Drug study aims to deliver targeted therapy against COVID-19 virus

Giving patients antibodies against the virus that causes COVID-19 could provide a new treatment for the disease, particularly for those who are not sick enough to be in the hospital, an Augusta University expert said.

A clinical trial into a drug that provides two targeted antibodies against SARS CoV2 is under way at AU Medical Center and this week will hopefully expand into newly diagnosed patients who do not need hospitalization, said Dr. Jose Vazquez, chief of infectious diseases at AU.

The drug uses what are called monoclonal antibodies that specifically target two areas of an important part of the virus known as the spike protein, which is how the virus attaches and enters human cells. The company that manufactures it, Regeneron Pharmaceuticals, took an interesting path to finding them.

According to a study published last month in the journal Science, company investigators pursued finding antibodies against SARS CoV2 in parallel routes. One was by taking mice genetically altered to have human immune responses and immunizing them with a piece of the virus protein. The other was to take blood from COVID-19 survivors and look for antibodies there. The scientists then screened thousands of potential candidates to see if they were capable of blocking the virus.

After whittling that down to 200 that were 70% effective at blocking the virus, the scientists focused on 40, then nine and finally ended up with four, including the two now included in the drug being tested at AU and other centers around the country. The two antibodies work on different areas of the protein to prevent what is known as “viral escape,” the virus creating a mutation against a single antibody that then allows it to thrive, according to the paper.

The proteins in the viral spike are the focus of intense scrutiny, research and now drug and vaccine development, Vazquez said as he displayed an illustration of the virus on his computer screen.

“All of the vaccines are going after this,” he said, pointing to the viral spike. “The reason they are going after this is this is the primary attachment to our cells.”

In particular, the drug’s antibodies target the tip of that spike, known as the receptor binding domain, which attaches to human cells through the ACE2 receptor, Vazquez said.

“So what we’re trying to do is block this” biding domain, he said. If the virus can’t attach, it can’t enter the cell and “it can’t multiply and it basically dies,” Vazquez said.

The effect is essentially the same as what the vaccines are trying to do, he said.

“The vaccines usually take 1-2 weeks to produce neutralizing antibodies,” Vazquez said. “This one, you have immediate neutralizing antibodies.”

It is also what convalescent plasma was hoping to achieve, giving infected patients the plasma from recovered patients in hopes they would get some of the antibodies the patient used to fight off the virus, he said. But in this case, doctors know the antibodies are there and know the exact dosage, Vazquez said.

Also, unlike other drugs and the plasma, this could be given to patients outside a hospital setting, where there are no effective therapies, he said.

“In the outpatient setting, there is nothing,” Vazquez said.

The drug, which is a single dose, would be given to patients within 72 hours of diagnosis.

“The earlier we start to treat this, the better off we are going to be,” he said.

COVID-19 drug study

Augusta University is helping to conduct a clinical trial for a drug to treate COVID-19. Because it is a randomized-control trial, patients will either receive the study drug or a placebo. For more information, call (706) 721-6869.