Casirivimab Plus Imdevimab Authorized for Post-exposure Prophylaxis Against COVID-19
The FDA has authorized the use of casirivimab plus imdevimab for post-exposure prophylaxis in people 12 years of age or older who are at high risk for progression to severe COVID-19. The authorization for the monoclonal antibody cocktail includes people 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 are at high risk of exposure because of infection occurring in the same institutional setting (such as in nursing homes or prisons).
In a phase 3 trial, the cocktail of casirivimab plus imdevimab was found to reduce the risk of symptomatic infections by 81% in those who were not infected when they entered the trial. In a subgroup of patients who met the criteria for high risk of progression to severe COVID-19, there was a 76% reduction in COVID-19 with this combination therapy compared with placebo. Casirivimab plus imdevimab reduced the risk of symptomatic infections by 62% in patients who were asymptomatic, regardless of their infection status. Patients with ongoing exposure may receive repeat dosing of casirivimab plus imdevimab monthly by intravenous infusion or subcutaneous injection.
Multiple analyses have shown that casirivimab plus imdevimab retains potency against the main variants of concerns circulating in the US, including the Delta (B.1.617.2; first identified in India), Gamma (P.1; first identified in Brazil), and Beta (B.1.351; first identified in South Africa) variants.
FDA. Fact sheet for health care providers. Emergency Use Authorization (EUA) of REGEN-COV™ (casirivimab and imdevimab). July 2021 (www.fda.gov/media/145611/download). Accessed 8/6/2021.