German investigators believe they have found a potential new drug that might be more effective in the treatment of severe acute respiratory syndrome (SARS) than drugs now being used against the deadly disease. In a research letter published in this week’s issue of The Lancet, the scientists outline results of a study comparing the standard drug used in SARS patients, ribavirin, with four additional antiviral drugs: 6-azauridine, pyrazofurin, mycophenolic acid, and glycyrrhizin. All were tested against two isolates of the SARS virus taken from SARS patients being treated at Frankfurt University.
The study showed glycyrrhizin, which is used to treat some HIV and hepatitis C infections, was most effective in inhibiting replication of the SARS virus. Ribavirin and mycophenolic acid, by contrast, did not affect replication of the virus, and 6-azauridine and pyrazofurin inhibited replication, but less effectively than glycyrrhizin. Researchers aren’t sure how the drug does the job, but suspect it may be related to its effect on the increased synthesis of nitric oxide, which is known to inhibit replication of several viruses.Investigators say glycyrrhizin should be studied further for a potential role in the treatment of SARS patients. They write, "Of all the compounds, glycyrrhizin was the most active in inhibiting replication of the SARS-associated virus".
