The NS3 gene product is an enzyme with multiple functions, including polyprotein processing. The enzyme cleaves four sites within the polyprotein, yielding the NS3, 4A, 4B, 5A, and 5B proteins. The NS4A protein is a critical cofactor for NS3 HCV protease activity. Drugs targeting NS3 are the most advanced of the new hepatitis C therpapies and are due to revolutionise patient care within the next 12 months. Tibotec is at the forefront of this revolution via the development of Telaprevir with our partners Vertex for non-US markets and recently published results indicating a sustained virlogical response in over 80% of patients, a considerable improvement over current standard of care.



Additionally, Tibotec and Medivir through a research collaboration agreement have discovered and are developing another inhibitor of the HCV NS3/4A protease, TMC435. TMC435 is a drug candidate that is in Phase IIb clinical trials that is taken once per day at doses that will not exceed 150mg, potentially making it an ideal partner in a drug cocktail. Data from the phase IIa trial (OPERA-1) were presented at the 44th Annual Meeting of the European Association for the Study of the Liver (EASL).