Chronic hepatitis C virus genotype 6 infection: response to pegylated interferon and ribavirin

HCV genotypes and their determinative role in hepatitis C treatment

Nowadays, exposure to infectious diseases caused by pathogenic viruses has become one of the major human concerns in health fields. In the meantime, hepatitis viruses are associated with health problems, especially in liver tissue. So far, several types of these viruses have been known including: HAV, HBV, HCV, HDV, HEV, and HGV. Nevertheless, it seems that hepatitis C is the major viral infection among all of the hepatitis infections. The cirrhosis and hepatocellular carcinoma are known as the most important pathological complications of this virus, from which seven genotypes have been identified. However, among these genotypes, the incidence rate of genotypes 1 and 3 is more than others. In this review, we have investigated the relationship between all HCV genotypes and therapeutic responses against them. Regarding heterogeneity between hepatitis C genotypes, it is not possible to access an effective vaccine against this virus, and treatment is the only applicable strategy. Response to treatment is different among genotypes, and it has resulted that each genotype has a specific therapeutic regimen of itself. Therefore, it seems that determination of hepatitis C genotype, as a key tool, is essential in controlling therapeutic regimen, improving local control programs and eventually producing an effective vaccine.

Revisiting policy on chronic HCV treatment under the Thai Universal Health Coverage: An economic evaluation and budget impact analysis

Thailand is encountering challenges to introduce the high-cost sofosbuvir for chronic hepatitis C treatment as part of the Universal Health Care's benefit package. This study was conducted in respond to policy demand from the Thai government to assess the value for money and budget impact of introducing sofosbuvir-based regimens in the tax-based health insurance scheme. The Markov model was constructed to assess costs and benefits of the four treatment options that include: (i) current practice-peginterferon alfa (PEG) and ribavirin (RBV) for 24 weeks in genotype 3 and 48 weeks for other genotypes; (ii) Sofosbuvir plus peginterferon alfa and ribavirin (SOF+PEG-RBV) for 12 weeks; (iii) Sofosbuvir and daclatasvir (SOF+DCV) for 12 weeks; (iv) Sofosbuvir and ledipasvir (SOF+LDV) for 12 weeks for non-3 genotypes and SOF+PEG-RBV for 12 weeks for genotype 3 infection. Given that policy options (ii) and (iii) are for pan-genotypic infection, the cost of genotype testing was applied only for policy options (i) and (iv). Results reveal that all sofosbuvir-based regimens had greater quality adjusted life years (QALY) gains compared with the current treatment, therefore associated with lower lifetime costs and more favourable health outcomes. Additionally, among the three regimens of sofosbuvir, SOF+PEG-RBV for genotype 3 and SOF+LDV for non-3 genotype are the most cost-effective treatment option with the threshold of 160,000 THB per QALY gained. The results of this study had been used in policy discussion which resulted in the recent inclusion of SOF+PEG-RBV for genotype 3 and SOF+LDV for non-3 genotype in the Thailand's benefit package.

HCV Genotype 6 Increased the Risk for Hepatocellular Carcinoma Among Asian Patients With Liver Cirrhosis

OBJECTIVES

Hepatitis C virus (HCV) infection is a well-documented risk factor for hepatocellular carcinoma (HCC). Seven HCV genotypes have been classified, and the genotypes show a great variety of geographic distribution. HCV genotype 6 is prevalent in Southeast Asia and has been less studied than the other genotypes.

METHODS

This follow-up study was designed to evaluate the natural history of HCV genotype 6. The cohort enrolled 851 Asian patients consisting of 222 with HCV genotype 6 and 629 with other genotypes. The incidence of HCC per 1,000 person-years of various HCV genotypes was estimated by dividing the new HCC cases to the person-years of follow-up. The adjusted hazards ratios (HRs) with 95% confidence intervals (CIs) were estimated by Cox's proportional hazards models.

RESULTS

After 4072 person-years of follow-up, there were 96 newly-developed HCC cases, confirming an incidence of 23.6 per 1000 person-years. By stratifying cirrhosis at study entry, the cumulative risk of HCC among HCV genotype 6 vs. non-6 was 2.9 vs. 2.2% for those without cirrhosis (P=0.45) and 76.2% (95% CI: 55.6-96.8%) vs. 36.2% (95% CI: 28.7-39.1%) for those with cirrhosis (P<0.05), respectively. Among patients with cirrhosis, HCV genotype 6 was significantly associated with HCC compared to patients with non-6 genotypes, with the adjusted HR=2.12 (1.33-3.39), P<0.05. In a model treating patients with genotypes other than 1 or 6 as the reference, the adjusted HR for HCC for HCV genotypes 1 and 6 were 1.13 (0.56-2.27) and 2.34 (1.12-4.86), respectively.

CONCLUSIONS

Among patients with cirrhosis, those with HCV genotype 6 infection should be given high priority for antiviral therapy to decrease HCC risk and for vigilant adherence to HCC surveillance.

Cost-effectiveness of the highly effective direct-acting antivirals in the treatment of chronic hepatitis C in Hong Kong

BACKGROUND AND AIM

In Asia-Pacific where cost is a major concern, peginterferon plus ribavirin (PR) often remain as the standard of care in chronic hepatitis C (CHC) treatment, while the direct-acting antivirals (DAAs) are commonly recommended as retreatment. Newer DAAs can achieve a sustained virological response (SVR) of nearly 100% with pan-genotypic coverage, that is "Highly Effective DAAs." We aimed to investigate the most desirable cost range for the Highly Effective DAAs using Hong Kong as an example.

METHODS

Markov modeling was performed using PR as the reference strategy. The cost-effectiveness of the Highly Effective DAAs was compared with sofosbuvir-PR (first-line and rescue) and boceprevir-PR therapies. A 50-year-old genotype 1b hepatitis C virus (HCV) infected treatment-naïve patient with METAVIR F3 was used as the base case scenario to reflect the commonest HCV genotype in Hong Kong.

RESULTS

The use of PR would incur a lifetime cost of US$35,854 and effectiveness of 14.85 quality-adjusted life-year (QALY). Sofosbuvir-PR as first-line treatment was dominated by other regimes. If Sofosbuvir-PR rescue therapy was used, the drug cost of Highly Effective DAAs should be set below US$43,553, with a cost-effectiveness ratio (CER) of US$3035/QALY compared with PR. In regions where Boceprevir-PR was still used as first-line therapy, the desirable drug cost of Highly Effective DAAs would be below US$56,985 to achieve a CER of US$5427/QALY.

