease (LRTD), including pneumonia and bronchiolitis, in infants. It is also a leading cause of hospitalization in all infants. Though the world’s first RSV vaccine (GSK’s Arexvy) was recently approved by the US Food and Drug Administration (FDA) to prevent RSV disease in older adults, their remains no vaccine nor antiviral treatment options for infants and young children.

At the 41st Annual Meeting of the European Society for Pediatric Infectious Diseases (ESPID), Sanofi presented nirsevimab data from their Hospitalized RSV Monoclonal Antibody Prevention (HARMONIE) study. This large, multicountry, European interventional clinical trial sought to determine the safety and efficacy of a single intramuscular dose of nirsevimab.

The HARMONIE phase 3b study recruited more than 8000 infants under 12 months of age across nearly 250 sites across Germany, France, and the United Kingdom. Investigators compared a single intramuscular dose of nirsevimab (<5 kg 50 mg; ≥5 kg 100 mg) to no intervention, and found nirsevimab reduced hospitalizations due to severe RSV-related LRTD by 83.21%.

Additional data from the HARMONIE trial suggest nirsevimab reduced the incidence of hospitalizations due to severe RSV-related LRTD, defined by requiring oxygen supplementation, by 75.71%. Nirsevimab also reduced all-cause LRTD hospitalization by 58.04% compared to infants who received no intervention. Throughout the HARMONIE trial, and into the 12-month follow-up period, nirsevimab maintained a favorable safety profile.

Nirsevimab is a long-acting antibody, in development by Sanofi and AstraZeneca, to protect all infants against RSV disease. “Monoclonal antibodies do not require the activation of the immune system to help offer timely, rapid, and direct protection against the disease,” stated Sanofi.

The RSV space is rapidly developing. Stay up to date with the latest RSV trials and approvals on Contagion.