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The real-world virological efficacy and safety of interferon-free direct-acting antiviral (DAA) therapy with sofosbuvir (SOF) and velpatasvir (VEL) were assessed in hepatitis C virus (HCV) genotype 1- and 2-infected patients with decompensated cirrhosis. A total of 65 patients with HCV-related decompensated cirrhosis (Child-Pugh score of 7 points or more) who were treated with the SOF/VEL regimen were enrolled. The sustained virological response (SVR) rate and safety profile were analyzed. SVR was defined as undetectable serum HCV RNA at 12 weeks after the end of treatment (SVR12). The percentages of patients with undetectable HCV RNA at 4, 8, and 12 weeks after the start of therapy were 81.2% (95% confidence interval [CI], 69.5-89.9) (52/64), 98.4% (95% CI, 91.2-100.0) (60/61), and 98.5% (95% CI, 91.7-100.0) (64/65), respectively. The overall SVR rate was 92.3% (95% CI, 83.0-97.5) (60/65). Albumin-bilirubin (ALBI) scores decreased during and after treatment (p < 0.001), and there were significant differences between baseline and end of treatment and between baseline and SVR12. Subgroup analyses showed no significant differences in SVR rates according to patient age, sex, HCV genotype (subtype), Child-Pugh classification, modified ALBI grade, presence of ascites, presence of hepatic coma, or history of hepatocellular carcinoma. In all subpopulations, the SVR rates were higher than 80%. There were no severe adverse events associated with the treatment. The SOF/VEL regimen showed good virological efficacy and acceptable safety even in patients with HCV-related decompensated cirrhosis., (© 2021 Wiley Periodicals LLC.)

Background: We aimed to describe the real-world efficacy and safety of combination therapy with ledipasvir and sofosbuvir (LDV/SOF) for chronic hepatitis C virus (HCV) genotype 1 (GT1) infection., Methods: This retrospective analysis of a prospective, nationwide, multicenter registry included GT1-infected patients treated with LDV/SOF for 12 weeks. We assessed the rate of sustained virological response at 12 weeks post-treatment (SVR12), incidence of adverse events, and serum markers of hepatocellular carcinoma (HCC)., Results: Among the 1461 patients included (mean age, 69 years; 29.5% aged > 75 years; cirrhosis, 23.8%; history of treatment for HCC, 10.9%), the overall SVR12 rate was 98.4% (1438/1461). Factors associated with treatment failure were cirrhosis (odds ratio, 4.19; p = 0.014) and resistance-associated substitutions (RASs) in NS5A at baseline (odds ratio, 7.78; p = 0.0004). The SVR12 rate in patients with cirrhosis and NS5A RASs was 93.0% compared to 100% in patients without cirrhosis or NS5A RASs. In patients with SVR, the levels of alpha-fetoprotein (AFP), AFP-L3, and Mac-2 binding protein glycosylation isomer (M2BPGi) decreased from baseline to end of treatment (from 13.4 ± 37.6 to 6.0 ± 10.6 ng/mL, p < 0.0001; from 2.2 ± 4.9 to 1.5 ± 6.3%, p < 0.005; and from 3.6 ± 3.7 to 2.0 ± 3.5 cut-off index, p < 0.0001; respectively). Adverse events were rare and not associated with age. No decrease in estimated glomerular filtration rate was observed in patients with baseline chronic kidney disease stage 3., Conclusions: LDV/SOF therapy is highly effective and safe in elderly Japanese patients with HCV GT1, even in the presence of cirrhosis or NS5A RASs. Patients with SVR may have a lower risk of HCC.

Sustained virological responses (SVR) by daclatasvir (DCV) and asunaprevir (ASV) therapy for genotype 1b hepatitis C virus (HCV) infected patients has been significantly affected by pre-existence of Y93 H resistance-associated variants (RAVs) in the non-structural protein 5A (NS5A) region. The aim of this study was to elucidate the dominancy of naturally occurring RAVs in viral quasispecies on treatment outcomes in patients with HCV. In total, 138 patients were prospectively selected from 152 patients treated with DCV and ASV, where evaluation of treatment outcomes at 12 weeks post-treatment was possible. Pre-treatment RAVs in the non-structural protein 3 and NS5A regions were detected by polymerase chain reaction (PCR)-Invader assays, and the ratio of Y93H RAVs in viral quasispecies was measured by quantitative PCR-Invader assay. Among 25 patients detected the Y93H RAV, the Y93H ratio was 1-25% in 5 patients, 26-75% in 7 patients, and ≥76% in 13 patients. Overall, SVR at 12 weeks after the completion of treatment (SVR12) was 91% (125/138), and those with Y93H ratios of <1%, 1-25%, 26-75%, and ≥76% were 99%, 100%, 71%, and 23%, respectively. Thus, the SVR12 decreased as the HCV Y93H ratio increased (P < 0.0001). The dominancy of pre-treatment RAVs of DCV and ASV affected its treatment outcomes, suggesting that evaluating the dominancy of HCV RAVs could be required for every other direct-acting antiviral agent treatments. J. Med. Virol. 89:99-105, 2017. © 2016 Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)

High rates of sustained virologic response (SVR) has been achieved in Japanese patients with chronic hepatitis C virus (HCV) genotype (GT)1 and GT2 infection treated with ledipasvir/sofosbuvir (LDV/SOF) ±ribavirin (RBV) and SOF+RBV, respectively. We evaluated the effect of baseline HCV NS5A and NS5B resistance-associated variants (RAVs) on treatment outcome and characterized variants at virologic failure. Baseline deep sequencing for NS5A and NS5B genes was performed for all GT1 patients. Deep sequencing of NS5A (GT1 only) and NS5B (GT1 and GT2) was performed for patients who failed treatment or discontinued early with detectable HCV RNA (i.e., >25 IU/mL). In patients with HCV GT1 infection, 22.3% (GT1a: 2/11; GT1b: 74/330) had ≥1 baseline NS5A RAV. The most frequent NS5A RAVs in GT1b were Y93H (17.9%, 59/330) and L31M (2.4%, 8/330). Despite the presence of NS5A RAVs at baseline, 100% and 97% of patients achieved SVR12, compared with 100% and 99% for those with no NS5A RAVs with LDV/SOF and LDV/SOF+RBV, respectively. All patients with NS5B RAVs at baseline achieved SVR12. Of the 153 patients with GT2 infection (GT2a 60.1%, GT2b 39.9%), 3.3% (5/153) experienced viral relapse. No S282T or other NS5B RAVs were detected at baseline or relapse; no change in susceptibility to SOF or RBV was observed at relapse. In conclusion, LDV/SOF and SOF+RBV demonstrate a high barrier to resistance in Japanese patients with HCV GT1 and GT2 infection. The presence of baseline NS5A RAVs did not impact treatment outcome in GT1 Japanese patients treated with LDV/SOF for 12 weeks., (© 2016 John Wiley & Sons Ltd.)

