Merck has won a major regulatory victory in Europe, with the European Commission approving its preventive therapy ENFLONSIA (clesrovimab) to protect newborns and infants from respiratory syncytial virus (RSV), a leading cause of infant hospitalizations worldwide.

 

The decision clears the way for rollout across all 27 EU member states, as well as Iceland, Liechtenstein and Norway, though access will depend on country-by-country reimbursement processes.

 

ENFLONSIA is a long-acting monoclonal antibody designed to shield infants through a typical five-month RSV season with a single, fixed dose—offering what the company describes as rapid and durable protection. However, it is противопоказicated for infants with hypersensitivity to its ingredients.

 

Health experts say the approval comes at a critical time, as RSV continues to pose a serious threat to young children.

 

“RSV can progress to severe conditions like bronchiolitis and pneumonia in both healthy and at-risk infants and is among the leading causes of infant hospitalization globally,” said Paolo Manzoni, Head of Maternal–Infant Medicine at University of Torino Hospital Degli Infermi and a clinical trial investigator. 

 

“The approval of ENFLONSIA in Europe represents an important public health achievement. Backed by strong clinical data from the CLEVER and SMART trials showing significant reductions in RSV disease incidence and RSV-associated hospitalizations, paired with dosing convenience, ENFLONSIA is a valuable new option with potential to help alleviate the burden of RSV on infants, families and health care systems.”

 

Merck executives framed the decision as a key step in expanding global access to RSV prevention.

 

“The European Commission approval of ENFLONSIA marks a significant milestone in our journey to enable broad access and help reduce the burden of RSV disease on infants around the world,” said Macaya Douoguih, vice president and head of global clinical development at Merck Research Laboratories. 

 

“We are proud to bring ENFLONSIA to infants in Europe and look forward to equipping families and health care providers with this important new preventive option to help address this widespread and potentially serious disease."

 

The approval is backed by late-stage clinical trials showing strong efficacy. In the pivotal CLEVER study, a single dose of ENFLONSIA reduced RSV-related lower respiratory infections by more than 60% and cut hospitalizations by over 84% compared to placebo over five months. Additional data showed even higher reductions in severe disease outcomes.