Antiviral efficacy of NS3-serine protease inhibitor BILN-2061 in patients with chronic genotype 2 and 3 hepatitis C

Abstract

BILN‐2061, a specific and potent peptidomimetic inhibitor of the HCV NS3 protease, has recently been shown to markedly lower serum hepatitis C virus (HCV)‐RNA levels in patients chronically infected with HCV genotype 1 in three 2‐day proof of principle studies. The aim of the current study was to assess the antiviral efficacy of BILN‐2061 in patients with genotypes 2 and 3 HCV infection. The antiviral efficacy, pharmacokinetics, and tolerability of 500 mg twice‐daily BILN‐2061 given as monotherapy for 2 days in 10 patients chronically infected with non–genotype 1 HCV (genotype 2: n = 3; genotype 3: n =7) and minimal liver fibrosis (Ishak score 0‐2) were assessed in a placebo‐controlled (placebo n = 2), double‐blind pilot study. HCV‐RNA levels decreased by ≥1 log₁₀ copies/mL in 4 of 8 patients treated with BILN‐2061. One patient showed a weak response of 10 copies/mL. Three of 8 treated patients showed no response. There was no correlation between baseline viral concentration or genotype and response. BILN‐2061 exhibited good systemic exposure after oral administration and was well tolerated. In conclusion, the antiviral efficacy of the HCV serine protease inhibitor BILN‐2061 is less pronounced and more variable in patients with HCV genotype 2 or 3 infection compared with previous results in patients with HCV genotype 1. A lower affinity of BILN‐2061 for the NS3 protease of genotypes 2 and 3 HCV is most likely a major contributor to these findings. (HEPATOLOGY 2005.)