Idun Pharmaceuticals Initiates Phase 2 Clinical Study of IDN-6556 in Hepatitis C Virus

Idun Pharmaceuticals, Inc. today announced that it has initiated a Phase 2 clinical study of IDN-6556 in patients infected with hepatitis C virus (HCV). The dose-response study will evaluate whether IDN-6556 can decrease the liver damage that occurs from hepatitis, an inflammation of the liver, which can be caused by HCV infection. Participants in this trial will have previously failed to respond to existing drugs for HCV and will receive one of several doses of IDN-6556, or placebo, given orally as a monotherapy for 3 months. This study will be conducted at fifteen sites in the U.S. and is expected to enroll up to 200 patients.

"The initiation of this Phase 2 clinical study of IDN-6556 is an important milestone in the development of this exciting new candidate for the treatment of diseases of the liver," said David Shapiro, M.D., Idun's Chief Medical Officer. "We believe that IDN-6556 has considerable potential to treat not only HCV but several other liver diseases based on the encouraging data from the previous clinical experiences. These data have been presented at a number of recent medical meetings including the American Association for the Study of Liver Disease, the European Association for the Study of the Liver and Digestive Disease Week. The current Phase 2 trial seeks to repeat and expand on the results observed in the previous trial and should provide important additional information about safety, dosage and markers of disease progression."

Additional information about participating in this clinical trial can be obtained at the Idun web site at www.idun.com.

IDN-6556

IDN-6556 is a first-in-class, small-molecule pan-caspase inhibitor being developed as a broad liver protectant. IDN-6556 efficiently targets the liver and has been shown to be highly effective in a variety of preclinical models of liver disease demonstrating both anti-inflammatory and anti-fibrotic activity. In previous human clinical trials, IDN-6556 was shown to be well tolerated following oral administration for up to two weeks across a wide range of doses. IDN-6556 significantly decreased elevated aminotransferase liver enzymes, a routine measure of liver damage, within days after administration.

Hepatitis C

The number of individuals with chronic hepatitis C infection is estimated at 2.7 million in the U.S. and up to 10 million patients worldwide. Principally due to the side effect profile and the expensive cost of current therapies, only about 13% of the chronically infected in the United States and roughly 7% of the chronically infected in other developed countries have been treated. Over 30% of patients with chronic hepatitis C will likely develop cirrhosis of the liver and ultimately require a liver transplant.

Idun

Idun Pharmaceuticals, Inc. is a privately-held biopharmaceutical company dedicated to the discovery and development of novel therapeutics in the areas of liver disease, inflammation, and cancer. Idun's lead product candidate, IDN-6556, is in clinical studies for both liver transplantation and in patients infected with hepatitis C virus. The company has a number of product candidates in advanced preclinical development for inflammation and cancer. Idun has an extensive patent portfolio comprised of 146 issued patents worldwide. Idun's corporate headquarters and research and development facility is located in San Diego, California. For more information please visit the company's web site at www.idun.com.