scholarly journals Characterization of Hepatitis C Virus Resistance from a Multiple-Dose Clinical Trial of the Novel NS5A Inhibitor GS-5885

2013 ◽  
Vol 57 (12) ◽  
pp. 6333-6340 ◽  
Author(s):  
Kelly A. Wong ◽  
Angela Worth ◽  
Ross Martin ◽  
Evguenia Svarovskaia ◽  
Diana M. Brainard ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Hcv Rna ◽  
Direct Acting Antivirals ◽  
Phenotypic Analysis ◽  
Median Viral Load ◽  
Ns5a Inhibitor ◽  
Treatment Naïve ◽  
Direct Acting

ABSTRACTGS-5885 is a novel hepatitis C virus (HCV) NS5A inhibitor. In a 3-day monotherapy study in treatment-naive genotype 1a (GT1a) and GT1b HCV-infected subjects, median viral load reductions ranged from 2.3 to 3.3 log10HCV RNA IU/ml across dosing cohorts (1, 3, 10, 30, or 90 mg once daily). Here, we report viral sequencing and phenotypic analysis of clinical isolates from this study. Detection of baseline NS5A amino acid substitutions at positions 28, 30, 31, or 93 in GT1a was associated with a reduced treatment response. In the GT1b cohort, Y93H was detected in 100% of subjects at day 4 or 14. In the Gt1a cohort, population sequencing detected NS5A resistance-associated mutations at day 4 or 14 for 3/10 subjects at the 1-mg dose and for all subjects dosed at ≥3 mg. A subset of mutants that confer a low level of reduced susceptibility to GS-5885 was not detected by population sequencing at the 30- and 90-mg doses. Subject-derived M28T, Q30R, L31M, and Y93C mutations all conferred >30-fold reductions in GS-5885 and daclatasvir susceptibilitiesin vitro. Site-directed NS5A mutants also showed reduced susceptibility to GS-5885. However, all NS5A mutants tested remained fully susceptible to other classes of direct-acting antivirals (DAAs), interferon alpha, and ribavirin. Importantly, the nonoverlapping resistance profile and high potency of GS-5885 support its further development with other direct-acting antivirals for the treatment of chronic HCV. (This study has been registered at ClinicalTrials.gov under registration number NCT01193478.)

scholarly journals Cross-Genotypic Examination of Hepatitis C Virus Polymerase Inhibitors Reveals a Novel Mechanism of Action for Thumb Binders

2014 ◽  
Vol 58 (12) ◽  
pp. 7215-7224 ◽  
Author(s):  
Auda A. Eltahla ◽  
Enoch Tay ◽  
Mark W. Douglas ◽  
Peter A. White
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
De Novo ◽  
Hcv Rna ◽  
Amino Acid Residues ◽  
Recombinant Enzymes ◽  
Polymerase Inhibitors ◽  
Binding Pockets ◽  
Direct Acting

ABSTRACTDirect-acting antivirals (DAAs) targeting proteins encoded by the hepatitis C virus (HCV) genome have great potential for the treatment of HCV infections. However, the efficacy of DAAs designed to target genotype 1 (G1) HCV against non-G1 viruses has not been characterized fully. In this study, we investigated the inhibitory activities of nonnucleoside inhibitors (NNIs) against the HCV RNA-dependent RNA polymerase (RdRp). We examined the ability of six NNIs to inhibit G1b, G2a, and G3a subgenomic replicons in cell culture, as well asin vitrotranscription by G1b and G3a recombinant RdRps. Of the six G1 NNIs, only the palm II binder nesbuvir demonstrated activity against G1, G2, and G3 HCV, in both replicon and recombinant enzyme models. The thumb I binder JTK-109 also inhibited G1b and G3a replicons and recombinant enzymes but was 41-fold less active against the G2a replicon. The four other NNIs, which included a palm I binder (setrobuvir), two thumb II binders (lomibuvir and filibuvir), and a palm β-hairpin binder (tegobuvir), all showed at least 40-fold decreases in potency against G2a and G3a replicons and the G3a enzyme. This antiviral resistance was largely conferred by naturally occurring amino acid residues in the G2a and G3a RdRps that are associated with G1 resistance. Lomibuvir and filibuvir (thumb II binders) inhibited primer-dependent but notde novoactivity of the G1b polymerase. Surprisingly, these compounds instead specifically enhanced thede novoactivity at concentrations of ≥100 nM. These findings highlight a potential differential mode of RdRp inhibition for HCV NNIs, depending on their prospective binding pockets, and also demonstrate a surprising enhancement ofde novoactivity for thumb RdRp binders. These results also provide a better understanding of the antiviral coverage for these polymerase inhibitors, which will likely be used in future combinational interferon-free therapies.

