New clinical data show antiviral activity of TMC435, an investigational protease inhibitor (PI) being developed by Tibotec BVBA for the treatment of chronic hepatitis C virus (HCV) infection. Tibotec will present findings from three TMC435 studies, including a late-breaker poster on the proof-of-principle phase IIa trial, OPERA-1 (TMC435-C201), at the American Association for the Study of Liver Disease’s (AASLD) Liver Meeting 2008 in San Francisco.