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.