Variations in the viral NS5B region in Japanese patients with chronic hepatitis C virus genotype 1b infection. No specific amino acid substitution was identified as determinants of treatment response to interferon/ribavirin combination therapy

OBJECTIVE: A recent study suggested that the substitution of amino acid 415 of HCV NS5B from phenylalanine to tyrosine in patients with HCV genotype 1a infection is induced by ribavirin and responsible for resistance to ribavirin therapy. The aim of this study was to evaluate whether specific variations in the HCV NS5B sequence in Japanese patients with HCV genotype 1b (HCV/1b) infection are associated with treatment response or selected by treatment with interferon-alpha/ribavirin combination therapy. METHODS: Eighteen Japanese patients with HCV/1b infection receiving interferon-alpha/ribavirin combination therapy for 24 weeks were studied. Five patients treated with interferon-alpha monotherapy for 24 weeks were also studied as controls. The entire HCV NS5B sequence before and after therapy was determined. RESULTS: All HCV isolates had tyrosine at position 415 of NS5B before and after therapy. Further analysis showed that no specific amino acid substitutions were identified to associate with clinical response and no specific amino acid substitutions were induced/selected by the clinical treatment. CONCLUSION: No specific HCV NS5B nucleotide/amino acid sequence variations, including amino acid 415 of NS5B, were identified as being associated with clinical treatment response or selected by the combination therapy in Japanese patients with HCV/1b infection.     

Usefulness of a new immunoradiometric assay of HCV core antigen to predict virological response during PEG-IFN/RBV combination therapy for chronic hepatitis with high viral load of serum HCV RNA genotype 1b

We investigated the clinical usefulness of a new immunoradiometric (IRM) assay of hepatitis C virus (HCV) core antigen in predicting virological response during pegylated interferon plus ribavirin (PEG-IFN/RBV) combination therapy for chronic hepatitis with high viral loads of serum HCV RNA genotype 1b. Thirty-nine patients received a regimen of PEG-IFNalpha-2b (1.5 microg/kg/week s.c.) in combination with RBV (600-1,000 mg/day). Of the 39 patients, 18 (46.2%) achieved sustained virological response (SVR), 11 (28.2%) attained partial response (PR) and 10 (25.6%) showed no response (NR). Four weeks after the start of therapy, 1- and 2-log reductions in the amount of HCV core antigen were observed in 20 (2/10) and 0% (0/10) showing NR, 91 (10/11) and 63.6% (7/11) with PRs, and 88.9 (16/18) and 55.6% (10/18) of patients with SVR, respectively. The 1- and 2-log reductions 4 weeks after the start of therapy were not a defining condition for PR and SVR. The amount of HCV core antigen was significantly different between SVR and PR patients on days 1 and 7, and between patients with NR and SVR at all points of time. In conclusion, this new IRM assay is useful in predicting virological response during PEG-IFN/RBV therapy.     

Achievement of sustained viral response after switching treatment from pegylated interferon α-2b to α-2a and ribavirin in patients with recurrence of hepatitis C virus genotype 1 infection after liver transplantation: a case report

We report a case in which sustained viral response was achieved after switching treatment from pegylated interferon (PEG-IFN) α-2b to α-2a and ribavirin (RBV) in patients with recurrence of hepatitis C virus (HCV) infection after living donor liver transplantation. The patient was a 62-year-old man with liver cirrhosis due to HCV genotype 1b infection. The patient had 8 amino acid (aa) substitutions in the interferon sensitivity-determining region, and had substitutions for mutant and wild-type at aa70 and aa91, respectively, in the core region. The patient had minor genotype (GG) IL28B single nucleotide polymorphisms (rs8099917). He had initially received interferon α-2b and RBV for 2 years, and later developed hepatocellular carcinoma (HCC). After surgical resection of HCC, he subsequently received PEG-IFN α-2b and RBV for 1.5 years, without undetectable viremia during the treatment course. Due to recurrence of HCC, the patient received a living donor liver transplantation. Later on, hepatitis C relapsed. For the management of relapse, he received another course of PEG-IFN α-2b and RBV. However, breakthrough viremia occurred. PEG-IFN was thus switched from α-2b to α-2a and RBV for another 17 months. The patient eventually achieved a sustained viral response.     

