Medivir’s investigational protease inhibitor TMC435 has received Fast Track designation from the FDA for treatment of chronic hepatitis C (CHC) genotype-1 infection, based on its potential to address medical needs in CHC infection compared to currently approved therapies.

TMC435 may offer high sustained virological response (SVR) rates in genotype-1 HCV-infected patients including hard-to-treat subgroups. It may also offer short treatment duration, an overall safety and tolerability profile and a convenient once-daily dosing regimen.

Medivir also will start a proof-of-concept oral, interferon-free phase II trial investigating the combination of TMC435, a once-daily NS3/4A protease inhibitor (PI), and Pharmasset's PSI-7977, a once-daily nucleotide NS5B polymerase inhibitor.

The study will investigate the efficacy and safety of 12 weeks or 24 weeks of TMC435 150 mg q.d. in combination with PSI-7977 400 mg q.d. with or without ribavirin in prior null responders to peginterferon/ribavirin therapy. The primary endpoint will be sustained virological response at 12 weeks (SVR12).