Hepatitis C Information Central

HAYWARD, Calif -- April 14, 1997 -- RiboGene, Inc. today announced that in a study in the April 14, 1997 issue of Virology, a team of researchers led by Dr. Michael Katze at the University of Washington discovered that the Hepatitis C virus (HCV) nonstructural 5A (NS5A) protein may contribute to the interferon-resistant phenotype of HCV.

Prior to the current report, the mechanism of HCV resistance to interferon therapy was unknown. Katze, a member of the company's Scientific Advisory Board showed that NS5A protein represses the action of PKR, a protein activated by interferon that shuts down viral protein synthesis thereby inhibiting replication of the Hepatitis C virus.

Based on the findings, RiboGene, with its expertise in high throughput screening and translational control of gene expression, has established a research program based on this viral target that will seek to identify new, small molecule therapeutics effective against the Hepatitis C virus.

Background on Hepatitis C virus

HCV, an RNA virus that targets the liver, is responsible for 150,000 to 250,000 new cases of hepatitis each year in the U.S. The virus, which typically has a six to nine-month incubation period, presents symptoms such as: fatigue, nausea, loss of appetite, dark urine, and jaundice; and if left untreated, leads to liver cancer and death.

According to a recent report by a committee sponsored by the National Institutes of Health, nearly four million individuals in the U.S. are infected with HCV. The report also noted that treatment of the disease with current drugs is disappointing and estimated that the number of U.S. deaths caused by HCV will triple in the next 10-20 years.

"This discovery explains the molecular mechanisms for interferon resistance, and points the way to a potential new target for therapeutic drugs to treat Hepatitis C," said the principal investigator, Katze, UW professor of microbiology and associate director of the UW's Regional Primate Research Center.

"The licensing agreement with the University of Washington, allows us to apply RiboGene's assay design expertise, which will result in a screening system capable of identifying highly selective and potent HCV therapies," stated Laura S. Lehman, Ph.D., vice president of Research for RiboGene.

RiboGene and the University of Washington have received a notice of allowance on certain of its patents surrounding this technology, and have other patents pending. Virology is a scientific journal published by Academic Press, RiboGene, Inc. is a privately held biotechnology company focused on the discovery and development of new classes of compounds that act through the translational control of gene expression.

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