Sincial respiratory virus: approved in the USA a new monoclonal antibody to protect infants with a single dose

The SINACIAL respiratory virus (RSV) – to which we have dedicated numerous insights – is one of the main infectious agents responsible for bronchiolitis and pneumonia in children under two years oldand it is the most frequent cause of hospitalization in babies in the United States and in many other countries. Every year, millions of cases are actually recorded all over the world, with seasonal peaks ranging from autumn to spring. In most cases the symptoms are mild, similar to those of a cold, but in the little ones – particularly in infants – the RSV can cause serious complicationsespecially in premature subjects or with chronic diseases.

To date there is no active pediatric vaccine against the RSV and the preventive options are limited. It is in this context that it is filed Clesrovimab-CFora monoclonal antibody recently approved by the Food and Drug Administration (FDA) In the United States for the prevention of infection in infants at their first seasonal exhibition to the virus.

Clesrovimab-CFor: how it works and who is intended

Developed by the multinational Msd (Merck & Co. in the USA and Canada), Clementrovimab -CFor – of which we had already spoken – is a long -lasting monoclonal antibody designed to offer a passive and immediate protection. It is administered via a Single 105 mg injectionregardless of the weight of the newborn, and guarantees one Five months coverage – Equivalent to the average duration of an RSV season, even if they are always longer.

Approval concerns children born during or just before the epidemic season of the virus. In infants born in the middle of the RSV season, administration can take place From the first days of life; For those born outside of this period, the drug should be administered before the start of the first following season. In case of cardiac surgery with bypass in the first months of life, a second dose is expected as soon as the newborn is stabilized.

Clinical effectiveness demonstrated

The clinical data underlying the approval of the FDA derive mainly from Two large -scale studies: the Clever Trial and the Smart Trial. The first, phase 2b/3, involved over 3,600 babies, evaluating the effectiveness of a single dose against the onset of serious respiratory infections. The results show one 60.5% reduction in cases of infection of the low respiratory tracts that need medical intervention and a reduction of 84.3% of the hospitalization from RSV in the five months following the administration.

The second study, Smart, instead went beyond involving infants considered to high risk complications from RSVincluding premature and children with chronic lung pathologies or congenital heart disease. Also in this case Clesrovimab-Cfor has shown an overlapping effectiveness to that of Pallivizumab (drug currently used in prophylaxis in newborns at risk), with a similar security profile and more lasting coverage.

Favorable security profile

Clesrovimab-CFor is generally well tolerated. The most common adverse reactions recorded in the trials have been mild or moderate and include Erythema (3.8%), swelling on the injection site (2.7%) and rash (2.3%). It must not be administered to children with a known story of serious allergic reactions to one of the components of the drug. As with other human monoclonal antibodies, there is a theoretical risk of anaphylaxis but in the trials the majority of reactions has been of grade 1 or 2. In addition, the drug can be administered in concomitance with routine childhood vaccines without compromising their tolerability.

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The opinion of the experts

“The RSV is one of the main causes of hospitalization in infants and can lead to very serious respiratory conditions, such as bronchiolitis and pneumonia” explained Octavio Ramilo of St. Jude Children’s Research Hospital of Memphis, in Tennessee, involved in the main clinical studies on the drug. “Clesrovimab-CFor offers a concrete alternative, with solid clinical data and an advantage in terms of comfort of administration”.

“This antibody represents a turning point in the ASV prevention,” he added Dean Y. Lipresident of the Merck Research Laboratories. “Our goal is to make it available already before the next RSV season, to reduce the impact of the disease on babies and health systems”.

Next steps

By the end of the month, the consultative committee for the immunization practices of the Centers for Disease Control and Prevention US will meet to formulate official recommendations on the use of Clesrovimab-Corfor in infants. The ruling will be crucial for the insertion of the drug into clinical practices in the USA and, in perspective and as often happens, also in other countries.

What is the syncial respiratory virus

The RSV (respiratory syncytial virus) is a very widespread pathogen that affects the respiratory tract, easily transmitting itself by air or by direct contact with contaminated surfaces. In most adults and healthy children it causes mild symptoms, but in babies can cause serious infections of the low respiratory tract.
In Europe the virus is responsible for tens of thousands of hospitalizations every year and the absence of a pediatric vaccine has pushed the research towards new preventive strategies, such as monoclonal antibodies. With the arrival of Clementrovimab-Cfor, for now only in the USA, a new phase is now opening in the fight against this virus in the most vulnerable subjects: babies.