Clesrovimab
| Monoclonal antibody | |
|---|---|
| Type | Whole antibody |
| Source | Human |
| Target | Respiratory syncytial virus F protein |
| Clinical data | |
| Trade names | Enflonsia |
| Other names | MK-1654, clesrovimab-cfor |
| AHFS/Drugs.com | Monograph |
| MedlinePlus | a625082 |
| License data |
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| Routes of administration | Intramuscular |
| Drug class | Antiviral |
| ATC code | |
| Legal status | |
| Legal status |
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| Identifiers | |
| CAS Number | |
| DrugBank | |
| UNII | |
| KEGG | |
| Chemical and physical data | |
| Formula | C6526H10118N1732O2039S40 |
| Molar mass | 146747.22 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.
Clesrovimab is a fully human immunoglobulin G1 kappa (IgG1κ) neutralizing monoclonal antibody with a triple amino acid substitution in the Fc region which increases binding to the neonatal Fc receptor leading to an extended serum half-life. Clesrovimab provides passive immunity by targeting the RSV outer membrane fusion protein to prevent viral entry into cells.