An old ebola drug being tested as a treatment for COVID-19 is capable of tricking the virus responsible for the deadly respiratory disease, a new University of Alberta study suggests. 

The drug remdesivir is capable of halting the coronavirus from replicating, according to new research published Monday in the Journal of Biological Chemistry.

The study, led by Matthias Götte, chair of medical microbiology and immunology at U of A, demonstrates how the antiviral drug disrupts the virus by attacking enzymes known as polymerases.

When viruses infect our body, they hijack our cells to replicate themselves, making more viruses that can go on to infect other cells or people, Götte said in a news release Monday.

Remdesivir takes advantage of the coronavirus’ natural life cycle, infiltrating the virus’ genome and effectively shutting down its ability to make copies of itself, he said. 

Replication of the virus relies on the polymerases, enzymes which synthesize the virus’ genome by assembling sequences of RNA molecules. Remdesivir inhibits this process by masquerading as a part of the virus itself and damaging it from the inside, Götte said.   

The drug has proven a “very potent inhibitor,” he said. 

“If you target the polymerase, the virus cannot spread, so it’s a very logical target for treatment,” Götte said.

“These coronavirus polymerases are sloppy and they get fooled, so the inhibitor gets incorporated many times and the virus can no longer replicate.” 

‘A very potent inhibitor’

The drug remdesivir has already been used intravenously to treat thousands of COVID-19 patients on a compassionate basis during the escalating pandemic. Clinical trial studies involving hundreds of patients around the globe began in early March.

And while the study supports the need for clinical study, results obtained in the lab cannot predict how the drug will work on people, Götte said. 

Ongoing clinical trials will be the true test, Götte said. Those results can be expected as early as April or May.

American biotechnology company Gilead Sciences developed the drug remdesivir as a response to the Ebola epidemic in West Africa, where it was tested in a clinical trial.

Results showed the drug was not particularly effective against Ebola, but testing on monkeys infected with MERS — the Middle East respiratory syndrome — suggested the drug could be effective against coronaviruses.

A previous study by Götte and his team, published in February, demonstrated that the drug was effective against MERS, a related coronavirus.

“We were optimistic that we would see the same results against the SARS-CoV-2 virus,” Götte said. SARS-CoV-2 virus is the coronavirus that causes COVID-19.

“We obtained almost identical results as we reported previously with MERS, so we see that remdesivir is a very potent inhibitor for coronavirus polymerases.”

Last month, Gilead Sciences announced two clinical studies to evaluate the safety and efficacy of remdesivir in about 1,000 adults diagnosed with COVID-19.

The company said the randomized studies will assess patients across Asia and in other countries where COVID-19 has been diagnosed in higher numbers.

Götte is optimistic the ongoing global effort to find effective treatments for COVID-19 will be successful.

“We are desperate, but we still have to keep the bar high for anything that we put into clinical trials,” Götte said.

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