Merck’s ENFLONSIA receives EU committee backing for at-risk children through their second RSV season
- CHMP recommended expanding ENFLONSIA’s indication to prevent RSV lower respiratory tract disease in at-risk children up to 24 months old.
- The European Commission will review the recommendation for the EU, Iceland, Liechtenstein and Norway; a decision is expected within two months.
- The recommendation is supported by the Phase 3 SMART trial, which studied children at increased risk across two RSV seasons.
- The US FDA set March 22, 2027, as its target action date for Merck’s application to expand the indication.
EU recommendation
The European Medicines Agency’s Committee for Medicinal Products for Human Use (CHMP) recommended expanding ENFLONSIA (clesrovimab) to prevent respiratory syncytial virus (RSV) lower respiratory tract disease in children up to 24 months of age who are at increased risk of severe disease through their second RSV season. The European Commission will review the recommendation for the EU, Iceland, Liechtenstein and Norway, with a decision expected within two months.
Eligible children and evidence
Children who may remain vulnerable include those born with chronic lung disease or congenital heart disease, and some early or moderately preterm children with specified risk conditions. The recommendation is supported by the Phase 3 SMART trial, which evaluated ENFLONSIA in infants and children at increased risk over two RSV seasons. In the second season, 276 eligible children received an additional open-label 210 mg dose; 99% had chronic lung disease or congenital heart disease.
Regulatory status
ENFLONSIA was approved in the US in June 2025 and in the EU in April 2026 for infants born during or entering their first RSV season. Merck’s US application to extend use to at-risk children under two is under FDA review, with a target action date of March 22, 2027.
Source: Merck