Unlabelled: An HCV outbreak occurred in 2012 in China, affecting hundreds of patients. We characterized HCV subtype 2a and 6a sequences from 60 and 102 patients, respectively, and co-analyzed them with 82 local controls and 103 calibrating references. The close grouping of the patients׳ sequences contrasted sharply with the diversity of local controls. Scaled by the calibrating references, the emergence of patients׳ isolates was estimated at 2-5 years before sampling. In contrast, the controls intermingled with the calibrating references that were much older. For both subtypes, the major and minor clusters could be defined, with the closeness to indicate linked transmission., Conclusion: HCV sequences from the study patients grouped into three subtype 2a and two subtype 6a clusters, in addition to three 6a solitary branches, representing descendants of eight earlier strains that were distinct and otherwise sporadic. Due to iatrogenic transmission through reusing needles, five strains were highly selected and preferentially spread., (Copyright © 2015. Published by Elsevier Inc.)

Background & Aims: The presence of resistance-associated variants (RAVs) of hepatitis C virus (HCV) attenuates the efficacy of direct acting antivirals (DAAs). The objective of this study was to characterize the susceptibility of RAVs to interferon-based therapy., Methods: Direct and deep sequencing were performed to detect Y93H RAV in the NS5A region. Twenty nine genotype 1b patients with detectable RAV at baseline were treated by a combination of simeprevir, pegylated interferon and ribavirin. The longitudinal changes in the proportion of Y93H RAV during therapy and at breakthrough or relapse were determined., Results: By direct sequencing, Y93H RAV became undetectable or decreased in proportion at an early time point during therapy (within 7 days) in 57% of patients with both the Y93H variant and wild type virus at baseline when HCV RNA was still detectable. By deep sequencing, the proportion of Y93H RAV against Y93 wild type was 52.7% (5.8%- 97.4%) at baseline which significantly decreased to 29.7% (0.16%- 98.3%) within 7 days of initiation of treatment (p = 0.023). The proportion of Y93H RAV was reduced in 21 of 29 cases (72.4%) and a marked reduction of more than 10% was observed in 14 cases (48.7%). HCV RNA reduction was significantly greater for Y93H RAV (-3.65±1.3 logIU/mL/day) than the Y93 wild type (-3.35±1.0 logIU/mL/day) (p<0.001)., Conclusion: Y93H RAV is more susceptible to interferon-based therapy than the Y93 wild type.

Daclatasvir is a novel NS5A inhibitor of hepatitis C virus (HCV). Daclatasvir combined with peginterferon α-2a and ribavirin in Japanese patients infected with genotype 1b HCV achieved sustained virological response (SVR) in 100% of treatment-naïve patients, due to high rates of favorable IL28B allele and genotype 1b. SVR 24 was achieved by asunaprevir and daclatasvir in 87.4% of intolerant and 80.5% of nonresponder patients. Baseline NS5A-resistant variants were detected and they failed to achieve SVR. Most patients with genotype 1a experienced virological breakthrough by dual oral treatment, and should be treated QUAD or replaced by all oral regimens that are more potent and have fewer side effects. IFN-free regimens including daclatasvir and asunaprevir for genotype 1 null responders should be tailored to subtype, and preexisting NS5A-resistant variants should be evaluated carefully before choosing the drugs. This regimen alone is unlikely to move forward without additional agents.

Inosine triphosphatase (ITPA) genetic variants are strongly associated with ribavirin (RBV)-induced anaemia during pegylated interferon (PEG-IFN) plus RBV therapy. However, the treatment efficacy of ITPA genetic variants has not been fully explored. We enrolled 309 individuals infected with hepatitis C virus genotype 1, who were treated with PEG-IFN plus RBV for 48 weeks. The ITPA SNP: rs1127354 and IL28B SNP: rs8099917 were genotyped. We examined the risk factors for severe anaemia up to week 12 after the start of treatment and treatment efficacy. The incidence of severe anaemia, ≥ 3 g/dL reduction or <10 g/dL of haemoglobin (Hb) up to week 12, was more frequent in patients with CC at rs1127354 [65% (145/224), 33% (73/224)] than in those with CA/AA [25% (21/85), 6% (8/85)] (P < 0.0001). ITPA genotype, pretreatment Hb level and age were independent predictive factors for severe anaemia: Hb < 10 g/dL. In IL28B favourable type, the sustained virologic response rate was higher in ≥ 60-year-old patients with CA/AA than in those with CC [71% (22/31) vs 40% (26/65), P = 0.005], although there was no significant difference in treatment efficacy according to ITPA genetic variants in the <60-year-old patients. The proportion of patients administered ≥ 80% of the dosage of RBV was significantly higher in the patients with CA/AA than in those with CC (P = 0.025), resulting in a lower relapse rate. In conclusion, ITPA genetic variants were associated with severe RBV-induced anaemia and could influence the efficacy of PEG-IFN plus RBV treatment among elderly patients with IL28B favourable type., (© 2013 John Wiley & Sons Ltd.)

Background: Efficacy of available therapies for patients with HCV who have previously failed treatment is limited. Two Phase III, open-label trials in Japan investigated efficacy and safety of simeprevir and peginterferon-α-2a/ribavirin (PR) combination therapy in treatment-experienced patients with genotype 1 HCV infection., Methods: In CONCERTO-2, prior non-responders to IFN-based therapy (N = 106) received simeprevir (TMC435) 100 mg QD with PR for 12 (SMV12, n = 53) or 24 weeks (SMV24, n = 53) followed by response-guided therapy (RGT) with PR for 12/36 (SMV12) or 0/24 (SMV24) weeks. In CONCERTO-3, relapsers after IFN-based therapy (N = 49) received simeprevir 100 mg QD with PR for 12 weeks followed by RGT with PR for 12/36 weeks. Primary endpoints were the rates of sustained virologic response 12 weeks after treatment end (SVR12)., Results: SVR12 rates were 52.8% (SMV12) and 35.8% (SMV24) for prior non-responders, and 95.9% for prior relapsers (SMV12; p ≤ 0.0001 vs null hypothesis, respectively). Most prior non-responders (SMV12: 81.1%; SMV24: 73.6%) and prior relapsers (95.9%) met RGT criteria and completed PR to Week 24. Of these, 60.5%, 48.7%, and 95.7%, respectively, achieved SVR12. Viral breakthrough occurred in 13.2 % (SMV12) and 11.3% (SMV24) of prior non-responders; no viral breakthrough occurred in prior relapsers. Viral relapse occurred in 38.6% (SMV12) and 51.1% (SMV24) of prior non-responders and 8.2% of prior relapsers. Simeprevir with PR was generally well tolerated in both studies., Conclusion: Re-treatment with 12 weeks of simeprevir QD with PR provided high SVR in treatment-experienced patients with chronic HCV genotype 1 infection, and allowed most patients to complete treatment in 24 weeks.