scholarly journals The Combination of Alisporivir plus an NS5A Inhibitor Provides Additive to Synergistic Anti-Hepatitis C Virus Activity without Detectable Cross-Resistance

2014 ◽  
Vol 58 (6) ◽  
pp. 3327-3334 ◽  
Author(s):  
Udayan Chatterji ◽  
Jose A. Garcia-Rivera ◽  
James Baugh ◽  
Katarzyna Gawlik ◽  
Kelly A. Wong ◽  
...  
Keyword(s):  
Chronic Hepatitis ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Chronic Hepatitis C ◽  
Cross Resistance ◽  
Target Domain ◽  
Ns5a Inhibitor ◽  
Direct Acting ◽  
Inhibitor Combination

ABSTRACTAlisporivir (ALV), a cyclophilin inhibitor, is a host-targeting antiviral (HTA) with multigenotypic anti-hepatitis C virus (HCV) activity and a high barrier to resistance. Recent advances have supported the concept of interferon (IFN)-free regimens to treat chronic hepatitis C. As the most advanced oral HTA, ALV with direct-acting antivirals (DAAs) represents an attractive drug combination for IFN-free therapy. In this study, we investigated whether particular DAAs exhibit additive, synergistic, or antagonistic effects when combined with ALV. Drug combinations of ALV with NS3 protease, NS5B polymerase, and NS5A inhibitors were investigated in HCV replicons from genotypes 1a, 1b, 2a, 3, and 4a (GT1a to -4a). Combinations of ALV with DAAs exerted an additive effect on GT1 and -4. A significant and specific synergistic effect was observed with ALV-NS5A inhibitor combination on GT2 and -3. Furthermore, ALV was fully active against DAA-resistant variants, and ALV-resistant variants were fully susceptible to DAAs. ALV blocks the contact between cyclophilin A and domain II of NS5A, and NS5A inhibitors target domain I of NS5A; our data suggest a molecular basis for the use of these two classes of inhibitors acting on two distinct domains of NS5A. These results providein vitroevidence that ALV with NS5A inhibitor combination represents an attractive strategy and a potentially effective IFN-free regimen for treatment of patients with chronic hepatitis C. Due to its high barrier and lack of cross-resistance, ALV could be a cornerstone drug partner for DAAs.

scholarly journals Hepatitis C Virus RNA Levels Following Virologic Failure With Direct-acting Antivirals: Implications for Lower Sensitivity Diagnostic Assays

2019 ◽  
Vol 70 (2) ◽  
pp. 327-330 ◽  
Author(s):  
Patrick R Harrington ◽  
Takashi E Komatsu ◽  
Hengrui Sun ◽  
Lisa K Naeger
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Virologic Failure ◽  
Post Treatment ◽  
Hcv Rna ◽  
Lower Sensitivity ◽  
Direct Acting Antivirals ◽  
Diagnostic Assays ◽  
Direct Acting ◽  
Rna Levels

