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HCV796: A selective nonstructural protein 5B polymerase inhibitor with potent anti‐hepatitis C virus activity In Vitro , in mice with chimeric human livers, and in humans infected with hepatitis C virus
Author(s) -
Kneteman Norman M.,
Howe Anita Y. M.,
Gao Tiejun,
Lewis Jamie,
Pevear Dan,
Lund Gary,
Douglas Donna,
Mercer David F.,
Tyrrell D. Lorne J.,
Immermann Frederick,
Chaudhary Inder,
Speth John,
Villano Stephen A.,
O'Connell John,
Collett Marc
Publication year - 2009
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1002/hep.22717
Subject(s) - ribavirin , hepatitis c virus , virology , interferon , ns5b , pegylated interferon , in vitro , biology , pharmacology , replicon , virus , hepatitis c , hepacivirus , medicine , biochemistry , dna , plasmid
Anti‐hepatitis C virus (HCV) drug development has been challenged by a lack of experience with inhibitors inclusive of in vitro, animal model, and clinical study. This manuscript outlines activity and correlation across such a spectrum of models and into clinical trials with a novel selective nonstructural protein 5B (NS5B) polymerase inhibitor, HCV796. Enzyme assays yielded median inhibitory concentration (IC 50 ) values of 0.01 to 0.14 μM for genotype 1, with half maximal effective concentration (EC 50 s) of 5 nM and 9 nM against genotype 1a and 1b replicons. In the chimeric mouse model, a 2.02 ± 0.55 log reduction in HCV titer was seen with monotherapy, whereas a suboptimal dose of 30 mg/kg three times per day in combination with interferon demonstrated a 2.44 log reduction ( P = 0.001 versus interferon alone) Clinical outcomes in combination with pegylated interferon and ribavirin have revealed additive efficacy in treatment naïve patients. Abnormal liver function test results were observed in 8% of HCV‐796 patients treated for over 8 weeks, resulting in suspension of further trial activity. Conclusion: The RNA‐dependent RNA polymerase inhibitor HCV796 demonstrated potent anti‐HCV activity consistently through enzyme inhibition assays, subgenomic replicon, and chimeric mouse studies. Strong correlations of outcomes in the mouse model were seen with subsequent clinical trials, including a plateau in dose‐related antiviral activity and additive impact from combination therapy with interferon. These outcomes demonstrate the utility of the range of in vitro and in vivo models now available for anti‐HCV drug development and support the potential utility of polymerase inhibitors in future combination therapies for HCV treatment. (H EPATOLOGY 2009.)