Background: New direct-acting antiviral agents are currently being developed to treat chronic HCV. The efficacy and safety of daclatasvir combined with peginterferon alfa-2a (alfa-2a) and ribavirin were assessed in a randomized, double-blind Phase IIa study of Japanese patients with chronic HCV genotype-1 infection., Methods: Japanese patients who were treatment-naive (n=25) or prior null (n=12) or partial (n=5) responders received once-daily daclatasvir 10 mg or 60 mg or placebo in combination with alfa-2a and ribavirin. Daclatasvir recipients with a protocol-defined response (HCV RNA<15 IU/ml at week 4 and undetectable at week 12) were treated for 24 weeks; placebo recipients and patients without a protocol-defined response were treated for 48 weeks., Results: Sustained virological response at 24 weeks post-treatment (SVR24) was achieved by 89% and 100% of treatment-naive patients receiving daclatasvir 10 mg and 60 mg, respectively, versus 75% in placebo recipients. Virological failure was more frequent in prior non-responder patients, with 50% and 78% achieving SVR24 in daclatasvir 10 mg and 60 mg groups, respectively. Adverse events occurred with similar frequency among treatment groups and were consistent with the adverse event profile of alfa-2a/ribavirin alone. The most commonly reported adverse events included pyrexia, alopecia, anaemia, lymphopenia, neutropenia, pruritus and diarrhoea. Three patients discontinued treatment due to anaemia., Conclusions: Daclatasvir combined with alfa-2a/ribavirin in treatment-naive patients showed greater efficacy than alfa-2a/ribavirin alone and was generally well tolerated. The 60-mg dose of daclatasvir achieved the highest rates of SVR24 in both treatment-naive and non-responder populations and will be evaluated in a Phase III clinical trial.

Objective: Some patients with chronic hepatitis C virus (HCV) infection fail to achieve complete early virologic response (EVR) despite a marked decrease in HCV RNA at 4 weeks. We investigated the characteristics and final treatment outcomes of this patient subpopulation., Methods: A total of 516 patients with HCV genotype 1 were enrolled. Background characteristics and final outcomes were compared between patients who achieved complete EVR and those who did not among patients whose HCV RNA levels decreased 3.0 log10 or more at 4 weeks., Results: 78 of 334 patients (23.4%) with a ≥3.0 log10 reduction in HCV RNA levels at 4 weeks failed to achieve complete EVR. Female sex, higher pretreatment HCV RNA levels and lower baseline alanine aminotransferase (ALT) activity were independently associated with failure of complete EVR. The rate of sustained virologic response (SVR) in patients without complete EVR was 47.4%, significantly lower than that in patients with complete EVR (89.7%, p < 0.0001)., Conclusions: Female patients, patients with higher pretreatment HCV RNA levels and patients with lower baseline ALT have a high likelihood of failure of complete EVR even when they had a ≥3 log10 reduction of HCV RNA at 4 weeks, resulting in a significantly lower SVR rate., (© 2014 S. Karger AG, Basel)

Background: Daclatasvir (DCV; BMS-790052) is a picomolar inhibitor of HCV non-structural protein 5A (NS5A) and has demonstrated efficacy in patients chronically infected with HCV., Methods: In the double-blind, randomized studies AI444021 and AI444022, 71 Japanese patients chronically infected with HCV genotype 1 (predominantly genotype 1b) received DCV (10 mg or 60 mg) plus peginterferon alfa-2b or alfa-2a and ribavirin. Virological failure occurred in 14% (5/36) of treatment-naive patients and 54% (19/35) of prior alfa/ribavirin non-responders. Resistance testing was performed on baseline samples and samples with HCV RNA≥1,000 IU/ml at week 1 through post-treatment week 24., Results: Baseline NS5A resistance-associated polymorphisms had less impact on virological response rates than IL28B genotype. All patients with virological failure had NS5A DCV-resistant variants at the time of failure. The predominant NS5A variants were L31V/M/I plus Y93H; this combination was detected in 100% (5/5) of treatment-naive patients and 74% (14/19) of non-responders with failure. Emergent resistance variants in prior non-responders (four viral breakthroughs, one relapse) were more varied with novel combinations such as L31F-ΔP32 and L28M-R30Q-A92K detected. Significant loss in DCV antiviral activity was generally only seen with ≥ two resistance-associated NS5A substitutions. All DCV-resistant variants were still detected at end of study., Conclusions: Virological failure in HCV genotype 1b treatment-naive Japanese patients receiving DCV plus alfa-2a/ribavirin or alfa-2b/ribavirin was associated with enrichment of NS5A resistance variants L31V/M-Y93H. In prior non-responders, emergent variants associated with failure also included NS5A-A92K or NS5A-ΔP32. As with L31-Y93 variants, these variants persisted.

Hepatitis C virus (HCV) subtype 1b, which infects approximately 70% of Japanese carriers, is likely to be more eradicable by a telaprevir regimen than subtype 1a because of the higher genetic barrier of Val(36) and Arg(155) substitutions. The aims of this exploratory study were to evaluate the virological response and safety of 24-week oral administration of telaprevir alone in chronic HCV subtype 1b infection. Fifteen treatment-naïve patients were treated with telaprevir 750 mg every 8 h for 24 weeks. All patients were Japanese whose median age was 58.0 years (range: 45-68), and six patients (40%) were men. Median baseline HCV RNA level was 6.80 log(10) IU/mL (range: 3.55-7.10). The HCV RNA levels decreased to undetectable in five patients (33%) within 8 weeks. Three patients (20%) with negative HCV RNA by Week 4 achieved end of treatment response. One patient (7%) who achieved sustained virological response had a low baseline viraemia of 3.55 log(10) IU/mL. Most of the adverse events including anaemia and skin disorders were mild to moderate. Developed variants were T54A and A156V/T/F/Y with or without secondary substitutions rather than V36M ± R155K. Telaprevir alone for 24 weeks in Japanese patients with HCV subtype 1b resulted in an sustained viral response rate of 7% (1/15) and was well tolerated for 24 weeks. These results will support the implementation of further studies on oral combination of telaprevir with other direct-acting antiviral agents in patients infected with HCV subtype 1b., (© 2012 Blackwell Publishing Ltd.)

Both baseline predictive factors and viral response at week 4 of therapy are reported to have high predictive ability for sustained virologic response to peginterferon and ribavirin combination therapy in patients with hepatitis C virus (HCV) genotype 1. However, it is not clear how these baseline variables and week 4 response should be combined to predict sustained virologic response. In this multicenter study, the authors investigated the impact of baseline predictive factors on the predictive value of week 4 viral response. Receiver-operating characteristic curve analyses were performed to evaluate the ability of week 4 reduction in HCV RNA levels to predict sustained virologic response in 293 Japanese patients infected with HCV genotype 1b. Analyses were performed in all patients and in patient subgroups stratified according to baseline variables. Overall, week 4 viral reduction demonstrates a high predictive ability for sustained virologic response. The sensitivity, specificity, positive predictive value (PPV), negative predictive value, and accuracy were higher than those of viral reduction at week 12. However, the best cut-off levels differ depending on the baseline factors and they were lower in patients with unfavorable baseline predictors. When patients had the TG/GG rs8099917 genotype, the best cut-off was markedly low with low PPV. Week 4 viral response can be a predictor of sustained virologic response in patients with HCV genotype 1 and is better than week 12 viral response. However, the cut-off levels should be modified based on the baseline predictive variables., (Copyright © 2012 Wiley Periodicals, Inc.)

