scholarly journals Preclinical Characterization of GSK2336805, a Novel Inhibitor of Hepatitis C Virus Replication That Selects for Resistance in NS5A

2013 ◽  
Vol 58 (1) ◽  
pp. 38-47 ◽  
Author(s):  
Jill Walker ◽  
Renae Crosby ◽  
Amy Wang ◽  
Ermias Woldu ◽  
Jessica Vamathevan ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Standard Of Care ◽  
Cross Resistance ◽  
Current Standard ◽  
Dna Viruses ◽  
Consensus Sequences ◽  
Genotype 1A ◽  
Rna And Dna

ABSTRACTGSK2336805 is an inhibitor of hepatitis C virus (HCV) with picomolar activity on the standard genotype 1a, 1b, and 2a subgenomic replicons and exhibits a modest serum shift. GSK2336805 was not active on 22 RNA and DNA viruses that were profiled. We have identified changes in the N-terminal region of NS5A that cause a decrease in the activity of GSK2336805. These mutations in the genotype 1b replicon showed modest shifts in compound activity (<13-fold), while mutations identified in the genotype 1a replicon had a more dramatic impact on potency. GSK2336805 retained activity on chimeric replicons containing NS5A patient sequences from genotype 1 and patient and consensus sequences for genotypes 4 and 5 and part of genotype 6. Combination and cross-resistance studies demonstrated that GSK2336805 could be used as a component of a multidrug HCV regimen either with the current standard of care or in combination with compounds with different mechanisms of action that are still progressing through clinical development.

scholarly journals Identification of Hepatitis C Virus NS5A Inhibitors

2009 ◽  
Vol 84 (1) ◽  
pp. 482-491 ◽  
Author(s):  
Julie A. Lemm ◽  
Donald O'Boyle ◽  
Mengping Liu ◽  
Peter T. Nower ◽  
Richard Colonno ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Amino Acid ◽  
Therapeutic Index ◽  
Dna Viruses ◽  
Genotype 1A ◽  
A Cell ◽  
Ns3 Protease ◽  
Derivatives Of ◽  
Rna And Dna

ABSTRACT Using a cell-based replicon screen, we identified a class of compounds with a thiazolidinone core structure as inhibitors of hepatitis C virus (HCV) replication. The concentration of one such compound, BMS-824, that resulted in a 50% inhibition of HCV replicon replication was ∼5 nM, with a therapeutic index of >10,000. The compound showed good specificity for HCV, as it was not active against several other RNA and DNA viruses. Replicon cells resistant to BMS-824 were isolated, and mutations were identified. A combination of amino acid substitutions of leucine to valine at residue 31 (L31V) and glutamine to leucine at residue 54 (Q54L) in NS5A conferred resistance to this chemotype, as did a single substitution of tyrosine to histidine at amino acid 93 (Y93H) in NS5A. To further explore the region(s) of NS5A involved in inhibitor sensitivity, genotype-specific NS5A inhibitors were used to evaluate a series of genotype 1a/1b hybrid replicons. Our results showed that, consistent with resistance mapping, the inhibitor sensitivity domain also mapped to the N terminus of NS5A, but it could be distinguished from the key resistance sites. In addition, we demonstrated that NS5A inhibitors, as well as an active-site inhibitor that specifically binds NS3 protease, could block the hyperphosphorylation of NS5A, which is believed to play an essential role in the viral life cycle. Clinical proof of concept has recently been achieved with derivatives of these NS5A inhibitors, indicating that small molecules targeting a nontraditional viral protein like NS5A, without any known enzymatic activity, can also have profound antiviral effects on HCV-infected subjects.

scholarly journals In VitroandIn VivoAntiviral Activity and Resistance Profile of the Hepatitis C Virus NS3/4A Protease Inhibitor ABT-450