CONCLUSIONS

The most desirable costs of the Highly Effective DAAs would be below US$43,553 if Sofosbuvir-PR rescue therapy is used and below US$56,985 if Boceprevir-PR therapy is used.

Hepatitis C virus therapy with peg-interferon and ribavirin in Myanmar: A resource-constrained country

AIM

To investigate peg-interferon (peg-IFN) and ribavirin (RBV) therapy in Myanmar and to predict sustained virologic response (SVR).

METHODS

This single-center, open-label, study was conducted in Myanmar between 2009 and 2014. A total of 288 patients infected with HCV genotypes 1, 2, 3 and 6 were treated with peg-IFN alpha-2a (180 μg/wk) or alpha-2b (50 to 100 μg as a weight-based dose) and RBV as a weight-based dose (15 mg/kg/d). Treatment duration was 48 wk for genotypes 1 and 6, 24 wk for genotype 2, and 24 or 48 wk for genotype 3 based on rapid virologic response (RVR). Those co-infected with hepatitis B received 48 wk of therapy.

RESULTS

Overall, SVR was achieved for 82% of patients and the therapy was well tolerated. All patients achieved SVR at equivalent rates regardless of HCV genotype (P = 0.314). Low fibrosis scores (P < 0.001), high baseline albumin levels (P = 0.028) and low baseline viral loads (P = 0.029) all independently predicted SVR. On the other hand, IL-28B TT and CC genotypes were not found to significantly predict SVR (P = 0.634; P = 0.618). Among those who completed treatment, the occurrence of RVR showed a > 96% positive predictive value for achieving SVR. Treatment duration did not significantly impact the likelihood of achieving SVR for patients infected with genotype 3 HCV (P = 0.371). The most common adverse events were fatigue (71%) and poor appetite (60%). Among patients with genotype 3 HCV, more patients in the 48-wk treatment group required erythropoietin than in the 24-wk treatment group (61.1% vs 49.2%).

CONCLUSION

SVR rates were high with peg-IFN and RBV therapy in Myanmar. Fibrosis scores, baseline albumin, HCV RNA levels and RVR independently predicted SVR.

Influence of Host and Viral Factors on Patients with Chronic Hepatitis C Virus Genotype 6 Treated with Pegylated Interferon and Ribavirin: A Systematic Review and Meta-Analysis

OBJECTIVES

We conducted a systematic review and meta-analysis of the influence of host and viral factors on the sustained virologic response (SVR) in hepatitis C virus genotype 6 (HCV-6) patients treated with pegylated interferon (PEG-IFN) and ribavirin (RBV).

METHODS

Data were retrieved from Medline, Embase, PubMed and the Cochrane Library for 'genotype 6' studies published up to December 2014 and for abstracts from international scientific meetings. Inclusion criteria were efficacy of PEG-IFN+RBV based on SVR, 24- or 48-week therapy and treatment-naïve patients. Patients with hepatitis B, D and E and HIV coinfection or another concurrent liver disease were excluded. Pooled standard difference, odds ratio and confidence intervals (CIs) were calculated using a random-effect model with STATA 11.

RESULTS

Fourteen studies were included in the meta-analysis. The pooled SVR rate was 80% (95% CI: 0.78-0.83, p < 0.0001; I2 = 71.2%). SVR of the PEG-IFN+RBV-treated HCV-6 patients was markedly higher than that of HCV-1 patients (80.1 vs. 55.3%). The SVR rate was significantly higher for the 48- than the 24-week treatment, but not different among HCV-infected patients with rs12979860 and ss469415590 polymorphisms of the ILFN4 gene (80.6% CC vs. 66.7% non-CC, p = 0.593; 81.1% TT/TT vs. 60% non-TT/TT, p = 0.288). Gender and type of PEG-IFN did not affect SVR rates.

CONCLUSIONS

Treatment outcomes for HCV-6 patients are superior to those for HCV-1 patients and comparable to those of HCV-2 and HCV-3 patients, especially at 48 weeks. The level of fibrosis affects treatment outcome, but SVR rates are not significantly different between genders. IL28B and IFNL4 polymorphisms are not significantly associated with HCV-6 treatment outcome.

Hepatitis C vaccine. Need of the hour

Hepatitis C virus (HCV) was first identified in 1989. HCV is a small, enveloped RNA virus. Globally, 3-4 million persons are infected with HCV each year, and are at risk of developing liver cirrhosis and/or liver cancer. The common modalities of the spread of hepatitis C infection are blood transfusions, injection drug use, unsafe therapeutic injections, and healthcare-related procedures. The standard treatment for hepatitis C has been combination antiviral therapy with interferon (IFN) and ribavirin, which are effective against all the genotypes of hepatitis viruses (pan-genotypic). A 12-month course of Peg-IFN/ribavirin treatment costs > $20 000. New HCV-specific antiviral drugs, especially in combination, have shown very high cure rates; however, the annual cost for a single subject ($82 000) make these unaffordable in most of the world. There is no hepatitis C vaccine. However, several vaccines in development, and some have shown promising preclinical results. Over the last few years, numerous HCV vaccine approaches have been assessed in mice and primates, but only a few vaccines have progressed to human trials. The challenge to develop HCV vaccine is to move into larger at-risk or infected populations to test efficacy.

HCV Infection and Interferon-Based Treatment Induce p53 Gene Transcription in Chronic Hepatitis C Patients

It is suggested that the tumor suppressor p53 gene, classified as an interferon-stimulated gene, is implicated in the interferon (IFN)-mediated innate immunity against viruses. This study aimed to examine the transcriptional response of the p53 gene to hepatitis C virus (HCV) infection and IFN-based therapy in chronic hepatitis C (CHC) patients. The study included 65 CHC patients (HCV genotype 1), treated with pegylated IFN-α and ribavirin, and 51 healthy individuals. p53 gene expression was quantified by real-time polymerase chain reaction in peripheral blood mononuclear cells (PBMCs). Analyses were performed before and at weeks 4 and 12 of treatment. p53 gene expression was significantly upregulated in CHC patients compared with healthy controls and at week 4 of therapy. No significant differences in p53 mRNA expression between rapid virologic responders, complete early virologic responders, and nonresponders were observed. No significant correlation was found between p53 gene expression and viral load. The results obtained indicate that HCV infection and IFN-based treatment induces p53 gene transcription in PBMCs. The p53 gene may therefore play a role in HCV infection but is not directly involved in treatment-induced HCV elimination. Moreover, variations in p53 gene expression do not determine on-treatment response in patients with chronic HCV genotype 1 infection.

