On Jun. 4, 2021, Regeneron announced the U.S. Food and Drug Administration (FDA) updated the Emergency Use Authorization (EUA) for REGEN-COV™, lowering the dose to 1,200 mg (600 mg casirivimab and 600 mg imdevimab), which is half the dose originally authorized. As part of the updated EUA, REGEN-COV should be administered by intravenous (IV) infusion; subcutaneous (SC) injections are an alternative when IV infusion is not feasible and would lead to a delay in treatment.

REGEN-COV is authorized for use under an EUA to treat mild-to-moderate COVID-19 in adults and pediatric patients (12 years of age and older weighing ≥40 kg) with positive results of direct SARS-CoV-2 viral testing, and who are at high risk for progression to severe COVID-19, including hospitalization or death. The Fact Sheet updates remove the previously authorized 2,400 mg IV REGEN-COV dose.

The updated FDA authorization is based on data from several trials, including a recently presented Phase 3 trial which showed REGEN-COV reduced the risk of hospitalization or death by 70% in high-risk non-hospitalized patients, and that the treatment effect was consistent between the 1,200 mg and 2,400 mg doses. The SC administration was authorized based on the totality of scientific evidence, incorporating clinical, viral load reduction and pharmacokinetic data.

In addition, in vitro research has shown that REGEN-COV retains potency against the main variants of concern circulating within the U.S., including the P.1 variant (first identified in Brazil, now classified by the World Health Organization [WHO] as Gamma) and the B.1.351 variant (first identified in South Africa, now classified by the WHO as Beta). Consequently, REGEN-COV remains available for use in all 50 states. The combined frequency of the P.1 and B.1.351 variants now exceeds 10% of new COVID-19 diagnoses across eight states (Arizona, California, Florida, Illinois, Indiana, Massachusetts, Oregon and Washington), and the prevalence of these and other variants continues to be closely monitored.

Overall, more than 9,000 people have received IV REGEN-COV in clinical trials in both hospitalized and non-hospitalized settings. In a pooled Phase 1/2/3 analysis of non-hospitalized patients, investigator-assessed infusion-related reactions (≥grade 2) were observed in 0.2% (10/4,026) of those who received REGEN-COV at the authorized dose or a higher dose. Rare anaphylactic reactions have been reported as part of the REGEN-COV clinical program. In trial participants who received study drug via SC injection, injection site reactions were observed in 12% of those treated with REGEN-COV (88/729) and 4% with placebo (10/240).