Regeneron Phase 3 trial data for REGEN-COV cocktail shows 70 percent reduced risk for non-hospitalized COVID-19 patients

A Regeneron Pharmaceuticals, Inc.-created drug cocktail of casirivimab with imdevimab, REGEN-COV, was recently shown to provide a 70 percent reduced risk of hospitalization or death and shortened symptom duration in non-hospitalized patients afflicted with COVID-19.

The drug cocktail is meant for those with mild to moderate cases of COVID-19. During a phase three trial, the drugs provided a four-day shorter symptom duration and significantly reduced viral load compared to patients given only a placebo. At both 1,200 mg and 2,400 mg doses, similar efficacy was observed, offering evidence for the Food and Drug Administration (FDA) to potentially add the lower dose to an existing emergency use authorization.

“Despite increasing vaccination rates, many continue to be diagnosed with COVID-19 who could benefit from REGEN-COV due to underlying conditions like asthma or COPD that put them at higher risk for severe disease,” Dr. Julie Philley, Chair of Internal Medicine at the University of Texas Health Science Center and trial investigator, said. “The Phase 3 trial showed REGEN-COV helped patients avoid hospitalization or even death while speeding up recovery time. These results add to the growing body of clinical evidence, real-world experience, and strong recommendations by the National Institutes of Health COVID-19 treatment guidelines that collectively underscore the urgent need to ensure all appropriate patients are treated.”

The phase three trial was a randomized, double-blind, placebo-controlled trial conducted on 4,567 high-risk outpatients diagnosed with COVID-19. All involved had at least one factor that made them more at risk for severe COVID-19 cases, from chronic lung disease to obesity or age.

The hospitalization and death risk reduction held through day 29 of the study. A safety assessment of 5,531 patients up to day 169, producing a safety profile consistent with topline results released in March. Among the patient groups, 1.1 percent suffered serious adverse events from the 1,200 mg group, 1.3 percent from the 2,400 mg group, and 4 percent from the placebo group. Most were COVID-19 related, and while the two treated groups experienced only one death each, there were five deaths among the placebo group.

Results were presented at the 2021 American Thoracic Society International Conference.