Idenix Pharmaceuticals Provides Update on Hepatitis C Clinical Development Programs

In January 2012, Idenix initiated a phase I clinical study of IDX719. The first part of the study evaluated the safety, pharmacokinetics and food effect of IDX719 in 40 healthy volunteers at single doses ranging from 5 to 100 mg. Eight healthy volunteers received 100 mg of IDX719 daily for seven days. All doses were well tolerated and pharmacokinetic data supports once-daily dosing in future studies. In the second part of the phase I study, single-ascending doses of IDX719 achieved substantial viral load reductions in the following cohorts of HCV-infected patients:

          --  A cohort of 12 HCV genotype 1-infected patients received single IDX719
              doses of 1, 5, 10, 25, 50 or 100 mg (2 patients per dose). Mean maximal
              viral load reductions were 1.9 log10, 2.6 log10, 3.3 log10, 3.7 log10,
              2.8 log10 and 3.5 log10, respectively;
        
          --  A cohort of three HCV genotype 2-infected patients received single
              IDX719 doses of 25, 50 or 100 mg (1 patient per dose). Maximal viral
              load reductions were 0.4 log10, 3.2 log10 and 3.5 log10, respectively;
              and
        
          --  A cohort of three HCV genotype 3-infected patients received single
              IDX719 doses of 25, 50 or 100 mg (1 patient per dose). Maximal viral
              load reductions were 2.2 log10, 3.7 log10 and 3.3 log10, respectively.

The single-dose data were presented at the Cambridge Healthtech Institute's 5th Annual HCV Drug Discovery meeting this week in San Diego, California. A three-day proof-of-concept study has initiated dosing and is designed to evaluate 64 treatment-naïve genotype 1, 2, 3 or 4 HCV-infected patients.

"These single-dose IDX719 data show potent viral load reductions, with some patients maintaining viral suppression out to three days," said Douglas Mayers, Chief Medical Officer of Idenix Pharmaceuticals. "We are pleased with the promising antiviral activity in genotypes 1, 2 and 3, and we look forward to seeing multiple-dose data in a larger number of patients from the ongoing three-day proof-of-concept study."

Additionally, Idenix has completed enrollment of the second cohort of 30 patients in the ongoing 12-week phase IIb study of IDX184, an HCV nucleotide inhibitor, in combination with pegylated interferon and ribavirin (PegIFN/RBV). IDX184 continues to be safe and well tolerated with no treatment-emergent serious adverse events reported and a side effect profile similar to that of PegIFN/RBV. As the study currently remains blinded, further data from the ongoing clinical trial will be available in the second half of 2012.

"Idenix's clinical programs have made significant progress in the past few months. For IDX184, we are looking forward to initiating a combination study with a protease inhibitor and ribavirin in the near-term to establish the safety and potency of an all-oral IDX184-containing regimen, and, if successful, potentially support a phase III clinical program," said Ron Renaud, Idenix's President and Chief Executive Officer. "We are also very pleased with the early viral load reduction data for IDX719. Our ultimate goal is to advance a proprietary, pan-genotypic HCV treatment regimen. We intend to evaluate the combination of IDX184 and IDX719 in a clinical trial that is planned to begin by the end of this year."