Features of hepatitis C virus infection, current therapies and ongoing clinical trials in ten Asian Pacific countries

Estimated hepatitis C virus (HCV) infection rates in the general populations were 1.3, 0.9, 0.4-1.0, 14.7, 0.1-0.3, 0.9-1.9, 1.0-2.0, 5, 4.4-8.6 and 0.5-1.3 % in Australia, Bangladesh, Mainland China, Egypt, Hong Kong, India, Japan, Pakistan, Taiwan and Turkey, respectively. The main HCV genotypes (Gs) are G1, G3, G1b, G4, G1b, G3, G1b, G3, G1b and G2, and G1 in Australia, Bangladesh, Mainland China, Egypt, Hong Kong, India, Japan, Pakistan, Taiwan and Turkey, respectively. Of IL28B genotypes, favorable alleles are ~50 % in Australia and Turkey, but 60-70 % in most of the other Asian countries. Peginterferon plus ribavirin is available in all ten Asian Pasific countries. In addition, HCV NS3/4A protease inhibitors with peginterferon plus ribavirin are currently available in several countries. Clinical trials of interferon-free regimens for HCV are ongoing in most of the ten Asian Pacific countries.

Seroprevalence, genotypic distribution and potential risk factors of hepatitis B and C virus infections among adults in Siem Reap, Cambodia

AIM

We investigated hepatitis B virus (HBV) and hepatitis C virus (HCV) infections among adults in Siem Reap, Cambodia, to consider the prevention strategy in cooperation with the Ministry of Health in Cambodia.

METHODS

Serological tests for determining HBV and HCV infections and questionnaires were performed from 2010 to 2012 among the general population in the province of Siem Reap. Multivariate logistic regression analysis was conducted to clarify the factors related to HBV and HCV infections.

RESULTS

There were 483 participants, comprising 194 men and 289 women (age range, 18-89 years). The prevalence of hepatitis B surface antigen was not very high at 4.6%, while anti-hepatitis B core (anti-HBc) was high at 38.5%. All HBV DNA samples were classified as genotype C. Anti-HBc showed the trend that the older the age, the higher the positive rate (P = 0.0002). The prevalence of HCV RNA and anti-HCV were 2.3% and 5.8%, respectively. HCV RNA was detected in 39.3% of anti-HCV positive samples and most of them were classified as genotype 6 (54.5%) and 1 (27.3%). Remarkably, in multivariate logistic regression analysis, history of operation and blood transfusion were significantly associated with the positivity for HBV infection and HCV RNA, respectively.

CONCLUSION

Our results showed that operation and blood transfusion were potential risk factors for HBV and HCV infection, respectively, and supposed that horizontal HBV transmission may be frequent in adults in Cambodia. Hence, for reducing HBV and HCV infections, it is necessary to improve the safety of blood and medical treatment.

Current status and emerging challenges in the treatment of hepatitis C virus genotypes 4 to 6

Hepatitis C virus (HCV) genotypes 4, 5 and 6 are mainly present in Africa, the Middle East and Asia and they have been less extensively studied with respect to epidemiology, natural disease history and therapeutic endpoints. Response rates to a 48-wk combined peginterferon/ribavirin treatment range to 40%-69% for HCV 4, 55%-60% for HCV 5 and 60%-90% for HCV 6. Response-guided schedules are recommended to optimize the outcomes of peginterferon/ribavirin treatment in HCV 4 and, in form of preliminary data, for HCV 6, but no data are yet available to support such an individualization of therapy for HCV 5. Recently, the direct-acting antivirals (DAAs) with pan-genotypic activities simeprevir, sofosbuvir and daclatasvir have been recommended in triple regimens with peginterferon/ribavirin for the treatment of HCV genotypes 4 to 6 infections. In the future, DAA-based interferon-free therapies are awaited to drastically improve treatment outcomes in HCV. However, efforts to improve treatment outcomes with peginterferon/ribavirin should continue, as the HCV 4-6 infected population is mainly based in resource-limited settings with restricted access to the costly DAAs.

Meta-analysis: superior treatment response in Asian patients with hepatitis C virus genotype 6 versus genotype 1 with pegylated interferon and ribavirin

OBJECTIVE

Our goal was to systematically and quantitatively assess treatment response between Asian patients with hepatitis C virus genotype 6 (HCV-6) and hepatitis C virus genotype 1 (HCV-1) treated for 48 weeks with pegylated interferon and ribavirin.

METHODS

We performed a literature search in MEDLINE and EMBASE for 'genotype 6' in August 2013. Additional abstracts from major international scientific conferences from 2012 to 2013 were reviewed. Studies included were original articles with ≥10 treatment-naïve Asian HCV-6 patients. Exclusion criteria were coinfections with hepatitis B virus, HIV and/or other liver diseases. Heterogeneity was defined as a Cochrane Q test with a p value of 0.10 and an I(2) statistic of >50%. RESULTS of a random-effects model are reported.

RESULTS

A total of 1,046 (503 HCV-6; 543 HCV-1) patients from 12 studies were included in the analysis. The pooled sustained virologic response (SVR) rate was 80.2% (95% CI 74.3-85.0, Q statistic = 20.87, p < 0.035; I(2) = 47.3%) for HCV-6 and 62.5% (95% CI 41.9-79.4, Q statistic = 52.41, p < 0.001; I(2) = 92.37) for HCV-1 patients. HCV-6 patients had a significantly higher SVR rate compared to HCV-1 patients (odds ratio 2.73, 95% CI 1.69-4.41, p < 0.001). Approximately one fourth of patients without early virologic response (EVR) achieved SVR, regardless of genotype (HCV-1, n = 6/23; HCV-6, n = 4/21).

CONCLUSIONS

Asian patients with HCV-6 can expect higher SVR rates (∼80%) than HCV-1 patients (∼63%). EVR as a stopping rule is less clear in Asian patients with HCV-6 and HCV-1.

Meta-analysis of patients with hepatitis C virus genotype 6: 48 weeks with pegylated interferon and ribavirin is superior to 24 weeks

BACKGROUND

Hepatitis C virus genotype 6 (HCV-6) is common in patients from Southeast Asia and the surrounding regions. Optimal treatment duration for HCV-6 is unknown given the inconclusive evidence from studies with varying methodologies and small sample sizes.

