Achillion Pharmaceuticals, Inc., a biopharmaceutical company, engages in the discovery, development, and commercialization of treatments for infectious diseases. The company focuses on the development of antivirals for the treatment of chronic hepatitis C and HIV infection; and the development of antibacterials for the treatment of resistant bacterial infections. Its products include ACH-1095, a NS4A antagonist that is in late-stage preclinical studies for the treatment of chronic hepatitis C infections; ACH-1625, a protease inhibitor, which is in the preparation for phase I initiation for the treatment of chronic hepatitis C infections; ACH-702, a preclinical candidate that is in preclinical stage with potency against a spectrum of bacterial pathogens, including methicillin-resistant staphylococcus aureus for drug resistant bacterial infections; and Elvucitabine, which completed phase II studies for the treatment of HIV infection. The company has a collaboration arrangement with Gilead Sciences, Inc. to develop and commercialize compounds for use in treating hepatitis C infection, which inhibit viral replication through a mechanism of action. The company was founded in 1998 and is based in New Haven, Connecticut.