In the Phase 3 MELODY trial, nirsevimab showed 74.5% efficacy against medically attended lower respiratory tract infections caused by RSV, in healthy infants
Nirsevimab reduces LRTI due to RSV. (Credit: Chokniti Khongchum from Pixabay.)
AstraZeneca and Sanofi announced that their monoclonal antibody vaccine nirsevimab has shown positive outcomes and met the primary efficacy endpoint in the Phase 3 MELODY trial.
MELODY is a randomised, placebo-controlled Phase 3 study, designed to determine the incidence of lower respiratory tract infections (LRTI) caused by a respiratory syncytial virus (RSV), compared to placebo.
In the study, healthy late preterm and term infants were randomised to receive a single 50mg or 100mg intramuscular dose of nirsevimab or placebo.
A single dose of nirsevimab vaccine in healthy infants showed 74.5% protection against, medically attended LRTI due to RSV, compared to placebo.
Sanofi vaccines research and development global head Jean-François Toussaint said: “With three pivotal late-stage trials, our research has been focused on delivering a first-in-class respiratory syncytial virus prevention for all infants.
“Our Phase III MELODY results in healthy late preterm and term infants represent a major milestone toward that goal. We are pleased nirsevimab has the potential to become the first immunization to protect all infants across the respiratory syncytial virus season, with only a single dose.”
AstraZeneca biopharmaceuticals R&D executive vice president Mene Pangalos said: “These data show for the first time, the potential to significantly protect all infants through their first respiratory syncytial virus season with a single dose immunisation and we look forward to working with health authorities to bring nirsevimab to infants as quickly as possible.”
In addition, the Phase 2/3 MEDLEY trial also showed that nirsevimab had similar safety and tolerability profile compared to Synagis (palivizumab).
The Phase 2/3 study evaluated the safety and pharmacokinetics of the drug in infants with congenital heart disease (CHD), chronic lung disease (CLD) and prematurity.
Nirsevimab induced serum levels that are comparable with those observed in the MELODY Phase 3 trial, demonstrating similar protection in this population.
Furthermore, a prespecified pooled analysis of the MELODY and Phase 2b trials showed that the proposed dose of nirsevimab reduced the hospitalisations caused by RSV.
RSV is a common, contagious virus that causes seasonal epidemics of lower respiratory tract infections (LRTI), leading to bronchiolitis and pneumonia in infants.
MELODY Phase 3 trial primary investigator William Muller said: “We know that respiratory syncytial virus has seen a resurgence with the easing of Covid-19 public health measures.
“This shows us a broad immunization approach is needed to help mitigate the substantial global burden respiratory syncytial virus places on infants, their families and healthcare services.
“These exciting data show that nirsevimab has the potential to offer RSV protection for all infants, which would be a paradigm shift in the approach to this disease.”