METHODS

A literature search for 'genotype 6' in MEDLINE and EMBASE in October 2013 produced 161 and 251 articles, respectively. Additional abstracts were identified from four major international GI/liver conferences in 2012/2013. Inclusion criteria were original studies with ≥10 HCV-6 treatment-naïve patients treated with pegylated interferon + ribavirin (PEG IFN+RBV). Exclusion criteria were coinfections with HBV, HIV, other HCV genotypes, and/or other liver diseases. Primary outcome was pooled sustained virologic response (SVR). Heterogeneity was defined by Cochrane Q test (p value of 0.10) and I (2) statistic (≥50 %).

RESULTS

A total of 13 studies with 641 patients were included. The pooled SVR estimate was 77 % (CI 70-83 %) (Q value = 38.4, p value <0.001, I (2) = 68.7 %) overall, 79 % (CI 73-84 %) for the 48-week group and 59 % (CI 46-70 %) for 24-week group, respectively. In studies with direct comparison of the two groups, SVR was superior in patients treated for 48 versus 24 weeks, OR 1.9 (CI 1.08-3.2, p = 0.026). In studies with direct comparison of patients with rapid virologic response (RVR), there was no difference in SVR between 48 versus 24 weeks, OR 1.74 (CI 0.65-4.64, p = 0.27).

CONCLUSION

Hepatitis C virus genotype 6 patients should be treated for 48 weeks, and those who achieve RVR may receive the shorter 24-week treatment duration. The high SVR (~80 %) with 48 weeks of PEG IFN+RBV therapy may be a cost-effective option for HCV-6 patients from resource-poor regions.

Increased prevalence of hepatitis C virus subtype 6a in China: a comparison between 2004-2007 and 2008-2011

Different hepatitis C virus (HCV) genotypes exhibit differences in disease pathogenesis and progression, as well as disease outcomes and response to therapy. Tracking the change of HCV genotypes in various epidemiological settings is critical for both disease surveillance and the development of improved antiviral treatment. Here, we tracked the changes in the prevalence of the HCV genotypes in China between 2004-2007 and 2008-2011. HCV-RNA-positive sera were collected from volunteer blood donors during the period 2008-2011. The genotypes were determined by phylogenic analysis using the NS5B and E1 sequences. Geographical and demographic distribution patterns related to the HCV genotypes obtained in 2008-2011 were compared with our previous study, which recorded data in the period 2004-2007. Pearson chi-square test and t-test were used to statistically analyze the results. In 2008-2011, HCV subtypes 1b and 6a were detected in 43.8 % (184/420) and 34.3 % (144/420), respectively. The male/female ratio was found to be higher for HCV genotype 6 than for genotypes 1 and 2. When compared with the period of 2004-2007, although no significant difference was found in gender or age for genotypes 1, 2, 3 and 6, the subtype 6a frequency was significantly increased from 11 % to 26.5 % in the blood donors from outside of Guangdong Province in 2008-2011. A pattern of increase in HCV subtype 6a was found in blood donors outside of Guangdong Province, indicating that HCV subtype 6a has rapidly spread from Guangdong to other regions of China over the past 10 years.

Impact of hepatitis C virus heterogeneity on interferon sensitivity: an overview

Hepatitis C virus (HCV) is a major cause of liver disease worldwide. HCV is able to evade host defense mechanisms, including both innate and acquired immune responses, to establish persistent infection, which results in a broad spectrum of pathogenicity, such as lipid and glucose metabolism disorders and hepatocellular carcinoma development. The HCV genome is characterized by a high degree of genetic diversity, which can be associated with viral sensitivity or resistance (reflected by different virological responses) to interferon (IFN)-based therapy. In this regard, it is of importance to note that polymorphisms in certain HCV genomic regions have shown a close correlation with treatment outcome. In particular, among the HCV proteins, the core and nonstructural proteins (NS) 5A have been extensively studied for their correlation with responses to IFN-based treatment. This review aims to cover updated information on the impact of major HCV genetic factors, including HCV genotype, mutations in amino acids 70 and 91 of the core protein and sequence heterogeneity in the IFN sensitivity-determining region and IFN/ribavirin resistance-determining region of NS5A, on virological responses to IFN-based therapy.

Efficacy and safety of pegylated interferon plus ribavirin therapy for chronic hepatitis C genotype 6: a meta-analysis

Background

Hepatitis C genotype 6 (HCV-6) is prevalent in Southeast Asia. Data on the efficacy of direct-acting antiviral agents in chronic HCV-6 patients is limited and pegylated interferon (Peg-IFN) plus ribavirin (RBV) combination therapy remains standard therapy for those patients.

Aim

Meta-analysis was performed to assess the efficacy and safety of Peg-IFN plus RBV combination therapy for chronic HCV-6 patients.

Methods

Relevant studies were found by database search through Medline, Embase, Web of Science and The Cochrane Library. All published clinical trials assessing the efficacy of Peg-IFN plus RBV combination therapy for chronic HCV-6 patients were included. Sustained virological response rate (SVR) was pooled. We performed additional meta-analyses to compare the SVR outcomes of 24 versus 48 weeks of treatment in four head-to-head trials. Another second meta-analysis was also conducted to compare the efficacy of combination Peg-IFN plus RBV therapy in HCV-6 versus HCV-1 patients.

Results

Thirteen studies met the inclusion criteria. The pooled SVR of all single arms was 75% (95% CI: 0.68–0.81). The SVR of 24 weeks treatment was significantly lower than that at 48 weeks, with a risk difference of −14% (95% CI: −0.25 to −0.02, p = 0.02). However, when restricted to the patients with rapid virological response (RVR), there was no significant effect on SVR between these two treatment groups, with a risk difference of −1% (95% CI: −0.1 to 0.07, p = 0.67). The SVR in HCV-6 patients was significantly higher than that in HCV-1 patients, with a relative risk of 1.35 (95% CI: 1.16–1.57, p<0.001). Side effects were common, but rarely caused treatment discontinuation.

Conclusions

The results of this meta-analysis suggest that Peg-IFN plus RBV is effective and safe for HCV-6 patients. Shortening treatment seems to be feasible in HCV-6 patients with RVR when tolerance to treatment is poor. However, this decision should be made cautiously.

