This analysis will focus on the monoclonal antibody casirivimab. The combination of casirivimab and imdevimab can be used as a treatment of moderate coronavirus disease 2019 (COVID-19) (FDA, 2021). This treatment works on a number of different variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), however it does not work with the Omicron variant (Sherchan & Cannady, 2022). Due to the prevalence of the Omicron variant at this time, the combination of casirivimab and imdevimab is no longer used in the United States. However, it is still a treatment to be considered with other variants of SARS-CoV-2. Severe acute respiratory syndrome coronavirus 2 is the virus that upon infection causes COVID-19 (CDC, 2021). It is a highly contagious virus that causes symptoms similar to a cold, flu, or pneumonia and mainly attacks the respiratory system (CDC, 2021). Symptoms can present between two and fourteen days after exposure with the most common symptoms being: fever or chills, cough, shortness of breath, fatigue, aches, etcetera (CDC, 2021). The combination of high contagion and potential for severe symptoms has led to 754 million total cases worldwide and a total of 6.8 million deaths (WHO).
Casirivimab is an IgG monoclonal antibody, as depicted below, that is linked to SARS-CoV-2 spike protein (Sherchan & Cannady, 2022). Casirivimab works by blocking natural binding processes, thus preventing cellular infection. Specifically, it binds to the spike protein S1 domain, which is an N-terminus signal peptide that houses the receptor-binding domain (RBD) of the virus (Huang et. al., 2020). The binding of casirivimab to the S1 RBD blocks the Angiotensin-converting enzyme 2 (ACE2) receptor of the cell, which is where SARS-CoV-2 attaches (Sherchan & Cannady, 2022). When casirivimab binds before SARS-CoV-2 it effectively blocks the cell from binding the SARS-CoV-2, which as a result, blocks virus entry and replication in the cell. Without attachment, disease symptoms are greatly improved due to a decreased viral load. With less virally infected cells COVID-19 overall would be less severe in the patient and would be more likely to clear up more quickly. In a study that looked at the difference in hospitalization and emergency room visits in those treated with casirivimab and imdevimab versus those with placebo, the first occurred in three percent of the patients, while the later averaged nine percent (Commissioner, 2020).
References
Commissioner, O. of the. (2020, November 21). Coronavirus (COVID-19) update: FDA
authorizes monoclonal antibodies for treatment of COVID-19. U.S. Food and Drug Administration. Retrieved February 5, 2023, from https://www.fda.gov/news-events/press-announcements/coronavirus-covid-19-update-fda-authorizes-monoclonal-antibodies-treatment-covid-19
CDC. (2021, November 4). Basics of covid-19. Centers for Disease Control and Prevention.
Retrieved February 5, 2023, from https://www.cdc.gov/coronavirus/2019-ncov/your-health/about-covid-19/basics-covid-19.html
FDA. (2021, January). Fact sheet for patients, parents and caregivers emergency use ...
Regeneron EUA HCP Fact Sheet 01242022. Retrieved February 5, 2023, from https://www.fda.gov/media/145612/download
Huang, Y., Yang, C., Xu, Xf. et al. Structural and functional properties of SARS-CoV-2 spike
protein: potential antivirus drug development for COVID-19. Acta Pharmacol Sin 41, 1141–1149 (2020). https://doi.org/10.1038/s41401-020-0485-4
Sherchan, R., & Cannady, P. (2022). Casirivimab - StatPearls - NCBI Bookshelf. StatPearls.
Retrieved February 5, 2023, from https://www.ncbi.nlm.nih.gov/books/NBK572124/
WHO. (n.d.). WHO coronavirus (COVID-19) dashboard. World Health Organization. Retrieved February 5, 2023, from https://covid19.who.int/
By: Joy Brewer
February 05, 2023
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