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Merck Announces Positive New Data for ENFLONSIA™ (clesrovimab) for Infants and Children Under 2 Years of Age at Increased Risk for Severe Respiratory Syncytial Virus (RSV) Disease Over Two RSV Seasons
RAHWAY, N.J., February 19, 2026--Merck Announces Positive New Data for ENFLONSIA™ (clesrovimab) for Infants and Children Under 2 at Increased Risk for Severe RSV Over Two RSV Seasons
About this update from Merck & Company, Inc.
[{"type":"image","alt":"","displaySize":"","headline":null,"caption":"","credit":null,"className":"","disableSlideshowImg":false,"size":{"original":{"width":480,"height":217,"url":"https://media.zenfs.com/en/business-wire.com/5af9b5c82857067df5ef8df81f116630"},"resized":{"url":"https://s.yimg.com/ny/api/res/1.2/GCedE1pKQvwgqhEqS0E4WA--/YXBwaWQ9aGlnaGxhbmRlcjt3PTk2MDtoPTQzNDtjZj13ZWJw/https://media.zenfs.com/en/business-wire.com/5af9b5c82857067df5ef8df81f116630","width":480,"height":217}},"lazy":false},{"type":"text","content":"Second season results from the Phase 3 SMART trial were presented at the 9th RSVVW Conference and will be shared with the U.S. FDA and other regulatory authorities","length":163,"tagName":"p","attribs":{}},{"type":"text","content":"RAHWAY, N.J., February 19, 2026--(BUSINESS WIRE)--Merck (NYSE: MRK), known as MSD outside of the United States and Canada, today announced positive second RSV season findings from the Phase 3 SMART trial (MK-1654-007) (NCT04938830) evaluating the safety, efficacy and pharmacokinetics of ENFLONSIA™ (clesrovimab) in infants and children at increased risk for severe respiratory syncytial virus (RSV) disease over two RSV seasons. The data were presented during an oral session (Abstract #P455) at RSVVW’26, the 9th conference of the Respiratory Syncytial Virus Foundation (ReSViNET) in Rome, Italy.","length":598,"tagName":"p"},{"type":"text","content":"New data from the SMART trial in children under 2 years of age who remained at increased risk for severe RSV disease through their second RSV season and received ENFLONSIA at the start of RSV season 2 showed that safety was generally consistent with safety observed in MK-1654-007 infants who received ENFLONSIA during RSV season 1. Additional safety data can be found below. Additionally, the monoclonal antibody (mAb) serum concentrations achieved in children under 2 years of age at increased risk for severe RSV disease through their second RSV season (secondary endpoint) were similar to those in healthy infants in the pivotal Phase 2b/3 CLEVER trial (MK-1654-004) (NCT04767373). Results from the SMART study support extrapolation of efficacy to children under 2 years of age at increased risk for severe RSV disease through RSV season 2.","length":844,"tagName":"p"},{"type":"text","content":""All children who received ENFLONSIA in their second RSV season were at i...