Another new COVID-19 treatment candidate entered clinical-stage testing on Thursday. Regeneron (NASDAQ:REGN) has started a human trial of REGN-COV2, a pair of antibodies that glom onto SARS-CoV-2, the coronavirus that causes the illness, and stop it from entering host cells.

Earlier this month, Eli Lilly (NYSE:LLY) leaped ahead of Regeneron to become the first company to begin clinical testing of an antibody-based treatment for COVID-19, but REGN-COV2 is the first candidate that uses two antibodies working in concert to clear existing COVID-19 infections.

Doctor checking blood samples.

Image source: Getty Images.

Potential improvement 

In terms of the testing and approval process, both Regeneron's REGN-COV2 and Eli Lilly's LY-CoV555 are miles behind Gilead Sciences' (NASDAQ:GILD) remdesivir, a broad-spectrum antiviral that was given an emergency use authorization to treat COVID-19 in May, but they could be worth the wait. While remdesivir indiscriminately inhibits an enzyme that most viruses use to replicate themselves, the pair of proteins that make up REGN-COV2 were engineered to interfere specifically with the spikes that SARS-CoV-2 uses to enter host cells.

Since REGN-COV2 mimics antibodies found in patients who recovered from COVID-19, there's a good chance that it will be safe enough for use as a preventative measure. 

Winning track record

Regeneron used the same approach to develop REGN-COV2 as it used to develop REGN-EB3, the most successful Ebola virus treatment that has been found thus far. The company began studies with REGN-EB3 in 2018 and the FDA is still reviewing an application that was submitted for the treatment earlier this year.

The company will begin adaptive phase 1-3 studies that will look for safety signals from a small number of patients before ramping up to see if the treatment produces a measurable benefit. It is beginning with one trial for hospitalized COVID-19 patients and another for non-hospitalized patients.

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