Hepatitis C virus genotypes circulating in patients with chronic hepatitis C in Thailand and their responses to combined PEG-IFN and RBV therapy

Different genotypes of hepatitis C virus (HCV) are circulating in different areas of the world. In Thailand, distribution of HCV genotypes has been investigated mostly in the central area while the information in other regions is limited. This study aimed to determine the HCV genotypes circulating in chronic hepatitis C patients in Chiang Mai, Thailand and to investigate the response of different HCV genotypes to pegylated interferon (PEG-IFN) and ribavirin (RBV) treatment. Patients infected chronically with HCV were treated with PEG-IFN/RBV based on the standard regimens for each HCV genotype and followed up the patients until the end of treatment and 6 months afterward. Out of 158 patients, three major HCV genotypes and eight subtypes were identified. Genotype 3 was the most predominant at 54.5%, followed by genotypes 1 (31%) and 6 (14.5%). Among subtypes, 3a was the most prevalent subtype (45%), followed by 1b (18.4%), 1a and 6f (each at 12.6%), 3b (9.5%), and 6a, 6i, 6n (each at 0.63%). Patients with genotype 3 showed higher rate of responding to the treatment at 80.2% compared to genotypes 1 (73.5%) and 6f (65%). Additionally, patients with genotype 6f showed higher rate of relapsing (25%) compared to genotypes 1 and 3 (14.3% and 16.3%, respectively). In conclusion, this study reported multiple HCV genotypes circulated in Thai patients and the response of different HCV genotypes to PEG-IFN/RBV treatment.

Nanomedicines in the treatment of hepatitis C virus infection in Asian patients: optimizing use of peginterferon alfa

Asia is endemic for hepatitis C virus (HCV) infection, which is the leading cause of cirrhosis, hepatic decompensation, hepatocellular carcinoma, and liver transplantation worldwide. HCV has six major genotypes and each HCV genotype has its specific geographic distribution. HCV genotypes 1, 2, 3, and 6 are common in Asia. The aim of HCV treatment is to eradicate the virus by effective therapeutic agents; viral clearance is durable after long-term post-treatment follow-up. In most Asian countries, peginterferon alfa (PEG-IFN α) in combination with ribavirin remains the standard of care, and the overall sustained viral response (SVR) rate in Asian HCV patients is higher than that in Western patients. The differences are most significant in patients with HCV genotype 1 (HCV-1) infection, which is attributed to the higher frequency of IFN-responsive or favorable interleukin-28B (IL-28B) genotype in Asian populations than in other ethnic populations. In addition, the introduction of response-guided therapy, where the optimized treatment duration is based on the early viral kinetics during the first 12 weeks of treatment, increases the SVR rate. Recently, telaprevir or boceprevir-based triple therapy was found to further improve the SVR rate in treated and untreated HCV-1 patients and has become the new standard of care in Western and some Asian countries. Many novel direct-acting antiviral agents, either in combination with PEG-IFN α plus ribavirin or used as IFN-free regimens are under active investigation. At the time of this writing, simeprevir and sofosbuvir have been approved in the US. Because the SVR rates in Asian HCV patients receiving PEG-IFN α plus ribavirin therapy are high, health care providers should judiciously determine the clinical usefulness of these novel agents on the basis of treatment duration, anticipated viral responses, patient tolerance, financial burdens, and drug accessibility.

Hepatitis C virus genotype 6: virology, epidemiology, genetic variation and clinical implication

Hepatitis C virus (HCV) is a serious public health problem affecting 170 million carriers worldwide. It is a leading cause of chronic hepatitis, cirrhosis, and liver cancer and is the primary cause for liver transplantation worldwide. HCV genotype 6 (HCV-6) is restricted to South China, South-East Asia, and it is also occasionally found in migrant patients from endemic countries. HCV-6 has considerable genetic diversity with 23 subtypes (a to w). Although direct sequencing followed by phylogenetic analysis is the gold standard for HCV-6 genotyping and subtyping, there are also now rapid genotyping tests available such as the reverse hybridization line probe assay (INNO-LiPA II; Innogenetics, Zwijnaarde, Belgium). HCV-6 patients present with similar clinical manifestations as patients infected with other genotypes. Based on current evidence, the optimal treatment duration of HCV-6 with pegylated interferon/ribavirin should be 48 wk, although a shortened treatment duration of 24 wk could be sufficient in patients with low pretreatment viral load who achieve rapid virological response. In addition, the development of direct-acting antiviral agents is ongoing, and they give high response rate when combined with standard therapy. Herein, we review the epidemiology, classification, diagnosis and treatment as it pertain to HCV-6.

Robust and persistent replication of the genotype 6a hepatitis C virus replicon in cell culture

Genotype 6 (GT6) hepatitis C virus (HCV) is prevalent in Southeast Asia and southern China, where it can constitute up to 50% of HCV infections. Despite this, no direct-acting antivirals are approved to treat GT6 HCV infection, and no cell culture systems have been described. In this study, we aimed to develop a GT6 HCV subgenomic replicon to facilitate the identification and development of new HCV therapies with pan-genotype activity. A subgenomic replicon cDNA encoding a GT6a consensus sequence plus an NS5A amino acid substitution (S232I) was synthesized. Electroporation of RNA encoding the GT6a replicon into Huh-7-derived cells consistently yielded 20 to 100 stable replicon colonies. Genotypic analyses of individual replicon colonies revealed new adaptive mutations across multiple viral nonstructural proteins. The E30V and K272R mutations in NS3 and the K34R mutation in NS4A were observed most frequently and were confirmed to enhance GT6a replicon replication in the presence of the NS5A amino acid substitution S232I. These new adaptive mutations allowed establishment of robust luciferase-encoding GT6a replicons for reproducible quantification of HCV replication, and the luciferase-encoding replicons enabled efficient determinations of antiviral activity for HCV inhibitors in a 384-well assay format. While nucleoside/nucleotide NS5B inhibitors and cyclophilin A inhibitors had similar antiviral activities against both GT6a and GT1b replicons, some nonnucleoside NS5B inhibitors, NS3 protease inhibitors, and NS5A inhibitors had less antiviral activity against GT6a replicons. In conjunction with other genotype replicons, this robust GT6a replicon system will aid in the development of pan-genotypic HCV regimens.

Epidemiology and treatment of hepatitis C genotypes 5 and 6

Chronic hepatitis C infection is a major global health problem. The WHO estimates the number of infected people worldwide to be approximately 170 million. The estimated number of hepatitis C virus (HCV)-infected people in Canada is approximately 250,000, with approximately 5000 Canadians newly infected each year. Based on the identification of genomic differences, HCV has been classified into six genotypes; genotype may influence the outcome of antiviral therapy. HCV genotypes 1, 2 and 3 are widely distributed throughout the world and have been the focus of the majority of epidemiological, natural course and treatment studies. Although HCV genotypes 5 and 6 are prevalent in certain geographical areas, they are studied less extensively. HCV genotypes 5 and 6 are uncommon in Canada and account for less than 5% of HCV-infected Canadians. However, immigration and travel can alter the epidemiology of these uncommon genotypes. The present article reviews and summarizes the available data regarding the epidemiology and treatment of HCV genotypes 5 and 6. Genotype 5 is endemic in the northern part of South Africa while genotype 6 is reported primarily in Asia. Available data show that 48 weeks of treatment with a combination of pegylated interferon and ribavirin lead to a higher sustained virological response compared with HCV genotypes 1 and 4. None of the approved direct-acting antiviral agents is currently recommended for the treatment of HCV genotypes 5 or 6.

