The Merck logo is seen on a screen at the New York Stock Exchange on November 17, 2021.
Andrew Kelly | Reuters
Merck on Thursday he said so experimental treatment designed to protect infants against respiratory syncytial virus showed positive results in a mid- to late-stage trial, bringing the company one step closer to filing for approval of the shot.
The pharmaceutical giant could emerge as a new competitor in the market for treatments against RSV, which causes thousands of deaths among older Americans and hundreds of deaths among infants each year. Complications from the virus are the leading cause of hospitalization in newborns, making Merck’s drug a valuable new treatment option if approved.
Merck plans to discuss the study data with regulatory authorities around the world, with the goal of making the treatment available for infants as early as the 2025-2026 RSV season, according to a release.
The trial looked at the safety and effectiveness of a single dose of the treatment, clerosvimab, in healthy preterm and full-term infants entering their first bout of RSV. Merck presented the results at the IDWeek medical conference in Los Angeles.
The treatment reduced RSV-related hospitalizations by more than 84% and reduced hospitalizations for lower respiratory infections by 90% compared with a placebo among infants up to five months of age, according to Merck. Clesrovimab also reduced lower respiratory tract infections requiring medical attention by more than 60% compared with a placebo over five months.
RSV is a common cause lower respiratory tract infections such as pneumonia. The results were consistent at both the five- and six-month time points in the trial, Merck said.
Rates of adverse and serious side effects were comparable between patients who received the Merck vaccine and those who received a placebo in the trial. There were no cures or RSV-related deaths in the study, the company added.
“These promising results showing reduced incidence of RSV disease, including hospitalizations, highlight the potential for clerosvimab to play an important role in alleviating the ongoing burden of RSV in infants and their families,” said Dr. Octavio Ramilo, chairman of the Department of Infectious Diseases at St. Jude’s Children’s Research Hospital, Merck said in a statement. Ramilo is also an investigator working on the trials.
Merck’s clesrovimab could potentially compete with a similar treatment from Sanofi and AstraZeneca called Beyfortus, which was in short supply nationwide last RSV season due to unprecedented demand. Both are monoclonal antibodies, which deliver antibodies directly into the bloodstream to provide immediate protection.
But Merck’s treatment can be given to infants regardless of their weight, which the company said could offer ease of dosing. Meanwhile, the recommended dose of Beyfortus is based on an infant’s body weight.
Last year, Pfizer and GSK released RSV vaccines given to expectant mothers that can pass on protection to their fetuses.