2014 ◽  
Vol 59 (2) ◽  
pp. 988-997 ◽  
Author(s):  
Tami Pilot-Matias ◽  
Rakesh Tripathi ◽  
Daniel Cohen ◽  
Isabelle Gaultier ◽  
Tatyana Dekhtyar ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Antiviral Agents ◽  
Cross Resistance ◽  
Hcv Rna ◽  
Genotype 1 ◽  
Common Amino Acid ◽  
Direct Acting Antiviral ◽  
Genotype 1A

ABSTRACTThe development of direct-acting antiviral agents is a promising therapeutic advance in the treatment of hepatitis C virus (HCV) infection. However, rapid emergence of drug resistance can limit efficacy and lead to cross-resistance among members of the same drug class. ABT-450 is an efficacious inhibitor of HCV NS3/4A protease, with 50% effective concentration values of 1.0, 0.21, 5.3, 19, 0.09, and 0.69 nM against stable HCV replicons with NS3 protease from genotypes 1a, 1b, 2a, 3a, 4a, and 6a, respectively.In vitro, the most common amino acid variants selected by ABT-450 in genotype 1 were located in NS3 at positions 155, 156, and 168, with the D168Y variant conferring the highest level of resistance to ABT-450 in both genotype 1a and 1b replicons (219- and 337-fold, respectively). In a 3-day monotherapy study with HCV genotype 1-infected patients, ABT-450 was coadministered with ritonavir, a cytochrome P450 3A4 inhibitor shown previously to markedly increase peak, trough, and overall drug exposures of ABT-450. A mean maximum HCV RNA decline of 4.02 log10was observed at the end of the 3-day dosing period across all doses. The most common variants selected in these patients were R155K and D168V in genotype 1a and D168V in genotype 1b. However, selection of resistant variants was significantly reduced at the highest ABT-450 dose compared to lower doses. These findings were informative for the subsequent evaluation of ABT-450 in combination with additional drug classes in clinical trials in HCV-infected patients. (Study M11-602 is registered at ClinicalTrials.gov under registration no. NCT01074008.)

scholarly journals Construction and characterization of chimeric hepatitis C virus E2 glycoproteins: analysis of regions critical for glycoprotein aggregation and CD81 binding

2000 ◽  
Vol 81 (12) ◽  
pp. 2873-2883 ◽  
Author(s):  
Arvind H. Patel ◽  
Jonny Wood ◽  
Francois Penin ◽  
Jean Dubuisson ◽  
J. A. McKeating
Keyword(s):  
Amino Acids ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Protein Misfolding ◽  
Hypervariable Region ◽  
Genotype 1A ◽  
Hypervariable Region 1 ◽  
Glycosylation Sites ◽  
Cd81 Binding

We compared the ability of two closely related truncated E2 glycoproteins (E2660) derived from hepatitis C virus (HCV) genotype 1a strains Glasgow (Gla) and H77c to bind a panel of conformation-dependent monoclonal antibodies (MAbs) and CD81. In contrast to H77c, Gla E2660 formed disulfide-linked high molecular mass aggregates and failed to react with conformation-dependent MAbs and CD81. To delineate amino acid (aa) regions associated with protein aggregation and CD81 binding, several Gla–H77c E2660 chimeric glycoproteins were constructed. Chimeras C1, C2 and C6, carrying aa 525–660 of Gla E2660, produced disulfide-linked aggregates and failed to bind CD81 and conformation-dependent MAbs, suggesting that amino acids within this region are responsible for protein misfolding. The presence of Gla hypervariable region 1 (aa 384–406) on H77 E2660, chimera C4, had no effect on protein folding or CD81 binding. Chimeras C3 and C5, carrying aa 384–524 or 407–524 of Gla E2660, respectively, were recognized by conformation-dependent MAbs and yet failed to bind CD81, suggesting that amino acids in region 407–524 are important in modulating CD81 interaction without affecting antigen folding. Comparison of Gla and H77c E2660 aa sequences with those of genotype 1a and divergent genotypes identified a number of variant amino acids, including two putative N-linked glycosylation sites at positions 476 and 532. However, introduction of G476N–G478S and/or D532N in Gla E2660 had no effect on antigenicity or aggregation.

