Vertex Pharmaceuticals and Tibotec have begun patient screening in a Phase III  study of the hepatitis C virus (HCV) protease inhibitor telaprevir for treatment-naive patients with chronic infection.

The ADVANCE trial will enroll 1,050 patients and evaluate two 24-week telaprevir-based regimens compared with a 48-week control arm. The primary endpoint of the study is sustained viral response, which is defined as undetectable HCV RNA 24 weeks after the completion of treatment, Vertex said.

Vertex and Tibotec are collaborating to develop and commercialize telaprevir in Europe, South America, Australia, the Middle East and other countries. Vertex retains commercial rights to telaprevir in North America and is collaborating with Mitsubishi Pharma to develop and commercialize telaprevir in Japan and other Asian countries.