Monoclonal antibodies and emerging agents may avert severe illness, especially for high-risk individuals.
Although vaccines remain the best preventive strategy for COVID-19, there is still a need for therapies to help avert progression to severe illness, especially for high-risk patients.
Monoclonal Antibodies
Monoclonal antibodies (mAbs) have the potential to prevent and treat COVID-19 by binding to an epitope in the SARS-CoV-2 spike protein to neutralize the virus. It is expected such therapies that directly target SARS-CoV-2 would have the greatest effect earlier in the disease course when pathogenesis is primarily driven by viral replication. Therefore, treatment should be started as soon as possible in those who test positive. Three anti–SARS-CoV-2 mAbs have received emergency use authorizations (EUAs) for mild to moderate COVID-19 in those who are at high risk for progression (see the Table1). Tixagevimab and cilgavimab (Evusheld) is a fourth anti–SARS-CoV-2 mAb under EUA for COVID-19. However, it is only authorized as pre-exposure prophylaxis for immunocompromised patients who may not mount an adequate immune response to vaccination or those with a history of severe adverse reactions to available vaccines.2 Its efficacy against the omicron variant is being determined.
Bamlanivimab and etesevimab are neutralizing mAbs that bind to different but overlapping, epitopes of the spike protein.3 A phase 3 trial in 1035 patients showed a 4.8% absolute risk reduction (ARR) in death or hospitalization in those who received the combination compared with a placebo.4 They are the only mAbs available for younger pediatric patients, including neonates, largely based on pharmacokinetic studies. However, efficacy may vary based on the dominant circulating strain.3
Casirivimab and imdevimab are recombinant mAbs that bind to nonoverlapping epitopes of the spike protein. Also known as the cocktail REGEN-CoV, a single intravenous infusion was associated with a 2.2% ARR in…