Merck's Clesrovimab Shows Major Success in Preventing RSV in Infants
Merck's clesrovimab reduces RSV risk and hospitalizations in infants during Phase 2b/3 trial
Breaking News
Oct 18, 2024
Simantini Singh Deo

Merck (NYSE: MRK), also known as MSD outside the U.S. and Canada, shared encouraging findings from its latest clinical trials on clesrovimab, an experimental monoclonal antibody aimed at shielding infants from respiratory syncytial virus (RSV). Data from the Phase 2b/3 trial (MK-1654-004), presented at IDWeek 2024 in Los Angeles (October 16-19), showed that a single dose of clesrovimab successfully met all key objectives, reducing RSV risk in both preterm and full-term babies during their first RSV season. The trial results were consistent over both five and six months of follow-up.
In addition, interim results from the ongoing Phase 3 trial (MK-1654-007) were also highlighted. Importantly, the incidence of adverse events (AEs) and serious AEs in the clesrovimab and placebo groups were similar, with no treatment-related or RSV-related deaths reported.
Dr. Octavio Ramilo, chair of the Department of Infectious Diseases at St. Jude’s Children’s Research Hospital and investigator for the MK-1654-004 and MK-1654-007 trials, said in a statement, “RSV continues to be a widespread seasonal infection that can affect both healthy and at-risk infants and is the leading cause of hospitalization for infants. The MK-1654-004 study evaluated a broad spectrum of RSV disease ranging from mild outpatient illness to severe disease requiring hospitalization. These promising results demonstrating decreased incidence of RSV disease, including hospitalizations, highlight the potential for clesrovimab to play an important role in helping to alleviate the continued burden of RSV on infants and their families.”
The trial's main goal was to assess how well clesrovimab could reduce RSV-related lower respiratory infections (MALRI) needing medical attention compared to a placebo. The results showed a 60.4% reduction in such infections over the five-month period following the dose (p<0.001). Additionally, clesrovimab cut RSV-related hospitalizations by 84.2% and hospitalizations due to RSV-linked lower respiratory infections by 90.9%. The treatment was also highly effective in reducing severe cases of MALRI, with a 91.7% decrease compared to the placebo group.