The Advance trial will enroll 1,050 treatment-naive genotype 1 hepatitis C virus (HCV) patients and will evaluate two 24-week telaprevir-based regimens in comparison to a 48-week control arm. The primary endpoint of the study is sustained viral response, defined as undetectable HCV RNA (<10 IU/mL) 24 weeks after the completion of treatment. In this study, rapid viral response criteria will be used to determine which telaprevir patients can stop all treatment at 24 weeks. This is the first Phase III study conducted to evaluate whether an investigational medicine for HCV may be able to both increase the rate of sustained viral response and shorten the duration of therapy to 24 weeks in patients with genotype 1 HCV infection compared to current treatment of 48 weeks. The Advance study will be conducted at more than 100 centers in the US, EU and certain other countries. Patient recruitment is being initiated in the US, while sites in other countries will start recruitment as national clinical trial applications for each country are approved. John McHutchison, principal investigator for the Advance study, said: "We're interested to see whether this trial will confirm the encouraging results seen thus far in Phase II studies of telaprevir. This study is another important step forward in the evaluation of novel medicines for the treatment of HCV."