scholarly journals Selection and Characterization of Hepatitis C Virus Replicons Dually Resistant to the Polymerase and Protease Inhibitors HCV-796 and Boceprevir (SCH 503034)

2008 ◽  
Vol 53 (2) ◽  
pp. 401-411 ◽  
Author(s):  
Mike Flint ◽  
Stanley Mullen ◽  
Anne M. Deatly ◽  
Wei Chen ◽  
Lynn Z. Miller ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Serine Protease ◽  
Protease Inhibitors ◽  
Nonstructural Protein ◽  
Pegylated Interferon ◽  
Replicative Capacity ◽  
Hsp90 Inhibitors ◽  
Ns5b Polymerase

ABSTRACT HCV-796 is a nonnucleoside inhibitor of the hepatitis C virus (HCV) nonstructural protein 5B (NS5B) polymerase, and boceprevir is an inhibitor of the NS3 serine protease. The emergence of replicon variants resistant to the combination of HCV-796 and boceprevir was evaluated. Combining the inhibitors greatly reduced the frequency with which resistant colonies arose; however, some resistant replicon cells could be isolated by the use of low inhibitor concentrations. These replicons were approximately 1,000-fold less susceptible to HCV-796 and 9-fold less susceptible to boceprevir. They also exhibited resistance to anthranilate nonnucleoside inhibitors of NS5B but were fully sensitive to inhibitors of different mechanisms: a pyranoindole, Hsp90 inhibitors, an NS5B nucleoside inhibitor, and pegylated interferon (Peg-IFN). The replicon was cleared from the combination-resistant cells by extended treatment with Peg-IFN. Mutations known to confer resistance to HCV-796 (NS5B C316Y) and boceprevir (NS3 V170A) were present in the combination-resistant replicons. These changes could be selected together and coexist in the same genome. The replicon bearing both changes exhibited reduced sensitivity to inhibition by HCV-796 and boceprevir but had a reduced replicative capacity.

A hepatitis C-vírus-bázispolimorfizmus jelentősége a kezelésben

2015 ◽  
Vol 156 (21) ◽  
pp. 849-854 ◽  
Author(s):  
István Tornai
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Protease Inhibitors ◽  
First Generation ◽  
Pegylated Interferon ◽  
Direct Acting Antivirals ◽  
Direct Acting Antiviral ◽  
Genotype 1A ◽  
Direct Acting ◽  
Ns5b Polymerase

The treatment of chronic hepatitis C has developed significantly during the last 25 years. In patients with genotype 1 infection 40–50% sustained virologic response could be achieved using pegylated interferon and ribavirin dual combination, which could be increased significantly with the introduction of direct acting antivirals. Three major groups of direct acting antivirals are known, which directly inhibit different phases of viral life cycle, by inhibiting the function of several non-structural proteins (NS3/4A protease, NS5A protein and NS5B polymerase). Due to the rapid replication rate of hepatitis C virus and the error-prone NS5B polymerase activity, mutant virions are generated, which might have reduced susceptibility to direct acting antiviral therapy. Since these resistance associated variants might exist before the antiviral therapy, they are still able to replicate during the direct acting antiviral treatment. Due to this selection pressure, the resistant virus will replace the wild type. This was especially detected during monotherapy, therefore, the first generation of direct acting antivirals have been combined with pegylated interferon and ribavirin, while recently interferon-free combinations are being developed including 2 or 3 direct acting antivirals. Using the first generation protease inhibitors boceprevir and telaprevir, it could have been seen, that the rate of resistance associated variants is higher and the therapeutic outcome is worse in patients with hepatitis C virus genotype 1a, than in 1b. Similar phenomenon was seen with the second generation of NS3/4A protease inhibitors as well as with NS5A or NS5B polymerase. This is due to the lower genetic barrier to resistance, ie. usually fewer mutations are enough for the emergence of resistance in genotype 1a. The selection of resistance associated variants is one of the most important challenges during the interferon-free therapy. Orv. Hetil., 2015, 156(21), 849–854.

scholarly journals In Vitro Selection and Characterization of Hepatitis C Virus Serine Protease Variants Resistant to an Active-Site Peptide Inhibitor

