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A single dose of REGEN-COV, a combination monoclonal antibody therapy, reduced the risk of COVID-19 by 81.6% several months after a single dose. UNC School of Medicine’s Myron Cohen, MD, leads monoclonal antibody research efforts as part of the NIH-sponsored COVID Prevention Network.


Regeneron Pharmaceuticals, Inc. announced additional positive results from a phase 3 clinial trial jointly run with the National Institute of Allergy and Infectious Diseases (NIAID), which assessed use of a single dose of investigational REGEN-COV® (1,200 mg administered via 4 subcutaneous injections) to prevent COVID-19 in uninfected individuals. The new analyses show REGEN-COV reduced the risk of contracting COVID-19 by 81.6% during the pre-specified follow-up period (months 2-8), maintaining the risk reduction during the first month after administration, which had been previously reported in The New England Journal of Medicine.

“Today’s new data demonstrate how a single dose of REGEN-COV can help protect people from COVID-19 for many months after administration,” said Myron S. Cohen, MD, who leads the monoclonal antibody efforts for the NIH-sponsored COVID Prevention Network (CoVPN) and is director of the Institute for Global Health & Infectious Diseases at the University of North Carolina at Chapel Hill. “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.”

Monoclonal antibody treatment uses antibodies manufactured in a laboratory that are designed to attached to the coronavirus to prevent it from entering into cells.

Through an innovative trial design, researchers were able to demonstrate the impact of REGEN-COV in high-risk household transmission settings (month 1, both pre- and post-exposure prophylaxis), as well as after the immediate risk of household infection had subsided (months 2-8, pre-exposure prophylaxis), when most infections were presumably acquired in the broader community.

REGEN-COV is currently authorized in the U.S. to treat people who are at high risk of serious consequences from COVID-19 infection who are either already infected (non-hospitalized) or in certain post-exposure prophylaxis settings. In the U.S., REGEN-COV is not authorized as a substitute for vaccination against COVID-19, or for pre-exposure prophylaxis for prevention of COVID-19, or 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.

Read more about the results from this trial.