REGEN-COV Shows Reduced Risk of Symptomatic COVID-19 in Phase 3 Trial

Regeneron Pharmaceuticals, a leading biotechnology company, has recently announced positive results from their phase 3 prevention trial, which is assessing their monoclonal antibody cocktail in reducing the risk and burden of COVID-19.

The trial was jointly run by the National Institute of Allergy and Infectious disease (NIAID), which is part of the National Institute of Health (NIH).

"These findings are very encouraging and suggest that REGEN-COV is highly effective at preventing symptomatic COVID-19 in household contacts of SARS-CoV-2 infected individuals," Dan H. Barouch, co-principal investigator of the trial said. “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.”

The Phase 3, double-blind, placebo-controlled trial looked at the effect of REGEN-COV on uninfected individuals with no anti-SARS-CoV-2 antibodies or any COVID-19 symptoms and lived in the same household as someone who tested positive for the virus within the previous 4 days.

All 1,505 participants of the trial were randomized 1:1 to receive either 1 dose of REGEN-COV or a placebo.

REGEN-COV is a monoclonal antibody cocktail consisting of casirivimab and imdevimab. The two were created specifically to block infectivity from the SARS-COV-2 virus, and are potent, virus-neutralizing antibodies.

Findings from the trial demonstrated that the treatment reduced the risk of symptomatic infections by 81%. Additionally, those who did develop symptomatic disease cleared the virus much faster and experienced a shorter duration of symptoms.

Adverse events occurred in 20% of those who received the cocktail, with serious events impacting only 1%. There were 0 hospitalizations in the REGEN-COV arm and 4 in the placebo arm.

"With more than 60,000 Americans continuing to be diagnosed with COVID-19 every day, the REGEN-COV antibody cocktail may help provide immediate protection to unvaccinated people who are exposed to the virus, and we are also working to understand its potential to provide ongoing protection for immunocompromised patients who may not respond well to vaccines," George D. Yancopoulos, President and Chief Scientific Officer at Regeneron said. "We thank the individuals, investigators and our collaborators involved in the trial, and look forward to rapidly discussing these results with regulatory authorities."