[Inhibitors of hepatitis C virus--therapeutic possibilities]

The search for new drugs against HCV contains new ways to obtain pro-drugs which inhibit translation and block viral proteins, and inhibit host proteins important in HCV-induced pathogenesis. This group of agents are serine protease NS3 inhibitors (telaprevir, boceprevir, R-7227, TMC-435, SCH 900518, GS-9256). The most advanced studies are developed with telaprevir and boceprevir; at present their effect in combined therapy with PegIFN-alpha and RBV in the III clinical phase is tested. The sustained viral response (SVR) was achieved at the level of 60-75%. This group of agents contains also inhibitors of NS5A domain, e.g. PPI-461 which shows antiviral and cytotoxic activity. The following prodrugs are NS3 helicase inhibitors, e.g. p14 peptide, whose IC50 equals 725 nM. Studies are continued on viral entry inhibitors (ITX-5061), therapeutic vaccines (IC-41, civaci, TG-4040, CT-1011, GI-5005) and immunomodulating preparations (ANA-773, IMO-3649, NOV-205). The agents acting on host proteins are a.o. cyclophilin inhibitors. The most advanced studies concern DEBIO 025 preparation which after phase I and II, underwent phase III of clinical studies in February 2010. Since 5 years there is a possibility to investigate the effects of these comounds in vitro with the use of Huh-7 line infected with HCV. These investigations allow to estimate the antiviral effectiveness and cytotoxicity of agents, and resistance of viral strains.