Merck announced positive Phase 3 clinical trial results for Enflonsia (clesrovimab), a monoclonal antibody designed to protect infants against respiratory syncytial virus (RSV) infection. The SMART trial demonstrated consistent safety profiles in children under 2 years old, supporting the company's regulatory strategy to broaden the treatment's approved use.
The biopharmaceutical company plans to submit the trial data to the U.S. Food and Drug Administration as it pursues expanded indication for children at elevated risk of severe RSV disease during a second respiratory season. RSV is a leading cause of lower respiratory tract infection in infants globally, with certain pediatric populations—including premature infants and those with congenital heart or chronic lung disease—facing heightened risk of severe complications.
Approval of an expanded indication would allow Merck to extend protection to a broader patient population beyond the currently approved use, potentially addressing a significant unmet medical need in pediatric infectious disease management. The FDA will evaluate the submitted clinical data as part of its standard review process.