Genetic variation in BCL-2 and response to interferon in hepatitis C virus type 4 patients

The prevalence of hepatitis C virus (HCV) infection varies across the world, with the highest number of infections reported in Egypt. BCL-2 gene polymorphism at codon 43 (127G/A) has been found to be a reliable and sensitive marker for the prediction of response to interferon therapy during viral infections. This study examined the correlation of BCL-2 gene polymorphism with the response to treatment with pegylated-IFN-alfa2b and ribavirin. Eighty patients with type 4 HCV and 40 healthy volunteers as controls were enrolled in a prospective study. Quantification of HCV-RNA by real-time PCR was performed for every patient, and gene polymorphism of BCL-2 (ala 43 Thr) was performed for all patients and controls. There was a statistically significant difference between non-responder patients and control group as regards the 43Thr genotype and allele (P<0.05). Also, there was a statistically significant difference between responders and non-responders (P<0.05) as regards 43Thr genotype and alleles. We conclude that BCL-2 gene polymorphism at codon 43 (127G/A) is a new biological marker to potentially identify responders and non-responders of HCV genotype 4 patients to achieving a sustained virological response to treatment with IFN in combination with ribavirin.     

Viral etiology of hepatocellular carcinoma and HCV genotypes in Taiwan

Etiologic variations of hepatocellular carcinoma (HCC) exist in different geographic areas of the world. Hepatitis B virus infection is associated with HCC. However, hepatitis C virus (HCV) infection plays an increasingly more important role in the development of HCC and is associated with more than 30% of HCC in Taiwan. The prevalence of HCV infection and HCV genotypes vary in different geographic areas. The prevalence of HCV genotype 1b (HCV-1b) was around 50-70% in Taiwan and even varied in different townships. In addition to host factors, HCV genotypes may be associated with the development of HCC. In our study, the prevalence of HCV-1b in patients with HCC was significantly higher than in those with liver cirrhosis and chronic hepatitis; multivariate analysis revealed that the disease severity was significantly correlated with age and HCV-1b. Furthermore, HCV-1b was associated with a lower response rate to interferon (IFN) therapy than HCV-2. Our study has demonstrated that mutations in the IFN sensitivity-determining region, spanning nucleotides 2,209-2,248 in the NS5A region, correlate with the sustained virological response to combination therapy with IFN and ribavirin in patients with chronic HCV-1b infection in Taiwan. A third-generation enzyme immunoassay for antibody to HCV can be used to predict viremia and monitor the virological response.     

Interferon resistance and ISDR (interferon sensitivity determining region)

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). While complete response was not obtained in the patients with HCV whose NS5A2209-2248 sequences were identical to that of HCV-J (wild type), all patients with HCV of 4 to 11 amino acid substitutions (mutant type) achieved complete response. We designed this region as the interferon sensitivity determining region(ISDR). Recently, a subgenomic HCV replicon system was established, and reported to replicate efficiently and continuously in human hepatoma Huh-7 cells. However, HCV replicon needs amino acid mutation, called as adaptive mutations, in NS5A for efficient replication. These findings demonstrate that the genetic structure of the NS5A domain is critical in HCV replication.     

