Recently a new drug was approved for use in COVID patients in India. Known as REGN-COV2, this new therapy is based on monoclonal antibodies targeting the SARS-CoV-2 virus responsible for COVID. So how
REGN-COV2 – Artificial "antibody cocktail"
Recently a new drug was approved for use in COVID patients in India. Known as REGN-COV2, this new therapy is based on monoclonal antibodies targeting the SARS-CoV-2 virus responsible for COVID. So how does it work? And is there any evidence behind the treatment?
Monoclonal antibodies are made from components of the human immune system. When the human body recognizes a bacteria or virus in the body, the immune system recognizes and processes proteins on the surface of that bacteria or virus. This is presented to the adaptive immune system, and antibodies have produced that lock onto these surface proteins, neutralizing their function and also tagging them for destruction by other white blood cells.
If we identify antibodies capable of efficiently tagging and neutralizing a certain virus, we can identify the cell capable of producing that antibody, clone it and produce it in vast quantities. The antibodies produced from this cloned cell line will be able to target the virus at the same efficiency and have the same ability to neutralize the virus. Just like with vaccines, there is a risk of mutations developing, resulting in changes in the surface protein that reduce binding and neutralizing effects of the antibodies, allowing them to escape and continue to cause disease
REGN-COV2 uses two neutralizing antibodies (Casirivimab/imdevimab), in an effort to minimize the ability of a mutant virus to develop resistance against the antibody cocktail, as the virus would need to develop mutations canceling both antibodies out at once. These antibodies neutralize the receptor-binding domain of SARS-CoV-2 spike protein, preventing viral entry through ACE2 receptors.
In a study published in the New England Journal of Medicine (one of the most prestigious journals in the medical field) data from 275 patients showed a drastic reduction in viral load in patients treated with REGN-COV2. This is clinically significant as hospitalized patients with severe symptoms have higher viral counts than non-hospitalized or asymptomatic patients, suggesting the hypoxaemic, shortness of breath symptoms are related to the viral count and resulting exaggerated immune response.
Based off this result the European Medicines Agency approved the use of REGN-COV2 antibody cocktail in patients who do not require supplemental oxygen but are at high risk of progressing to severe COVID-19.
FDA regulations currently recommend it for patients who are COVID positive with risk factors that may result in their hospitalization but do not recommend it for patients who are already hospitalized, requiring O2 therapy because of COVID or need chronic O2 therapy.
Those that fall into the high-risk categories include patients with a high BMI (over 35), diabetes, on immunosuppressive treatment or with an immunosuppressive disease, over 65 years of age or those with chronic diseases such as renal disease, cardiovascular disease, COPD, or other developmental disorders.