Regeneron’s Antibody Cocktail Appears Effective in Hospitalized COVID Patients

Regeneron has released positive initial results from an ongoing phase 1/2/3 study evaluating its antibody cocktail, casirivimab and imdevimab, in hospitalized COVID-19 patients who require low-flow oxygen.

The trial is assessing patients who had not started mounting an immune response to the coronavirus, measured by the lack of antibodies in their system, referred to as being seronegative. The seronegative patients receiving the cocktail had a reduced risk of mortality risk and of needing mechanical ventilation of approximately 50 percent, the company said.

In total, the trial enrolled 217 seronegative and 270 seropositive patients, with both groups receiving low-flow oxygen.

Regeneron’s CEO George D. Yancopoulos cautioned that “while the virology results from this analysis of hospitalized patients were robust, the clinical efficacy data are based on a small data set of events and cannot be viewed as conclusive at this stage.”

The FDA granted the antibody cocktail an Emergency Use Authorization in November for high-risk COVID-19 patients who aren’t currently hospitalized, and HHS begin distributing the treatment nationwide immediately as part of the federal government’s Operation Warp Speed initiative (DID, Nov. 24, 2020).

To meet the surging demand, Regeneron entered into a manufacturing partnership with Roche in August and has said it expects to provide enough of the antibody cocktail to treat approximately 300,000 patients in the U.S. by the end of January.

The antibody cocktail is also being evaluated in the UK’s RECOVERY trial, which has enrolled 2,000 hospitalized patients in the arm assessing the cocktail with standard-of-care vs. standard-of-care alone, the company said. ― Jason Scott