Schering-Plough Corporation reported that a novel investigational protease inhibitor developed by Schering-Plough Research Institute (SPRI) was shown to be a potent inhibitor of hepatitis C virus (HCV) replication in vitro, according to data provided by researchers.

The hepatitis C protease is a viral enzyme complex that is essential to the replication of the hepatitis C virus. By interfering with viral replication, HCV protease inhibitors may represent a new antiviral approach to treating hepatitis C patients.

"The development of protease inhibitors has been a major milestone in the treatment of HIV infection. Now companies such as Schering-Plough are beginning to test the first of similar drugs to treat the hepatitis C virus, which can cause fatal liver disease and has infected millions of people worldwide," said Francesco Negro, divisions of gastroenterology and hepatology, and of clinical pathology, University Hospital, Geneva, Switzerland, who presented the data. "Hepatitis C protease inhibitors have the potential to have the same impact on HCV therapy that the HIV drugs have had," he said.

"These encouraging findings suggest this class of drugs is a promising area of research in the treatment of hepatitis C," said Cecil B. Pickett, president of Schering-Plough Research Institute. "Once developed, these protease inhibitors, either alone or in combination with existing therapies, may help in eradicating the hepatitis C virus in patients chronically infected with the disease. Our lead compound in this area has just begun clinical testing."

Schering-Plough has a dedicated HCV protease inhibitor development program. Its researchers, leaders in the structural biology of HCV, are using their expertise to design potent antiviral agents that can inhibit the enzyme activities required for HCV maturation and replication. As the worldwide leader in developing new and more effective treatments for hepatitis C, Schering-Plough is well positioned to develop and market innovative therapies that target HCV replication. The company in 1991 introduced the first product approved in the United States for treating chronic hepatitis C and in 1998 launched the first combination therapy. In 2001, Schering-Plough introduced the first pegylated interferon therapy.

Today, PEG-Intron (peginterferon alfa-2b) Powder for Injection in combination with Rebetol (ribavirin, USP) Capsules is the most prescribed treatment for hepatitis C worldwide. More than 300,000 hepatitis C patients worldwide, including 175,000 U.S. patients, have received this combination therapy since its introduction in 2001.