Sanofi, AstraZeneca mark big leap toward filing of RSV drug in 2022, with safety data in hand to challenge Synagis
The last big piece of the data package that Sanofi and AstraZeneca needed to file their RSV antibody with the FDA is now in.
In a Phase II/III trial involving babies who were born preterm or had chronic lung disease or congenital heart disease, the partners said, nirsevimab showed a similar safety and tolerability profile compared to Synagis — the standard and only drug currently available for the same group. They are eyeing a filing in the first half of 2022.
Like Synagis, nirsevimab is an intramuscular injection designed to prevent serious lower respiratory tract infection by respiratory syncytial virus. The difference? While Synagis must be given monthly for the entire RSV season, nirsevimab’s extended half-life means one dose can last the whole winter.
“Given the typical RSV season lasts nearly five months, there is a potential advantage to providing a preventative option that could help protect all infants with one dose for the entire season,” said Joseph Domachowske, primary investigator of the trial, dubbed MEDLEY.
Investigators assessed safety by monitoring the side effects among 925 infants in the trial for close to a year after they were dosed. Sanofi and AstraZeneca didn’t break down the exact number of adverse events in either the nirsevimab or Synagis arm.
Infants were given the antibodies right before they enter their first RSV season — or at birth if they were born during it.
Although the MEDLEY trial had zeroed in on those at highest risk, Sanofi and AstraZeneca have much broader ambitions.
Earlier this year, they teased topline data suggesting that nirsevimab protected babies for the entire season, cutting lower respiratory tract infections in both healthy preterm and term infants. Previous results from a Phase IIb trial focused on preterm infants suggested the reduction of medically attended RSV infections was as big as 70% over placebo.
“RSV is the major remaining pediatric infectious disease with no preventative option available to all infants,” said Jean-François Toussaint, global head of R&D at Sanofi Pasteur. “We believe nirsevimab has the potential to become an important and innovative routine immunization for all infants – those born prematurely or at term, healthy or with health conditions.”
Under a €645 million alliance inked back in 2017, AstraZeneca is in charge of development through initial approvals as well as manufacturing, while Sanofi spearheads commercialization. AstraZeneca had since divested US rights to Synagis to Sobi (AbbVie is marketing the drug in the rest of the world).
SVB Leerink analyst Geoffrey Porges has forecast a blockbuster market for the drug, predicting that it will eclipse Synagis’ $1.4 billion in sales.