2003 ◽  
Vol 77 (6) ◽  
pp. 3669-3679 ◽  
Author(s):  
Caterina Trozzi ◽  
Linda Bartholomew ◽  
Alessandra Ceccacci ◽  
Gabriella Biasiol ◽  
Laura Pacini ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Serine Protease ◽  
In Vitro Selection ◽  
Three Dimensional ◽  
Host Cells ◽  
Dimensional Structure ◽  
In Vitro Systems

ABSTRACT The hepatitis C virus (HCV) serine protease is necessary for viral replication and represents a valid target for developing new therapies for HCV infection. Potent and selective inhibitors of this enzyme have been identified and shown to inhibit HCV replication in tissue culture. The optimization of these inhibitors for clinical development would greatly benefit from in vitro systems for the identification and the study of resistant variants. We report the use HCV subgenomic replicons to isolate and characterize mutants resistant to a protease inhibitor. Taking advantage of the replicons' ability to transduce resistance to neomycin, we selected replicons with decreased sensitivity to the inhibitor by culturing the host cells in the presence of the inhibitor and neomycin. The selected replicons replicated to the same extent as those in parental cells. Sequence analysis followed by transfection of replicons containing isolated mutations revealed that resistance was mediated by amino acid substitutions in the protease. These results were confirmed by in vitro experiments with mutant enzymes and by modeling the inhibitor in the three-dimensional structure of the protease.

Potent and selective small molecule NS3 serine protease inhibitors of Hepatitis C virus with dichlorocyclopropylproline as P2 residue

2008 ◽  
Vol 16 (4) ◽  
pp. 1874-1883 ◽  
Author(s):  
Kevin X. Chen ◽  
Bancha Vibulbhan ◽  
Weiying Yang ◽  
Kuo-Chi Cheng ◽  
Rong Liu ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Serine Protease ◽  
Protease Inhibitors ◽  
Small Molecule ◽  
Serine Protease Inhibitors

scholarly journals Pharmacokinetic Interactions between the Hepatitis C Virus Inhibitors Elbasvir and Grazoprevir and HIV Protease Inhibitors Ritonavir, Atazanavir, Lopinavir, and Darunavir in Healthy Volunteers

2019 ◽  
Vol 63 (4) ◽  
Author(s):  
Hwa-Ping Feng ◽  
Luzelena Caro ◽  
Christine Fandozzi ◽  
Xiaoyan Chu ◽  
Zifang Guo ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Protease Inhibitors ◽  
Nonstructural Protein ◽  
Phase 1 ◽  
Geometric Mean ◽  
Hiv Treatment ◽  
Hiv Protease ◽  
Hiv Protease Inhibitors ◽  
Pharmacokinetic Interactions

ABSTRACT The combination of the hepatitis C virus (HCV) nonstructural protein 5A (NS5A) inhibitor elbasvir and the NS3/4A protease inhibitor grazoprevir is a potent, once-daily therapy indicated for the treatment of chronic HCV infection in individuals coinfected with human immunodeficiency virus (HIV). We explored the pharmacokinetic interactions of elbasvir and grazoprevir with ritonavir and ritonavir-boosted HIV protease inhibitors in three phase 1 trials. Drug-drug interaction trials with healthy participants were conducted to evaluate the effect of ritonavir on the pharmacokinetics of grazoprevir (n = 10) and the potential two-way pharmacokinetic interactions of elbasvir (n = 30) or grazoprevir (n = 39) when coadministered with ritonavir-boosted atazanavir, lopinavir, or darunavir. Coadministration of ritonavir with grazoprevir increased grazoprevir exposure; the geometric mean ratio (GMR) for grazoprevir plus ritonavir versus grazoprevir alone area under the concentration-time curve from 0 to 24 h (AUC0–24) was 1.91 (90% confidence interval [CI]; 1.31 to 2.79). Grazoprevir exposure was markedly increased with coadministration of atazanavir-ritonavir, lopinavir-ritonavir, and darunavir-ritonavir, with GMRs for grazoprevir AUC0–24 of 10.58 (90% CI, 7.78 to 14.39), 12.86 (90% CI, 10.25 to 16.13), and 7.50 (90% CI, 5.92 to 9.51), respectively. Elbasvir exposure was increased with coadministration of atazanavir-ritonavir, lopinavir-ritonavir, and darunavir-ritonavir, with GMRs for elbasvir AUC0–24 of 4.76 (90% CI, 4.07 to 5.56), 3.71 (90% CI, 3.05 to 4.53), and 1.66 (90% CI, 1.35 to 2.05), respectively. Grazoprevir and elbasvir had little effect on atazanavir, lopinavir, and darunavir pharmacokinetics. Coadministration of elbasvir-grazoprevir with atazanavir-ritonavir, lopinavir-ritonavir, or darunavir-ritonavir is contraindicated, owing to an increase in grazoprevir exposure. Therefore, HIV treatment regimens without HIV protease inhibitors should be considered for HCV/HIV-coinfected individuals who are being treated with elbasvir-grazoprevir.