Impact of ribavirin exposure on early virological response to hepatitis C therapy in HIV-infected patients with chronic hepatitis C

BACKGROUND: The use of pegylated interferon (PEG-IFN) plus ribavirin (RBV) is currently the recommended treatment for chronic hepatitis C virus (HCV) infection. Coinfection with HIV is a negative predictor of response, for reasons not well understood. METHODS: We examined the virological response at weeks 4 and 12 in 198 HCV/HIV-coinfected patients enrolled in a prospective trial in which PEG-IFN alpha 2a (180 microg per week) and RBV (1000-1200 mg daily) were provided. RESULTS: In an on-treatment analysis, 52.8% of patients achieved undetectable HCV-RNA (<600 IU/ml) at week 4, while 63% and 77.2% of patients had a decline of at least 2 and 1 log10, respectively. At week 12, 73.1% of patients reached undetectable HCV-RNA, and 83.5% and 89% achieved at least a 2- and 1-log10 drop, respectively. More than 85% of HCV genotypes 2/3 cleared HCV-RNA at week 4, a proportion significantly higher when compared with genotypes 1 (33.8%) and 4 (28.6%). Multivariate logistic regression analysis identified genotype 3 and RBV exposure (mg/kg of body weight) as independent predictors of virological response at week 12 of therapy. CONCLUSION: Early virological response rates to PEG-IFN plus RBV in HCV/HIV-coinfected patients seem to be similar to those reported for HCV-monoinfected subjects. The use of suboptimal doses of RBV in most earlier trials might account for the low response rates seen in coinfected patients. To our knowledge, this is the first report demonstrating that RBV exerts a significant independent effect on early virological response. Therefore, strategies aimed at optimizing doses and adherence to RBV might help to improve responses to HCV therapy in coinfected patients.     

Sustained negativity for HCV-RNA over 24 or more months by long-term interferon therapy correlates with eradication of HCV in patients with hepatitis C virus genotype 1b and high viral load

OBJECTIVE: We assessed whether sustained negativity for HCV-RNA over 24 or more months by long-term interferon (IFN) therapy correlates with eradication of HCV in patients with hepatitis C virus genotype 1b and high viral load or not. METHODS: The number of patients with HCV-genotype 1b and high viral load exceeding 1 Meq/ml who received 6 MU of natural IFN-alpha daily for 2-8 weeks, followed by three times/week for 16-22 weeks and negativity for HCV-RNA during IFN administration was 403. Forty-one of 403 patients received 6 MU of natural IFN-alpha three times/week for more than 18 months after the initial IFN therapy (long-term-IFN-group). Three hundred and two patients did not receive any IFN treatment for 6 months after the termination of the 6-month course (6-month-IFN-group). Sustained virological response (SVR) was defined as negative HCV-RNA at both 3 and 6 months after the completion of IFN therapy. RESULTS: SVR was noted in 73.2% (30/41) of long-term-IFN-group and 18.2% (55/302) of 6-month-IFN-group. Multivariate analysis showed that long-term IFN therapy was the most significant contributor to SVR (p < 0.0001). CONCLUSION: Sustained negativity of HCV-RNA for 24 or more months by long-term IFN therapy correlated with SVR in patients with genotype 1b and high viral load.     

Resistance analysis of the hepatitis C virus NS3 protease inhibitor asunaprevir

Asunaprevir (BMS-650032) is a potent hepatitis C virus (HCV) NS3 protease inhibitor demonstrating efficacy in alfa interferon-sparing, direct-acting antiviral dual-combination regimens (together with the NS5A replication complex inhibitor daclatasvir) in patients chronically infected with HCV genotype 1b. Here, we describe a comprehensive in vitro genotypic and phenotypic analysis of asunaprevir-associated resistance against genotypes 1a and 1b using HCV replicons and patient samples obtained from clinical studies of short-term asunaprevir monotherapy. During genotype 1a resistance selection using HCV replicons, the primary NS3 protease substitutions identified were R155K, D168G, and I170T, which conferred low- to moderate-level asunaprevir resistance (5- to 21-fold) in transient-transfection susceptibility assays. For genotype 1b, a higher level of asunaprevir-associated resistance was observed at the same selection pressures, ranging from 170- to 400-fold relative to the wild-type control. The primary NS3 protease substitutions identified occurred predominantly at amino acid residue D168 (D168A/G/H/V/Y) and were associated with high-level asunaprevir resistance (16- to 280-fold) and impaired replication capacity. In asunaprevir single-ascending-dose and 3-day multiple-ascending-dose studies in HCV genotype 1a- or 1b-infected patients, the predominant pre-existing NS3 baseline polymorphism was NS3-Q80K. This substitution impacted initial virologic response rates in a single-ascending-dose study, but its effects after multiple doses were more ambiguous. Interestingly, for patient NS3 protease sequences containing Q80 and those containing K80, susceptibilities to asunaprevir were comparable when tested in an enzyme assay. No resistance-associated variants emerged in these clinical studies that significantly impacted susceptibility to asunaprevir. Importantly, asunaprevir-resistant replicons remained susceptible to an NS5A replication complex inhibitor, consistent with a role for asunaprevir in combination therapies.     

