By Fineline Cube 
The US Food and Drug Administration (FDA) granted approval to Merck, Sharp & Dohme’s (MSD; NYSE: MRK) Enflonsia (clesrovimab-cfor) for single-dose immunization in infants to protect against respiratory syncytial virus (RSV)-associated illnesses during their first RSV season. This long-acting monoclonal antibody provides immediate, rapid, and durable protection throughout the typical 5-month RSV season.
Clinical Trial Results
The FDA’s decision followed the review of results from the pivotal Phase IIb/III CLEVER study (MK-1654-004), which demonstrated a 60.5% reduction in RSV-associated medically attended lower respiratory tract infections (MALRI) requiring ≥1 LRI or severity marker. Additionally, there was an 84.3% reduction in RSV-related hospitalizations, with enhanced efficacy as disease severity increased.
Additional Trial Data
Supporting data also came from the Phase III SMART trial (MK-1654-007), evaluating the safety and efficacy of Enflonsia compared to palivizumab in infants at high risk for severe RSV disease.-Fineline Info & Tech