Experimental Ebola drug remdesivir could stop SARS-CoV-2 from replicating by acting on a key enzyme, according to a new study from the University of Alberta.
Last month, the World Health Organization (WHO) announced the launch of a multinational trial, testing the four most promising therapeutic avenues for COVID-19.
One of these avenues is remdesivir, a drug that research scientists initially developed for the treatment of Ebola, but which has recently shown some promise in fighting coronaviruses.
Following on from this evidence, and reports that the drug may have helped some patients seeking treatment for COVID-19 to recover, scientists have been studying remdesivir’s effects on SARS-CoV-2.
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Most recently, a team of investigators from the University of Alberta in Edmonton, Canada, has conducted an in vitro study to see if remdesivir would act on SARS-CoV-2 in the same way that it appears to act on SARS-CoV and MERS-CoV.
The researchers report their findings in the Journal of Biological Chemistry.
Last year, University of Alberta researchers showed that remdesivir could stop MERS-CoV in its tracks by interfering with the mechanism that allows the virus to replicate and spread.
“We were optimistic that we would see the same results against the SARS-CoV-2 virus,” says Prof. Matthias Götte, who contributed to both studies.
In the new study, the researchers expressed RNA-dependent RNA polymerases present in SARS-CoV and SARS-CoV-2 in insect cells. These polymerases are enzymes that allow each of the two coronaviruses to replicate.
They then exposed the enzymes to remdesivir and observed what happened. The researchers saw that the drug effectively acted on the two viruses’ polymerases in the same way, inhibiting proliferation.
“We obtained almost identical results as we reported previously with MERS, so we see that remdesivir is a very potent inhibitor for coronavirus polymerases,” says Prof. Götte.
“If you target the polymerase, the virus cannot spread, so it’s a very logical target for treatment,” he goes on to explain.
“These coronavirus polymerases are sloppy, and they get fooled, so the inhibitor gets incorporated many times, and the virus can no longer replicate.”
– Prof. Matthias Götte
This evidence suggests that remdesivir could be an effective “direct-acting antiviral” against SARS-CoV-2, as the team terms it.
Nevertheless, the investigators note that laboratory studies, while they indicate that the drug is a promising therapeutic avenue, cannot confirm that it would be safe in humans.
Prof. Götte and his colleagues emphasize that to confirm the drugs’ effectiveness and safety in the context of a COVID-19 treatment, we must wait for the result of clinical trials, which are already underway.
“We’ve got to be patient and wait for the results of the randomized clinical trials,” the researcher notes.
Prof. Götte also declares that current and previous research from his laboratory that has involved remdesivir was possible partly thanks to funding and other support from Gilead Sciences, a biopharmaceutical company that produces the drug.
The researcher goes on to emphasize the importance of laboratory-based studies that are focused on potential therapeutics.
“We are desperate [to find an effective treatment for COVID-19], but we still have to keep the bar high for anything that we put into clinical trials,” he says.
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