Regeneron’s COVID-19 Antibody Cocktail Shows 8-Month Preventative Protection

A single dose of Regeneron’s COVID-19 antibody cocktail, REGEN-COV, slashed the risk of contracting the coronavirus by 81.6 percent up to eight months after treatment in a phase 3 trial.

While a study published in The New England Journal of Medicine in August showed patients given REGEN-COV ― casirivimab and imdevimab ― experienced a massive reduction in risk of incurring COVID-19 infection one month after treatment, Regeneron’s new data show the treatment can act as a preventive far longer than initially thought.

And the findings, from a late-stage study co-administered with the National Institute of Allergy and Infectious Diseases, carry special significance for certain populations.

“These results demonstrate that REGEN-COV has the potential to provide long-lasting immunity from SARS-CoV-2 infection, a result particularly important to those who do not respond to COVID-19 vaccines, including people who are immunocompromised,” said Myron Cohen, who oversees monoclonal antibody initiatives for the National Institutes of Health-sponsored COVID Prevention Network.

In addition, Regeneron said no one in the experimental arm was hospitalized due to COVID-19 compared with six people in the placebo group during the eight-month assessment period.

The FDA originally granted REGEN-COV an Emergency Use Authorization (EUA) in November 2020 to treat mild-to-moderate COVID-19 in patients 12 years and older who are at high risk of progressing to severe disease. In July, the agency expanded that EUA to include its use as a preventive in those who have been exposed to the coronavirus or who are at high risk of being exposed because of where they work or live (DID, Aug. 2).

And the new findings could spur a boost in sales, at a time when Regeneron faces looming competition from Merck’s and Ridgeback Biotherapeutics’ COVID-19 antiviral pill, molnupiravir, likely to soon be authorized by the FDA, as well as Pfizer’s investigational COVID-19 oral therapy, Paxlovid (07321332 plus ritonavir), which is poised to hit the market in the coming months if authorized (DID, Nov. 8).

The new data will also help support Regeneron’s FDA submission for full approval of REGEN-COV. Last month, the agency gave the company’s Biologics License Application a priority review with a target action date of April 13, 2022. ― Jason Scott