Regeneron's antibody cocktail protects against COVID-19 for up to 8 months, giving hope to the immunocompromised

People with compromised immune systems who are unable to develop adequate responses to vaccines may soon have an option to protect against COVID-19.

A phase 3 trial of Regeneron’s antibody cocktail showed the treatment reduced the risk of infection by 81.6% over a period of two to eight months. Results previously reported in The New England Journal of Medicine from the same trial showed REGEN-COV reduced the risk of infection by 81.4% during the first month 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,” Myron Cohen, M.D., a University of North Carolina professor who leads the monoclonal antibody efforts for the National Institutes of Health-sponsored COVID prevention network, said in a statement.

In the study of 1,683 uninfected individuals—run jointly with the National Institute of Allergy and Infectious Diseases—investigators recorded 45 symptomatic infections from months 2 to 8. Of the 841 people who received REGEN-COV, none required hospitalization, while in the placebo group of 842, six people required hospitalization.

REGEN-COV is authorized in the U.S. to treat non-hospitalized patients who are already infected and at a high risk of developing a severe case of the virus. It also is sanctioned in certain cases as post-exposure prophylaxis. REGEN-COV has not been cleared for use as a substitute for vaccination. But the latest results help make a case for the medicine as a prevention tool, especially in the roughly 3% of U.S. residents who are immunocompromised.

RELATED: Regeneron pushes its versatile antibody cocktail closer to finish line as a multiuse COVID treatment

Though this study only included subcutaneous injection, under the current emergency use authorization for post-exposure prophylaxis, REGEN-COV can be delivered either by way of subcutaneous injection or intravenously. 

Regeneron Chief Scientific Officer George Yancopoulos, M.D., Ph.D., said that REGEN-COV could be the answer for immunocompromised people who have become “prisoners of the pandemic.” He added in the statement that the company will “rapidly” provide the data to regulatory authorities.

Over the last two quarters, Regeneron has registered sales of $3.4 billion for REGEN-COV. That figure includes only a small portion of the 1.4 million doses it agreed to supply the U.S. government in mid-September. Regeneron sells the cocktail for $2,100 per dose and the U.S. provides it free to patients.

RELATED: Surprise COVID-19 antibody sales of $804M help Regeneron trounce expectations in third quarter

Roche partners with Regeneron on the manufacture and distribution of REGEN-COV, handling sales outside of the U.S. During its third-quarter earnings call last week, Regeneron said that Roche would assist in the supply effort to the U.S.

“If global demand warrants, we have the capacity to produce between four to five million 1.2 gram doses in 2022, excluding any further supply contributions from Roche,” Regeneron CEO Len Schleifer, M.D., Ph.D., said on the conference call.