FDA Approves Clesrovimab To Protect Against RSV In Infants

June 10, 2025

MedPage Today (6/9) reports Merck announced Monday that “the FDA approved clesrovimab (Enflonsia) to prevent lower respiratory tract disease from respiratory syncytial virus (RSV) in infants born during or entering their first RSV season.” The company explained that “the long-acting monoclonal antibody is designed to provide ‘rapid and durable protection’ through 5 months – the typical length of an RSV season – with a 105-mg dose, regardless of weight.” The agency’s approval was “based on results from the pivotal phase IIb/III CLEVER trial, which showed that a single dose of clesrovimab protected against RSV disease and prevented RSV hospitalizations among healthy preterm and full-term infants.”