Review article: the epidemiology and therapy of chronic hepatitis C genotypes 4, 5 and 6

BACKGROUND

The global burden of hepatitis C (HCV) infection is mostly found in Africa, the Middle East and Asia, where HCV genotypes 4, 5 and 6 are common. The literature on these genotypes is sparse and this synopsis will review characteristics of patients infected with these genotypes.

AIM

To review characteristics of patients infected with HCV genotypes 4, 5 and 6.

METHODS

PubMed search for 'hepatitis C' AND 'genotype 4', 'hepatitis C' AND 'genotype 5', and 'hepatitis C' AND 'genotype 6' was conducted and relevant articles were reviewed.

RESULTS

Intravenous drug use is generally responsible for HCV genotype 4 infection in developed countries, but unsafe medical practices cause most cases of HCV genotypes 4, 5 and 6 in endemic countries. The sustained virological response (SVR) rate for patients with HCV genotype 4 who receive pegylated interferon and ribavirin for 48 weeks ranges from 40% to 70% in various small studies. The SVR rate is in the 60-70% range for HCV genotype 5 and 70-80% range for HCV genotype 6 following 48 weeks with pegylated interferon and ribavirin. Preliminary data suggest that a shorter course of 24 weeks of pegylated interferon and ribavirin may be acceptable for HCV genotype 6, with an SVR rate of approximately 70%.

CONCLUSIONS

The current standard-of-care therapy for HCV genotypes 4, 5 and 6 is pegylated interferon and ribavirin for 48 weeks. A shorter course with 24 weeks of therapy may be considered for patients with genotype 6. Newer and much more effective therapies may be forthcoming in the next few years.

[Efficacy of peginterferon and ribavirin combination therapy of chronic hepatitis C: a pooled analysis]

BACKGROUND/AIMS

A combination of peginterferon and ribavirin is the standard therapy for chronic hepatitis C (CHC). However, the respective study has not been carried out in a large scale in Korea. The purpose of this study was to collect the studies that have been reported in Korea in order to analyze the therapeutic effect of combination therapy and compare to find racial difference.

METHODS

Twenty-eight papers related to the therapeutic effect of combination therapy in CHC patients were analyzed based on pooled analysis.

RESULTS

Based on the analysis for genotype 1 in Korea, early virologic response (EVR), end of treatment response (ETR), and sustained virologic response (SVR) were 79.6% (125/157), 80.1% (166/207), and 62.7% (341/543). The EVR, ETR, and SVR for genotype 2 and 3 were 89.4% (119/133), 92.2% (203/220), and 84.1% (434/516). Data from other Asians showed that EVR and SVR for genotype 1 were 88.9% (290/326) and 64.4% (491/762) respectively and 88.8% (135/152), and 79.4% (151/190) for genotype 2 and 3 respectively. In Western, EVR and SVR for genotype 1 were 51.3% (1,981/3,860) and 42.4% (1,798/4,231) respectively, and for genotype 2 and 3 were 87.7% (350/399) and 77.8% (533/685) respectively. Based on the comparative analysis, no statistical difference in SVR between Koreans and other Asians (p=0.955) was observed; However, the SVR of Koreans was higher with significance than that of Westerns (p<0.001) On the other hand, there was no difference what so ever, in SVR for genotype 2 amongst the different races.

CONCLUSIONS

The SVR of combination therapy for the Korean chronic hepatitis C patients was similar to other Asians but higher than Westerns.

Role of viral and host factors in interferon based therapy of hepatitis C virus infection

The current standard of care (SOC) for hepatitis C virus (HCV) infection is the combination of pegylated interferon (PEG-IFN), Ribavirin and protease inhibitor for HCV genotype 1. Nevertheless, this treatment is successful only in 70-80% of the patients. In addition, the treatment is not economical and is of immense physical burden for the subject. It has been established now, that virus-host interactions play a significant role in determining treatment outcomes. Therefore identifying biological markers that may predict the treatment response and hence treatment outcome would be useful. Both IFN and Ribavirin mainly act by modulating the immune system of the patient. Therefore, the treatment response is influenced by genetic variations of the human as well as the HCV genome. The goal of this review article is to summarize the impact of recent scientific advances in this area regarding the understanding of human and HCV genetic variations and their effect on treatment outcomes. Google scholar and PubMed have been used for literature research. Among the host factors, the most prominent associations are polymorphisms within the region of the interleukin 28B (IL28B) gene, but variations in other cytokine genes have also been linked with the treatment outcome. Among the viral factors, HCV genotypes are noteworthy. Moreover, for sustained virological responses (SVR), variations in core, p7, non-structural 2 (NS2), NS3 and NS5A genes are also important. However, all considered single nucleotide polymorphisms (SNPs) of IL28B and viral genotypes are the most important predictors for interferon based therapy of HCV infection.

Hepatitis C genotype 6: A concise review and response-guided therapy proposal

Hepatitis C genotype 6 is endemic in Southeast Asia [prevalence varies between 10%-60% among all hepatitis C virus (HCV) infection], as well as also sporadically reported outside the area among immigrations. The diagnosis of HCV genotype can be inaccurate with earlier methods of genotyping due to identical 5’-UTR between genotype 6 and 1b, hence the newer genotyping methods with core sequencing are preferred. Risk factors and clinical course of HCV genotype 6 do not differ considerably from other genotypes. Treatment outcome of HCV genotype 6 with a combination of pegylated interferon and ribavirin is superior to genotype 1, and nearly comparable to genotype 3, with expected sustained virological response (SVR) rates of 60%-90%. Emerging data suggests that a shorter course 24-wk treatment is equally effective as a standard 48-wk treatment, particularly for those patients who attained undetectable HCV RNA at week 4 (RVR). In addition, baseline and on-treatment predictors of response used for other HCV genotypes appear effective with genotype 6. Although some pan-genotypic direct-acting antivirals have completed phase II/III studies (sofosbuvir and simeprevir) with clinical benefit demonstrated in small number of patients with genotype 6, broad availability of these agents in Southeast Asia may not be expected in the near future. While awaiting the newer therapy, response-guided therapy seems appropriate for patients with HCV genotype 6. Patients with RVR (representing > 70% of patients) are suitable for 24-wk treatment with expected SVR rates > 80%. Patients without RVR and/or those with poor response predictors may benefit from 48 wk of therapy, and a detectable HCV RNA at week 12 (with no early virological response) serves as a stopping rule. This treatment scheme is likely to have a major economic impact on HCV therapy, particularly in Southeast Asia, wherein treatment can be truncated securely in the majority of patients with HCV genotype 6.

