AstraZeneca (AZ) and Sanofi’s long-acting antibody nirsevimab met the primary endpoint in a late-stage respiratory syncytial virus (RSV) trial in healthy infants.
RSV, a common and contagious pathogen that causes seasonal epidemics of LRTI, is the leading cause of hospitalisations in infants globally.
The phase 3 MELODY trial was designed to determine the incidence of medically attended lower respiratory tract infections (LRTI) due to RSV in healthy infants entering their first RSV season.
In this trial, healthy late preterm and term infants, born at 35 weeks or greater gestational age, were randomised to receive a single 50mg or 100mg injection of nirsevimab or placebo.
Nirsevimab hit the primary endpoint of a statistically significant reduction in the incidence of LRTIs caused by RSV compared to placebo in this population, AZ and Sanofi announced yesterday.
According to the companies, nirsevimab is the first potential immunisation to show protection against RSV in the general infant population in a phase 3 trial.
The MELODY trial is ongoing to collect additional safety data, with detailed results to be presented at forthcoming medical meeting.
The evaluation of the primary efficacy endpoint of MELODY trial was conducted ‘earlier than anticipated’, due to the global public health measures designed to curb COVID-19 reducing the circulation of all respiratory viruses including RSV.
As such, a ‘sufficient’ number of cases had accrued prior to the pandemic to evaluate nirsevimab’s ability to prevent LRTI caused by RSV compared with placebo.
“These ground-breaking results mark a major scientific advancement in our effort to provide protection against respiratory syncytial virus for all infants,” said Mene Pangalos, executive vice president, BioPharmaceuticals R&D at AZ.
“Nearly all children will contract the virus before age two, leading to nearly 30 million acute lower respiratory tract infections globally each year. Nirsevimab has the potential to provide a significant public health benefit as the first respiratory syncytial virus immunisation for the general infant population,” he added.
In 2017, AZ and Sanofi teamed up to develop and commercialise nirsevimab – then known as MEDI8897 – for the prevention of LRTI caused by RSV.
In addition to the MELODY trial, nirsevimab is being evaluated in the phase 2/3 MEDLEY trial, which is assessing the monoclonal antibody (mAb) compared to the older RSV treatment Synagis (palivizumab) among preterm infants and children with chronic lung disease (CLD) and congenital heart disease (CHD).
The MELODY, MEDLEY and another phase 2b trial will form the basis of regulatory submissions for nirsevimab planned for 2022.