Regeneron eyes prevention nod for COVID-19 antibody cocktail with simpler injection

Regeneron’s Roche-partnered COVID-19 antibody cocktail, already authorized to thwart disease progression in sick patients, has come up with new data showing it can prevent the disease altogether at a lower dose in healthy people.

Among healthy individuals who lived with an infected person, the antibody therapy cut the risk of developing symptomatic COVID by 81% in a phase 3 trial jointly run with the National Institutes of Health, Regeneron said Monday. While the drug is currently authorized as an intravenous infusion, the new study hit its mark with a simpler, under-the-skin version.

The company now plans to take the data to the FDA and request an expanded emergency use authorization of the two-drug cocktail, dubbed REGEN-COV, as a COVID preventative measure, just like a vaccine.

“These data suggest that REGEN-COV can complement widespread vaccination strategies, particularly for those at high risk of infection,” said Myron Cohen, M.D., who leads NIH-sponsored COVID antibody trials. He also pointed out that the Regeneron drug has shown in lab dishes that it remains powerful in neutralizing emerging coronavirus variants.

The argument for an antibody therapy as an alternative preventative option alongside the many vaccines out there is that it can offer readily available immune protection. For a vaccine, recipients must have a strong enough immune system to generate coronavirus-fighting antibodies by themselves, and that process takes time.

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The current NIH-run study enrolled 1,505 people who had lived with an infected person within the prior four days. They received either one dose of subcutaneous REGEN-COV at 1,200 mg or placebo.

The drug’s efficacy showed up shortly after an injection, with the risk reduction of symptomatic COVID amounting to 72% in the first week. The reduction after the first week was 93%. For currently available vaccines, the top-line COVID risk reduction rates were calculated with only cases counted from seven days after complete vaccination.

The trial also hit key secondary endpoints. Even in those who developed symptoms, REGEN-COV takers cleared the virus and its symptoms faster.  

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“The rapid and robust protection, together with the subcutaneous route of administration, support the practical utility of these antibodies in protecting against COVID-19 in multiple settings, including after high-risk exposures,” Dan Barouch, M.D., Ph.D., co-principal investigator of the trial, said in a statement. He suggested that the therapy could also help those who have compromised immune systems and therefore may not respond well to vaccines.

Before Regeneron, Eli Lilly had shown its anti-coronavirus antibody, bamlanivimab, could reduce the risk of developing symptomatic COVID by 57% among residents and staffers of long-term care facilities in another NIH-run phase 3 trial. That drug, however, is given intravenously.

What’s more, the efficacy of single-agent bamlanivimab against SARS-CoV-2 variants has recently come under question, and the federal government has halted distributing the drug as a treatment for nonhospitalized patients out of that concern. By contrast, REGEN-COV is a combination of two antibodies, casirivimab and imdevimab. 

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In a separate phase 3 win Regeneron unveiled Monday, REGEN-COV as a 1,200-mg subcutaneous injection showed it could pare down the risk of progressing to symptomatic COVID by 31% among asymptomatic patients with a confirmed coronavirus infection.

“These data pave the way for REGEN-COV to be used before patients become symptomatic, with a more convenient subcutaneous administration,” Katharine Bar, M.D., co-principal investigator of the trial, said in a statement.

Previously, the IV formulation of the drug earned its emergency go-ahead after showing it could reduce hospitalization or death by 70% among high-risk mild-to-moderate symptomatic outpatients in another phase 3 trial. The current FDA emergency nod for that use is for a higher, 2,400-mg IV dose.

Regeneron penned a deal with the U.S. government in January, adding up to 1.25 million doses of REGEN-COV on top of an original 300,000 doses it’s supplying to the U.S.