Background: The importance of the reduction in hepatitis C virus (HCV) RNA levels 4 and 12 weeks after starting peginterferon (PEG-IFN) and ribavirin combination therapy has been reported to predict a sustained virologic response (SVR) in patients infected with HCV genotype 1. We conducted a multicenter study to validate this importance along with baseline predictive factors in this patient subpopulation., Methods: A total of 516 patients with HCV genotype 1 and pretreatment HCV RNA levels ≥5.0 log(10) IU/mL who completed response-guided therapy according to the AASLD guidelines were enrolled. The reduction in serum HCV RNA levels 4 and 12 weeks after starting therapy was measured using real-time PCR, and its value in predicting the likelihood of SVR was evaluated., Results: The area under the receiver operating characteristics (ROC) curve was 0.852 for 4-week reduction and 0.826 for 12-week reduction of HCV RNA levels, respectively. When the cut-off is fixed at a 2.8-log(10) reduction at 4 weeks and a 4.9-log(10) reduction at 12 weeks on the basis of ROC analysis, the sensitivity and specificity for SVR were 80.9% and 77.9% at 4 weeks and were 89.0% and 67.2% at 12 weeks, respectively. These variables were independent factors associated with SVR in multivariate analysis. Among 99 patients who showed a delayed virologic response and completed 72-week extended regimen, the area under ROC curve was low: 0.516 for 4-week reduction and 0.482 for 12-week reduction of HCV RNA levels, respectively., Conclusions: The reduction in HCV RNA levels 4 and 12 weeks after starting combination therapy is a strong independent predictor for SVR overall. These variables were not useful for predicting SVR in patients who showed a slow virologic response and experienced 72-week extended regimen.

Unlabelled: Innate immunity plays an important role in host antiviral response to hepatitis C viral (HCV) infection. Recently, single nucleotide polymorphisms (SNPs) of IL28B and host response to peginterferon α (PEG-IFNα) and ribavirin (RBV) were shown to be strongly associated. We aimed to determine the gene expression involving innate immunity in IL28B genotypes and elucidate its relation to response to antiviral treatment. We genotyped IL28B SNPs (rs8099917 and rs12979860) in 88 chronic hepatitis C patients treated with PEG-IFNα-2b/RBV and quantified expressions of viral sensors (RIG-I, MDA5, and LGP2), adaptor molecule (IPS-1), related ubiquitin E3-ligase (RNF125), modulators (ISG15 and USP18), and IL28 (IFNλ). Both IL28B SNPs were 100% identical; 54 patients possessed rs8099917 TT/rs12979860 CC (IL28B major patients) and 34 possessed rs8099917 TG/rs12979860 CT (IL28B minor patients). Hepatic expressions of viral sensors and modulators in IL28B minor patients were significantly up-regulated compared with that in IL28B major patients (≈ 3.3-fold, P < 0.001). However, expression of IPS-1 was significantly lower in IL28B minor patients (1.2-fold, P = 0.028). Expressions of viral sensors and modulators were significantly higher in nonvirological responders (NVR) than that in others despite stratification by IL28B genotype (≈ 2.6-fold, P < 0.001). Multivariate and ROC analyses indicated that higher RIG-I and ISG15 expressions and RIG-I/IPS-1 expression ratio were independent factors for NVR. IPS-1 down-regulation in IL28B minor patients was confirmed by western blotting, and the extent of IPS-1 protein cleavage was associated with the variable treatment response., Conclusion: Gene expression involving innate immunity is strongly associated with IL28B genotype and response to PEG-IFNα/RBV. Both IL28B minor allele and higher RIG-I and ISG15 expressions and RIG-I/IPS-1 ratio are independent factors for NVR., (Copyright © 2011 American Association for the Study of Liver Diseases.)

Background: Treatment of genotype 1b chronic hepatitis C virus (HCV) infection has been improved by extending peg-interferon plus ribavirin combination therapy to 72 weeks, but predictive factors are needed to identify those patients who are likely to respond to long-term therapy., Methods: We analyzed amino acid (aa) substitutions in the core protein and the interferon sensitivity determining region (ISDR) of nonstructural protein (NS) 5A in 840 genotype 1b chronic hepatitis C patients with high viral load. We used logistic regression and classification and regression tree (CART) analysis to identify predictive factors for sustained virological response (SVR) for patients undergoing 72 weeks of treatment., Results: When patients were separately analyzed by treatment duration using multivariate logistic regression, several factors, including sex, age, viral load, and core aa70 and ISDR substitutions (P = 0.0003, P = 0.02, P = 0.01, P = 0.0001, and P = 0.0004, respectively) were significant predictive factors for SVR with 48 weeks of treatment, whereas age, previous interferon treatment history, and ISDR substitutions (P = 0.03, P = 0.01, and P = 0.02, respectively) were the only significant predictive factors with 72 weeks of treatment. Using CART analysis, a decision tree was generated that identified age, cholesterol, sex, treatment length, and aa70 and ISDR substitutions as the most important predictive factors. The CART model had a sensitivity of 69.2% and specificity of 60%, with a positive predictive value of 68.4%., Conclusions: Complementary statistical and data mining approaches were used to identify a subgroup of patients likely to benefit from 72 weeks of therapy.

Background & Aims: Pegylated interferon and ribavirin (PEG-IFN/RBV) therapy for chronic hepatitis C virus (HCV) genotype 1 infection is effective in 50% of patients. Recent studies revealed an association between the IL28B genotype and treatment response. We aimed to develop a model for the pre-treatment prediction of response using host and viral factors., Methods: Data were collected from 496 patients with HCV genotype 1 treated with PEG-IFN/RBV at five hospitals and universities in Japan. IL28B genotype and mutations in the core and IFN sensitivity determining region (ISDR) of HCV were analyzed to predict response to therapy. The decision model was generated by data mining analysis., Results: The IL28B polymorphism correlated with early virological response and predicted null virological response (NVR) (odds ratio=20.83, p<0.0001) and sustained virological response (SVR) (odds ratio=7.41, p<0.0001) independent of other covariates. Mutations in the ISDR predicted relapse and SVR independent of IL28B. The decision model revealed that patients with the minor IL28B allele and low platelet counts had the highest NVR (84%) and lowest SVR (7%), whereas those with the major IL28B allele and mutations in the ISDR or high platelet counts had the lowest NVR (0-17%) and highest SVR (61-90%). The model had high reproducibility and predicted SVR with 78% specificity and 70% sensitivity., Conclusions: The IL28B polymorphism and mutations in the ISDR of HCV were significant pre-treatment predictors of response to PEG-IFN/RBV. The decision model, including these host and viral factors may support selection of optimum treatment strategy for individual patients., (Copyright © 2010 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.)

The aim of the present study was to clarify the significance of viral factors for pretreatment prediction of sustained virological response to pegylated-interferon (PEG-IFN) plus ribavirin (RBV) therapy for chronic hepatitis C using data mining analysis. Substitutions in the IFN sensitivity-determining region (ISDR) and at position 70 of the HCV core region (Core70) were determined in 505 patients with genotype 1b chronic hepatitis C treated with PEG-IFN plus RBV. Data mining analysis was used to build a predictive model of sustained virological response in patients selected randomly (n = 304). The reproducibility of the model was validated in the remaining 201 patients. Substitutions in ISDR (odds ratio = 9.92, P < 0.0001) and Core70 (odds ratio = 1.92, P = 0.01) predicted sustained virological response independent of other covariates. The decision-tree model revealed that the rate of sustained virological response was highest (83%) in patients with two or more substitutions in ISDR. The overall rate of sustained virological response was 44% in patients with a low number of substitutions in ISDR (0-1) but was 83% in selected subgroups of younger patients (<60 years), wild-type sequence at Core70, and higher level of low-density lipoprotein cholesterol (LDL-C) (≥ 120 mg/dl). Reproducibility of the model was validated (r(2) = 0.94, P < 0.001). In conclusion, substitutions in ISDR and Core70 of HCV are significant predictors of response to PEG-IFN plus RBV therapy. A decision-tree model that includes these viral factors as predictors could identify patients with a high probability of sustained virological response., (Copyright © 2011 Wiley-Liss, Inc.)