Abstract We analyzed post-treatment hepatitis C virus (HCV) RNA levels from 330 subjects who experienced virologic failure in clinical trials of direct-acting antivirals. We demonstrated that 97% had post-treatment Week 12 HCV RNA >10 000 IU/mL, above reported sensitivity limits of novel diagnostic assays being considered for simplified HCV treatment monitoring.

scholarly journals Visualization of Positive and Negative Sense Viral RNA for Probing the Mechanism of Direct-Acting Antivirals against Hepatitis C Virus

Viruses ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1039
Author(s):  
Dandan Liu ◽  
Philip R. Tedbury ◽  
Shuiyun Lan ◽  
Andrew D. Huber ◽  
Maritza N. Puray-Chavez ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Rna Viruses ◽  
Drug Efficacy ◽  
Confocal Imaging ◽  
Hcv Rna ◽  
Direct Acting Antivirals ◽  
Infected Cells ◽  
Positive Strand Rna ◽  
Direct Acting

RNA viruses are highly successful pathogens and are the causative agents for many important diseases. To fully understand the replication of these viruses it is necessary to address the roles of both positive-strand RNA ((+)RNA) and negative-strand RNA ((−)RNA), and their interplay with viral and host proteins. Here we used branched DNA (bDNA) fluorescence in situ hybridization (FISH) to stain both the abundant (+)RNA and the far less abundant (−)RNA in both hepatitis C virus (HCV)- and Zika virus-infected cells, and combined these analyses with visualization of viral proteins through confocal imaging. We were able to phenotypically examine HCV-infected cells in the presence of uninfected cells and revealed the effect of direct-acting antivirals on HCV (+)RNA, (−)RNA, and protein, within hours of commencing treatment. Herein, we demonstrate that bDNA FISH is a powerful tool for the study of RNA viruses that can provide insights into drug efficacy and mechanism of action.

scholarly journals In Vitro Antiviral Profile of Ruzasvir, a Potent and Pangenotype Inhibitor of Hepatitis C Virus NS5A

2018 ◽  
Vol 62 (11) ◽  
Author(s):  
Ernest Asante-Appiah ◽  
Rong Liu ◽  
Stephanie Curry ◽  
Patricia McMonagle ◽  
Sony Agrawal ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Antiviral Activity ◽  
De Novo ◽  
Antiviral Agents ◽  
Cross Resistance ◽  
Hcv Rna ◽  
Direct Acting Antiviral ◽  
Direct Acting

ABSTRACT Inhibition of NS5A has emerged as an attractive strategy to intervene in hepatitis C virus (HCV) replication. Ruzasvir (formerly MK-8408) was developed as a novel NS5A inhibitor to improve upon the potency and barrier to resistance of early compounds. Ruzasvir inhibited HCV RNA replication with 50% effective concentrations (EC50s) of 1 to 4 pM in Huh7 or Huh7.5 cells bearing replicons for HCV genotype 1 (GT1) to GT7. The antiviral activity was modestly (10-fold) reduced in the presence of 40% normal human serum. The picomolar potency in replicon cells extended to sequences of clinical isolates available in public databases that were synthesized and tested as replicons. In GT1a, ruzasvir inhibited common NS5A resistance-associated substitutions (RASs), with the exception of M28G. De novo resistance selection studies identified pathways with certain amino acid substitutions at residues 28, 30, 31, and 93 across genotypes. Substitutions at position 93 were more common in GT1 to -4, while changes at position 31 emerged frequently in GT5 and -6. With the exception of GT4, the reintroduction of selected RASs conferred a ≥100-fold potency reduction in the antiviral activity of ruzasvir. Common RASs from other classes of direct-acting antiviral agents (DAAs) did not confer cross-resistance to ruzasvir. The interaction of ruzasvir with an NS3/4A protease inhibitor (grazoprevir) and an NS5B polymerase prodrug (uprifosbuvir) was additive to synergistic, with no evidence of antagonism or cytotoxicity. The antiviral profile of ruzasvir supported its further evaluation in human trials in combination with grazoprevir and uprifosbuvir.

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