CAMBRIDGE, Mass.--(BUSINESS WIRE)--Vertex Pharmaceuticals Incorporated (Nasdaq: VRTX) today announced that it will begin Phase 3 evaluation of telaprevir, Vertex’s lead investigational hepatitis C protease inhibitor. The primary focus will be a global, 3-arm pivotal controlled trial that will evaluate two 24-week telaprevir-based regimens in approximately 1050 treatment-naïve genotype 1 HCV patients. In this study, rapid viral response (RVR) criteria will be used to determine which telaprevir patients can stop all treatment at 24 weeks. A second study of approximately 400-500 HCV patients is planned to evaluate a 48-week telaprevir-based regimen, to confirm the results from Phase 2 studies and provide additional evidence that supports the 24-week regimen that is being evaluated in the primary Phase 3 trial. The Company expects that both studies will run concurrently and that the first trial will begin enrolling patients in March 2008.