Gilead Sciences Inc. is an independent biopharmaceutical company focused to discovery, development and commercialization of proprietary therapeutics for important viral diseases, including the currently marketed product VISTIDE (cidofovir injection) for the treatment of cytomegalovirus (CMV) retinitis, a sight-threatening viral infection in patients with acquired immune deficiency syndrome (AIDS). The Company received FDA clearance for VISTUDE in June 1996. Many of the Company's products or products in development are nucleotide analogues, including VISTIDE, PREVEON (adefovir dipivoxil), adefovir dipivoxil for hepatitis B and PMPA. Nucleotides exist in every human cell and are the building blocks of the nucleic acids DNA and RNA. In addition, the Company is developing products to treat diseases caused by human immunodeficiency virus (HIV), hepatitis B virus (HBV) and influenza virus, including PREVEON, GS 4104, and PMPA. During the Summer 1999, Gilead merged with NeXstar Pharmaceuticals Inc. NeXstar Pharmaceuticals, Inc., now a wholly-owned subsidiary of Gilead Sciences, Inc.