scholarly journals Hepatitis C Virus NS3 Inhibitors: Current and Future Perspectives

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Kazi Abdus Salam ◽  
Nobuyoshi Akimitsu
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Protease Inhibitors ◽  
Standard Of Care ◽  
Pegylated Interferon ◽  
Virologic Response ◽  
Hcv Infection ◽  
Main Concern ◽  
Pegylated Interferon Plus Ribavirin ◽  
Direct Acting

Currently, hepatitis C virus (HCV) infection is considered a serious health-care problem all over the world. A good number of direct-acting antivirals (DAAs) against HCV infection are in clinical progress including NS3-4A protease inhibitors, RNA-dependent RNA polymerase inhibitors, and NS5A inhibitors as well as host targeted inhibitors. Two NS3-4A protease inhibitors (telaprevir and boceprevir) have been recently approved for the treatment of hepatitis C in combination with standard of care (pegylated interferon plus ribavirin). The new therapy has significantly improved sustained virologic response (SVR); however, the adverse effects associated with this therapy are still the main concern. In addition to the emergence of viral resistance, other targets must be continually developed. One such underdeveloped target is the helicase portion of the HCV NS3 protein. This review article summarizes our current understanding of HCV treatment, particularly with those of NS3 inhibitors.

Hepatitis C virus NS3-4A serine protease inhibitors: SAR of moiety with improved potency

2005 ◽  
Vol 15 (19) ◽  
pp. 4180-4184 ◽  
Author(s):  
A. Arasappan ◽  
F.G. Njoroge ◽  
T.-Y. Chan ◽  
F. Bennett ◽  
S.L. Bogen ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Serine Protease ◽  
Protease Inhibitors ◽  
Serine Protease Inhibitors

scholarly journals Development of Cell-Based Assays for In Vitro Characterization of Hepatitis C Virus NS3/4A Protease Inhibitors

2005 ◽  
Vol 49 (4) ◽  
pp. 1381-1390 ◽  
Author(s):  
Victoria Chung ◽  
Anthony R. Carroll ◽  
Norman M. Gray ◽  
Nigel R. Parry ◽  
Pia A. Thommes ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Vaccinia Virus ◽  
Protease Inhibitors ◽  
Expression System ◽  
Recombinant Vaccinia Virus ◽  
Enzyme Linked Immunosorbent Assay ◽  
Recombinant Vaccinia

ABSTRACT A recombinant vaccinia virus, expressing the NS3-to-NS5 region of the N clone of hepatitis C virus (HCV), was generated and utilized both in a gel-based assay and in an enzyme-linked immunosorbent assay (ELISA) to evaluate the pyrrolidine-5,5-trans-lactams, a series of inhibitors of the HCV NS3/4A protease. The absolute levels of processed, mature HCV nonstructural proteins in this system were found to decrease in the presence of the trans-lactams. Monitoring of this reduction enabled end points and 50% inhibitory concentrations to be calculated in order to rank the active compounds according to potency. These compounds had no effect on the transcription or translation of the NS3-5 polyprotein at concentrations shown to inhibit NS3/4A protease, and they were shown to be specific inhibitors of this protease. The ELISA, originally developed using the vaccinia virus expression system, was modified to utilize Huh-7 cells containing an HCV replicon. Results with this assay correlated well with those obtained with the recombinant vaccinia virus assays. These results demonstrate the utility of these assays for the characterization of NS3/4A protease inhibitors. In addition, inhibitors of other viral targets, such as polymerase and helicase, can be evaluated in the context of the replicon ELISA.

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