A new monoclonal antibody to protect newborns from respiratory syncytial virus

Respiratory syncytial virus (RSV) prevention for infants could soon expand to include an additional option. This is a new prophylactic monoclonal antibody, clesrovimab, developed to provide up to five months of protection against lower respiratory tract disease in infants and children. The Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) has recently recommended approval for this monoclonal antibody.

Respiratory Syncytial Virus: Impacts and Prevention

In our region, RSV is a typically seasonal virus (autumn-winter) and is responsible for respiratory problems that can cause serious illnesses, such as pneumonia and bronchiolitis, in young children and vulnerable individuals due to age and underlying health conditions, requiring hospitalization. Global estimates, for children under 5 alone, speak of approximately 3.6 million hospitalizations per year, over 200,000 in Europe. "Most RSV-related hospitalizations occur in healthy full-term newborns," explains Luigi Orfeo , director of the Center of Excellence for Women and Newborn Children at Gemelli Hospital on Isola Tiberina. Preventing infection in the youngest children is possible.

To date, there are two monoclonal antibodies available (palivizumab, which requires repeated administration, and nirsevimab, which is long-lasting), and a vaccine reserved for pregnant women for passive immunization of newborns. "Monoclonal antibodies for the prevention of respiratory syncytial virus infection," added Alberto Villani , Coordinator of the Pediatrics Unit at the Bambino Gesù Children's Hospital in Rome, "represent one of the most important medical advances in recent decades, having proven to be an extraordinary weapon capable of minimizing the devastating effects of bronchiolitis in infants and reducing short-term (deaths, intensive care admissions, hospitalizations) and long-term (outcomes in adulthood such as COPD) healthcare costs, thus promoting the sustainability of our National Health System."

The new monoclonal antibody

Clesrovimab is a new, long-acting monoclonal antibody that can be administered at the same dose to all newborns regardless of weight. The indications for use include administration to infants during their first epidemic season, i.e., those born during the season, or just before the start of autumn for infants born in previous months.

European approval expected by the end of the year

The manufacturer announced that the new monoclonal antibody could be approved in Europe as early as the end of the year. The drug's efficacy and safety—already approved in the U.S.—are based on two clinical trials that tested it in full-term and preterm infants up to one year of age, and compared it with palivizumab in infants at increased risk (palivizumab is indicated for children considered at higher risk of RSV disease). Efficacy against hospitalizations at 5 months was 84% ​​compared to a placebo, while the new antibody showed comparable efficacy compared to monthly palivizumab injections. Erythema, swelling at the injection site, and rash were the most common adverse reactions.

“The CHMP's positive opinion opens the door to a new solution that guarantees solid protection and safety data together with a single dosage that guarantees greater simplicity and organizational practicality,” commented Caterina Rizzo , Professor of General and Applied Hygiene, Department of Translational Research and New Technologies in Medicine and Surgery at the University of Pisa. “We look forward to this new prophylaxis option becoming part of our prevention arsenal to protect the youngest children and their families.”