Amino acid variations in hepatitis C virus p7 and sensitivity to antiviral combination therapy with amantadine in chronic hepatitis C

BACKGROUND: Formation of transmembrane ion channels by hepatitis C virus (HCV) p7 and abrogation of channel function by amantadine was demonstrated in vitro. The relevance of HCV p7 amino acid (aa) variations for response to antiviral therapy with amantadine is unknown. METHODS: HCV p7 was sequenced in 86 individuals who were infected with HCV genotype 1. Thirty-six of 86 patients received amantadine within an interferon-alpha (IFN-alpha)-based antiviral therapy. Helical wheel modelling for HCV p7 was performed. RESULTS: No significant correlation of overall aa variations within HCV p7 was observed with response to IFN-alpha-based therapy with amantadine in HCV genotype 1alpha/b infected patients. When analysis was restricted to non-conservative aa variations, a higher number of aa substitutions within complete HCV p7 and transmembrane helix 2 was associated with non-response in HCV-1b-infected patients receiving therapy with amantadine (P=0.015 and P=0.037, respectively), without amantadine (P=0.106 and P=0.118, respectively), and in the total cohort of HCV-1b-infected patients (P=0.00007 and P=0.011, respectively). Furthermore, substitution L20F was observed more often in non-responders than responders with HCV-1b infection and therapy with amantadine (P=0.099). By in silico modelling, aa 20 was located toward the p7 channel lumen. Substitution L20F may impair amantadine action by altering the shape of the ion channel pore. CONCLUSION: Substitution L20F within HCV p7 may be associated with non-response to combination therapy specifically with amantadine in HCV-1b-infected patients. Non-responders with HCV-1b infection showed higher numbers of non-conservative aa variations within HCV p7 than responders, irrespective of the application of amantadine.     

Open, randomized, multicentre italian trial on PEG-IFN plus ribavirin versus PEG-IFN monotherapy for chronic hepatitis C in HIV-coinfected patients on HAART

BACKGROUND: Chronic hepatitis C is common and aggressive in HIV-positive patients, so the development of a well-tolerated HCV therapy is a priority. We evaluated the efficacy and safety of pegylated interferon alpha2b (PEG-IFN) plus ribavirin (RBV) versus PEG-IFN monotherapy in HIV/HCV-coinfected patients undergoing highly active antiretroviral therapy (HAART), and analysed the predictive factors of response. METHODS: An Italian, multicentre, open-label trial including 135 coinfected patients, randomized to PEG-IFN 1.5 microg/kg/week plus RBV 400 mg twice daily (n=69, arm A) or PEG-IFN 1.5 microg/kg/week (n=66, arm B) for 48 weeks. We assessed the predictive values of early virological response (EVR) at week 8 (HCV-RNA drop >2 log10 compared with baseline or undetectable levels) on sustained virological response (SVR). RESULTS: Fifty-five patients (28 from arm A and 27 from arm B) completed 48 weeks of therapy. At the end of treatment, 20/28 patients in arm A and 11/27 in arm B had HCV-RNA <50 IU/ml. In a per-protocol analysis, SVR was reached by 54% of patients in arm A (genotype 2-3, 11/16; genotype 1-4, 4/12) and 22% in arm B (genotype 2-3, 3/15; genotype 1-4, 3/12). In an intention-to-treat analysis, the SVR was 22% in arm A (genotype 2-3, 11/32; genotype 1-4, 4/37) versus 9% in arm B (genotype 2-3, 3/32; genotype 1-4, 3/34). The best predictors of SVR were the use of combination therapy, infection with HCV genotype 3 versus genotype 1, and EVR at week 8. Thirty patients (15 from arm A and 15 from arm B) dropped out of the trial prematurely due to side effects. The positive predictive value of EVR at week 8 was 65%, the negative predictive value was 86%. CONCLUSIONS: PEG-IFN plus RBV can be considered a solid option for the treatment of HIV/HCV-coinfected patients. The key to successfully improving efficacy is strong compliance through strict overall patient monitoring, in order to best manage drug toxicity. EVR assessment at week 8 may become a useful stategy in the management of therapy.     

