CAMBRIDGE, Mass., Jan. 28, 2013 (GLOBE NEWSWIRE) -- Idenix Pharmaceuticals, Inc. (Nasdaq:IDIX), a biopharmaceutical company engaged in the discovery and development of drugs for the treatment of human viral diseases, today announced a non-exclusive collaboration with Janssen Pharmaceuticals, Inc. for the clinical development of all-oral direct-acting antiviral (DAA) HCV combination therapies. The collaboration will evaluate combinations including IDX719, Idenix's once-daily pan-genotypic NS5A inhibitor, simeprevir (TMC435), a once-daily protease inhibitor jointly developed by Janssen and Medivir AB, and TMC647055, a once-daily non-nucleoside polymerase inhibitor, boosted with low dose ritonavir, being developed by Janssen. Clinical development plans include an initial drug-drug interaction study to begin in the first quarter of 2013, followed by phase II studies as agreed between the companies, and pending approval from regulatory authorities. The phase II program is expected to first evaluate the two-DAA combination of IDX719 and simeprevir plus ribavirin for 12 weeks in treatment-naïve HCV-infected patients. Subsequently, the companies plan to evaluate a three-DAA combination of IDX719, simeprevir and TMC647055/r, with and without ribavirin. The clinical trials will be conducted by Idenix. Both companies retain all rights to their respective compounds under this agreement. "We are very pleased to be working with Janssen and look forward to initiating a phase II study in the first quarter of this year," said Ron Renaud, Idenix's President and Chief Executive Officer. "This will allow us to achieve a key goal of ours for 2013, which is to advance the development of IDX719 as part of all-oral HCV combinations in two- and three-drug regimens." ABOUT IDX719 IDX719 is an NS5A inhibitor with low picomolar, pan-genotypic antiviral activity in vitro. To date, IDX719 has been safe and well tolerated after single and multiple doses of up to 100 mg in healthy volunteers (n=36; up to 7 days duration) and HCV-infected patients (n=69; up to 3 days duration). There have been no treatment-emergent serious adverse events reported in the program. IDX719 has demonstrated potent pan-genotypic antiviral activity in HCV-infected patients with mean maximal viral load reductions up to approximately 4.0 log 10 IU/mL across HCV genotypes 1-4 in a proof-of-concept, three-day monotherapy study. ABOUT SIMEPREVIR (TMC435) Simeprevir is a once-daily potent investigational hepatitis C protease inhibitor in late Phase 3 clinical development being jointly developed by Janssen R&D Ireland and Medivir AB to treat chronic hepatitis C virus infections. Simeprevir is being investigated in combination with PegIFN/RBV in Phase 3 trials and is also being evaluated with Direct-acting Antiviral (DAA) agents in three other Phase 2 interferon-free combinations both with and without ribavirin (RBV). For further details please visit http://www.medivir.com . ABOUT TMC647055 TMC647055 is a potent non-nucleoside hepatitis C polymerase inhibitor with broad genotypic coverage. TMC647055 is in Phase 2 clinical development and is developed by Janssen R&D Ireland to treat chronic hepatitis C virus infections. TMC647055 is being investigated in combination with other DAA agents in all oral interferon-free regimens. There have been no treatment-emergent serious adverse events reported in the program.