Virus World

Regeneron said that a single dose of its antibody cocktail REGEN-COV reduced the risk for COVID-19 by nearly 82% up to 8 months after administration in a phase 3 trial. REGEN-COV, which contains 600 mg each of the monoclonal antibodies casirivimab and imdevimab, was authorized for emergency use by the FDA in November 2020 for the treatment of mild to moderate COVID-19 in high-risk patients. The FDA expanded the emergency use authorization in July to include post-exposure prophylaxis.  Trial results announced Monday by Regeneron showed that, compared with placebo, people who received a single dose of REGEN-COV had an 81.6% reduced risk for developing COVID-19 during a 2-to-8-month follow-up period (95% CI, 59.8%-91.6%) and an 81.5% reduced risk for developing COVID-19 at any time during the 8 months after receiving REGEN-COV (95% CI, 70.6%-88.4%). Myron S. Cohen, MD, who leads the monoclonal antibody efforts for the NIH-sponsored COVID Prevention Network and is director of the Institute for Global Health & Infectious Diseases at the University of North Carolina at Chapel Hill, said the findings “demonstrate how a single dose of REGEN-COV can help protect people from COVID-19 for many months after administration.” "These results demonstrate that REGEN-COV has the potential to provide long-lasting immunity from SARS-CoV-2 infection, a result particularly important to those who do not respond to COVID-19 vaccines, including people who are immunocompromised,” Cohen said.

Regeneron said the data build on previously published findings in The New England Journal of Medicine, which reported a risk reduction of 81.4% in the first month. The newly announced findings were from an 8-month follow-up that continued to compare outcomes from more than 1,600 people assigned to receive a single dose of the cocktail or placebo. In all, seven people in the treatment arm and 38 in the placebo arm developed COVID-19 within 2 to 8 months. George D. Yancopoulos, MD, PhD, president and chief scientific officer at Regeneron, said the data “add to the increasing body of evidence supporting the use of REGEN-COV to prevent COVID-19 in uninfected individuals.” “With infections still occurring despite widespread vaccination, the immunocompromised face an ongoing risk of encountering the virus during their daily lives,” Yancopoulos said in a statement. “We intend to rapidly share these additional data with regulatory authorities to help those in most need of protection from COVID-19.”

The FDA has expanded its EUA for Regeneron's COVID-19 drug as a preventative therapy for those who have been exposed to the disease and who are at high risk to progress to a severe case.  With its rapid mutations, the evolutionary process of the coronavirus makes it a moving target. And so it is with treatments for the disease, which can quickly become in vogue or obsolete.  Case in point for the former: Regeneron’s antibody cocktail REGEN-COV. Over the last few months, nearly every development in the COVID-19 antibody market has broken in favor of the treatment, a combination of casirivimab and imdevimab. On Friday, the FDA granted emergency use authorization to REGEN-COV as a preventative measure for those who have been exposed to COVID-19 and who are at high risk to progress to a severe case because they are not fully vaccinated or are not expected to mount an adequate antibody response to vaccination.  About 3% of the U.S. population won't respond fully to COVID-19 vaccines, including patients on chemotherapy, people with hematologic cancers and others, Regeneron says.

The FDA based its decision on a phase 3 trial, run jointly with the National Institutes of Health, which showed that REGEN-COV cut the risk of developing symptomatic COVID by 81% among healthy individuals who lived with an infected person. The study tested the med in 1,505 people who lived with an infected person within the prior four days. Those who received an infusion of REGEN-COV showed 72% efficacy against symptomatic COVID over the first week and 93% beyond the first week. Additionally, among those who developed symptoms, REGEN-COV recipients cleared the virus faster than those in the placebo group.  While vaccine recipients need time to build an effective antibody response, especially with a two-shot regimen, a direct injection of antibodies can offer more immediate protection.   The FDA granted REGEN-COV its initial EUA in November for patients with newly diagnosed COVID-19 who are at a high risk of progressing to severe disease. Since then, the drug Regeneron’s therapy has gained FDA nods for a subcutaneous injection and at a smaller dose. Regeneron's antibody trailed Eli Lilly's antibody onto the market, but it has since proven more resilient against mutations than its rival. Another antibody drug gained FDA approval two months ago. But sotrovimab, a joint effort from GlaxoSmithKline and Vir Biotechnology, has yet to secure a supply deal from the United States.