Achillion Pharmaceuticals, Inc., a leader in the discovery and development of treatments for the most challenging infectious diseases, today announced that its abstract titled “Virological Response, Safety, and Pharmacokinetic Profile Following Single- and Multiple-Dose Administration of ACH-0141625 Protease Inhibitor to Healthy Volunteers and HCV Genotype-1 Patients” has been accepted as a late breaking poster presentation at the International Liver Congress™ 2010 being held April 14-18 in Vienna, Austria.

Two additional abstracts on the compound’s virology and hepatoselectivity titled Preclinical Antiviral Activity, Combination and Resistance of ACH-1625, A Potent HCV NS3 Protease Inhibitor, and Characterization of the Hepatoselective Distribution of ACH-1625, a Potent, Clinical Stage HCV NS3 Protease Inhibitor had previously been accepted for poster presentation.

Achillion’s posters will be displayed from Thursday, April 15 at 8:00 a.m. through Saturday, April 17 at the end of the day’s sessions.

The International Liver Congress 2010 by the European Association for the Study of the Liver (EASL) provides an opportunity for approximately 7,500 clinicians and scientists from around the world to receive the latest research, perspectives and treatments of liver disease from principal experts in the field.

ACH-1625 is an HCV protease inhibitor designed and synthesized based on crystal structures of enzyme/inhibitor complex. ACH-1625 is an open chain, non-covalent, reversible inhibitor of NS3 protease. In preclinical studies, ACH-1625 demonstrated high potency, unique pharmacokinetic properties and an excellent safety profile at high drug exposures. With its rapid and extensive partitioning to the liver, as well as high liver/plasma ratios demonstrated in preclinical studies, Achillion believes that ACH-1625 has the potential for once daily dosing. ACH-1625 has shown low single-digit nanomolar potency that is specific to HCV. It is equipotent against HCV genotypes 1a and 1b at IC50~1nM.

In phase 1a safety studies with ACH-1625, subjects in the single ascending dose (SAD) segment of the study received single doses ranging from 50 mg to 2000 mg. Subjects in the phase 1a multiple ascending dose (MAD) segment of the study received 5 days of ACH-1625 up to a maximal dose of 2000 mg per day. Preliminary data from the SAD and MAD trial segments demonstrated ACH-1625 was well tolerated at all doses and there were no serious adverse events, no clinically significant changes in vital signs, electrocardiograms (ECGs), or laboratory evaluations. All reported adverse events were classified as mild or moderate, were transient and showed no apparent dose relationship.

In Phase 1b clinical studies with ACH-1625, HCV-infected patients received doses of 600 mg and 500 mg twice daily. Preliminary results showed that a mean reduction in viral load of 3.94 log10 and 4.25 log10, respectively, was achieved in the treatment groups, as compared to a mean reduction of 0.22 log10 and 0.29 log10, respectively, in the placebo groups. Safety results from this dosing group were similar to those observed in the phase 1a segment of the trial. There were no serious adverse events, no clinically significant changes in vital signs, electrocardiograms (ECGs), or laboratory evaluations. All reported adverse events were classified as mild or moderate, were transient and showed no apparent dose relationship. Furthermore, all patients had viral loads that remained suppressed for at least 7 days after dosing was completed, maintaining a mean reduction of more than 2.0log10 from baseline through day 12, the last day of viral load measurement in the study.