scholarly journals Structural and Antigenic Definition of Hepatitis C Virus E2 Glycoprotein Epitopes Targeted by Monoclonal Antibodies

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Giuseppe Sautto ◽  
Alexander W. Tarr ◽  
Nicasio Mancini ◽  
Massimo Clementi
Keyword(s):  
Immune Response ◽  
Monoclonal Antibodies ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Structural Characteristics ◽  
Standard Of Care ◽  
Surface Glycoprotein ◽  
Current Standard ◽  
Humoral Immune ◽  
Promising Tool

Hepatitis C virus (HCV) is the major cause of chronic liver disease as well as the major indication for liver transplantation worldwide. Current standard of care is not completely effective, not administrable in grafted patients, and burdened by several side effects. This incomplete effectiveness is mainly due to the high propensity of the virus to continually mutate under the selective pressure exerted by the host immune response as well as currently administered antiviral drugs. The E2 envelope surface glycoprotein of HCV (HCV/E2) is the main target of the host humoral immune response and for this reason one of the major variable viral proteins. However, broadly cross-neutralizing monoclonal antibodies (mAbs) directed against HCV/E2 represent a promising tool for the study of virus-host interplay as well as for the development of effective prophylactic and therapeutic approaches. In the last few years many anti-HCV/E2 mAbs have been evaluated in preclinical and clinical trials as possible candidate antivirals, particularly for administration in pre- and post-transplant settings. In this review we summarize the antigenic and structural characteristics of HCV/E2 determined through the use of anti-HCV/E2 mAbs, which, given the absence of a crystal structure of this glycoprotein, represent currently the best tool available.

scholarly journals The Combination of Grazoprevir, a Hepatitis C Virus (HCV) NS3/4A Protease Inhibitor, and Elbasvir, an HCV NS5A Inhibitor, Demonstrates a High Genetic Barrier to Resistance in HCV Genotype 1a Replicons

2016 ◽  
Vol 60 (5) ◽  
pp. 2954-2964 ◽  
Author(s):  
Frederick C. Lahser ◽  
Karin Bystol ◽  
Stephanie Curry ◽  
Patricia McMonagle ◽  
Ellen Xia ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Protease Inhibitor ◽  
Cross Resistance ◽  
Hcv Rna ◽  
Wild Type ◽  
Genetic Barrier ◽  
Potent Effect ◽  
Ns5a Inhibitor ◽  
Genotype 1A

ABSTRACTThe selection of resistance-associated variants (RAVs) against single agents administered to patients chronically infected with hepatitis C virus (HCV) necessitates that direct-acting antiviral agents (DAAs) targeting multiple viral proteins be developed to overcome failure resulting from emergence of resistance. The combination of grazoprevir (formerly MK-5172), an NS3/4A protease inhibitor, and elbasvir (formerly MK-8742), an NS5A inhibitor, was therefore studied in genotype 1a (GT1a) replicon cells. Both compounds were independently highly potent in GT1a wild-type replicon cells, with 90% effective concentration (EC90) values of 0.9 nM and 0.006 nM for grazoprevir and elbasvir, respectively. No cross-resistance was observed when clinically relevant NS5A and NS3 RAVs were profiled against grazoprevir and elbasvir, respectively. Kinetic analyses of HCV RNA reduction over 14 days showed that grazoprevir and elbasvir inhibited prototypic NS5A Y93H and NS3 R155K RAVs, respectively, with kinetics comparable to those for the wild-type GT1a replicon. In combination, grazoprevir and elbasvir interacted additively in GT1a replicon cells. Colony formation assays with a 10-fold multiple of the EC90values of the grazoprevir-elbasvir inhibitor combination suppressed emergence of resistant colonies, compared to a 100-fold multiple for the independent agents. The selected resistant colonies with the combination harbored RAVs that required two or more nucleotide changes in the codons. Mutations in the cognate gene caused greater potency losses for elbasvir than for grazoprevir. Replicons bearing RAVs identified from resistant colonies showed reduced fitness for several cell lines and may contribute to the activity of the combination. These studies demonstrate that the combination of grazoprevir and elbasvir exerts a potent effect on HCV RNA replication and presents a high genetic barrier to resistance. The combination of grazoprevir and elbasvir is currently approved for chronic HCV infection.

