Assessment of early virological response to antiviral therapy by comparing four assays for HCV RNA quantitation using the international unit standard: implications for clinical management of patients with chronic hepatitis C virus infection

WHO International Standards for nucleic acid tests are used widely to compare the different assays used in HCV RNA quantitation. The aim of the study was to assess the impact of the international unit standard for measuring HCV RNA in the management of patients with chronic hepatitis C virus (HCV) infection. Twenty‐seven naïve patients infected chronically by HCV were treated with ribavirin plus PEG‐interferon‐alfa‐2b for 48 weeks. SVR was obtained for 16 patients (the other were non‐responders). For HCV RNA quantitation, four assays were undertaken: Versant HCV RNA 3.0 (Bayer), Real time PCR (TaqMan, Roche), LCx HCV RNA (Abbott), and Cobas Amplicor‐Monitor v2 (Roche). Considering a 2‐log decline at Week 12 after the beginning of therapy, discordant results were found with the four HCV RNA methods in predicting SVR or non‐response. At Week 4 and Week 12, significant differences were observed between Versant HCV RNA 3.0 versus PCR HCV Taqman, Versant HCV RNA 3.0 versus LCx HCV RNA, Cobas Monitor Amplicor HCV 2.0 versus LCx HCV RNA, and Cobas Monitor Amplicor HCV 2.0 versus PCR HCV Taqman (P < 0.001). The HCV RNA cutoff, given a 100% negative predictive value at Week 4 and Week 12, differed with the assays used to quantify HCV RNA, despite the use of the IU/ml units. Eighty‐nine percent of serum values for HCV RNA were concordant by the IU standard. All assays, however, failed to detect HCV RNA in some cases. Despite the use of the IU standard HCV‐infected patients might be monitored with only one assay. J. Med. Virol. 78:208–215, 2006. © 2005 Wiley‐Liss, Inc.     

Intrahepatic MxA and PKR protein expression in chronic hepatitis C virus infection

The therapeutic effect of interferon-alpha and ribavirin in the treatment of chronic hepatitis C viral infection is limited. To identify patient characteristics that may predict responsiveness to treatment, the intrahepatic protein expression of two directly induced IFN-alpha effector proteins, MxA and PKR, were studied. Forty liver biopsy samples from patients with a variety of chronic liver diseases were stained for MxA and PKR protein using immunohistochemical techniques. In a HCV patient cohort, 30 liver biopsies were stained for MxA and PKR protein prior to treatment with IFN-alpha and ribavirin. PKR protein expression was not upregulated in viral liver disease. In contrast, MxA protein expression was significantly upregulated in viral liver disease (P = 0.005). In chronic HCV liver disease, moderate to strong cytoplasmic expression of MxA protein was observed in hepatocytes and monocytes, indicating endogenous hepatocellular IFN-alpha pathway activation. In the HCV patient cohort treated with combination therapy, strong pre-treatment MxA hepatocyte expression was predictive of a non-response to treatment (odds ratio 9.33; P = 0.01; 95% confidence interval 1.63-53.2). This effect was independent of HCV genotype and viral load. It is concluded that pretreatment hepatocellular MxA expression may become a useful predictor of response to combination treatment with IFN-alpha and ribavirin.     

Real-time PCR assays for hepatitis C virus (HCV) RNA quantitation are adequate for clinical management of patients with chronic HCV infection

Because of the use of viral kinetics during polyethylene glycol (PEG)-interferon-ribavirin therapy and the development of specific new anti-hepatitis C virus (anti-HCV) drugs, assessment of the efficacy of anti-HCV drugs needs to be based not on end-point PCR assays but on real-time PCR. The aim of this study was to determine if the two available commercial real-time PCR assays, the Abbott RealTime HCV assay and the Roche Cobas TaqMan HCV assay, can become the standard for HCV RNA quantification. We investigated the prognostic relevance of HCV RNA viral loads at baseline, week 4, and week 12 to a rapid and early virological response to antiviral therapy by using the two assays. Of 59 na?ve patients chronically infected by HCV (41 infected with genotype 1) who were treated with ribavirin plus PEG-interferon alfa-2b for 48 weeks, 24 patients (41%) showed a sustained virological response (SVR). With the two assays, viral loads were highly correlated, irrespective of genotype (R2=0.94 for all cases). No difference in diagnostic value was found between the Abbott and Roche assays at week 4, with respective negative predictive values (NPVs) of 84% and 78% and positive predictive values (PPVs) of 62% and 56% (not significant), and at week 12, the respective NPVs were 91% and 90% and PPVs were 44% and 46% (not significant). At week 12, 83% (20/24) and 96% (23/24) of patients with SVR tested negative for HCV RNA by the Abbott and Roche assays, respectively (the difference is not significant). In conclusion, the high sensitivities and large dynamic ranges of the Abbott and Roche assays show that a single real-time quantitative PCR assay is fully adequate for clinical and therapeutic management of HCV.     

