Merck Seeks FDA Approval to Expand RSV Drug Use

Merck has submitted a supplemental Biologics License Application to the FDA to expand its use of ENFLONSIA, an RSV drug, to children under two years old at increased risk for severe respiratory syncytial virus disease through their second RSV season.

The application is based on data from the Phase 3 SMART trial, which enrolled early or moderate preterm infants and infants with chronic lung disease of prematurity or congenital heart disease. In the first RSV season, 502 participants received a 105 mg dose of ENFLONSIA while 501 received monthly palivizumab.

The FDA has set a target action date of March 22, 2027 for its decision on the application. ENFLONSIA is already approved in more than 40 countries, including the United States, Canada, and the European Union, for use in infants during their first RSV season.