A recent milestone in the fight against respiratory syncytial virus (RSV) was achieved with the approval of Merck’s clesrovimab by the Food and Drug Administration. Marketed under the name Enflonsia, this monoclonal antibody product is designed to protect infants under the age of 12 months from RSV. The wholesale price for Enflonsia has been set at $556 per dose, matching the price of its competitor, Beyfortus (nirsevimab) from Sanofi and AstraZeneca.
One notable difference between Enflonsia and Beyfortus is the dosing regimen. While Beyfortus offers two different doses based on a baby’s weight, Enflonsia provides a single dosage for all infants. This streamlined approach may simplify the administration process for healthcare providers and families, reducing the risk of dosage errors.
Enflonsia is currently approved for use only in a child’s first year when they face RSV, unlike Beyfortus, which can also be used in high-risk infants during their second RSV season. Merck is conducting a study to compare Enflonsia to Synagis, another RSV monoclonal antibody product, with the possibility of expanding its approval to include high-risk children in their second RSV season.
The Advisory Committee on Immunization Practices was expected to evaluate the use of Enflonsia at its upcoming meeting in June. However, the recent dismissal of the entire committee raises concerns about the meeting’s proceedings. Despite this development, the Health and Human Services Department confirmed that the meeting will proceed as scheduled.
Merck anticipates accepting orders for Enflonsia in July, with shipments planned for the 2025 RSV season. The efficacy of Enflonsia in reducing medically attended lower respiratory infections and RSV hospitalizations by significant margins underscores its importance in protecting infants from severe illness.
In recent years, the introduction of preventive tools for RSV has been a significant breakthrough. Pfizer’s Abrysvo vaccine, designed for pregnant individuals, helps transfer maternal antibodies to the fetus, offering protection during the critical RSV season. Additionally, babies born to unvaccinated mothers can receive monoclonal antibody treatment to safeguard against RSV.
The availability of Enflonsia, along with other preventive measures, marks a significant step forward in combating RSV and reducing its impact on families and the healthcare system. As research continues and advancements are made in RSV prevention, the outlook for infant health is becoming increasingly promising.
