The trial was designed to study the interaction between valopicitabine, Idenix’s lead drug candidate for the treatment of hepatitis C, pegylated interferon and ribavirin compared to pegylated interferon and ribavirin, the current standard of care, in patients infected with the genotype-1 strain of the hepatitis C virus (HCV). The study demonstrated no pharmacokinetic or pharmacodynamic drug-drug interaction between valopicitabine and ribavirin.
The triple combination showed consistently higher rates of HCV PCR-negativity, defined as serum HCV RNA levels below 20 copies/mL, compared to the standard of care at every point analyzed in this study. Additionally, the tolerability of the triple combination was satisfactory, with only three discontinuations from the study.
The key secondary endpoints for the study were antiviral activity, safety and tolerability at 12 weeks. Of patients that completed 12 weeks of therapy, 72.2% of patients treated with triple combination therapy achieved HCV PCR-negativity, compared to 61.5% of patients treated with the standard of care.
There were three discontinuations from the study, all due to adverse events (AEs), one of which was attributed by the clinical investigator to valopicitabine-related gastrointestinal toxicity. The two other AEs, including a serious adverse event (SAE), were attributed by the clinical investigators to pegylated interferon or pegylated interferon/ribavirin. All of the discontinuations occurred in the triple combination arm.