Casirivimab

Casirivimab is a monoclonal antibody combined with Imdevimab in Regeneron's antibody cocktail known as REGN-COV2 for the treatment of COVID-19. This drug is a combination of antibodies derived from humanized VelocImmune® mice in addition to blood samples from patients who have recovered from COVID-19. These antibodies have been formulated to bind to multiple locations on the SARS-COV-2 spike protein, preventing viral escape.

On November 21 2020, the FDA authorized emergency approval of REGEN-COV2 to treat mild to moderate COVID-19 in patients aged 12 years and older. Casirivimab and imdevimab are investigational recombinant human IgG1 monoclonal antibodies that, at this time, are not officially approved by the FDA. They are reserved for Emergency Use Authorization (EUA) only. In November 2021, the same indication was approved by the EMA.

Full safety and efficacy data are not yet available, and further evaluation of this investigational therapy will continue.

According to the Emergency Use Authorization (EUA) by the FDA and EMA, indevimab is used only with casirivimab to prevent COVID-19 and treat mild to moderate COVID-19 from laboratory-confirmed SARS-CoV-2 infection in patients aged 12 years of age and older who weigh at least 40 kg. Treatment is reserved for patients who are at high risk for progressing to require hospitalization or severe COVID-19.

This combination may only be administered by intravenous infusion in healthcare settings with immediate access to treatment for infusion reactions and anaphylaxis, and the ability to activate the emergency medical system (EMS), as required.

Limitations of use

Imdevimab and casirivimab are not for use in patients currently hospitalized due to COVID-19, patients requiring oxygen therapy due to COVID-19, patients requiring increases in baseline oxygen flow rate from COVID-19, or patients on oxygen therapy for non-COVID-19 related morbidity.