The opinion by the
Committee for Medicinal Products for Human Use of the
European Medicines Agency was based on data from two randomized, double-blind, placebo-controlled multicenter clinical trials that investigated the efficacy and safety of nirsevimab in healthy preterm (premature) and full-term infants entering their first RSV season. The studies demonstrated that nirsevimab prevents lower respiratory tract infection caused by RSV requiring medical attention (such as
bronchiolitis and
pneumonia) in term and preterm infants during their first RSV season. The safety of nirsevimab was also evaluated in a phase II/III, randomized, double‑blind, multi-center trial in infants who were born five or more weeks prematurely (less than 35 weeks gestation) at higher risk for severe RSV disease and infants with chronic lung disease of prematurity (i.e. long-term respiratory problems faced by babies born prematurely) or
congenital heart disease. The results of this study showed that nirsevimab had a similar safety profile compared to
palivizumab (Synagis). The US
Food and Drug Administration (FDA) evaluated the safety and efficacy of nirsevimab based on three trials, two of which were randomized, double-blind, placebo-controlled, multicenter clinical trials (Trials 03, 04 and 05). The key measure of efficacy was the incidence of medically attended RSV lower respiratory tract infection (MA RSV LRTI), evaluated during the 150 days after nirsevimab administration. MA RSV LRTI included all health care provider visits (physician office, urgent care, emergency room visits and hospitalization) for lower respiratory tract disease with worsening clinical severity and a positive RSV test. Trial 03 included 1,453 preterm infants (born at greater than or equal to 29 weeks of gestational age up to less than 35 weeks of gestation) who were born during or entering their first RSV season. Of the 1,453 preterm infants in the trial, 969 received a single dose of nirsevimab and 484 received placebo. Among infants who were treated with nirsevimab, 25 (2.6%) experienced MA RSV LRTI compared with 46 (9.5%) infants who received placebo. nirsevimab reduced the risk of MA RSV LRTI by approximately 70% relative to placebo. For Trial 04, the primary analysis group within the trial included 1,490 term and
late preterm infants (born at greater than or equal to 35 weeks in gestational age), 994 of whom received a single dose of nirsevimab and 496 of whom received placebo. Among infants who were treated with nirsevimab, 12 (1.2%) experienced MA RSV LRTI compared with 25 (5.0%) infants who received placebo. Nirsevimab reduced the risk of MA RSV LRTI by approximately 75% relative to placebo. Trial 05, a randomized, double-blind, active (
palivizumab)-controlled, multicenter trial, supported the use of nirsevimab in children up to 24 months of age who remain vulnerable to severe RSV disease through their second RSV season. The trial enrolled 925 preterm infants and infants with chronic lung disease of prematurity or congenital heart disease. The safety and pharmacokinetic data from Trial 05 provided evidence for the use of nirsevimab to prevent MA RSV LRTI in this population. The FDA granted the application for nirsevimab a
fast track designation. and granted approval of Beyfortus to AstraZeneca. == Society and culture ==