The efficacy and safety of telaprevir - a new protease inhibitor against hepatitis C virus.

IMPORTANCE OF THE FIELD: Hepatitis C virus (HCV) is the main agent of chronic hepatitis, liver cirrhosis and hepatocellular carcinoma in the western world. It affects more than 170 million people worldwide. HCV treatment, based on the combination of Peg-interferon and ribavirin, is effective in about 50% of treated patients. Therefore, there is a need to develop new drugs active against HCV. AREAS COVERED IN THIS REVIEW: Data were obtained by searching for all full articles on Medline and abstracts presented at major international congresses on viral hepatitis. WHAT THE READER WILL GAIN: A review of clinical data about the efficacy and safety of telaprevir (VX-950), the HCV protease inhibitor that is in the most advanced phase of clinical development. TAKE HOME MESSAGE: Telaprevir has an acceptable pharmacokinetic profile and seems to be a potent antiviral drug against HCV, although, owing to a low genetic barrier, resistant variants emerge within a few days when used in monotherapy, thereby decreasing its efficacy. Consequently, telaprevir has been combined with pegylated-interferon and ribavirin in clinical trials. This triple combination is more effective but has a higher rate of adverse events (notably rash) than the standard of care, despite the shorter duration of therapy.