Enanta Pharmaceuticals, Inc., a research and development-focused biotechnology company focuses on discovering and developing small molecule drugs for the treatment of viral infections and liver diseases. The company's research and development focuses on four disease targets: Hepatitis C virus (HCV), Hepatitis B virus (HBV), Non-alcoholic Steatohepatitis (NASH), and Respiratory Syncytial Virus (RSV). Its lead product is paritaprevir, a protease inhibitor designed for use against HCV. The company also develops HCV protease inhibitor in phase III development with AbbVie, as well as a HCV program using a different class of molecules known as cyclophilin inhibitors. In addition, it has a program in non-alcoholic steatohepatitis; and discovers programs in other areas of viral infection and liver disease. Enanta Pharmaceuticals, Inc. has a collaborative development and license agreement with AbbVie to develop and commercialize HCV NS3 and NS3/4A protease inhibitors. The company was founded in 1995 and is headquartered in Watertown, Massachusetts.