Role of IL28B and inosine triphosphatase polymorphisms in the treatment of chronic hepatitis C virus genotype 6 infection

IL28B and inosine triphosphatase (ITPA) polymorphisms are able to predict treatment response and degree of ribavirin-related anaemia, respectively, in the treatment of chronic hepatitis C virus (HCV) infection. However, their roles in the treatment of chronic HCV genotype 6 remain undetermined. Sixty patients who were infected with HCV genotype 6 were commenced on 48 weeks of combination pegylated interferon and ribavirin therapy. Response to therapy, profiles of haemoglobin changes and platelet counts during therapy and their associations with IL28B rs8099917 and ITPA rs1127354 polymorphisms were analysed. The overall sustained virologic response (SVR) rate was 91.7%. 18 patients (30.0%) required a reduction in ribavirin dosage. The distribution of IL28B rs8099917 TT/TG genotypes and ITPA rs1127354 CC/CA genotypes were in Hardy-Weinberg equilibrium. IL28B rs8099917 TT genotype, when compared to TG genotype, was significantly associated with an increased SVR rate (96.2% and 62.5%, respectively) and was the only clinical parameter that predicted SVR (P = 0.014). The same significant association was observed when analysing allelic frequencies (T vs G, P = 0.001). ITPA rs1127354 CA genotype, when compared to CC genotype, was associated with lesser degree of anaemia throughout therapy (P < 0.05 for all time points). ITPA polymorphisms showed no association with changes in platelet count throughout therapy (P > 0.05 for all time points) and was not associated with SVR (P = 0.640). In chronic HCV genotype 6 infection, IL28B polymorphisms were associated with response to therapy. ITPA polymorphisms influenced the degree of anaemia but not thrombocytopenia during therapy.

Prevalence of IL-28B and ITPA genotypes in Chinese Han population infected persistently with hepatitis C virus genotype 6 or HCV-1

The geographic distribution, demographics, epidemiology, host factors, and clinical characteristics of persistent HCV-6 infection in China need further characterization. This multicenter study enrolled 63 patients with persistent HCV-6 infection and 63 patients with persistent HCV-1 infection as controls. Blood biochemistry, quantitation of HCV RNA levels, and identification of host IL-28B genotypes (rs12979860, rs8099917, and rs12980275) and ITPA genotype (rs1127354) were performed to estimate potential variability in host factors that may affect response to treatment. The mean HCV-6 RNA level (3.8E6 IU/ml) was significantly higher than that in patients infected with HCV-1 (1.7E6 IU/ml; P < 0.001). Patients persistently infected with HCV-6 had a high prevalence of IL-28B rs12979860 CC genotype (92.1%), rs8099917 TT genotype (93.7%), and rs12980275 AA genotype (90.5%). Their prevalence in patients infected with HCV-1 was only modestly lower (82.5%, 84.1%, and 82.5%, respectively; P > 0.05). The inosine triphosphate pyrophosphatase (ITPA) SNP rs1127354 CC genotype was present in 66.7% of patients infected with HCV-6, comparable to that of patients infected with HCV-1 (65.1%; P > 0.05). There were no differences in the liver function, proportion of hepatic cirrhosis patients or patients with increased serum glucose between these two groups. Persistent HCV-6 infection in Chinese Han is found mainly in the southern China. Chinese Han with chronic HCV-1 or HCV-6 infection have IL-28B genotypes, suggesting responsiveness to interferon-based pharmacotherapy. Most patients (67%) possess the ITPA genotype associated with susceptibility to ribavirin-induced hemolysis. The routes of transmission for HCV-6 genotype were more diversified than HCV-1 genotype. The outbreak of HCV-6 infection through blood transfusion progressed faster than HCV-1.

Correlation of viral loads with HCV genotypes: higher levels of virus were revealed among blood donors infected with 6a strains

Background

Both HCV genotypes and viral loads are predictors of therapeutic outcomes among patients treated with α-interferon plus ribavirin; however, such correlation has only been studied for genotypes 1, 2, and 3 but not for genotype 6.

Methodology/Findings

299 voluntary blood donors were recruited who were HCV viremic. Their mean age was 31.8; the male/female ratio was 3.82 (225/59). The viral loads of HCV were measured using the COBAS AmpliPrep/COBAS TaqMan test (CAP/CTM) while HCV genotypes were determined by direct sequencing the partial NS5B region. HCV genotypes 1, 2, 3, and 6 were determined in 48.9%, 8.7%, 12.3%, and 30.1% of the donors, respectively, and the levels of mean viral loads in genotype 1 and 6 significantly higher than that of 2 and 3 (P<0.001). As a whole, the viral loads in male donors were higher than in female (P = 0.006). Moreover, the donors' gender and HCV genotypes are independently correlated with the measured viral loads.

Conclusion

HCV genotype 1 and 6 had significantly higher viral loads than genotype 2 and 3.

Comparison of three different HCV genotyping methods: core, NS5B sequence analysis and line probe assay

To evaluate the capacity of Versant HCV genotype assay (LiPA) 2.0 to identify hepatitis C virus (HCV) genotypes, 110 serum samples were collected from chronic hepatitis C patients. Three methods were compared: core sequence analysis, NS5B sequence analysis and the INNO-LiPA assay. The result showed that 102 (92.7%) of the samples were amplified in either or both regions, of which 97 were amplified in the core region and 62 were amplified in the NS5B region. Correlation analysis showed that amplification rates of subgenomic regions were associated with viral loads. Basic local alignment search tool (BLAST) and phylogenetic analysis showed that the 102 samples were classified into 5 categories: subtype 1b, 2a, 3a, 3b and 6a at frequencies of 61.8% (63), 9.8% (10), 3.9% (4), 3.9% (4) and 20.6% (21), respectively. Compared with sequencing methods, 66.7% (68) of the 102 samples were identified completely by LiPA 2.0, whereas 19.6% (20) were assigned incompletely (indistinguishable or not identified subtype) and 13.7% (14) were misclassified. Of 21 genotype 6a samples, 11 were mistyped as 1b. In conclusion, LiPA 2.0 was not suitable for identifying HCV genotypes in the samples tested, whereas core sequence analysis remained an ideal method for genotyping HCV.

