Antibody cocktail ‘rapidly’ prevents and treats COVID, study finds
By Katie Camero
April 12, 2021
New results from a multi-stage Regeneron clinical trial show that a cocktail of special antibodies can reduce risks of developing symptomatic COVID-19 by 81% if someone is not already infected with the virus. And for those who still get infected, the drug can help clear the virus from their bodies faster and shorten the duration of their symptoms.
A separate trial found that the cocktail, called REGEN-COV, is also able to reduce people’s chances of developing coronavirus symptoms if dealing with an asymptomatic infection by 76% after three days, the American biotechnology company Regeneron announced Monday.
The cocktail was given emergency-use authorization by the Food and Drug Administration in November, and is currently being used to treat mild to moderate COVID-19 in adults and children at least 12 years old who face high risks for severe disease and who are not hospitalized; it was the same drug given to former President Donald Trump when he tested positive for coronavirus in October.
Researchers say these antibodies can help protect people from infection and disease alongside vaccinations, and may be particularly useful for those waiting to get their shots or for those with compromised immune systems who may not respond well to vaccines.
“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,” Dr. George Yancopoulos, president and chief scientific officer at Regeneron, said in a statement. “These Phase 3 data provide even more evidence that REGEN-COV… can change the course of COVID-19 infection in non-hospitalized patients” by effectively preventing asymptomatic patients from becoming symptomatic.
Participants in the late-stage trial were enrolled only if they didn’t have any COVID-19 symptoms, didn’t have coronavirus antibodies and lived with someone who tested positive within the past four days. People that tested negative were assigned to the “prevention trial” (1,505) and those who tested positive were put in the “treatment trial” (204).
All participants were then randomly given one dose of the antibody cocktail or a placebo administered via a subcutaneous injection, which is when a short needle delivers drugs into the tissue layer between the skin and muscle. The technique is typically used when drugs are given in small doses or need to be delivered quickly.
COVID-19 vaccines, for reference, are given intramuscularly, or in the muscle.
What the ‘prevention trial’ found
In addition to finding that the antibody cocktail reduced risks of developing symptomatic infections by 81% in people who were not infected, the trial found that the drug helped clear symptoms in one week, compared to three weeks in the placebo group, in those who did develop infections.
“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,” Dr. Dan Barouch, co-principal investigator of the trial and director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center in Boston, said in the statement. “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.”
Side effects occurred in 20% of the participants who received the cocktail and included fever, itchy skin, chills and abdominal pain. No one who got the drug was hospitalized. Two people who received the cocktail died, but their deaths were not caused by COVID-19 or the drug, according to the company.
What the ‘treatment trial’ found
The antibody cocktail was found to prevent people with asymptomatic infections from progressing to symptomatic ones by 76% after three days.
The researchers also learned that the drug cut the number of weeks patients experienced symptoms by 45% and reduced their viral load — the amount of virus in their body — by more than 90%. This means people treated with REGEN-COV may be less likely to spread the virus once infected.
Side effects similar to the other trial occurred in 34% of the participants. No one was hospitalized or died.
About the REGEN-COV Antibody Cocktail
REGEN-COV (casirivimab with imdevimab) is a cocktail of two monoclonal antibodies (also known as REGN10933 and REGN10987) that was designed specifically to block infectivity of SARS-CoV-2, the virus that causes COVID-19, using Regeneron’s proprietary VelocImmune® and VelociSuite® technologies. The two potent, virus-neutralizing antibodies that form the cocktail bind non-competitively to the critical receptor binding domain of the virus’s spike protein, which diminishes the ability of mutant viruses to escape treatment and protects against spike variants that have arisen in the human population, as detailed in Science.
Under an EUA issued by the U.S. Food and Drug Administration (FDA), REGEN-COV is currently available in the U.S. to treat mild-to-moderate COVID-19 in adults, as well as in pediatric patients at least 12 years of age and weighing at least 40 kg, who have received positive results of direct SARS-CoV-2 viral testing and are at high risk for progressing to severe COVID-19 and/or hospitalization. REGEN-COV has not been approved by the FDA but has been authorized for emergency use. This use is authorized only for the duration of the declaration that circumstances exist justifying the authorization of the emergency use under section 564(b)(1) of the Act, 21 U.S.C. § 360bbb-3(b)(1), unless the authorization is terminated or revoked sooner.
REGEN-COV is currently authorized and available in a 2,400 mg IV dose, with infusion times as short as 20 minutes. The criteria for ‘high-risk’ patients are described in the Fact Sheet for Healthcare Providers. In the U.S., REGEN-COV is not authorized for use in patients who are hospitalized due to COVID-19 or require oxygen therapy, or for people currently using chronic oxygen therapy because of an underlying comorbidity who require an increase in baseline oxygen flow rate due to COVID-19.
Under this EUA, REGEN-COV is available throughout the U.S. – information on availability in your area is available from the Department of Health and Human Services and the National Infusion Center Association.
Regeneron is collaborating with Roche to increase global supply of REGEN-COV. Regeneron is responsible for development and distribution of the treatment in the U.S., and Roche is primarily responsible for development and distribution outside the U.S. The companies share a commitment to making the antibody cocktail available to COVID-19 patients around the globe and will support access in low- and lower-middle-income countries through drug donations to be made in partnership with public health organizations.