Trends in the Treatment of Chronic Hepatitis C Virus Infection

2009 ◽  
Vol 22 (4) ◽  
pp. 405-418 ◽  
Author(s):  
Jennifer J. Kiser
Keyword(s):  
Chronic Hepatitis ◽  
Hepatitis C Virus ◽  
Liver Disease ◽  
Hepatitis C ◽  
Chronic Hepatitis C ◽  
Standard Of Care ◽  
New Drugs ◽  
Current Standard ◽  
Course Of Illness ◽  
Chronic Hepatitis C Virus

Despite reductions in the incidence of new hepatitis C virus infections, infections from previous decades continue to place a substantial burden on our health care system. Although the course of the disease is highly variable, approximately 20% to 30% of patients develop cirrhosis, end-stage liver disease, or hepatocellular carcinoma. Fortunately, treatment with our current standard of care, peginterferon a and ribavirin, can reduce the complications of chronic liver disease. However, these drugs are associated with significant adverse effects, many patients are ineligible for treatment, and only 50% are cured. Thus, there is a tremendous need to improve our current therapies and develop new compounds for this disease. This review highlights the transmission, pathophysiology, and course of illness; the pharmacokinetics, proposed mechanisms of action, adverse events, and potential drug interactions with peginterferon a and ribavirin; current treatment trends; the role of the pharmacist in the treatment of this disease; and investigational drugs in later stages of clinical development. Despite the initial hope that these new drugs would replace our current standard of care, it has become clear that ribavirin and peginterferon a will continue to play an important role in the treatment of chronic hepatitis C virus in the years to come.

scholarly journals Identification and Characterization of Broadly Neutralizing Human Monoclonal Antibodies Directed against the E2 Envelope Glycoprotein of Hepatitis C Virus

2009 ◽  
Vol 83 (23) ◽  
pp. 12473-12482 ◽  
Author(s):  
Teresa J. Broering ◽  
Kerry A. Garrity ◽  
Naomi K. Boatright ◽  
Susan E. Sloan ◽  
Frantisek Sandor ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Envelope Glycoprotein ◽  
Cross Reactivity ◽  
Human Antibody ◽  
Human Monoclonal Antibodies ◽  
Genotype 1A ◽  
Neutralizing Monoclonal Antibody

ABSTRACT Nearly all livers transplanted into hepatitis C virus (HCV)-positive patients become infected with HCV, and 10 to 25% of reinfected livers develop cirrhosis within 5 years. Neutralizing monoclonal antibody could be an effective therapy for the prevention of infection in a transplant setting. To pursue this treatment modality, we developed human monoclonal antibodies (HuMAbs) directed against the HCV E2 envelope glycoprotein and assessed the capacity of these HuMAbs to neutralize a broad panel of HCV genotypes. HuMAb antibodies were generated by immunizing transgenic mice containing human antibody genes (HuMAb mice; Medarex Inc.) with soluble E2 envelope glycoprotein derived from a genotype 1a virus (H77). Two HuMAbs, HCV1 and 95-2, were selected for further study based on initial cross-reactivity with soluble E2 glycoproteins derived from genotypes 1a and 1b, as well as neutralization of lentivirus pseudotyped with HCV 1a and 1b envelope glycoproteins. Additionally, HuMAbs HCV1 and 95-2 potently neutralized pseudoviruses from all genotypes tested (1a, 1b, 2b, 3a, and 4a). Epitope mapping with mammalian and bacterially expressed proteins, as well as synthetic peptides, revealed that HuMAbs HCV1 and 95-2 recognize a highly conserved linear epitope spanning amino acids 412 to 423 of the E2 glycoprotein. The capacity to recognize and neutralize a broad range of genotypes, the highly conserved E2 epitope, and the fully human nature of the antibodies make HuMAbs HCV1 and 95-2 excellent candidates for treatment of HCV-positive individuals undergoing liver transplantation.

