Chronic hepatitis C is a disease of the liver caused by the hepatitis C virus (HCV). It is estimated that there are approximately 4 million Americans and 170 million people worldwide infected with HCV. Hepatitis C leads to chronic liver disease or cirrhosis, and can lead to death in 1-5% of infected people. It is also the leading indication for liver transplant in the U.S.

Currently the only approved treatment for HCV is interferon combined with ribavirin. The course of treatment ranges from 6 to 12 months and is only effective in approximately half of those treated. It is also associated with significant side effects. As a result of its limited efficacy and tolerability, less than 3% of people diagnosed with HCV actually receive treatment, and approximately one third of these experience a successful treatment outcome.

We are developing a series of phosphoramidate nucleotide analogues, which we refer to as protides, that target the RNA-dependent RNA polymerase (NS5b) of HCV. We believe that our protides possess several pharmacological advantages over nucleosides alone, which include a significant increase in antiviral activity, higher concentrations of the triphosphate in liver, and potentially less toxicity due to reduced systemic exposure.

In 2009 we selected INX-189 as our clinical candidate and initiated IND-enabling studies. In May, 2010 we initiated a Phase I single ascending dose study of INX-189 in healthy volunteers. For more information about this trial, please go to www.ClinicalTrials.gov.

Subject to the outcome of this ongoing study we anticipate initiating a Phase Ib study of INX-189 in treatment naïve genotype 1 patients in the second half of 2010.