What is an antibody cocktail and what trials are being done at UC Davis Health?

Q&A with Timothy Albertson on the antibodies President Trump received, clinical trials and the goals


Timothy Albertson, chair of internal medicine and specialist in pulmonary and critical care, is leading two UC Davis Health’s three trials of REGN-COV2, Regeneron Pharmaceuticals’ investigational antibody cocktail for the treatment and prevention of COVID-19.

Timothy Albertson is leading two of UC Davis Health's three trials of an antibody cocktail from Regeneron Pharmaceuticals
Timothy Albertson is leading two of UC Davis Health's three trials of an antibody cocktail from Regeneron Pharmaceuticals

Is there anything to be learned about the antibody cocktail from President Trump’s treatment?

This use of the antibody cocktail was not part of a controlled trial, and we are looking at a single person being treated, so it is extremely difficult to draw any conclusion about its efficacy. It was reported that the president also was given the antiviral drug remdesivir (UC Davis Health helped pioneer its use for COVID-19), the steroid dexamethasone, and famotidine, an over-the-counter heartburn medicine — all of which are still in clinical trials testing their use against COVID-19 — among other things. So, no conclusions can be drawn.

What antibody trials is UC Davis Health connected with?

We are part of three national clinical trials of the investigational antibody cocktail produced by Regeneron Pharmaceuticals, REGN-COV2. I’m leading two studies for patients diagnosed with COVID-19.

One is looking at patients who are sick enough to be admitted to the hospital but not sick enough to be in the intensive care unit, at least initially. The other study is looking at outpatients with mild disease or who are just beginning to have symptoms and recuperating at home. We are evaluating the efficacy and safety of the cocktail as a possible treatment for COVID-19 patients. Preliminary data was released recently and showed improvement in the outcomes of these patients.

We have another trial by led by Stuart Cohen, chief of the Division of Infectious Diseases and director of hospital epidemiology and infection control. He is looking at patients who have been exposed to family members or co-workers who are infected by COVID-19 but haven’t shown symptoms yet. So that trial is testing the effectiveness and safety of the antibody cocktail to prevent COVID-19. 

We are both hoping more COVID-19 patients and potential participants will volunteer for these trials.

What is an antibody cocktail?

An antibody is a protein made by immune cells that is just the right shape and size to attach itself to a specific spot on a particular foreign substance, such as a virus or bacteria in the blood. By attaching, the antibody can potentially directly stop these invaders from causing an infection, or it can mark them for destruction by immune cells.

The REGN-COV2 antibody cocktail in these trials is a combination of two potent, complementary, virus-neutralizing antibodies. They were selected by Regeneron scientists after screening thousands of options. Each binds to the spike proteins on the virus, which is that corona we see in pictures of the virus. Those spikes allow the virus to attach to and penetrate other cells. If we block that interaction, the virus is less successful at binding to healthy cells

How does the REGN-COV2 antibody cocktail work?

The antibodies in these studies attach to the spike proteins, preventing them from anchoring to host cells. Think of these antibodies as tiny versions of Pac-Man, just the right shape to clamp down and bind to the spikes of the coronavirus. When the spike protein is blocked, the virus may not be able to enter and infect cells.

The two antibodies work together to block the spike protein at two different places on the protein. By lowering the ability of the virus to infect cells, the cocktail may help to stop COVID-19 symptoms from getting worse.

What is a monoclonal antibody?

“Monoclonal” means each antibody was produced by making identical copies — or clones — of a single antibody gene in a single B cell. These B cells are a type of white blood cell that produces antibodies that attack invading viruses, bacteria and toxins.

Where do these antibodies come from for the cocktail?

One antibody comes from a human survivor of COVID-19. A B cell that makes the antibody was harvested from the person’s blood and the gene for the antibody was isolated and copied in the lab. The other antibody is from a mouse that has been engineered to have a human immune system. The mouse had the coronavirus spike protein injected into it, then its antibody was isolated and cloned. The cocktail does not contain human blood products. 

Can the antibody cocktail be used outside of the clinical trials?

Because the investigational cocktail is still going through trials, there is not enough information yet to determine whether it is safe and effective to treat or prevent COVID-19. For this reason, it has not yet been approved by the Food and Drug Administration (FDA). However, Regeneron has applied for “emergency use authorization” from the FDA, so, if granted, it could in the future be given to certain patients who may benefit.

How does someone volunteer to be in one of the trials?

To see if you qualify for COVID-19 clinical trials at UC Davis Health, contact Maya Juarez at mmjuarez@ucdavis.edu or Skyler Pearson at sjpearson@ucdavis.edu.