Background: Chronic hepatitis C (CHC) genotype 1b patients with high viral load are resistant to peginterferon (PEG-IFN) and ribavirin (RBV) combination therapy, especially older and female patients., Methods: To elucidate the factors affecting early and sustained viral responses (EVR and SVR), 409 genotype 1b patients CHC with high viral loads who had received 48 weeks of PEG-IFN/RBV therapy were enrolled. The amino acid (aa) sequences of the HCV core at positions 70 and 91 and of the interferon sensitivity determining region (ISDR) were analyzed. Host factors, viral factors, and treatment-related factors were subjected to multivariate analysis., Results: Male gender, low HCV RNA load, high platelet count, two or more aa mutations of ISDR, and wild type of core aa 70 were independent predictive factors for SVR. In patients with over 80% adherences to both PEG-IFN and RBV, male gender, mild fibrosis stage, and wild type of core aa 70 were independent predictors for SVR., Conclusions: Independent predictive factors for SVR were: no aa substitution at core aa 70, two or more aa mutations in the ISDR, low viral load, high values of platelet count, mild liver fibrosis and male gender.

Background & Aims: Clinical significance of molecules involving innate immunity in treatment response remains unclear. The aim is to elucidate the mechanisms underlying resistance to antiviral therapy and predictive usefulness of gene quantification in chronic hepatitis C (CH-C)., Methods: We conducted a human study in 74 CH-C patients treated with pegylated interferon alpha-2b and ribavirin and 5 nonviral control patients. Expression of viral sensors, adaptor molecule, related ubiquitin E3-ligase, and modulators were quantified., Results: Hepatic RIG-I, MDA5, LGP2, ISG15, and USP18 in CH-C patients were up-regulated at 2- to 8-fold compared with nonhepatitis C virus patients with a relatively constitutive Cardif. Hepatic RIG-I, MDA5, and LGP2 were significantly up-regulated in nonvirologic responders (NVR) compared with transient (TR) or sustained virologic responders (SVR). Cardif and RNF125 were negatively correlated with RIG-I and significantly suppressed in NVR. Differences among clinical responses in RIG-I/Cardif and RIG-I/RNF125 ratios were conspicuous (NVR/TR/SVR = 1.3:0.6:0.4 and 2.3:1.3:0.8, respectively). Like viral sensors, ISG15 and USP18 were significantly up-regulated in NVR (4-fold and 2.3-fold, respectively). Multivariate and receiver operator characteristic analyses revealed higher RIG-I/Cardif ratio, ISG15, and USP18 predicted NVR. Lower Cardif in NVR was confirmed by its protein level in Western blot. Also, transcriptional responses in peripheral blood mononuclear cells to the therapy were rapid and strong except for Cardif in not only a positive (RIG-I, ISG15, and USP18) but also in a negative regulatory manner (RNF125)., Conclusions: NVR may have adopted a different equilibrium in their innate immune response. High RIG-I/Cardif and RIG-I/RNF125 ratios and ISG15 and USP18 are useful in identifying NVR.

Background/aims: To elucidate whether ribavirin acts as a mutagen in the clinical setting and to clarify the relationship between ribavirin-induced mutations and virological response to combined therapy., Methods: Thirty-four patients with hepatitis C virus (HCV) genotype 1b received ribavirin monotherapy for 4 weeks, followed by a 24-week course of IFN/ribavirin therapy. HCV mutations during a non-treatment observation period and during subsequent ribavirin monotherapy were determined, and the relationship between mutations and response to subsequent IFN/ribavirin therapy was evaluated., Results: Serum HCV significantly decreased from 6.90 to 6.56 log10copy/ml in response to ribavirin monotherapy (P < 0.0001). Nucleotide mutations in the NS5A and NS5B regions occurred during ribavirin monotherapy at a rate of 2.9 x 10(-2)/site/year and 1.3 x 10(-2)/site/year, respectively, a significantly higher rate than the mutation rates during the prior non-treatment observation period (0.60 x 10(-2)/site/year and 0.24 x 10(-2)/site/year, P = 0.02, respectively). Mutation rates in the NS5A region were significantly higher in sustained viral responders (SVRs, n = 10) than in non-responders (8.8 x 10(-2)/site/year vs. 0.38 x 10(-2)/site/year, P = 0.0005, respectively). In the NS5A region, non-synonymous mutations only occurred in SVRs., Conclusions: Ribavirin may act as a mutagen, and mutations occurring during ribavirin therapy correlate with the virological response to subsequent IFN/ribavirin combination therapy.

Background and Aim: Combination treatments of interferon-alpha (IFN) and ribavirin (RBV) are more effective than those of IFN alone in hepatitis C virus (HCV) infection. However, mechanisms of the action of the combination regimen are not well understood. To elucidate the viral genetic basis of IFN plus RBV combination therapy, genetic variabilities of HCV-1b were analyzed., Methods: We performed pair-wise comparisons of full-length HCV genomic sequences in three patients' sera before and after initiation of IFN plus RBV treatment. Subsequently, we analyzed amino acid sequences of the NS5B region, which codes for the viral RNA-dependent RNA polymerase, and compared these with the outcomes of the therapy in 81 patients., Results: Analysis of the entire HCV sequence in patients who received IFN plus RBV therapy did not show consistent amino acid changes between before and after the initiation of the therapy. NS5B sequence analyses revealed that mutations at positions 300-358 of NS5B, including polymerase motif B to E, occurred more frequently in a group of patients exhibiting a sustained viral response (SVR) or an end-of-treatment response (ETR) compared with a group of patients exhibiting a non-response (NR). Closer examination revealed that mutations at aa 309, 333, 338 and 355 of NS5B occurred significantly more frequently in the SVR plus ETR group than in the NR group (P = 0.0004). Multivariate analysis showed that the number of mutations at these four sites was an independent predictor of SVR plus ETR versus NR., Conclusions: Particular amino acid changes in the NS5B region of HCV may correlate with outcomes of IFN plus RBV combination therapy., (Copyright 2005 Blackwell Publishing Asia Pty Ltd.)

In hepatitis C virus (HCV) genotype 2b infection, viral eradication (sustained viral response; sVR) is obtained in about 40% by interferon monotherapy, whereas a considerable proportion of non-sVR patients exhibit sustained biochemical response (sBR) showing normal biochemical values despite persistent viraemia. However, the mechanism of sBR has not yet been established. In this study, we analysed serial changes in full-length sequences of HCV genotype 2b before and after interferon (IFN) therapy in five patients with sBR and five with no response (NR; persistent viraemia and abnormal biochemical values after IFN therapy). The overall substitution rate of amino acids in the full-length HCV genome was higher in the sBR group than in the NR group [2.22 +/- 0.48 (10(-3) changes/site/year) vs 1.04 +/- 0.30: P = 0.002]. When the genetic changes were analysed for individual HCV proteins, the sBR group had significantly higher substitution rates of amino acid in NS4A [8.82 +/- 2.80 (10(-3) changes/site/year) vs 0: P = 0.001]. These amino acid changes in sBR were mainly located in the binding motifs of HLA class I molecules including those frequently found in the Japanese population. These results demonstrated that the greater amino acid changes of HCV arising during interferon therapy are associated with the establishment of sBR. Although functional significance of these changes awaits further investigation, the finding that amino acid changes in NS4A in sBR patients are mainly located in the HLA class I binding motifs illustrated the potential roles of the escape mutations of HCV genome from CTLs in the decreasing activities of hepatitis in sBR.