原发性肝细胞癌与HCV分型的关系

了解原发性肝细胞癌 (HCC)患者HCV基因型分布现状及其关系。选择山西省肿瘤医院 1996年间住院的HCVRNA阳性、临床上确诊的HCC患者血清标本 13份 ,非肝癌癌症患者血清标本 15份 ,1996 - 1997年HCVRNA阳性的公共场所从业人员血清标本 15份 ,用特异性引物进行RT -PCR基因分型。结果表明 ,13例HCVRNA阳性的HCC患者 ,除 1例未能分型外 ,其余 12例均为HCV 1b型 (100% )。 15例非肝癌癌症患者 ,除 13例 (86.67% )为 1b型感染者外 ,其余均为 2a型 (13.33% )。 15例从业人员中 ,不仅检出了 1b型感染 (86.6 7% ) ,还检出 2a型、1/2混合型各 1例。所有标本中 1b型、2a型、1b/2a混合型的构成分别为 38/42 (90.48% )、3/42(7.14 % )、1/42 (2.38% ) ,以 1b型的比例最高 ,未检出 1a、2b和 3a型。证明HCVRNA 1b型与HCC的关系较为密切 ,同时也是山西地区HCV感染的优势株.     

Predicting the therapeutic response in patients with chronic hepatitis C: the role of viral kinetic studies

A substantial proportion of patients infected with hepatitis C virus (HCV) genotype 1 still does not respond to pegylated interferon-alfa/ribavirin (IFN/RBV) therapy. Factors which identify potential non-responders are needed to limit exposure to drugs in patients unlikely to benefit from treatment and to save health care resources. Host predictive factors have a low negative predictive value. In contrast, viral factors have a high precision in predicting outcome of therapy. Viral kinetics are the basis for the study of response of therapy. The decrease in viral load within 24 h after administration of a single test dose of conventional IFN reflects the IFN-sensitivity of the virus strain and predicts the outcome of conventional IFN/RBV therapy even before treatment with a specificity of 100% and a sensitivity of 83%. In contrast to conventional IFN, the two available PEG-IFN preparations differ considerably in how they suppress viral replication, and cut-off values have to be prospectively established separately for each drug. Patients without an early virological response (HCV-RNA either undetectable or decrease by >or=2 log10 after 12 weeks) (EVR), do not achieve a sustained virological response (SVR; negative predictive value: 97-98%). Thus, in the absence of an EVR, treatment should be stopped. The outcome of PEG-IFN alfa-2a/RBV combination therapy is dependent on the rapidity of the virological response. Patients who become HCV-RNA negative after 4 weeks have the best chance of achieving an SVR. The rapidity of viral elimination may be a useful guide to tailoring the length of treatment in patients with an EVR.     