Influence of HCV genotype 1 subtypes on the virus response to PEG interferon alpha-2a plus ribavirin therapy

New factors that influence the viral response in HCV non-genotype 2/3 patients must be identified in order to optimize anti-HCV treatment. This multicenter prospective study evaluates the influence of HCV variability and pharmacological parameters on the virological response of these patients to pegylated interferon α2a (peg-IFN-α2a: 180 μg/week) and ribavirin (RBV; 800-1,200 mg/day) for 48 weeks. HCV subtypes were identified by sequencing the NS5B region. Serum RBV and peg-IFN-α2a concentrations were measured at weeks 4 and 12. The 115 patients (67 men; median age = 49, range 31-76) included 64 who had never been treated and 27 co-infected with HIV. The mean baseline HCV RNA was 6.30 ± 0.06 log IU/ml and the HCV genotypes were: G1 (n = 93) with 1a (n = 37) and 1b (n = 50), G4 (n = 20) and G5 (n = 2). Most patients (79/108; 73%) had an early virological response. Independent predictors of an early virological response were interferon naive patients (OR= 2.98, 95% CI: 1.15-7.72) and RBV of >2,200 ng/ml at week 12 (OR = 3.41, 95% CI: 1.31-8.90). Forty of 104 patients (38%) had a sustained virological response. The only independent predictors of a sustained virological response were subtype 1b (OR = 6.82, 95% CI: 1.7-26.8), and HCV RNA <15 IU/ml at week 12 (OR = 25, 95% CI: 6.4-97.6). Thus a serum RBV concentration of >2,200 ng/ml was associated with an early virological response and patients infected with HCV subtype 1b had a better chance of a sustained virological response than did those infected with subtype 1a.     

Mutations within the hepatitis C virus genotype 1b E2-PePHD domain do not correlate with treatment outcome

The hepatitis C virus (HCV) envelope protein 2 (E2) interacts in vitro with the interferon alpha (IFN-alpha)-inducible double-stranded RNA-activated protein kinase, suggesting a possible mechanism by which HCV may evade the antiviral effects of IFN-alpha. Variability in the part of the HCV E2 gene encoding the carboxy-terminal part of the protein, which includes the interaction domain (E2-PePHD), was explored in 25 patients infected with HCV genotype 1b and receiving IFN-alpha therapy. PCR products were generated and sequenced for 15 patients with a sustained response and for 10 patients with no virological response after treatment with IFN-alpha and ribavirin. PePHD amino acid sequences were obtained for isolates from serum collected before and during treatment, after 2 months in responders, and after 6 months in nonresponders. Quasispecies analysis of the pretreatment PePHD region was performed for isolates from patients displaying amino acid substitutions in this domain on direct sequencing. The E2-PePHD sequence was highly conserved in both resistant and susceptible genotype 1b strains and was identical to the prototype HCV type J sequence. No significant emergence of PePHD mutants during therapy was observed in our clonal analysis, and sporadic mutations and treatment outcomes were not found to be correlated. The PePHD sequence before or during treatment cannot be used to predict reliably the outcome of treatment in HCV type 1b-infected patients.     