Objectives: A high virological response rate can often be shown to be obtained with PEG-IFN alpha-2b and ribavirin combination therapy in chronic hepatitis C patients. Viral dynamics have been utilized for the evaluation of antiviral effects, especially the exponential second decay slope, which represents the elimination of infected cells., Methods: Forty-nine patients were randomly assigned to the IFN alpha-2b group (n = 26) or the PEG-IFN alpha-2b group (n = 23). Ribavirin was administered equally to both groups. Measuring the serum concentration of HCVRNA, the exponential viral decay during phase 1 and 2 was calculated., Results: The exponential decay slope in phase 2 during the first 2 weeks was greater in the IFN alpha-2b group than in the PEG-IFN alpha-2b group; however, from weeks 3 to 4, it was greater in the PEG-IFN alpha-2b group than in the IFN alpha-2b group. Interestingly, in the PEG-IFN alpha-2b group, the exponential decay slope was greater from weeks 3 to 4 after initiating combination therapy than during the weeks 1-2 (p < 0.01), despite administration of the same PEG-IFN alpha-2b dose (1.5 microg/kg once weekly)., Conclusions: In PEG-IFN alpha-2b and ribavirin combination therapy, elimination of infected cells may be pronounced following an increase in serum ribavirin concentration in chronic hepatitis C patients with genotype 1b infection and a high viral load., (Copyright 2004 S. Karger AG, Basel)

Background/aims: To address the molecular mechanism for enhanced antiviral efficacy associated with a frequent dosing of interferon (IFN)-beta., Methods: Serum hepatitis C viral (HCV) dynamics, double-stranded RNA-activated protein kinase (PKR) mRNA and MxA mRNA levels in peripheral blood mononuclear cells (PBMC) were analyzed serially in 140 patients who were randomly assigned to a twice daily (3 MU bid) or once daily (6 MU qd) administration group., Results: In twice daily group, the rate of HCV decline during the second phase was 2-fold greater than in the once daily group (P=0.04). Peak PKR and MxA gene expression levels in the first phase (observed 4 h after a single administration) were 2-fold higher in the once daily group. However, the expression in the second phase was maintained at a significantly higher level in the twice daily group. Initial and peak expression levels were related to initial viral load. Basal expressions in PBMC were significantly correlated with those in the liver tissue (PKR, r=0.81; MxA, r=0.75, respectively, P<0.0001)., Conclusions: Our data suggest that elimination of HCV-infected cells is enhanced by twice daily dosing of IFN-beta, and that this enhanced effect is associated with a higher intracellular expression of PKR and MxA during the second phase.

The correlation between hepatitis C virus (HCV) genomic sequences and circulating HCV RNA levels was assessed to investigate the genetic elements affecting viral load. The interferon sensitivity-determining region (ISDR) sequence and the serum viral load were strongly correlated in 226 patients examined. Analysis of the entire HCV genome from six patients (three with a high and the others with a low viral load) with similar ISDR sequences identified several candidate residues associated with viral load. The amino acid (aa) sequences of these candidate residues and flanking regions in 67 additional patients revealed that only the residue at aa 962 varied significantly between the HCV patients with low and high serum loads (P=0.042). At this position, alanine was observed more frequently in the patients with a high viral load. In conclusion, our results strongly suggest that serum HCV RNA loads are inversely correlated with amino acid substitutions in the ISDR, and aa 962 was identified as a possible second determinant of serum HCV RNA load.

Hepatitis C virus (HCV) is known to infect and replicate within peripheral blood mononuclear cells (PBMC), thereby enabling the direct evaluation of antiviral mechanisms by analyzing HCV dynamics in PBMC. To address potential molecular differences associated with distinct antiviral regimens, we studied HCV dynamics in both serum and PBMC in 44 patients with HCV genotype 1b and high viral load who were randomly assigned to the following 4 different treatment groups: 1) combination therapy with 6 MU daily of interferon alfa 2b (IFN-alpha2b) plus 800 mg of ribavirin; 2) monotherapy with 6 MU daily of IFN-alpha2b; 3) monotherapy with twice-daily intravenous administration with 3MU of IFN-beta; and 4) monotherapy with daily intravenous administration with 6 MU of IFN-beta. HCV-RNA levels were measured serially using highly sensitive real-time detection polymerase chain reaction (PCR). HCV dynamics in both the serum and PBMC showed a "biphasic" pattern. The exponential decay slopes of the second phase were significantly higher in the combination or twice-daily dosing regimen groups compared with groups 2 or 4 (0.10 +/- 0.08 vs. 0.02 +/- 0.09 or 0.16 +/- 0.09 vs. 0.02 +/- 0.04 day(-1); P <.05 or P <.0005, respectively). Moreover, the viral half-lives in the second phase were significantly shorter in these groups (73.2 +/- 42.5 vs. 240.1 +/- 120.7 or 56.0 +/- 44.6 vs. 361.6 +/- 293.5 hours; P <.05 or P <.05, respectively). Additionally, the slope of HCV decline in PBMC tended to be higher in the combination regimens, as compared with monotherapy. Taken together, our data on HCV dynamics provide molecular insight into utilization of combination or twice-daily dosing regimens to increase rates of sustained viral eradication of HCV.

Background and Aims: Chronic hepatitis C is a slowly progressive disease and eventually causes hepatocellular carcinoma in many patients. Although interferon (IFN) therapy has been used for viral eradication, its success rate is only about 30%. In patients in whom it has failed (non-responders), there are several patterns of serum alanine aminotransferase (ALT) values, and detection of serum HCV-RNA during and after IFN therapy and improved long term prognosis were reported in patients whose serum ALT values were normalised by IFN therapy even if HCV viraemia persisted. The present study sought to clarify the virological characteristics contributing to these differences., Methods: Complete or partial length dominant sequences of hepatitis C virus genotype 1b (HCV-1b) were determined by direct sequencing. Firstly, the complete sequences of HCV-1b genomes were determined in six non-responders; three showed normalisation of serum ALT values during IFN-alpha therapy and the other three did not. Subsequently, the amino acid residues that were different in the two groups were further analysed retrospectively in another 82 patients., Results: Comparison of the sequences suggested an association between amino acids 2154-2172 of HCV-1b and serum ALT normalisation. A retrospective analysis of 82 patients revealed that the number of amino acid substitutions in this region was the only statistically significant variable associated with ALT normalisation (odds ratio 31.0; 95% confidence interval 5.0-286) in multivariate analyses., Conclusions: A HCV genomic region that correlates with the ALT response to IFN therapy appears to be present in virologically IFN ineffective patients.