scholarly journals In VitroResistance Profile of the Hepatitis C Virus NS3 Protease Inhibitor BI 201335

2011 ◽  
Vol 56 (1) ◽  
pp. 569-572 ◽  
Author(s):  
Lisette Lagacé ◽  
Peter W. White ◽  
Christiane Bousquet ◽  
Nathalie Dansereau ◽  
Florence Dô ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Protease Inhibitor ◽  
Protease Inhibitors ◽  
Alpha Interferon ◽  
Phenotypic Characterization ◽  
Genotype 1A ◽  
Ns3 Protease

ABSTRACTThein vitroresistance profile of BI 201335 was evaluated through selection and characterization of variants in genotype 1a (GT 1a) and genotype 1b (GT 1b) replicons. NS3 R155K and D168V were the most frequently observed resistant variants. Phenotypic characterization of the mutants revealed shifts in sensitivity specific to BI 201335 that did not alter susceptibility to alpha interferon. In contrast to macrocyclic and covalent protease inhibitors, changes at V36, T54, F43, and Q80 did not confer resistance to BI 201335.

scholarly journals Inhibition of Hepatitis C Virus Replicon RNA Synthesis by PSI-352938, a Cyclic Phosphate Prodrug of β-d-2′-Deoxy-2′-α-Fluoro-2′-β-C-Methylguanosine

2011 ◽  
Vol 55 (6) ◽  
pp. 2566-2575 ◽  
Author(s):  
Angela M. Lam ◽  
Christine Espiritu ◽  
Eisuke Murakami ◽  
Veronique Zennou ◽  
Shalini Bansal ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Cross Resistance ◽  
Content Type ◽  
Dna And Rna ◽  
Genotype 1A ◽  
B Virus ◽  
Cyclic Phosphate ◽  
Nonnucleoside Inhibitors

ABSTRACTPSI-352938 is a novel cyclic phosphate prodrug of β-d-2′-deoxy-2′-α-fluoro-2′-β-C-methylguanosine 5′-monophosphate that has potent activity against hepatitis C virus (HCV)in vitro. The studies described here characterize thein vitroanti-HCV activity of PSI-352938, alone and in combination with other inhibitors of HCV, and the cross-resistance profile of PSI-352938. The effective concentration required to achieve 50% inhibition for PSI-352938, determined using genotype 1a-, 1b-, and 2a-derived replicons stably expressed in the Lunet cell line, were 0.20, 0.13, and 0.14 μM, respectively. The active 5′-triphosphate metabolite, PSI-352666, inhibited recombinant NS5B polymerase from genotypes 1 to 4 with comparable 50% inhibitory concentrations. In contrast, PSI-352938 did not inhibit the replication of hepatitis B virus or human immunodeficiency virusin vitro. PSI-352666 did not significantly affect the activity of human DNA and RNA polymerases. PSI-352938 and its cyclic phosphate metabolites did not affect the cyclic GMP-mediated activation of protein kinase G. Clearance studies using replicon cells demonstrated that PSI-352938 cleared cells of HCV replicon RNA and prevented replicon rebound. An additive to synergistic effect was observed when PSI-352938 was combined with other classes of HCV inhibitors, including alpha interferon, ribavirin, NS3/4A inhibitors, an NS5A inhibitor, and nucleoside/nucleotide and nonnucleoside inhibitors. Cross-resistance studies showed that PSI-352938 remained fully active against replicons containing the S282T or the S96T/N142T amino acid alteration. Replicons that contain mutations conferring resistance to various classes of nonnucleoside inhibitors also remained sensitive to inhibition by PSI-352938. PSI-352938 is currently being evaluated in a phase I clinical study in genotype 1-infected individuals.

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