New Hepatitis C NS5A Inhibitor ACH-2928 Shows Potent Antiviral Activity

Achillion's novel once-daily hepatitis C virus (HCV) NS5A inhibitor ACH-2928 was well-tolerated and lowered viral load by more than 3.6 log in a 3-day monotherapy study, the company announced this week. These findings suggest ACH-2928 may be a promising candidate for inclusion in future oral direct-acting antiviral regimens.

Below is an edited excerpt from an Achillion press release describing the study and its findings.

Achillion Announces Preliminary Phase 1b Proof-of-Concept Data With ACH-2928 NS5A Inhibitor for the Treatment of Hepatitis C

• Achieves 3.68 log10 reduction in HCV RNA after three days of treatment

New Haven, Conn. -- December 5, 2011 -- Achillion Pharmaceuticals, Inc. (Nasdaq:ACHN), a leader in the discovery and development of small molecule drugs to combat the most challenging infectious diseases, today reported proof-of-concept data from its Phase 1b clinical trial of ACH-2928, a first-generation NS5A inhibitor, demonstrating that patients treated with ACH-2928 achieved a mean maximum 3.68 log₁₀ reduction in HCV RNA after three-day monotherapy of 60 mg once daily. The compound also demonstrated good safety and tolerability both in healthy volunteers and in patients with chronic hepatitis C (HCV).

ACH-2928, Achillion's first generation inhibitor of the NS5A protein, was discovered through the Company's NS5A inhibitor program. Achillion also recently nominated a second-generation NS5A inhibitor, ACH-3102, which is currently undergoing IND-enabling studies and is expected to be advanced into clinical trials during the first half of 2012.

"We believe NS5A inhibitors have emerged as an important component for an all-oral, direct acting antiviral (DAA) regimen," commented Michael D. Kishbauch, President and Chief Executive Officer of Achillion. "Furthermore, NS5A inhibitors, when combined with a protease inhibitor, have achieved sustained viral responses in clinical trials in tough to treat genotype 1 HCV populations. We believe this highlights the potential to form a proprietary interferon-free DAA combination regimen for the treatment of HCV within Achillion's pipeline."

ACH-2928 Phase 1 Program

In July 2011, Achillion initiated dosing in a randomized, double-blind, placebo-controlled phase 1a/1b clinical trial to investigate the safety, tolerability, pharmacokinetic profile and antiviral activity of ACH-2928. The trial consists of three segments: assessment of single ascending oral doses (SAD) in healthy volunteers, evaluation of 3 days of oral repeat doses in subjects with genotype 1a or 1b HCV, and a 5-day multiple ascending doses segment in healthy volunteers.

During the oral repeat doses segment in subjects infected with HCV, a total of 10 patients were enrolled with 2 patients (genotype 1a) receiving placebo and 8 patients (7 genotype 1a and 1 genotype 1b) treated with 3 doses of 60 mg ACH-2928 administered once daily. No serious adverse events (SAE) were reported and there were no patient discontinuations during treatment. The mean maximum HCV RNA decline during therapy was 3.68 log₁₀ compared to a 0.54 log₁₀ decline for patients receiving placebo. There were no viral breakthroughs observed during ACH-2928 monotherapy.

Preliminary data from the SAD trial segment demonstrated ACH-2928 was well tolerated at all doses evaluated up to and including the maximum dose of 500 mg. 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, and were transient in nature.

Based upon these preliminary results, the ongoing Phase 1 study will continue to evaluate the pharmacokinetic, pharmacodynamic, and antiviral profile of ACH-2928. These Phase 1 results have been submitted for presentation at a medical meeting being held during the second quarter of 2012. In parallel, Achillion is advancing its second generation NS5A inhibitor ACH-3102 through IND-enabling studies and the Company expects to initiate clinical development during the first half of 2012.

"As we continue to evaluate ACH-2928 in this Phase 1 study, we are also working rapidly to advance ACH-3102, which has shown in preclinical studies to possess the same potent activity against genotype 1a HCV as ACH-2928, as well as enhanced activity against resistant HCV mutants that have been observed in this patient population," stated Milind Deshpande, PhD, President of Research and Development and Chief Scientific Officer. "We believe these results validate our NS5A development program, and look forward to developing an all-oral combination for clinical evaluation that includes one of our protease inhibitors and an NS5A inhibitor next year."

About NS5A Inhibitors

The 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. Achillion's NS5A inhibitors, including ACH-2928 and ACH-3102, possess potent in vitroactivity against all HCV genotypes and demonstrate, in preclinical studies, additive to synergistic activity when combined with NS3 protease inhibitors, NS5B polymerase inhibitors, and ribavirin. In preclinical studies, ACH-2928 and ACH-3102 have demonstrated excellent potency, in the pico-molar range, against HCV RNA replication, including potent activity against genotype 1a while ACH-3102 has been shown to possess enhanced activity against recognized genotype 1 resistant variants.

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 hepatitis C and resistant bacterial infections.

For more information on Achillion Pharmaceuticals, please visit www.achillion.comor call 203-624-7000.

12/9/11

Source

Achillion Pharmaceuticals. Achillion Announces Preliminary Phase 1b Proof-of-Concept Data With ACH-2928 NS5A Inhibitor for the Treatment of Hepatitis C. Press release. December 5, 2011.