A Merck medicine developed to prevent respiratory syncitial virus disease (RSV) in babies has gained FDA approval, introducing competition to products that can already advance from Pfizer and Sanofi.
Monday’s regulatory decision for the antibody, known in development as Clesrovimab, covers its use in newborns and babies that enter their first RSV season, which covers the months of autumn and winter. For those born the RSV season, Classrovimab will be administered shortly after birth. Merck will market its new product under the Enflonsia brand.
RSV infection generally leads to symptoms that resemble the common cold in healthy people. But in babies and older adults, disease caused by RSV infection can lead to attractive respiratory complications for life. For almost three decades, the only product approved by the FDA to protect babies from the lower respiratory tract disease by RSV was Synagis, an antibody developed and marketed by Astrazeneca. That product approval covered its use only premature babies. This antibody has a short half life that requires a monthly dose. The most recent advances in RSV research have led products, such as Merck’s Enflonsia, which require only an injection.
Enlambo is an antibody designed to last in the body for approximately five months, which is long enough to protect a baby through a typical RSV season. The FDA decision for the product is based on the results of a phase 2b/3 clinical trial controlled with placebo that registered 2,858 babies that intertwine their first RSV season. The results showed a 60.5% reduction in the incidence of infections associated with the RSV compared to the placebo for five months. The antibody also led to a reduction in hospitalizations associated with RSV for five months. The most common adverde effect was the injection site reactions. In a phase 3 test that compared cooonsing with Synagis, the security of the Merck medication was comparable to the astrazeneca product.
The presence of Pfizer in RSV is through Abroysvo, a composite vaccine or a designed version of the RSV F -protein antigen F. First it was approved for use in older adults in 2023. Later that year, the vaccine was approved for maternal immunization, in which the immunization of a pregnant mother leads to the production of antibodies that are transmitted to the baby. Last year, the FDA extended Abysvo’s label to include adults aged 18 to 59. Pfizer reported $ 755 million in Revenue of Abroysvo in 2024 in all its approved uses, 15.1% less than the previous year. The company attributed the decrease to a significant reduction in vaccination rates of the United States for older adults, partly compensated by the strong demand for product use for maternal immunization.
Sanofi Beyfortus, approved in 2023, has become the dominant product for child protection of the RSV. Similar to Merck’s new RSV product, Beyfortus is a prolonged action antibody that, although technically a medicine, intends to protect as a vaccine. The antibody is designed with technology that gives it a half -life that lasts about five months. The R&D executive of Sanofi, Jon Heinrichs, told Medcity News in 2023 that Beyfortus’s progress on maternal immunization is that the administration can be scheduled to sacrifice the greatest protection. On the contrary, the moment of a birth can only be estimated, so the antibodies produced from maternal immunization can no longer be effective when the RSV season arrives or the season can decrease.
Beyfortus is administered as a single intramuscular injection. Sanofi reported $ 1.6 billion in income for the product in 2024, more than double its sales in the previous year. Unlike Beyfortus, whose dosage depends on the weight of a patient, Merck’s Encalesia occurs as the same dose of 105 mg independently or the patient’s weight. In a prepared statement, Dean Li, president of Merck Research Laboratories, said the company is committed to making Enflonsia available before the start of the next RSV season.
The recommendations for the use of the vaccine come from the advisory committee of control and prevention of diseases on immunization practices (ATCI). This committee is scheduled to convene June 25 to 27. Merck said he hopes ACIP discussing clamping in this meeting.
When the ACIP meeting occurs, it will have a completely new list. The Department of Health and Human Services announced on Monday that the 17 members of the committee session have been eliminated. HHS said that 13 or those members were appointed in 2024 under President Biden. All members will be replaced by new members currently under consideration. The secretary of the HHS, Robert F. Kennedy Jr., said in the announcement that “a clean sweep is necessary to restore public confidence in the science of vaccines.” Kennedy said, without evidence, that the Committee of Independent Advisors had been operating “as a rubber seal for the industry -gain obtaining agendas.”
The problem of the tok of the American Medical Association with the dismissal of the members of ACIP, stating that it has been trusted in the Committee to provide advice and guidance of sciences and data.
“Doctors, parents, community leaders and public health officials trust them for clinical guidance, public health information and knowledge,” said Dr. Bruce Scott, president of the association, in a statement sent by email. “Today’s action to eliminate the 17 members of Acip Socava who trust and restore a transparent process that has saved innumerable lives. With a continuous measles outbreak and the decrease in child vaccination rates of routine, this movement beyond diseases.”
Readink Partners, Daina Graybosch, said the shot of ACIP members increases risk for all vaccine manufacturers. The CDCs generally adopt ACIP recommendations and, according to the Law on low -price health care, payers must cover the vaccines recommended by ACIP without restriction or shared cost. In the best case, the new members of the committee will need time to catch up, which potentially delayed recommendations for less controversial products, such as Merck’s Enflonsia, said in a note sent to investors. In the worst case, the Committee could change the current recommendations for existing vaccines. While the composition of the new committee has not yet been determined, Graybosch said that new members will probably sympathize with at least Kennedy’s vaccine beliefs, as the apology with autism.
“Since today’s statement criticizes that the committee” has never recommended against a vaccine “, he suggests that ACIP could be more critical of vaccines, which could negatively affect the recommendations of approach and green vaccines or evidence,”