THURSDAY, March 5, 2020 (HealthDay News) -- An Ebola drug that's proven effective against some coronaviruses may also work against the new COVID-19 coronavirus, scientists say.

Remdesivir was developed by Gilead Sciences in response to the 2014 West African Ebola virus epidemic.

"We know the drug works against different coronaviruses, like MERS [Middle East respiratory syndrome] and SARS [severe acute respiratory syndrome], and we know the novel coronavirus is very similar to SARS," said virologist Matthias Götte, of the University of Alberta in Canada. "So I would say I'm cautiously optimistic that the results our team found with remdesivir and MERS will be similar with COVID-19."

The researchers said they discovered why remdesivir is effective in treating the MERS and SARS coronaviruses, and that's the key to their report.

Until now, there hadn't been a published explanation of why remdesivir may work against coronaviruses.

"Even if you know a drug works, it can be a red flag if you don't know how it works," Götte said in a university news release. "It is reassuring if you know exactly how it works against the target.

"What our study showed was that remdesivir essentially mimics one of the natural building blocks for RNA synthesis necessary for genome replication of the virus," Götte said. When the drug is incorporated into the growing RNA chain, the virus can no longer replicate, the researchers found.

Results from ongoing clinical trials of remdesivir treatment in patients with COVID-19 are expected by the end of April. But even if remdesivir proves effective, it won't be a silver bullet.

"It's likely we'll need more than one drug to properly fight emerging diseases like COVID-19, as we have with HIV and hepatitis C virus infections," Götte said. "Ideally, we will have a couple of drugs because certain strains could be resistant to certain treatments."

A recent report in the New England Journal of Medicine said a patient with COVID-19 was given remdesivir on the seventh day of illness and showed major improvement the following day and eventually recovered.

At a recent press conference in Beijing, Dr. Bruce Aylward, the assistant director-general of the World Health Organization, said remdesivir is the only drug available that may be effective against COVID-19.

The new study was published recently in the Journal of Biological Chemistry.

More information

The U.S. Centers for Disease Control and Prevention has more on COVID-19.