Researchers at The Ohio State University Medical Center found the drug leflunomide significantly reduces infectious virus production in both cultured cells and in animal studies.
“Leflunomide has the potential to provide a unique, two-way intervention by reducing viral load and, at the same time, reducing the massive inflammatory response thought to be responsible for the breathing difficulties and lung injury that occurs in serious RSV illness,” says W. James Waldman, researcher and director of pathology graduate studies at Ohio State’s College of Medicine.
The findings are online today (3/30) and will be published in the April issue of the journal Antiviral Therapy.
Researchers compared treatment using leflunomide to treatment with ribavirin, the only anti-viral therapy currently approved for RSV. While tests in cultured cells showed a higher concentration of each drug was equally effective at stopping the production of the infectious virus, leflunomide was more effective than ribavirin at a lower dose. In animal studies, leflunomide dramatically reduced virus production whether treatment began the same day as viral inoculation or on day three following inoculation.
According to Waldman, there are other advantages that set leflunomide apart as a potential treatment for RSV. It is already approved as an anti-inflammatory drug and is a convenient oral medication, compared to the current therapy consisting of an inhalant administered via face mask for several hours per day over three to seven days.
Waldman also says the anti-viral properties of leflunomide differ from current therapies because it works at a different stage of the virus life cycle, giving it potential to treat drug-resistant strains.
“The drug is very effective at controlling virus production. Now we need to determine exactly how it works on the molecular level,” says Waldman.
RSV is a virus that infects the lungs, and nearly all children will contract RSV by age two. Generally healthy people recover in one to two weeks. However, some infants, young children and older adults with certain conditions can develop severe infections. Those at higher risk for severe illness include premature infants, children with congenital heart or chronic lung disease, children or adults with compromised immune systems and adults over age 65. More than 160,000 people die from RSV worldwide each year.
Funding for this research was provided by the National Institutes of Health. Waldman is noted as a co-inventor and holds a patent for the anti-viral use of leflunomide.
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