Treatment of chronic hepatitis C in southern Taiwan

Chronic hepatitis C virus (HCV) infection may lead to cirrhosis and hepatocellular carcinoma. Interferon (IFN)-alpha is effective in the treatment of chronic hepatitis C. The rate of response to IFN is enhanced by increasing the IFN dose. Extending the treatment duration can reduce the relapse rate. Addition of ribavirin to IFN increases the sustained virological response (SVR). Thus, combination therapy with IFN and ribavirin was adopted for the treatment of chronic hepatitis C in Kaohsiung Medical University Hospital in 1998. Approximately 60% of patients receiving IFN/ribavirin therapy gained SVR. IFN 6 million units three times per week combined with daily ribavirin for 6 months achieved SVR more frequently than combination therapy with 3 million units. Factors for SVR in these combination regimens were HCV genotype, viral load and early virological response. Long-term follow-up of patients treated with IFN has shown that SVR might reduce the risk of progression to cirrhosis and hepatocellular carcinoma. Pegylated (peg)-IFN has a longer half-life and better efficacy. Combination therapy with peg-IFN and ribavirin accomplished higher SVR than conventional IFN and ribavirin. A multicenter clinical trial was conducted in Taiwan to compare the efficacy of combination therapy between peg-IFN/ribavirin and conventional IFN/ribavirin for 6 months. SVR was higher in patients receiving peg-IFN and ribavirin, especially in those infected with HCV genotype 1b. Based on the results obtained, the national health insurance started to sponsor the combination therapy in October 2003, with a suggested duration for 6 months. Some small-scale studies in Taiwan have postulated higher SVR for treatment duration of 12 than of 6 months in patients with genotype 1b. Further investigation should be conducted in the near future.     

Prolonged negative HCV-RNA status led to a good outcome in chronic hepatitis C patients with genotype 1b and super-high viral load

OBJECTIVE: We examined whether a sustained negative HCV-RNA status for 48 weeks affects the outcome in patients with genotype 1b and super-high viral load, and also investigated whether the outcome is affected by the induction therapy of twice-daily pre-administrated interferon (IFN)-beta. METHODS: 78 eligible patients were divided into four groups. 40 were patients assigned to the short treatment protocol. 13 patients received 3 MU IFN-beta twice daily for 2 weeks followed by IFN-alpha2b+ribavirin for 22 weeks (beta-induction group: group 1). 27 patients received IFN-alpha2b+ribavirin for 24 weeks (standard combination group: group 2). 38 patients were assigned to the maintenance treatment protocol. All of the 13 in the beta-induction group (group 3) and 21 of 25 patients in the standard combination group (group 4) who were negative HCV-RNA PCR at week 24 had IFN monotherapy to maintain a negative HCV-RNA result for 48 weeks. RESULTS: An HCV-RNA-negative status at week 24 was observed in 96% (25/26) of groups 1 and 3 versus in 79% (41/52) of groups 2 and 4 (p<0.01). The sustained virological response (SVR) was 38% (5/13) in group 1 and 11% (3/27) in group 2 (p<0.05). In the maintenance treatment, SVR was observed in 46% (6/13) of group 3 and 32% (8/25) of group 4 (NS). CONCLUSIONS: A sustained negative HCV-RNA status for 48 weeks might be associated with viral elimination in patients with genotype 1 and super-high viral load.     

2'-,5'-Oligoadenylate synthetase response ratio predicting virological response to PEG-interferon-alpha2b plus ribavirin therapy in patients with chronic hepatitis C

OBJECTIVE: Although all the mechanisms of elimination of hepatitis C virus (HCV) by Interferon (IFN) have not been fully elucidated, the 2'-5'-oligoadenylate (2-5A) system is one of the mechanisms of the antiviral effect of IFN. Consequently, the measurement of 2'-5'-oligoadenylate synthetase (2-5AS) activity could be useful for the evaluation of IFN treatment. This retrospective study was aimed at assessing whether 2-5AS activity functions as a clinical marker of virological response to PEG-interferon-alpha2b (PEG-IFN) plus ribavirin therapy of chronic hepatitis C. METHODS: The 32 patients included in this study had high viral loads of serum HCV-RNA of genotype 1b with chronic hepatitis C. All the patients received a regimen of PEG-IFN plus ribavirin for 48 weeks, and were then divided into two groups: one group (effective group) with undetectable serum HCV-RNA levels at 24 weeks (n = 22) of therapy, the other group (ineffective group) with persistent presence of HCV-RNA in serum at 24 weeks (n = 10). The 2-5AS activity in serum was measured 2, 8 and 12 weeks before initial administration. RESULTS: The 2-5AS response ratio (measured value/measured value of baseline 2-5AS) at 2, 8 and 12 weeks after the administration in the effective group was significantly higher than that in the ineffective group. CONCLUSIONS: These results suggest that the ratio of 2-5AS is closely related to the antiviral effect, and that the measurement of 2-5AS response ratio may be a useful clinical parameter of virological response to PEG-IFN plus ribavirin therapy of chronic hepatitis C.     