Virological tools to diagnose and monitor hepatitis C virus infection

Approximately 200 million people are chronically infected with hepatitis C virus (HCV). Infection with HCV is curable by therapy, with the current standard treatment based on the combination of pegylated interferon-α and ribavirin. Viral eradication is achieved in approximately half of treated patients. In 2011 a new antiviral treatment based on a triple combination with a protease inhibitor will become available. Virological tools are essential to diagnose HCV infection but they have found their principal application in guiding treatment decisions and assessing the virological responses to therapy. These include the anti-HCV antibody assay, measurements of HCV core antigen and HCV viral load and HCV genotyping. The HCV RNA can be ideally assayed by a real-time assay with a limit of detection of 10–15 IU/mL. Monitoring of viral kinetics during the early phases of antiviral treatment is crucial in making treatment decisions such as early stopping rules and also in optimizing the treatment duration. The HCV genotype should be assessed before the start of treatment because it determines the treatment length and ribavirin dose and also offers prognostic information on treatment outcomes as certain genotypes respond more favourably to treatment.     

Predictive factors of virological non-response to interferon-ribavirin combination therapy for patients infected with hepatitis C virus of genotype 1b and high viral load

Patients with high viral load (> or =1.0 x 10(5) IU/ml) of hepatitis C virus (HCV) genotype 1b do not achieve high sustained virological response rates to interferon (IFN)/ribavirin combination therapy. Previous studies suggested that pretreatment amino acid (aa) substitution patterns in the HCV core region could affect virological non-response especially in patients who could not achieve HCV-RNA negativity during treatment. The present study evaluated 167 consecutive Japanese adults with high HCV genotype 1b viral load who received combination therapy for > or =24 weeks. A case-control study matched for age, sex, genotype, and viral load was conducted to investigate the predictive factors for virological non-response, especially absolute virological non-response (patients who could not achieve >2 log decline of HCV RNA from baseline during the initial 24 weeks of therapy). Virological non-response was identified in 26.3% of patients, and 45.5% of these were absolute virological non-responders. Multivariate analysis identified ribavirin dose <11.0 mg/kg, moderate-to-severe hepatocyte steatosis, and substitutions of aa 70 and/or 91 in the core region as significant independent factors associated with virological non-response. The majority of absolute virological non-responders had such substitutions in the core region (95.0%), as well as substitution of glutamine at aa 70 and/or methionine at aa 91 (90.0%). In the present work, such substitutions significantly affected the viral kinetics in virological non-responders. The results suggest that viral, host, and treatment-related factors determine the response to IFN/ribavirin combination therapy in patients with high HCV genotype 1b viral load, and that amino acid substitution patterns in the core region is potentially useful pretreatment predictor of virological non-response.     

Predictive value of early HCV RNA quantitation for sustained response in nonresponders receiving daily interferon and ribavirin therapy

The prognostic value of early hepatitis C virus (HCV)-RNA load was evaluated among nonresponder patients to previous interferon (IFN) therapy treated with daily IFN and ribavirin. One hundred-six nonresponders (83 men), mean age 44.8 +/- 11 years, were treated with IFN-alpha 2b 3 MU/day for 24 weeks, followed by 3 MU x 3/week for 24 weeks plus ribavirin 1-1.2 g/day for 48 weeks. HCV RNA was quantified by Versant HCV RNA 3.0 assay (Bayer). The predictive values of the baseline and the change in viral load at week 1, 4, and 12 for sustained virological responses were analyzed using receiver operating characteristic (ROC) curves, as well as predictive values of >2 log(10) drop from baseline by weeks 1, 4, and 12 in combination with undetectable HCV RNA for sustained virological response. Thirty-two patients (30.2%) were sustained virological responders. The highest area under the curve was obtained at week 4. The unquantifiable HCV RNA level, in combination with at least a 2 log(10) drop in viral load by week 4 and week 12, had a negative predictive value of 96% and 97%, respectively. Nonresponse can be predicted as early as week 4 or week 12 in nonresponders treated with daily IFN and ribavirin.     

Expression of interferon receptor genes in the liver as a predictor of interferon response in patients with chronic hepatitis C.

