SciClone Pharmaceuticals, Inc. Announces Data Presentations At AASLD Regarding ZADAXIN's Activity In Hepatitis B

SAN MATEO, CA -- (MARKET WIRE) -- 11/16/2005 -- SciClone Pharmaceuticals (NASDAQ: SCLN) today announced abstract presentations of pre-clinical and clinical data from two separate studies evaluating the activity of ZADAXIN®, also known as thymosin alpha 1, against the hepatitis B virus (HBV). These abstracts were presented during the annual conference of the American Association for the Study of Liver Diseases (AASLD) in San Francisco, California. Clinical results were presented from a retrospective study evaluating ZADAXIN's effect on complete response depending upon the genotype, or strain, of HBV infection. This study was conducted by Dr. Yun-Fan Liaw of Chang Gung Memorial Hospital and University in Keelung, Taiwan. Results from this analysis indicate that therapy with ZADAXIN led to a higher response rate in HBV patients infected with genotype B than it did for HBV patients infected with genotype C. This conclusion suggests that the likelihood a patient has of achieving a complete response following ZADAXIN therapy could be predicted if the patient is infected with either HBV genotype B or HBV genotype C. Pre-clinical results were presented from a study evaluating the effect of ZADAXIN on the production of T helper 1 (Th1) and T helper 2 (Th2) cytokines in white blood cells from e-antigen negative HBV patients. This study was conducted in the laboratory of Dr. Pietro Andreone of the Department of Internal Medicine and Hepatology at the University of Bologna in Bologna, Italy. Results from this study show that ZADAXIN induces a significant increase in the production of Th1 cytokines while simultaneously causing a decrease in the production of Th2 cytokines, which are often associated with persistence of infection. Conversely, interferon alpha alone did not modify the production of Th1 cytokines and led to an increase in the production of Th2 cytokines. Furthermore, ZADAXIN and interferon alpha in combination produced a synergistic effect on the production of Th1 cytokines and reversed the stimulatory effect of interferon alpha on Th2 cytokine production.