To explore the relationship between responses to interferon (IFN) and the mutation patterns in the IFN sensitivity-determining region (ISDR; amino acid positions 2209-2248) in the NS5A gene of hepatitis C virus genotype 1b, a cohort of 334 patients was analyzed. The number of mutations in the ISDR was higher in patients with sustained response (SR) than in patients with transient or no response (P<.001). Patients with viruses mutated at positions 2209 (P=.02), 2216 (P=.01), or 2227 (P=.02) more frequently experienced SR than did those without these mutations. Mutation occurred most frequently at position 2218, where the presence of cysteine was significantly associated with SR. Thus, the mutation pattern in the ISDR affects the virologic response to IFN and reflects different influences on the function of the NS5A protein. ISDR sequence analysis would allow the prediction of clinical IFN efficacy in individual patients.

Virological response to interferon (IFN) is poor in patients with plasma levels of HCV RNA higher than 1 Meq/ml and genotype 1b hepatitis C viral infection. In 60 patients, a randomized control study was conducted to compare 3 MU of IFN-beta twice daily for four weeks (group A) and 6 MU once a day for four weeks (group B) followed by a four-week administration of 6 MU once a day. The plasma levels of HCV RNA, determined by an amplicore-monitor method, for patients in group A were significantly lower than those for group B at the fourth and eighth day of IFN administration, and complete virological responses were noted in two patients from group A but none in group B. It is concluded that twice daily administration of 3 MU IFN-beta is more effective than once a day 6 MU in the early phase of IFN therapy.

The activity of hepatitis varies in chronic hepatitis C virus (HCV) infection. Some patients show persistently normal serum alanine aminotransferase (ALT) values, whereas the others show high-ALT values and progress to liver cirrhosis or hepatocellular carcinoma. However, virological mechanisms causing hepatitis have not fully been elucidated. We analyzed serial changes in full-length HCV sequences in 10 patients with various profiles of hepatitis activity. In the nonstructural 5A (NS5A) and NS5B, the rate of amino acid changes, as well as the proportion of nonsilent ones, was low in patients with normal ALT values compared with those with abnormal ALT (for the rate of amino acid changes, 0 x 10(-3) vs 3.19 x 10(-3) changes/site/year (P = 0.037) in NS5A and 0 x 10(-3) vs 1.22 x 10(-3) changes/site/year (P = 0.023) for NS5B, for the proportion of nonsilent changes, 4 vs 22% (P = 0.017) in NS5A and 0 vs 16% (P = 0. 039) in NS5B). Also, the flare-up of hepatitis coincided with higher nucleotide/amino acid substitution rates in NS5B. In conclusion, the genomic structures of the NS5A and NS5B regions may correlate with hepatitis activity in chronic hepatitis C., (Copyright 1999 Academic Press.)

A close correlation was reported between amino acid mutations in the nonstructural protein 5A (interferon [IFN] sensitivity-determining region [ISDR]) of hepatitis C virus (HCV)-1b and the response to IFN therapy. The dynamic change of ISDR quasispecies during IFN treatment was investigated in 22 patients. In 18 nonresponders, the number of ISDR mutations in major quasispecies decreased after therapy (P=.039). In each nonresponder, the percentage of wild-type (no mutations in the ISDR) quasispecies increased after treatment (P=.008), whereas the percentages of intermediate- (1-3 mutations) and mutant-type (>/=4 mutations) quasispecies decreased (P=.037 and P=.043, respectively). No mutant-type quasispecies were detected after therapy. Four complete responders had only quasispecies with >/=3 mutations before therapy. Thus, HCVs have fewer mutations in the ISDR after IFN therapy than those before therapy. These IFN-resistant HCVs were already present before therapy as minor quasispecies and were selected by IFN in nonresponders.

An association has been reported between mutations in the amino acid residues 2209-2248 of the nonstructural protein 5A (NS5A) gene (interferon-sensitivity determining region [ISDR]) and interferon efficacy in hepatitis C virus (HCV)-1b infection. This relationship was analyzed in chronic HCV-2 infection. Forty patients with HCV-2a and 35 with HCV-2b were treated with interferon alfa for 6 months with a total dose of 468 to 860 million units. Pretreatment NS5A sequences were determined by direct sequencing. A higher complete and sustained response rate was observed in HCV-2a than in HCV-2b (70% vs. 34%; P =.003). Serum HCV-RNA levels were lower in complete responders than nonresponders in HCV-2a (P =.049) and HCV-2b (P =. 02). The number of amino acid mutations was greater in complete responders than nonresponders in NS5A2193-2228 (the region corresponding to the ISDR of HCV-1b) alone (P =.049), or NS5A2163-2228 consisting of NS5A2193-2228 plus its upstream region (P =.02) in HCV-2a, but not in HCV-2b. A significant inverse correlation was observed between serum HCV-RNA levels and the number of amino acid mutations in NS5A2193-2228 (P =.003) or NS5A2163-2228 (P =.005) in HCV-2a. With multivariate analysis, the number of substitutions in NS5A was an independent predictor for complete response in HCV-2a (odds ratio: 6.4; P =.03). Interferon efficacy is associated with amino acid variations in the NS5A protein in HCV-2a infection.

The extreme 5'-proximal sequences of the hepatitis C virus (HCV) genome including the 5'untranslated region (5'UTR) and the first 30 nucleotides of the core region are highly conserved, and serve as an internal ribosome entry site (IRES) that initiates the cap-independent translation of HCV polyprotein. Mutations in the IRES sequence have been shown to cause changes in the efficiency of protein translation in vitro. However, the significance of genetic variations in the IRES is not fully known in clinical settings. Pretreatment sera of 25 patients with HCV-1b infection who were treated with interferon were amplified by polymerase chain reaction (PCR), and the IRES sequence was directly sequenced. Correlation of interferon responses or other clinical features with IRES sequence variability was studied. Eleven of 25 patients were sustained responders (SR) of interferon treatment (negative serum HCV RNA and normal alanine transaminase levels for 6 months after the end of interferon treatment), and the other 14 patients were nonresponders ([NR], defined as any patient with positive serum HCV RNA within 6 months after the end of interferon therapy). In each patient, one to four nucleotide substitutions were found compared with the consensus sequence of HCV-1b genotype. There were no differences in the number of nucleotide substitutions between either SR and NR (mean, 1.8 in SR, 2.1 in NR; P = .30), and no specific variations associated with SR or NR were observed. Although NR had significantly higher serum levels of pretreatment HCV RNA than SR (median, 16 vs. <0.5 Meq/mL; P = .02), there was no correlation between the HCV-RNA level and the number of nucleotide substitutions in the IRES (mean, 1.9 nucleotide substitutions in 12 patients with HCV RNA <0.5 Meq/ mL vs. 2.1 nucleotide substitutions in 13 patients with HCV RNA >0.5 Meq/mL; P = .61). Sequence variability of the IRES has no influence on interferon efficacy or serum HCV-RNA concentrations in patients with chronic HCV-1b infection.

