Abstract

Hepatitis C virus (HCV) has deceived researchers for seventeen years now and although the current therapy regimen has been optimized by the development of pegylated interferon-α and the addition of ribavirin, no new agent to treat HCV infected patients has yet reached the market. A new era is approaching the HCV research due to new developments for the propagation of the virus in a cell-based system, which may lead to new drug innovations. Efforts in the search of new treatments for HCV infected patients are either focused on direct antiviral drugs, targeting the structural components or enzymes encoded by the virus, or indirect antiviral drugs, targeting host cell components (immunomodulators etc.). An inspection of the drug pipeline for HCV reveals representatives from both classes and of different mechanisms of action. Among the direct acting antiviral agents, inhibitors of the NS3 protease, the NS5B polymerase, and the viral RNA are the most intensively explored. However, there is also on-going and promising preclinical research, in different stages, on other potential targets as the structural protein E2 (for cell-entry inhibitors), the NS3 helicase, the p7 ion-channel, and the multifunctional NS5A protein. The combat of HCV will certainly require a combination of drugs of different mechanisms in order to reduce the emergence of resistance. The latest developments in the discovery of agents to treat HCV are reviewed, with special focus on direct small-molecule antiviral drugs, from a medicinal chemistry perspective.

Keywords: HCV, Hepatitis C, inhibitors, antiviral drugs, antiviral targets, NS3 protease, NS3 helicase, NS5B polymerase