Achillion Initiates Phase 2 Interferon-Free Trial of Sovaprevir and ACH-3102 for Genotype 1 HCV

All-Oral Trial to Evaluate the Safety and Efficacy of a 12-Week Regimen of Sovaprevir, ACH-3102 and Ribavirin for Genotype 1 Treatment-Naive HCV Patients

NEW HAVEN, Conn., April 16, 2013 (GLOBE NEWSWIRE) -- Achillion Pharmaceuticals, Inc. (Nasdaq:ACHN) today announced that it has initiated an international Phase 2 clinical trial with sovaprevir and ACH-3102 for the treatment of genotype 1 chronic hepatitis C (HCV). The trial will evaluate an all-oral 12-week interferon-free regimen consisting of sovaprevir, ACH-3102, and ribavirin in patients with chronic HCV who have not received prior therapy.

"With the initiation of this study, Achillion embarks on an aggressive and robust Phase 2 program. In previous clinical trials, both sovaprevir and ACH-3102 were shown to be efficacious, safe, well-tolerated, and had demonstrated a high barrier to resistance. Hence, we believe that a combination of these two agents for the treatment of chronic hepatitis C has the potential to be well-tolerated and provide high SVR rates," commented Milind Deshpande, Ph.D., President of Research and Development and Chief Scientific Officer of Achillion.

"Based upon the highly competitive SVR rates achieved to date with sovaprevir and the robust and unique single-agent activity observed with ACH-3102, our cornerstone NS5A inhibitor, we are optimistic about the results from this interferon-free trial," commented Michael Kishbauch, President and Chief Executive Officer of Achillion. "Achillion looks forward to reporting all-oral results from our ongoing clinical trials including RVR results from the -007 sovaprevir and ACH-3102 study during the third quarter of this year, as well as providing the updated SVR results later this month from our safety and tolerability study of ACH-3102 and ribavirin for the treatment of genotype 1b HCV."

Summary of Phase 2 '-007' Trial of Sovaprevir and ACH-3102

This is a Phase 2 trial which will evaluate the safety, tolerability and efficacy of 12 weeks of sovaprevir, ACH-3102 and ribavirin in up to 50 treatment-naïve patients with chronic genotype 1 HCV. Initially, 30 patients will be enrolled and randomized to receive either a combination of sovaprevir, ACH-3102 and ribavirin or matching placebos. Once daily 200 mg or 400 mg doses of sovaprevir with ACH-3102, given as a 150 mg loading dose followed by a 50 mg once daily dose, in combination with ribavirin, will be evaluated in this trial. Primary endpoints include safety, tolerability, and sustained virologic response 4 weeks after the completion of dosing (SVR4). The trial is expected to enroll patients at sites in the United States, Canada, New Zealand and Australia.

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, more than twice as widespread as HIV. Three-fourths of the 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 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 -007 clinical trial of sovaprevir and ACH-3102 in combination with ribavirin, as well as with respect to other ongoing clinical studies. Among the 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.

In addition, any forward-looking statement in this press release represents Achillion's views only as of the date of this press release and should not be relied upon as representing its views as of any subsequent date. Achillion disclaims any obligation to update any forward-looking statement, except as required by applicable law.

CONTACT: Company Contact:
         Glenn Schulman
         Achillion Pharmaceuticals, Inc.
         Tel. (203) 624-7000
         gschulman@achillion.com
         
         Investors:
         Mary Kay Fenton
         Achillion Pharmaceuticals, Inc.
         Tel. (203) 624-7000
         mfenton@achillion.com
         
         Media:
         Sally Barton
         Ogilvy PR
         Tel. (212)880-5240
         sally.barton@ogilvy.com
         
         Investors:
         Seth Lewis
         The Trout Group, LLC
         Tel. (646) 378-2952
         slewis@troutgroup.com