In chronic hepatitis C virus (HCV) infection, genotypes other than genotype 1b of HCV (HCV-1b) and low serum HCV-RNA levels are known to be associated with favorable outcome of interferon alfa (IFN-alpha) therapy. In addition, we recently reported a close correlation between the number of mutations in amino acid sequences 2209 to 2248 of the nonstructual protein 5A gene (NS5A2209-2248) of HCV-1b and the response to IFN-alpha. In the present study, we analyzed these viral factors in relation to the efficacy to IFN-beta, another type I IFN. The pretreatment sera of 40 patients treated with IFN-beta intravenously at 6 MU daily for 42 days were studied. HCV genotypes, serum HCV-RNA levels, and the amino acid sequence of NS5A2209-2248 in HCV-1b were determined. A sustained complete response to IFN therapy occurred in none of the ten patients with the wild-type HCV-1b who had an NS5A2209-2248 sequence identical to the prototype HCV-1b and in none of the six patients with the intermediate-type HCV-1b that had 1 mutation. In contrast, complete responses occurred in the following: 4 of 6 patients with the mutant-type HCV-1b that had five to ten mutations; 6 of 13 patients with genotype 2a of HCV (HCV-2a); and 2 of 5 patients with genotype 2b of HCV (HCV-2b). Among patients with the mutant-type HCV-1b or genotype 2 of HCV (HCV-2) the rate of complete response was significantly higher (12 of 24 vs. 0 of 16 patients, P < .001) and HCV-RNA levels were significantly lower (4.5 [4.0-6.5] vs. 6 [4.5-6.5] log copies/mL, median [range]; P < .001) compared with patients with the wild- or the intermediate-type HCV-1b. Patients with the mutant-type HCV-1b or HCV-2 whose HCV-RNA levels were lower than 6 log copies/mL had a complete response rate of 75% (12 of 16 patients) in contrast to 0% (0 of 24 patients) of the others (P < .001). These results indicate that the mutant-type HCV-1b or HCV-2 are sensitive to IFN-beta as well as IFN-alpha. In conclusion, the determination of HCV genotypes, NS5A2209-2248 of HCV-1b and serum HCV-RNA levels may facilitate the selection of patients with a high likelihood of response to IFN-beta.

Recent reports have shown that response to interferon treatment is influenced by hepatic iron contents in patients with chronic hepatitis C. In those reports, however, hepatitis C virus (HCV) genotypes and serum HCV-RNA levels were not examined. The aim of the present study was to investigate whether hepatic iron contents influence the response to interferon in patients with chronic hepatitis C and whether HCV genotypes and serum HCV-RNA levels play a role in this relationship. Among 65 patients with chronic hepatitis C, hepatic iron contents were significantly high in patients with a history of excess drinking of alcohol (more than 80 g/day) compared to those without, and significantly low in female patients before menopause. Having excluded these patients, hepatic iron contents were significantly higher in patients with genotype 1b infection than those with genotype 2a and 2b infection. There was no significant correlation between hepatic iron contents and plasma HCV-RNA levels. Among the patients with genotype 1b infection, hepatic iron contents were significantly lower in the responders to interferon than those in the nonresponders (429 +/- 100 vs 875 +/- 110 micrograms/g liver, P < 0.05). From these results, it is concluded that response to interferon is mainly influenced by HCV genotypes, while hepatic iron contents may play an important role in response to interferon in patients with genotype 1b infection.

Background: A region associated with sensitivity to interferon has been identified in the nonstructural protein 5A (NS5A) of hepatitis C virus (HCV) genotype 1b. The region spans amino acid residues 2209 to 2248 (NS5A2209-2248) of HCV-J, a strain of HCV-1b whose complete genomic sequence has been identified. We examined whether the NS5A2209-2248 sequence present before therapy could be used as a predictor of the response to interferon therapy in patients with chronic HCV-1b infection., Methods: We retrospectively analyzed 84 patients with chronic HCV-1b infection who had received interferon alfa (total dose, 516 million to 880 million units) for six months. Pretreatment serum samples were analyzed. The amino acid sequence of NS5A2209-2248 was determined by direct sequencing of the HCV genome amplified by the polymerase chain reaction (PCR) and was compared with the established sequence for HCV-J., Results: A complete response, as evidenced by the absence of HCV RNA in serum on nested reverse-transcription PCR for six months after therapy, did not occur in any of the 30 patients whose NS5A2209-2248 sequences were identical to that of HCV-J (wild type). Five of 38 patients (13 percent) with 1 to 3 changes in NS5A2209-2248 (intermediate type) had complete responses, as did all 16 patients with 4 to 11 amino acid substitutions (mutant type), indicating that the mutant type was significantly associated with a complete response (P < 0.001). Although baseline serum HCV RNA levels, as measured by a branched-chain DNA assay, were lower in patients with the mutant type of NS5A2209-2248 than in those with the other types (P < 0.001), multivariate analyses revealed that the number of amino acid substitutions in NS5A2209-2248 was the only variable associated with an independent effect on the outcome of interferon therapy (odds ratio, 5.3; 95 percent confidence interval, 1.6 to 18; P = 0.007)., Conclusions: In patients with chronic HCV-1b infection, there is a substantial correlation between responses to interferon and mutations in the NS5A gene.

We have previously demonstrated that sensitivity to interferon is different among hepatitis C virus (HCV) quasispecies simultaneously detected in same individuals and that interferon-resistant HCV quasispecies are selected during the treatment. To determine the genetic basis of their resistance to interferon, HCV genotype-1b was obtained from serum of three patients before and during interferon therapy, and their full-length nucleotide and deduced amino acid sequences were determined. Comparison of the pairs of interferon-resistant and interferon-sensitive HCV isolates in respective individuals demonstrated clusters of amino acid differences in the COOH-terminal half of the NS5A region (codon 2154-2383), which contained a common unique amino acid difference at codon 2218. Additional sequence data of the COOH-terminal half of the NS5A region obtained from six interferon-resistant and nine interferon-sensitive HCV confirmed the exclusive existence of missense mutations in a 40 amino acid stretch of the NS5A region around codon 2218 (from codon 2209 to 2248) in interferon-sensitive HCV. On the other hand, this region of interferon-resistant HCV was identical to that of prototype HCV genotype-1b (HCV-J, HCV-JTa, or HC-J4). We designated this region as the interferon sensitivity determining region. Thus, HCV genotype-1b with the prototype interferon sensitivity determining region appears to be interferon-resistant strains. The specific nature of these mutations might make it possible to predict prognostic effects of interferon treatment.

Although persistent hepatitis C virus infection is closely associated with the development of hepatocellular carcinoma, the nature of hepatitis C virus replication in the hepatocellular carcinoma tissue has not been fully characterized. To study this, carcinoma and non-carcinoma tissues were obtained from five patients with hepatocellular carcinoma. Total RNA was recovered from each tissue, and a portion of the envelope gene of replicating hepatitis C virus was amplified by minus-strand-specific reverse transcription and nested polymerase chain reaction. The amplified cDNA was examined by single strand conformation polymorphism analysis and sequencing. Hepatitis C virus replication was detected in both carcinoma and non-carcinoma tissues in four patients who were positive for serum hepatitis C virus markers. In one patient, a single species with identical envelope 2 genome was obtained from both carcinoma and non-carcinoma tissues. In the other three patients, the replicating hepatitis C virus existed as a mixture of 2-5 species with different but highly homologous (82-99%) envelope 2 genomes (quasispecies populations). The constitution of viral populations was different between carcinoma and non-carcinoma tissues. A total of ten sequences were recovered; four sequences were found in both tissues, two were found in carcinoma tissues, and four were found in non-carcinoma tissues. The difference in the constitution of quasispecies populations between carcinoma and non-carcinoma tissues confirms the unequivocal replication of hepatitis C virus in both tissues, and may imply the presence of different biological properties among hepatitis C virus with different sequences.