Broad spectrum antiviral drug may inhibit more coronaviruses: study

WASHINGTON, March 6 (Xinhua) -- American researchers reported a promising experimental broad spectrum antiviral drug against coronaviruses in this week's mBio, a journal of American Society of Microbiology.

Coronaviruses are RNA viruses and have caused lethal outbreaks of severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) that span multiple continents.

Previous studies have shown that the drug named GS-5734 inhibits strains of SARS and MERS coronaviruses that infect human airways and the lower respiratory tract, as well as infection by the Ebola virus.

The researchers have reported that the drug also inhibits murine hepatitis virus, or MHV, which is closely related to several human coronaviruses that can cause respiratory tract infections, sometimes as severe as SARS.

The researchers tested the drug on mini models of human lungs consisting of airway epithelial cells, collected from lung transplants, because those cells express the genes and proteins of the airways that are targeted by coronavirus infections, researchers can use them as a facsimile for host tissue, according to Ralph C. Baric at the University of North Carolina at Chapel Hill.

The researchers also identified how the virus fights back against the drug, which is crucial information for predicting whether an antiviral might be effective in human hosts.

Like many antivirals, GS-5734 is a nucleoside analog, a class of drugs that work by inhibiting the replication of the virus. However, because viruses evolve so rapidly, they quickly develop mutations that confer resistance to these drugs.

Researchers at Vanderbilt identified the genetic mutations in the coronaviruses triggered by exposure to GS-5723. Those mutations, however, significantly weakened the virus, which suggests that the drug may be effective enough to outpace viral evolution.

"The location being targeted doesn't seem to have much capacity to evolve and escape the effects of the drug, says Baric. "Drug resistance was very difficult to achieve."

To date, no retroviral drug has been approved to treat coronaviruses infections. Enditem