Clesrovimab

Clesrovimab
Monoclonal antibody
TypeWhole antibody
SourceHuman
TargetRespiratory syncytial virus F protein
Clinical data
Trade namesEnflonsia
Other namesMK-1654, clesrovimab-cfor
License data
Routes of
administration
Intramuscular
Drug classAntiviral
ATC code
  • None
Legal status
Legal status
Identifiers
CAS Number
DrugBank
UNII
KEGG
Chemical and physical data
FormulaC6526H10118N1732O2039S40
Molar mass146747.22 g·mol−1

Clesrovimab, sold under the brand name Enflonsia, is a fully human immunoglobulin G1 kappa monoclonal antibody designed to prevent respiratory syncytial virus (RSV) infection. It is a respiratory syncytial virus (RSV) F protein-directed fusion inhibitor. It was developed by Merck, and was approved for medical use in the United States in June 2025.