Interferon (IFN) receptor mRNA expression patterns in the liver have been shown to correlate with the effectiveness of IFN therapy in patients with hepatitis C virus (HCV) infection. However, it is not clear to what extent this factor contributes to the short (primary)- and long (sustained)-term results of IFN treatment with respect to biochemical and virological remission. Eighty-two patients who subsequently received lymphoblastoid IFN-alpha therapy underwent liver biopsies before IFN therapy. Possible factors that might correlate with IFN response were chosen and analyzed. The primary biochemical and virological responses at the end to treatment (24 weeks) were 63% and 43% vs. 46% and 32% for sustained biochemical and virological remission at the end of follow-up (48 weeks), respectively. In univariate analysis, the absence of HCV genotype 1b, a low titer of HCV RNA, and the expression of IFN receptor mRNA were significantly correlated with sustained biochemical and virological responses to IFN therapy. Multiple logistic regression analysis showed that IFN receptor mRNA expression and the absence of genotype 1b were significant predictors of the sustained biochemical and virological effectiveness of IFN therapy. IFN receptor mRNA expression predicted a sustained virological response to IFN therapy with a positive predictive value of 100% with genotype non-1b and had a negative predictive value of 97% with genotype 1b. It is concluded that expression of IFN receptor genes in the liver is a useful index for predicting the short- and long-term efficacy of IFN therapy in patients with chronic HCV infection.     

The NS5a gene of hepatitis C virus in patients treated with interferon-alpha

Patients infected with hepatitis C virus (HCV) genotype 3 have a better response to interferon-alpha (IFN-alpha) therapy than those infected with genotype 1. There are extensive sequence differences between genotypes in the 3' half of the NS5a gene. An association between IFN-alpha response and the interferon sensitivity-determining region (ISDR) (amino acids 2209-2248) of HCV genotype 1b has been described [Enomoto et al. (1996) New England Journal of Medicine 334:771-776]. A prospective study was conducted to determine whether the derived NS5A amino acid sequence or quasi-species diversity could predict response to IFN-alpha therapy. Serum samples were obtained before, during, and after treatment from 35 IFN-alpha-treated patients chronically infected with HCV (eight with type1b,13 with type1a, and 14 with type3a). Nucleotide sequences were determined, and amino acid sequences corresponding to residues 2178-2390 of the polyprotein were derived. Quasi-species complexity was analysed by amplification of the ISDR region (2270-2403), followed by single-stranded conformation polymorphism (SSCP). No amino acid sequence that could be used to predict response to treatment was found, and there was no selection of specific amino acid residues during treatment. A striking lack of variability was seen in HCV genotype 3a, but the small degree of variation could suggest an effect on response. SSCP showed that variation in the predominant NS5a sequence occurred in the presence and absence of therapeutically administered IFN-alpha. HCV quasi-species diversity pretreatment did not predict IFN-alpha treatment outcome. The conclusion of the study is that the amino acid sequence of NS5a cannot be used to predict the efficacy of treatment with IFN-alpha in HCV-infected patients in Scotland. No evidence was found to support the selection of IFN-alpha-resistant strains in the NS5a gene.     

Hepatitis C virus genetic variability in patients undergoing antiviral therapy

Hepatitis C virus (HCV) has been the subject of intense research and clinical investigations due to its worldwide prevalence and major role in chronic liver disease. Like most RNA viruses, HCV circulates in vivo as a complex population of different but closely related viral variants, commonly referred to as a quasispecies. Recent studies suggest that ribavirin might exert an antiviral effect against HCV through both mutagenic effect and an impairment of RNA replication. The introduction of alpha interferon (IFN-alpha) plus ribavirin combination therapy was an important breakthrough in the treatment of chronic HCV infection. However, the rate of sustained virological response is still unsatisfactory, particularly in patients infected with HCV genotype 1. Viral persistence, a hallmark of HCV, may result from a dynamic control of the host response by the virus. In children with chronic HCV infection, the viral population is initially highly homogeneous, but diversifies during prolonged infection which seems to be a common event during chronic hepatitis C in childhood. Coinfection of human immunodeficiency virus 1 (HIV-1) patients by HCV can complicate the treatment of these patients with highly active antiretroviral therapy (HAART). HIV coinfection is associated with a decrease of HCV quasispecies variability, which appears to be reversed by effective HAART.     

