Regeneron’s COVID-19 Cocktail Snags Expanded EUA Indication

The therapy can now be used for post-exposure prevention in people at high risk for progression to severe disease.

The FDA has updated Regeneron Pharmaceuticals’ Emergency Use Authorization (EUA) for the investigational COVID-19 antibody cocktail REGEN-COV (casirivimab and imdevimab).

REGEN-COV can now be used for post-exposure prophylaxis in people at high risk for progression to severe COVID-19, who are not fully vaccinated or are not expected to mount an adequate response to vaccination, and have been exposed to a SARS-CoV-2 infected individual, or who are at high risk of exposure to an infected individual because of infection occurring in the same institutional setting, Regeneron said in a press release.

In those who require repeat dosing for ongoing exposure, Regen-Cov can also now be administered monthly. This new indication in people aged 12 and older is in addition to the previously granted authorization to treat non-hospitalized patients.

“The FDA authorization enables certain people at high risk of developing severe COVID-19 infection to access REGEN-COV if they have been exposed to the virus – the first time an antibody treatment has been authorized for this purpose,” George D. Yancopoulos, M.D., Ph.D., president and chief scientific officer of Regeneron, said in a statement. “With this authorization, the FDA specifically highlights the needs of immunocompromised people, including those taking immunosuppressive medicines, who may not mount an adequate response to vaccination, who are exposed to a person with COVID-19 or are in an institutional setting and are at high risk of exposure because of infection occurring in the same setting.”

Multiple analyses, including a recent publication in Cell, have shown that REGEN-COV retains potency against the main variants of concern circulating within the US, including Delta (B.1.617.2), Gamma (P.1) and Beta). Additionally a phase 3 study, published August 4 in the New England Journal of Medicine, found REGEN-COV met its primary endpoint, reducing the risk of symptomatic infections by 81%, with a 93% reduction of symptomatic infections after the first week. No dose-limiting toxicities were observed.

In the United States, REGEN-COV is authorized 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.

The pharma maker is working with the FDA as it undertakes its review of REGEN-COV in a broader group of people including in a pre-exposure prophylactic setting for people who are immunocompromised, and in patients hospitalized due to COVID-19, Yancopoulos said.

Experts estimate that about 3% of the U.S. population may not respond fully to COVID-19 vaccination because of immunocompromising conditions or immunosuppressive medicines, according to Regeneron. “This includes people receiving chemotherapy, people with hematologic cancers such as chronic lymphocytic leukemia, people receiving stem cells or hemodialysis, people who have received organ transplants, and/or people taking certain medications that might blunt immune response (e.g., mycophenolate, rituximab, azathioprine, anti-CD20 monoclonal antibodies, Bruton tyrosine kinase inhibitors),” the company said.

For patients who aren’t expected to mount an adequate immune response to vaccination and who have an ongoing exposure to SARS-CoV-2 for more than four weeks, the initial 1,200 mg dose can be followed by subsequent repeat dosing of REGEN-COV 600 mg once every four weeks for the duration of ongoing exposure, according to Regeneron.