- Powers J, Piper D, Li Y, Mayorga V, Anzola J, Chen J, et al. SAR and mode of action of novel non-nucleoside inhibitors of hepatitis C NS5b RNA polymerase. J Med Chem. 2006;49:1034-46 pubmed..Structure-activity relationships and structural studies have identified the mechanism of action for compounds in this series, several of which possess drug-like properties, as unique, reversible, covalent inhibitors of HCV NS5b. ..