Predictors of viral kinetics to peginterferon plus ribavirin combination therapy in Japanese patients infected with hepatitis C virus genotype 1b

For chronic hepatitis C virus (HCV) infection, evaluation of response to peginterferon (PEG-IFN) plus ribavirin (RBV) therapy based on viral kinetics is useful as an early predictor of treatment efficacy, but the underlying mechanisms of the different viral kinetics to treatment are still unclear. The response to 48-week PEG-IFN-RBV combination therapy was evaluated in 160 Japanese adult patients infected with HCV genotype 1b and determined the rapid virological response (at 4 weeks), early virological response (at 12 weeks), end-of treatment response, and sustained virological response (6 months after end of treatment). The proportion of patients who showed rapid, early and sustained virological, and end-of treatment responses were 50%, 73%, 47%, and 71%, respectively. Furthermore, 66% of patients who achieved early virological response also showed sustained virological response. Multivariate analysis identified substitutions of amino acid (aa) 70 and 91 in the HCV core region (double-wild-type) as a predictor of early HCV-RNA negativity, rapid, early, and sustained virological responses and end-of treatment response, and lipid metabolic factors (high levels of LDL cholesterol and total cholesterol) as predictors of early and rapid virological responses and end-of treatment response. Male sex and low levels of alpha-fetoprotein were other predictors of sustained virological response. Furthermore, female sex and severity of liver fibrosis were determinants of lack of sustained virological response in spite of early virological response. This study identified predictors of efficacy of PEG-IFN-RBV therapy based on viral kinetics in Japanese patients infected with HCV genotype 1b.     

Add‐on therapy of pitavastatin and eicosapentaenoic acid improves outcome of peginterferon plus ribavirin treatment for chronic hepatitis C

Despite the use of pegylated‐interferon (peg‐IFN) plus ribavirin combination therapy, many patients infected with hepatitis C virus (HCV)‐1b remain HCV‐positive. To determine whether addition of pitavastatin and eicosapentaenoic acid (EPA) is beneficial, the “add‐on” therapy option (add‐on group) was compared retrospectively with unmodified peg‐IFN/ribavirin therapy (standard group). Association of host‐ or virus‐related factors with sustained virological response was assessed. In HCV replicon cells, the effects of pitavastatin and/or EPA on HCV replication and expression of innate‐immunity‐ and lipid‐metabolism‐associated genes were investigated. In patients infected with HCV‐1b, sustained virological response rates were significantly higher in the add‐on than standard group. In both groups, sustained virological response rates were significantly higher in patients with genotype TT of IL‐28B (rs8099917) than in those with non‐TT genotype. Among the patients with non‐TT genotype, sustained virological response rates were markedly higher in the add‐on than standard group. By multivariate analysis, genome variation of IL28B but not add‐on therapy remained as a predictive factor of sustained virological response. In replicon cells, pitavastatin and EPA suppressed HCV replication. Activation of innate immunity was obvious in pitavastatin‐treated cells and EPA suppressed the expression of sterol regulatory element binding protein‐1c and low‐density lipoprotein receptor. Addition of pitavastatin and EPA to peg‐IFN/ribavirin treatment improved sustained virological response in patients infected with HCV‐1b. Genotype variation of IL‐28B is a strong predictive factor in add‐on therapy. J. Med. Virol. 85:250–260, 2013. © 2012 Wiley Periodicals, Inc.     

Correlation of interferon-induced expression of MxA mRNA in peripheral blood mononuclear cells with the response of patients with chronic active hepatitis C to IFN-alpha therapy.

MxA, a protein with selective activity against certain viruses, is an accepted specific indicator of type I interferon (IFN) activity. We have developed an internally controlled quantitative-competitive PCR to measure the amounts of MxA mRNA expressed in peripheral blood mononuclear cells (PBMC). This assay is more sensitive, quantitative, and easily applied to serial clinical samples than previously described methods. We have applied this assay retrospectively to 27 patients with chronic active hepatitis C given IFN-alpha2. Most such patients gain no sustained benefit but nevertheless suffer from the side effects, expense, and inconvenience of the treatment. Fourteen of the 27 had been classified on clinical grounds as responders and 13 as nonresponders at the end of a 6 month treatment period. We measured MxA mRNA in PBMC obtained before and after 8 weeks of IFN-alpha2 treatment. All the patients expressed some level of mRNA before treatment began, and after 8 weeks of treatment, the level rose in 19. This increase was significant (p < 0.001) only in patients classified as responders. This strongly suggests that hepatitis C virus (HCV) patients who express increased amounts of MxA mRNA in their PBMC during IFN-alpha treatment are most likely to obtain long-term benefit. If this finding is confirmed in future prospective studies, it will provide an extremely important predictive marker for managing IFN-alpha therapy in patients with HCV.     