Hepatitis C Virus Genotype 1 to 6 Protease Inhibitor Escape Variants: In Vitro Selection,Fitness, and Resistance Patterns in the Context of the Infectious Viral Life Cycle

Hepatitis C virus (HCV) NS3 protease inhibitors (PIs) are important components of novel HCV therapy regimens. Studies of PI resistance initially focused on genotype 1. Therefore, knowledge about the determinants of PI resistance for the highly prevalent genotypes 2 to 6 remains limited. Using Huh7.5 cell culture-infectious HCV recombinants with genotype 1 to 6 NS3 protease, we identified protease positions 54, 155, and 156 as hot spots for the selection of resistance substitutions under treatment with the first licensed PIs, telaprevir and boceprevir. Treatment of a genotype 2 isolate with the newer PIs vaniprevir, faldaprevir, simeprevir, grazoprevir, paritaprevir, and deldeprevir identified positions 156 and 168 as hot spots for resistance; the Y56H substitution emerged for three newer PIs. Substitution selection also depended on the specific recombinant. The substitutions identified conferred cross-resistance to several PIs; however, most substitutions selected under telaprevir or boceprevir treatment conferred less resistance to certain newer PIs. In a single-cycle production assay, across genotypes, PI treatment primarily decreased viral replication, which was rescued by PI resistance substitutions. The substitutions identified resulted in differential effects on viral fitness, depending on the original recombinant and the substitution. Across genotypes, fitness impairment induced by resistance substitutions was due primarily to decreased replication. Most combinations of substitutions that were identified increased resistance or fitness. Combinations of resistance substitutions with fitness-compensating substitutions either rescued replication or compensated for decreased replication by increasing assembly. This comprehensive study provides insight into the selection patterns and effects of PI resistance substitutions for HCV genotypes 1 to 6 in the context of the infectious viral life cycle, which is of interest for clinical and virological HCV research.     

Genotype does not affect pattern of HCV RNA decrease among responders during interferon treatment of chronic hepatitis C. Consensus Interferon Study Group

We assessed differences in the pattern of HCV RNA decrease for HCV genotypes 1, 2, and 3 during interferon treatment to determine if the lower response rates observed among genotype 1 patients were related to a slower decrease in HCV clearance. Serum HCV RNA values of 472 chronic hepatitis C patients treated with either consensus interferon (CIFN) or interferon alfa-2b (IFN alfa-2b) were evaluated. Neither virological sustained responders nor relapsers differed in the pattern of serum HCV RNA decrease based on genotype. Virological sustained responders infected with genotype 1 cleared HCV RNA as rapidly as sustained responders who were infected with genotype 2 or 3. Relapsers had a slower rate of serum HCV RNA decrease than did virological sustained responders. Nonresponders differed in the pattern of serum HCV RNA decrease based on genotype: HCV genotype 3 patients had the greatest decrease in serum HCV RNA; genotype 2 patients had an intermediate decrease; and genotype 1 patients had the least serum HCV RNA decrease. HCV genotype 1 patients treated with CIFN had a greater decrease in serum HCV RNA during therapy than did patients treated with IFN alfa-2b. However, there was no difference in the magnitude of serum HCV RNA decrease between the two interferon treatments for patients infected with genotype 2 or 3. In summary, both genotype and ultimate response to treatment are determinants of the pattern and rate of serum HCV RNA change during interferon therapy of chronic hepatitis C.     

