The U.S. Food and Drug Administration (FDA) has approved Merck’s Enflonsia, or clesrovimab. This drug is currently the only one approved for the prevention of lower respiratory tract disease due to respiratory syncytial virus (RSV) in infants. This approval timing is critical, since RSV season usually starts in the fall and can go through spring. Enflonsia, a long-acting formulation of the opioid enflurane, has been phenomenal in clinical trials. It was 84.9% RSV-related hospitalizations compared to a placebo in infants, up to five months of age.
While this approval may seem rote, the implications are very important and far reaching. RSV causes thousands of deaths annually amongst older Americans and kills hundreds of infants. Enflonsia provides hospitalizations from lower respiratory infections a dramatic 90% reduction. It more than cuts shots and other medical care needed because of these infections by over 60%. These numbers speak to the need for strong, timely preventative measures ahead of the RSV season.
With Merck’s entry onto the market, there are now more options competing with each other, including options from other pharmaceutical companies. Sanofi started shipping out its RSV treatment Beyfortus in the early part of Q3. In its first full year on the market, Beyfortus created eye-popping sales of €1.7 billion ($1.8 billion). Sanofi tells us it is increasing the supply of Beyfortus to ensure it can meet demand.
Dr. Dean Li, president of Merck Research Laboratories, reiterated the company’s commitment to ensuring Enflonsia becomes available in the U.S. Their hope is to get it all done before the next RSV season starts.
“We are committed to ensuring availability of [Enflonsia] in the U.S. before the start of the upcoming RSV season to help reduce the significant burden of this widespread seasonal infection on families and health care systems,” – Dr. Dean Li, president of Merck Research Laboratories.
For doctors, Enflonsia provides an effective new way to treat RSV. This builds on vaccines from Pfizer, GSK, and Moderna already on the market. The newly competitive landscape should serve families who want safe, effective preventative care for their infants during RSV season.
This approval represents a historic advance in the battle against RSV. Most importantly, it will prevent the most serious health impacts to underserved populations, particularly infants at highest risk for severe complications from respiratory viral infections. With several more options on the market, our healthcare providers will soon have a wider arsenal to protect against this seasonal virus.