Medivir announces that Idenix Pharmaceuticals today released interim data from the ongoing phase II HELIX-1 clinical trial evaluating an all-oral, direct-acting antiviral (DAA) HCV combination regimen of samatasvir (IDX719), Idenix’s once-daily pan-genotypic NS5A inhibitor, and simeprevir , a once-daily protease inhibitor jointly developed by Janssen R&D Ireland and Medivir, and ribavirin.
The combination regimen of the study was well-tolerated. In the treatment-naïve, non-cirrhotic, genotype 1b or 4 HCV-infected patients receiving 50 mg of samatasvir and 150 mg of simeprevir plus ribavirin for 12 weeks, 85 percent (n=17/20) of the patients achieved SVR4 (undetectable HCV RNA four weeks after end of treatment). The 50 mg dose of samatasvir is the selected dose in the ongoing 3-DAA HELIX-2 clinical trial. The HELIX-1 study results are expected to be presented at a scientific meeting in 2014.
The HELIX-1 trial is the first study in HCV-infected patients to commence under a non-exclusive collaboration agreement between Idenix and Janssen which was established in January 2013. The HELIX-1 trial is a phase II 12-week, randomized, parallel group study evaluating the antiviral activity, safety and tolerability of samatasvir and simeprevir in treatment-naïve, non-cirrhotic, genotype 1b or 4 HCV-infected patients.
Patients in part A of the study (n=63) were enrolled in one of three treatment groups receiving 50, 100, or 150 mg samatasvir once-daily for 12 weeks in combination with 150 mg of simeprevir plus a weight-based dose of ribavirin. In part B of the ongoing HELIX-1 study, exploratory cohorts of patients have been added to evaluate the safety and antiviral activity of a 25 mg dose of samatasvir in genotype 1b-infected patients and of a 100 mg dose of samatasvir in genotype 6-infected patients.
A second phase II trial (HELIX-2) was initiated in December 2013 evaluating samatasvir, simeprevir and TMC647055, a once-daily non-nucleoside polymerase inhibitor plus a low-dose ritonavir being developed by Janssen, with and without ribarivin in genotype 1-infected patients who are either treatment-naïve or have previously relapsed after treatment with pegylated interferon and ribavirin.