Idenix Pharmaceuticals has started patient enrolment in the Phase II HELIX-2 clinical trial designed for assessing an all-oral, direct-acting antiviral (DAA) hepatitis c virus (HCV) combination therapy of samatasvir, simeprevir and TMC647055 for the treatment of HCV infection.
Samatasvir is a once-daily pan-genotypic NS5A inhibitor of Idenix; simeprevir is a once-daily NS3/4A protease inhibitor jointly developed by Janssen R&D Ireland and Medivir; while TMC647055 is a once-daily NS5B non-nucleoside polymerase inhibitor boosted with low-dose ritonavir developed by Janssen.
The 12-week, randomised, open-label HELIX-2 trial is aimed at evaluating the efficacy, safety and tolerability of the combination therapy.
During the HELIX-2 trial, patients will be given 50mg samatasvir, 75mg of simeprevir and 450mg of TMC647055/ritonavir (30mg), each once daily for 12 weeks, with or without ribavirin.
The Phase II trial is the second study in HCV-infected patients to start under a non-exclusive collaboration deal signed with Janssen in January 2013.
The company said that the HELIX-1 trial of samatasvir in combination with simeprevir was commenced in May 2013 and is ongoing.
Idenix chief medical officer Doug Mayers said: "With the advancement of the samatasvir programme, as well as that of our novel nucleotide prodrug inhibitor, IDX21437, we anticipate initiating the evaluation of our own HCV combination regimen in 2014."
Idenix's deal with Janssen was aimed at the clinical development of all-oral direct-acting antiviral (DAA) HCV combination therapies and is assessing combinations, including samatasvir, simeprevir, and TMC647055.
Under the deal, both Idenix and Janssen retain all rights to their respective compounds.
Samatasvir has so far been safe and well-tolerated after single and multiple doses of up to 150mg in healthy volunteers up to 14 days duration, and in HCV-infected patients up to 12 weeks duration.
Simeprevir is an NS3/4A protease inhibitor jointly developed to treat chronic hepatitis C infection in combination with other antivirals in HCV genotype 1- and 4-infected subjects with compensated liver disease, including cirrhosis.
Currently, TMC647055 is in Phase II clinical development for the treatment of chronic hepatitis C virus infections.