US FDA panel backs Sanofi-AstraZeneca's preventive RSV therapy

[June 09, 2023]  By Raghav Mahobe and Mariam Sunny

(Reuters) -The U.S. Food and Drug Administration advisers on Thursday backed the use of Sanofi and partner AstraZeneca's experimental antibody to prevent respiratory syncytial virus (RSV) infections in infants.

The advisers voted unanimously in favor of using the antibody, nirsevimab, in newborns and infants to prevent infections in their first RSV season.

In a separate 19-2 vote, the panel backed the therapy's use in children aged up to two years who are vulnerable to severe illness through their second RSV season.

Swedish Orphan Biovitrum's treatment Synagis is currently the only approved preventive therapy in the United States for high-risk infants against RSV, a leading cause of hospitalizations during an infant's first year of life.

Unlike Synagis, which is given as monthly injections, nirsevimab is a long-acting therapy expected to be given once every season to prevent infection regardless of additional medical conditions in infants.

"This is probably the closest thing to an RSV vaccine that we have and it really moves the field forward," said panel member Nimish Patel.

Two studies showed the therapy was effective in preventing lower respiratory tract infections, the FDA staff reviewers had said on Tuesday.

A company logo is seen at the AstraZeneca site in Macclesfield, Britain, May 11, 2021. REUTERS/Phil Noble/File Photo

The panel vote comes a few weeks after advisers to the FDA backed the use of Pfizer's maternal vaccine, boosting its chances to become the first shot to protect infants from RSV. It is not known how the therapy works in infants whose mothers have received experimental RSV shots.

"I think there will need to be studies that are done to figure out when one is more useful than the other," panelist Karen Kotloff said.

Nirsevimab's peak sales are estimated to touch $2 billion, according to Morningstar analyst Dampen Conover.

The advisory panel provides non-binding recommendations to the FDA, which is expected to make a decision on the therapy by the third quarter.

(Reporting by Mariam Sunny and Raghav Mahobe in Bengaluru; Editing by Maju Samuel)

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