Regeneron, Roche COVID-19 antibody cocktail slashes hospitalizations and tackles variants in phase 3

Regeneron
Regeneron expects to report $260 million in sales of the COVID antibody cocktail in the U.S. in the first quarter. (Regeneron)

Even as COVID-19 vaccines roll out across the globe, promising to eventually spark herd immunity to the virus, Regeneron’s executives have been preaching the value of having a powerful antibody cocktail on hand to treat those who do get sick—and to protect those who aren’t vaccinated.

Now Regeneron and its partner Roche have fresh phase 3 data to back up the theory. And if regulators agree with them, they could have a blockbuster on their hands, analysts have estimated.

The treatment, a combination of casirivimab with imdevimab, lowered the risk of hospitalization or death in high-risk, non-hospitalized patients by 70% compared with placebo, the companies said. The drug combo also retained its potency against five major variants, including those originating in South Africa, the U.K. and New York City. It was effective at three different doses, as well.

The drug combo, REGEN-COV, won emergency use authorization from the FDA in November, and the agency has said that it’s the only antibody treatment shown to tackle the new variants. But armed with the new data, Regeneron plans to ask the FDA to update its guidance to include the lowest dose tested in the trial, 1,200 mg.

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But the combo also faces competition from Eli Lilly's antibody cocktail. In a separate phase 3 trial, Eli Lilly's combo of bamlanivimab and etesevimab recently posted an 87% reduction in hospitalizations and deaths in high-risk patients who were treated early in the course of their infection. That drug combo also carries an FDA emergency use authorization in high-risk patients.

Both Roche and Regeneron called attention to the relevance of the new trial results to the ongoing effort to protect high-risk people from COVID-19 and emerging variants of the virus. All of the patients in the phase 3 trial had at least one risk factor for developing serious complications of the virus. Nearly 60% were obese, for example, while more than half were over age 50 and 36% had cardiovascular disease.

"With so many people still getting infected, as well as recent data showing that REGEN-COV addresses emerging variants, these data underscore the need to rapidly adopt REGEN-COV as standard-of-care to offer high-risk patients their best chance to reduce serious consequences like hospitalization or death," said study investigator Suraj Saggar, D.O., chief of infectious disease at Holy Name Medical Center in Teaneck, NJ, in a statement.

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Regeneron expects to report $260 million in sales of the COVID antibody cocktail in the U.S. in the first quarter, the company said. SVB Leerink analysts sent a note to clients Tuesday estimating that sales of the treatment could hit $2.6 billion in the second quarter. Morningstar analyst Karen Andersen said last fall that it could rake in $6 billion in sales this year. That’s double the peak sales she projected for Gilead Sciences’ Veklury (remdesivir).

Under their partnership, Regeneron handles U.S. marketing of the combo while Roche sells the cocktail outside the U.S. The European Medicines Agency (EMA) is conducting a rolling review of the combo, but the agency in February said the treatment could be used in patients who are at high risk of progressing to severe COVID-19 before the review is complete. Detailed data from the phase 3 will be shared with regulatory authorities across the world, Roche said in a statement.

But will the world still need COVID-19 treatments, given that the vaccine supply is expected to ramp up considerably in the coming months? Roche’s chief medical officer and head of global product development, Levi Garraway, M.D., Ph.D., pointed out that there were 3 million new cases of COVID-19 reported worldwide just last week. Therefore the antibody cocktail could find a market, “particularly in light of recent evidence showing that casirivimab and imdevimab together retain activity against key emerging variants,” he said.

Meanwhile, other trials of the Regeneron/Roche treatment are ongoing around the world. Investigators are testing it in hospitalized patients in the U.K., and in family members of people who have been infected with COVID-19, to see if it can prevent infections from the virus altogether.