Regeneron has released their antibody cocktail for treating mild to severe cases of COVID-19. Their antibody cocktail consists of casirivimab and imdevimab both of which are monoclonal antibodies which when given together have been shown to have significant anti-viral activity against COVID-19 for patients who are in the high risk category (defined extensively here) for having deleterious effects. Some of the high risk category patients are those who are immunocompromised, older adults (>65) or older adults above 55 years of age who have certain ailments such as respiratory diseases such as COPD, heart disease or hypertension to name a few. Youngsters are part of their high risk category too, anyone from 12-17 who may have chronic heart issues or other serious chronic diseases. The idea here is simple, anyone with a serious disease that puts their immune system at risk is a good candidate for these cocktail drugs.
How do these drugs work? If you look at the ending of the names of the two drugs in the cocktail you can see that they end with vimab. This tells us that they are virus specific (VImab) monoclonal antibodies (viMAB). Antibodies are part of your immune system. When your body gets presented with anything that shouldn’t be there like say a common cold virus, the circulating B cells in your body will come into contact with the offending virus (antigen). This contact stimulates the B cell to turn into a plasma cell which produces specific antibodies against the specific antigen, in this case a common cold virus. The contact of the B cell with the antigen also triggers an event that causes T helper cells (also part of the immune system) to come and attach to the B cell further stimulating the B cell to divide itself and make more plasma cells. More plasma cells means more antibodies will be produced. So in essence the B cell is a military recruiter/drafter/boot camp that helps make soldiers (antibodies) against the offending antigen (the enemy). The antibodies that are made your body are very specific against the antigen that it is trying to overcome. Once antibodies are made towards a certain antigen, it is memorized by a type of B cell called memory B cells, which remember what a specific antigen looks like should you be exposed to it again. People who are immunocompromised cannot count on their immune system to provide the protection I just outlined. This is where the cocktail of antibodies come into play, they help provide the support your body needs to mount the attack necessary against COVID-19.
For this particular antibody cocktail to work the way it is supposed to, you need to give it to the patient before the disease has progressed too far. The idea is to give it to these high risk patients as soon as they come up positive for virus hopefully before disease progresses too far. The idea is to mobilize an army before the enemy hits, makes sense right? As Regeneron puts it, if you are already on high flow oxygen or some sort of ventilation then this drug is not the best for you (whether they established this through their study or don’t have enough data to know this is still unknown to me at this time).
The antibody cocktail are very highly specific to COVID-19 and are produced in cells that are highly characterized. The cells being used to make the antibodies were made using one single isolated clone cell, therefore we know that each and every subsequent cell made from it will be an exact clone and the fore we can be sure of the quality of the products it makes. The antibodies made in these type of cells are known as monoclonal antibodies. The cocktail of antibodies attach to a part of the virus that prevents its ability to attach and therefore not be able to enter human cells.
Antibody therapy is not new, it’s been been around for quite sometime. Look for those TV ads that advertise them, they end with the letters MAB indicating they are monoclonal antibodies As the drugs have been released under the FDA emergency use provision more data will come in as we use the drug as to whom the drugs have the most positive impact on. President Trump was administered this drug when he was diagnosed as having the virus a month ago. The timeliness of the administration of this cocktail of antibodies indicates even more the importance of testing for COVID-19 especially if you are in the high risk category. The impacts on COVID-19 positive patients who are otherwise healthy and are not in the high risk category is something that needs to be evaluated but in the meanwhile, these drugs are available to those who are most highly likely impacted to a greater degree than the average healthy individual.
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