On Jul. 30, 2021, Regeneron announced that the U.S. Food and Drug Administration (FDA) had updated the Emergency Use Authorization (EUA) for the investigational COVID-19 antibody cocktail REGEN-COV™ (casirivimab and imdevimab). The authorization now includes 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 (such as in nursing homes or prisons).

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. REGEN-COV is not a substitute for vaccination against COVID-19, and is not authorized for pre-exposure prophylaxis to prevent COVID-19.

Experts estimate that approximately 3% of the U.S. population may not respond fully to COVID-19 vaccination because of immunocompromising conditions or immunosuppressive medicines. 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). This authorization enables these groups to use REGEN-COV to prevent infection in post-exposure and certain institutional settings.

Under the EUA for post-exposure prophylaxis, REGEN-COV can be administered by subcutaneous injection or intravenous infusion. For people 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.

REGEN-COV has not been approved by the FDA, but is currently authorized 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.