Achillion Reports 100% SVR12 From Second Cohort of Patients in the Previously-Completed Six Week Phase 2 Trial Evaluating Odalasvir (ACH-3102) and Sofosbuvir for Genotype 1 HCV ("Proxy Study")

- 100% SVR12 reported for all patients treated for six- (n=18) or eight-weeks (n=12) —
- Odalasvir (ACH-3102) is the subject of an exclusive, worldwide development and commercialization license granted to Janssen -

NEW HAVEN, Conn., Sept. 17, 2015 (GLOBE NEWSWIRE) -- Achillion Pharmaceuticals, Inc. (Nasdaq:ACHN) today announced additional interim results from a Phase 2 study evaluating odalasvir (also known as ACH-3102), a NS5A inhibitor, in combination with sofosbuvir, without ribavirin, for either six or eight weeks of treatment in patients with treatment-naïve genotype 1 chronic hepatitis C virus (HCV) infection. Of the patients treated for six weeks in this cross-over cohort, 100 percent (n=6/6) remained HCV RNA undetectable twelve weeks after completing therapy (SVR12). Previously, Achillion reported results from this study including 100 percent SVR24 for the initial cohorts including 12 patients treated for eight weeks and 100 percent SVR24 for 12 patients treated for six weeks.

In May 2015, Achillion announced it had granted Janssen Pharmaceuticals, Inc. (Janssen), one of the Janssen Pharmaceutical Companies of Johnson & Johnson, an exclusive, worldwide license to develop and, upon regulatory approval, commercialize HCV products and regimens containing one or more of Achillion's HCV assets which include odalasvir, ACH-3422, and sovaprevir.

ACH-3102 - 017: Phase 2 pilot study evaluating six- and eight-weeks of treatment in combination with sofosbuvir for genotype 1 treatment-naïve HCV

Achillion conducted a Phase 2, open-label, randomized, partial-crossover study to evaluate the efficacy, safety, and tolerability of eight weeks or six weeks of odalasvir and sofosbuvir, a marketed nucleotide polymerase inhibitor, without ribavirin, in treatment-naïve genotype 1 HCV-infected patients. The primary objective of the study was determination of sustained viral response 12 weeks (SVR12) after the completion of therapy. Eighteen patients were initially enrolled, including six observational patients (group 1). Twelve patients completed eight weeks of treatment consisting of 50 mg of odalasvir and 400 mg of sofosbuvir administered once daily while observational patients received no drug during this phase of the trial. Ten of the 12 patients receiving eight weeks of treatment had genotype 1a HCV. At baseline, the median HCV RNA was 7.15 log10 (range 5.5 — 7.8 log10). Of the 12 patients, 100 percent achieved SVR24. Odalasvir and sofosbuvir were well tolerated with no significant adverse events, ECG findings, or lab abnormalities observed during treatment.

Following achievement of the pre-specified response rate of 100 percent, the six observational patients plus six additional patients (group 2) were enrolled and received six weeks of treatment consisting of 50 mg of odalasvir and 400 mg of sofosbuvir administered once daily. Median HCV RNA at baseline was 6.95 log10 (range 6.2 — 8.0 log10) and six patients had GT 1a HCV. Of the 12 patients, 100 percent achieved SVR24.

Six additional rollover patients (group 3), enrolled into the final cohort, also received six weeks of treatment consisting of 50 mg of odalasvir and 400 mg of sofosbuvir administered once daily. Baseline characteristics included five of six patients with genotype 1a HCV, four of six patients with non-CC IL28B (two patients with IL28B TT), and a median baseline HCV RNA of 6.32 log10 IU/ml (range 6.0 — 7.3 log10 IU/ml). In all, a total of 18 patients (group 2 and 3) received six weeks of treatment and all subjects, 100 percent, achieved SVR12.

About the Achillion Worldwide HCV Collaboration with Janssen

On May 19, 2015, Achillion announced it had granted Janssen Pharmaceuticals, Inc. (Janssen), one of the Janssen Pharmaceutical Companies of Johnson & Johnson, an exclusive, worldwide license to develop and, upon regulatory approval, commercialize HCV products and regimens containing one or more of Achillion's HCV assets which include odalasvir (ACH-3102), ACH-3422, and sovaprevir. A key objective of the collaboration is to develop a short-duration, highly effective, pan-genotypic, oral regimen for the treatment of HCV. Achillion announced on August 3, 2015 that Alios Biopharma Inc., part of the Janssen Pharmaceutical Companies (Janssen) had initiated a Phase 1 clinical trial to evaluate the potential effect of simeprevir and odalasvir on the pharmacokinetics of AL-335 in healthy volunteers. Janssen previously stated its goal of initiating Phase 3 development with a triple regimen for HCV by early 2017.

About HCV

The hepatitis C virus (HCV) is one of the most common causes of viral hepatitis, which is an inflammation of the liver. It is currently estimated that more than 150 million people are infected with HCV worldwide including more than 5 million people in the United States. Three-quarters 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.

About Achillion Pharmaceuticals

Achillion is seeking to apply its expertise in biology and structure-guided design and a deep understanding of patient and clinician needs to develop innovative treatment solutions aimed at improving patients' lives. Achillion believes that its scientific excellence, integrated capabilities and experienced team position it to successfully achieve its goal of advancing new products along the entire continuum from the bench to the patient. Achillion's pipeline is currently focused on small molecule therapeutics for infectious disease and complement-related diseases. www.achillion.com

Cautionary Note Regarding 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. Achillion may use words such as "expect," "anticipate," "project," "intend," "plan," "aim," "believe," "seek," " estimate," "can," "focus," "will," 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: comply with its obligations under and otherwise maintain its collaboration agreement with Janssen on the agreed upon terms; demonstrate, either alone or through its collaborators, the requisite safety, efficacy and combinability of its drug candidates, and advance the preclinical and clinical development of its drug candidates under the timelines it projects in current and future clinical trials; obtain and maintain necessary regulatory approvals; obtain and maintain 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 effectively and successfully; manage expenses; manage litigation; raise the substantial additional capital needed to achieve its business objectives; and successfully execute on its business strategies. 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 year ended December 31, 2014, its quarterly report on Form 10-Q for the quarter ended June 30, 2015, 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 duty to update any forward-looking statement, except as required by applicable law.


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

Investors:
Tricia Truehart
The Trout Group, LLC
Tel. (646) 378-2953
ttruehart@troutgroup.com