Pharmasset, Inc. (Pharmasset) is a clinical-stage pharmaceutical company engaged in discovering, developing and commercializing drugs to treat viral infections. The Company’s focus is on the development of oral therapeutics for the treatment of hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV). Its research and development efforts focus on a class of compounds known as nucleoside analogs, which act to inhibit the natural enzymes required for viral replication. Pharmasset has three clinical-stage product candidates, two of which the Company is developing and one of which it is developing through a collaboration with F. Hoffmann-La Roche Ltd and Hoffmann-La Roche Inc. (collectively Roche). The products are clevudine, for the treatment of chronic HBV infection; R7128, a pro-drug of PSI-6130 for the treatment of HCV, and Racivir, for the treatment of HIV.