Prediction of successful outcome in a randomised controlled trial of the long-term efficacy of interferon alpha treatment for chronic hepatitis C

To evaluate the efficacy of a 12-month course of recombinant interferon alpha (IFN-alpha2b), and to assess predictive factors of successful response to IFN therapy in chronic active hepatitis C (HCV CAH), 242 patients with histologically proven HCV CAH were assigned randomly to two groups, one treated with IFN-alpha2b (3 MU three times weekly, intramuscularly), the other untreated. To determine the efficacy of IFN-alpha2b 12 months after therapy, a second liver biopsy was carried out on 100 treated patients and 27 untreated patients. The biochemical, virological, and serological response of patients followed up for at least 50 months after treatment was also evaluated to confirm the efficacy of IFN-alpha2b. The genotypes of infecting HCV, anti-HCV core IgM, and HCV-RNA concentrations were also analysed and the predictors of response determined by univariate and multivariate analyses. Response was defined in terms of the normalisation of aminotransferase activities and the disappearance of HCV-RNA. The overall long-term response was 39.4%. Anti-HCV core IgM levels were significantly lower in long-term responders. Patients with increased levels of IgM anti HCV core (>3.8 sample/cut-off), infected with genotype 1b were nonresponders. Liver histology improved significantly in patients with long-term response. Multivariate analysis identified three independent predictors of the likelihood of long-term response to IFN therapy: age younger than 40 years, basal anti-HCV core IgM levels < or = 3.8, and genotypes other than 1b. These data indicate that the treatment with IFN-alpha2b used in this randomised controlled trial is effective in HCV CAH. Anti-HCV core IgM was the strongest predictor of long-term response in the present study.     

Influence of three successive antiviral treatments on viral heterogeneity in nonresponder chronic hepatitis C patients.

The purpose of the present study was to assess the viral diversity of hepatitis C virus (HCV) in six nonresponder patients during three unsuccessful treatments. These patients were treated successively with IFN-alpha2a (IFN-alpha) at a posology of 3.10(6) units (MIU) three times a week, 10 MIU three times a week, and a combination of IFN-alpha (3 MIU) plus ribavirin (1,000 mg/day). However, only two chronically infected patients could be included in the study due to the persistence of HCV RNA during the three successive treatments. The viral diversity was analysed by cloning and sequencing the HVR-1 region. The treatment of the two nonresponder patients was associated with the persistence of a wide diversity in the viral population and with the emergence of new or minor variants. Under the influence of standard doses of IFN-alpha, a rearrangement of the quasispecies present was observed at this time point. No significant change in viral load or in the complexity of the quasispecies was observed. A second treatment with a high dose of IFN-alpha induced a significant decrease in the associated viral load and, in one case, resulted in a radical change of the viral diversity. Administration of a combination of IFN-alpha and ribavirin did not affect the evolution of the variants but was followed by the emergence of various multiple variants. These results reinforce the hypothesis of the presence of preexisting quasispecies best adapted to the host environment, and therefore resistant to any current therapy.     

Interferon-induced, antiviral human MxA protein localizes to a distinct subcompartment of the smooth endoplasmic reticulum.

Human MxA protein belongs to the superfamily of dynamin-like large GTPases that are involved in intracellular membrane trafficking. MxA is induced by interferons-alpha/beta (IFN-alpha/beta) and is a key component of the antiviral response against RNA viruses. Here, we show that MxA localizes to membranes that are positive for specific markers of the smooth endoplasmic reticulum, such as Syntaxin17, but is excluded from other membrane compartments. Overexpression of MxA leads to a characteristic reorganization of the associated membranes. Interestingly, Hook3, mannose-6-phosphate receptor, and Lamp-1, which normally accumulate in cis- Golgi, endosomes, and lysosomes, respectively, also colocalized with MxA, indicating that these markers were redistributed to the MxA-positive compartment. Functional assays, however, did not show any effect of MxA on endocytosis or the secretory pathway. The present results demonstrate that MxA is an IFN-induced antiviral effector protein that resembles the constitutively expressed large GTPase family members in its capacity to localize to and reorganize intracellular membranes.