The onslaught of the SARS-CoV-2 (COVID-19) pandemic has presented an “unprecedented challenge to develop and identify effective medication strategies.”1 Among several agents under investigation, monoclonal antibodies have emerged as key “promising” interventions for disease management.2 Given that many of these new agents are still under development, the US Food and Drug Administration (FDA) has issued several emergency use authorizations (EUAs) to make these agents available on an emergent basis to affected patients.
At present, 3 monoclonal antibody therapies have EUA status: the combination of bamlanivimab and etesevimab (Eli Lilly), the combination of casirivimab and imdevimab (also called REG-COV, Regeneron), and sotrovimab (GlaxoSmithKline and Vir Biotechnology). Other agents are under development but have not yet received EUA.
To shed light on antibody therapy for COVID-19, we spoke to Jason C. Gallagher, PharmD, Clinical Professor and Clinical Specialist at Temple University in Philadelphia. Dr Gallagher is also the Infectious Diseases Director, PGY2 Residency in Infectious Diseases Pharmacy at Temple University and a coauthor of the updated Infectious Disease Society of America’s Guideline on the Treatment and Management of COVID-19.3
What is the mechanism of action of monoclonal antibodies for COVD-19?
Most monoclonal antibodies under development for COVID-19 target the spike glycoprotein, which is what the virus uses to enter host cells.4 When the spike protein is blocked, the result is that viral attachment and entry into our cells is blocked. Putting it another way, monoclonal antibodies take the normal response that the immune system would generate over time and, when administered early in the course of the infection, they “jump start” this process and accelerate it so the antibodies can go to work sooner than we can develop them. For this reason, antibody therapy should be initiated as soon as possible after a positive diagnosis, preferably within 10 days.5
Who should receive antibody therapy?
The IDSA recommends that antibody therapy should be administered to patients with mild to moderate COVID-19 at high risk for progression to severe disease.
What are the advantages of having multiple available antibody regimens, rather than just one?
An increasing concern in treating COVID-19 is the presence of a range of variants that might be resistant to treatment. Some of these variants have reduced susceptibility to the currently available antibodies, while others are more responsive, so it is helpful to have multiple antibody treatment options available for use, based on variants in a given geographical area.
More information is available on the monoclonal antibody EUA fact sheets. It encourages use of antibody treatments, with a particular focus on treatment selection based on local variants.