COVID-19 a moving target
However, Dr. Fales noted that COVID-19 is a moving target with emerging variants. The criteria for populations at high risk have also broadened since the start of the study, he said.
“A great example is pregnancy is now included as high risk, and that would have likely been a specific contraindication of patients in this clinical trial,” he said.
Dr. Fales said Michigan has been using both REGEN-COV and the Eli Lilly combination of bamlanivimab and etesevimab, which also has an emergency use authorization (EUA) from the Food and Drug Administration, with positive results.
REGEN-COV has an EUA to treat people who are at high risk of serious consequences from COVID-19, including those who are already infected (nonhospitalized) or those in certain postexposure prophylaxis settings.
“We’re seeing very low hospitalization rates and few deaths in a state that is predominately Delta,” Dr. Fales said. “So, this makes us feel that we’re doing the right thing and supports the current efforts around the country to make monoclonal antibody therapy available to high-risk patients.”
Dr. Joshi noted that trial results have been emerging from other monoclonal antibody cocktails with different COVID-19 patient groups.
However, he said in an interview, “how much more effective they would be than this is something we’d have to look at, as 71% effectiveness in keeping people out of the hospital is pretty good for any treatment.”
“These are great numbers, but vaccination itself keeps you from getting the disease in the first place and not just for a short time period. This treatment is just that – a treatment. It gets you through that episode but it doesn’t mean you won’t get sick again. You don’t develop an immune response as you do with the vaccine,” he said.
Dr. Weinreich agreed: “This is not a substitute for a vaccine except for the small group who get the vaccine and their bodies can’t respond to it because they’re significantly immunocompromised.”
The results from this paper “are one piece of a large, multistudy, phase 3 program that basically spans from prophylaxis all the way to hospitalization and pretty much the gamut – all of them – have worked. All of these studies have shown dramatic improvement in whatever the definitive regulatory endpoint is,” Dr. Weinreich said.
He said discussions are ongoing for full regulatory approval in the United States and for expanding the EUA for other populations, including pre-exposure prophylaxis, “which the [United Kingdom’s] authority has already granted us but the FDA has not.”
The study is funded by Regeneron and the Department of Health & Human Services. Dr. Weinreich is a vice president of Regeneron. Dr. Joshi reported no relevant financial relationships. Dr. Fales holds stock in Eli Lilly.
A version of this article first appeared on Medscape.com.