Identification of anthranilic acid derivatives as a novel class of allosteric inhibitors of hepatitis C NS5B polymerase.

A series of potent anthranilic acid-based inhibitors of the hepatitis C NS5B polymerase has been identified. The inhibitors bind to a site on NS5B between the thumb and palm regions adjacent to the active site as determined by X-ray crystallography of the enzyme-inhibitor complex. Guided by both molecular modeling and traditional SAR, the enzyme activity of the initial hit was improved by approximately 100-fold, yielding a series of potent and selective NS5B inhibitors with IC50 values as low as 10 nM. These compounds were also inhibitors of the HCV replicon in cultured HUH7 cells.