Ribavirin Antagonizes the In Vitro Anti-Hepatitis C Virus Activity of 2′- C -Methylcytidine, the Active Component of Valopicitabine

Abstract
Ribavirin antagonizes the in vitro anti-hepatitis C virus (HCV) activity of the pyrimidine nucleoside analogue 2′- C -methylcytidine, the active component of the experimental anti-HCV drug valopicitabine. In contrast, the combination of ribavirin with either the purine nucleoside analogue 2′- C -methyladenosine or the HCV protease inhibitor VX-950 resulted in an additive antiviral activity. These findings may have implications when planning clinical studies with valopicitabine.