In the third quarter of 2008, SciClone and Sigma-Tau expect to report final results for a phase 3 trial evaluating the triple therapy of thymalfasin (ZADAXIN), pegylated interferon alpha and ribavirin to treat hepatitis C (HCV) non-responder patients. This nearly completed phase 3 trial is multi-center, double-blinded, randomized, and placebo controlled.

We recently reported promising interim blinded results from this phase 3 trial. Although these are interim blinded results and include both treatment and control group patients, we believe the data trend is promising. We estimate for this trial that the sustained virologic response (SVR) rate, the percentage of treated patients that would succeed in being long-term ‘virus-free’, could be 15 to 20% for the thymalfasin treated group. This would compare favorably to the SVR rates of 3 to 8% from other recent trials retreating HCV non-responders with only pegylated interferon alpha and ribavirin without thymalfasin.

About Hepatitis C

There are over 5 million chronically infected hepatitis C carriers in the U.S. and Europe , which together comprise a multi-billion dollar market for HCV therapeutics. In these major pharmaceutical markets, an estimated 160,000 patients each year try therapy for the first time, but half fail current therapy, pegylated interferon in combination with ribavirin. These non-responder patients have few therapeutic options and thymalfasin is one of the only products in development that specifically targets this large and growing group of patients. SciClone estimates the HCV market for products to address non-responder patients to be in excess of $1 billion, and thymalfasin could be a key component of this therapeutic regimen.