Evolution of HVR-1 quasispecies after 1-year treatment in HIV/HCV-coinfected patients according to the pattern of response to highly active antiretroviral therapy

Hepatitis C virus (HCV) variability is mainly attributed to the ability of the virus to respond to host immune pressure, acting as a driving force for the evolution of quasispecies. This study was aimed at studying the changes in HVR-1 heterogeneity and the evolution of HCV quasispecies in HIV/HCV-coinfected patients according to the pattern of response to highly active antiretroviral therapy (HAART). Sixteen HIV/HCV-coinfected patients harbouring HCV genotype 1 and who had been on HAART for at least 1 year, 8 showing increasing CD4+ T-cell counts (immunological responders) and 8 showing a stable or decreasing CD4+ T-cell counts (immunological nonresponders), were selected from a prospective cohort study. After 1 year of HAART, 11 patients showed HIV viral load <2.6 log10 cp/ml (virological responders), and 5 showed HIV viral load above this value (virological non-responders). Plasma samples, collected before starting therapy and after 1 year of HAART, underwent clonal sequence analysis for HVR-1 region of HCV. Nonsynonymous/synonymous substitutions ratio (Ka/Ks), aminoacidic complexity (normalized Shannon entropy) and diversity (p-distance), were considered as parameters of quasispecies heterogeneity. After 1 year of HAART, heterogeneity of HVR-1 quasispecies significantly decreased in virological non-responders, whereas the heterogeneity tended to increase in virological responders. The differences in the evolution were less stringent, when considering immunological response. On the other hand, profound qualitative modifications of HVR-1 quasispecies were observed only in patients with both immunological and virological HAART response. On the whole, these findings suggest that, in patients undergoing HAART, the extent of HCV variability and the evolution of HVR-1 quasispecies is influenced by the pattern of response to antiretroviral therapy.     

A case of successful hepatitis C virus eradication by 24 weeks of telaprevir-based triple therapy for a hemophilia patient with hepatitis C virus/human immunodeficiency virus co-infection who previously failed pegylated interferon-α and ribavirin therapy

In Japan, the human immunodeficiency virus (HIV) and hepatitis C virus (HCV) coinfection of some patients with hemophilia was caused by the transfusion of imported blood products, such as unheated coagulation factor. With the development of antiretroviral therapy (ART) for HIV, chronic HCV infection has become a major cause of liver disease and mortality for hemophiliac patients coinfected with HCV/HIV. Data is limited regarding the efficacy and safety of antiviral therapy with the HCV protease inhibitor telaprevir (TVR) in combination with pegylated interferon-α (PegIFN-α) and ribavirin (RBV) for hemophilia patients coinfected with HCV/HIV. We report a case of a Japanese patient with hemophilia and HCV/HIV coinfection who had partial response to prior to PegIFN-α and RBV therapy. This is the first published report of 24-week TVR-based triple therapy for a hemophilia patient coinfected with HCV/HIV. The patient had HCV genotype 1a infection with a high viral load. His single-nucleotide polymorphism of the interleukin 28B (rs8099917) gene was the TT major allele. He presented with undetectable HIV RNA and a high CD4⁺ T cell counts by taking ART including tenofovir, emtricitabine and raltegravir. He was again treated for HCV with TVR plus PegIFN-α2b and RBV for the first 12 weeks, followed by the continuation of PegIFN-α2b and RBV for 12 additional weeks while continuing ART. He had rapid virological response and achieved sustained virological response with the 24-week treatment. No serious adverse events such as skin rash, severe anemia or exacerbated bleeding tendency were observed, only a mild headache. No dose adjustment was necessary when tenofovir and raltegravir were used in combined with TVR, and no HIV breakthrough was observed. TVR-based triple therapy with ART could can an effective treatment for hemophilia patients coinfected with HCV (genotype 1)/HIV regardless of prior response. TVR can be used in combination with tenofovir, emtricitabine and raltegravir for patients with hemophilia. Furthermore, patients with undetectable HCV RNA at week 4 could be successfully treated with a 24-week regimen.