About ACH-3102The NS5A protein is a clinically validated target that serves multiple functions at various stages of the HCV life cycle including involvement in virion production, interaction with host proteins and association with interferon-resistance. ACH-3102, Achillion's second generation NS5A inhibitor, has demonstrated potent activity against all HCV genotypes in vitro and in preclinical studies achieved additive to synergistic activity when combined with NS3 protease inhibitors, NS5B polymerase inhibitors, interferon and ribavirin. In preclinical studies, ACH-3102 demonstrated excellent potency, in the pico-molar range, against wild type HCV RNA replication, as well as potency against resistant mutants that have been identified in clinical studies. ACH-3102 was deemed to be safe and well-tolerated in Phase 1 development and achieved mean maximal reductions in HCV RNA of 3.78 log 10 after a single dose. ACH-3102 has been granted fast track designation by the FDA and is currently being evaluated in Phase 2 for the treatment of HCV. About HCV The hepatitis C virus is the most common cause of viral hepatitis, which is an inflammation of the liver. It is currently estimated that more than 170 million people are infected with HCV worldwide including more than 5 million people in the United States, making HCV more than twice as widespread as HIV. Three-fourths of the global HCV patient population is undiagnosed; it is a silent epidemic and a major global health threat. Chronic hepatitis, if left untreated, can lead to permanent liver damage that can result in the development of liver cancer, liver failure or death. Few therapeutic options currently exist for the treatment of HCV infection. The current standard of care is limited by its specificity for certain types of HCV, significant side-effect profile, and injectable route of administration. About Achillion Pharmaceuticals Achillion is an innovative pharmaceutical company dedicated to bringing important new treatments to patients with infectious disease. Achillion's proven discovery and development teams have advanced multiple product candidates with novel mechanisms of action. Achillion is focused on solutions for the most challenging problems in infectious disease including HCV and resistant bacterial infections. For more information on Achillion Pharmaceuticals, please visit www.achillion.com or call 1-203-624-7000. Forward-Looking Statements This press release includes forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 that are subject to risks, uncertainties and other important factors that could cause actual results to differ materially from those indicated by such forward-looking statements, including statements with respect to: the expected potency, safety, tolerability, effectiveness and other characteristics of sovaprevir and ACH-3102; and Achillion's expectations regarding timing for the commencement, completion and reporting of results of its clinical trials of both ACH-3102 in combination with ribavirin and sovaprevir in combination with ACH-3102. We may use words such as "expect," "anticipate," "project," "intend," "plan," "believe," "seek," " estimate," and "may" and similar expressions to identify such forward-looking statements. Among the important factors that could cause actual results to differ materially from those indicated by such forward-looking statements are risks relating to, among other things Achillion's ability to: replicate in later clinical trials positive results found in earlier stage clinical trials of sovaprevir, ACH-3102 and its other product candidates; advance the development of its drug candidates under the timelines it anticipates in current and future clinical trials; obtain necessary regulatory approvals; obtain patent protection for its drug candidates and the freedom to operate under third party intellectual property; establish commercial manufacturing arrangements; identify, enter into and maintain collaboration agreements with appropriate third-parties; compete successfully with other companies that are seeking to develop improved therapies for the treatment of HCV; manage expenses; and raise the substantial additional capital needed to achieve its business objectives. These and other risks are described in the reports filed by Achillion with the U.S. Securities and Exchange Commission, including its Annual Report on Form 10-K for the fiscal year ended December 31, 2012 and its subsequent SEC filings.