Telaprevir: a hepatitis C NS3/4A protease inhibitor

BACKGROUND

Telaprevir is a hepatitis C NS3/4A protease inhibitor approved by the US Food and Drug Administration as part of combination therapy for the management of chronic hepatitis C virus (HCV) genotype 1 infection.

OBJECTIVE

The article reviews published literature on telaprevir, including its chemistry, mechanism of action, resistance, pharmacodynamic and pharmacokinetic properties, drug interactions, therapeutic efficacy, HIV/HCV coinfection, pharmacogenomics, adverse events, pharmacoeconomics, and dosing and administration.

METHODS

English-language literature was included. Searches of MEDLINE and BIOSIS databases from 1975 through January 2012 were performed. Emphasis was placed on reference citations involving clinical trials, randomized controlled trials, and research in humans. Additional publications were found by searching the reference lists of identified articles and reviewing abstracts from recent scientific meetings. Search terms included, but were not limited to, telaprevir, VX-950, hepatitis C virus genotype 1, resistance, pharmacology, pharmacokinetics, pharmacodynamics, drug interactions, pharmacogenomics, adverse events, and therapeutic use.

RESULTS

Review of the databases revealed 471 publications/abstracts on this subject. Of these, 85 were chosen based on the review criteria. Two Phase III studies investigated the efficacy and tolerability of telaprevir administered for 12 weeks (T12) when used with peginterferon alfa and ribavirin (PR) in treatment-naive subjects. The ADVANCE study reported that patients who had an extended rapid virologic response (eRVR; an undetectable HCV RNA level at both 4 and 12 weeks of treatment) with triple therapy could be treated with PR for a total of 24 weeks (T12PR24 group) versus standard PR treatment for 48 weeks (PR48 group [control]). The proportions of patients who achieved sustained virologic response (SVR; undetectable HCV RNA concentration at 24 weeks after the completion of therapy) in the T12PR24 and PR48 groups were 89% and 44%, respectively. The ILLUMINATE study reported T12PR24 was noninferior to T12PR48 in patients with an eRVR to combination therapy. In the REALIZE study, patients with a history of relapse responded well to T12PR48 compared with PR48 (SVR, 83% vs 24%). Telaprevir is a substrate/inhibitor of cytochrome P450 (CYP3A4) and a substrate/inhibitor of P-glycoprotein and poses an important risk for drug interactions. Adverse drug events (ADEs) reported most commonly with triple therapy compared with the T or PR regimen alone were rash, pruritus, nausea, diarrhea, and anemia. The serious AEs most commonly reported during T + PR therapy were anemia, rash, and pruritus. Two reports concluded that T combined with PR was not cost-effective due to the high cost of telaprevir. One study reported that the combination of T + PR would be cost-effective if the treatment rate of HCV genotype 1 infected patients reached 50%.

CONCLUSION

Including telaprevir as part of triple therapy for the management of chronic HCV genotype 1 infection significantly increases the likelihood of achieving an SVR over standard dual drug therapy (PR) in both treatment-naive and -experienced patients. However, due to the high cost, the use of triple therapy with telaprevir will likely be limited to patient groups known to respond poorly to dual therapy.

Epidemiology, responses, and way forward: the silent epidemic of viral hepatitis and HIV coinfection in Vietnam

Viral hepatitis is a disease of great concern to public health that is now met by a favorable momentum to combat the global epidemic. This article is intended to highlight the importance of viral hepatitis in the Vietnam population as well in the group of people living with HIV/AIDS (PLWHA). We reviewed available data on epidemiology and response on hepatitis B virus (HBV) and hepatitis C virus (HCV) and HIV coinfection in Vietnam. The hepatitis B surface antigen (HBsAg) prevalence in the general population ranged from 5.7% to 24.7%. The anti-HCV prevalence ranged from 0.38% to 4.3% in the general population, while among people who inject drugs (PWIDs) it ranged from 31% to 97.2%. The HBV prevalence among PLWHA is similar to the general population, while HCV/HIV coinfection is concentrated in some groups. Anti-HCV prevalence among HIV-infected PWIDs can be as high as 98.5%. Developing policies for diagnosis and treatment of chronic HBV and HCV infections are critical priorities in order to prevent clinical progression to cirrhosis and liver cancer.

Response-guided therapy for patients with hepatitis C virus genotype 6 infection: a pilot study

The optimal duration of treatment with pegylated interferon (PEG-IFN) plus ribavirin (RBV) in patients with hepatitis C virus (HCV) genotype 6 is unknown. This study was aimed at determining treatment response on the basis of rapid virological response (RVR) of HCV genotype 6 in comparison with genotypes 1 and 3. Sixty-six treatment naïve patients were treated with PEG-IFN-α2a (180 μg/week) plus weight-based RBV (1000-1200 mg/day). Patients with genotype 1 n = 16) and genotype 3 (n = 16) were treated for a fixed duration of 48 and 24 weeks, respectively. Patients with genotype 6 (n = 34) who achieved RVR were treated for 24 weeks (response-guided therapy) and the remaining patients were treated for 48 weeks (standard therapy). The mean baseline HCV RNA levels were not statistically different between groups (6.4 ± 0.8, 6.0 ± 1.0 and 6.5 ± 0.8 Log(10) IU/mL for genotypes 1, 3 and 6, respectively). Patients with genotypes 1, 3 and 6 achieved RVR in 43.8%, 87.5% and 73.5% of cases, respectively. One patient with genotype 1 and 3 with genotype 6 were considered nonresponders and discontinued therapy. Sustained virological response (SVR) was achieved in 62.5%, 81.3% and 76.5% of patients with genotypes 1, 3 and 6, respectively. The SVR rate in patients with genotype 6 who underwent response-guided therapy was 88%. This pilot study suggested that the SVR rate of HCV genotype 6 was at an intermediate level between those of genotypes 3 and 1. Treatment with PEG-IFN plus RBV for 24 weeks may be sufficient for patients with genotype 6 who achieve RVR. Prospective randomized trials are required to evaluate this response-guided strategy in a larger number of patients with genotype 6.

A randomized trial of 48 versus 24 weeks of combination pegylated interferon and ribavirin therapy in genotype 6 chronic hepatitis C

BACKGROUND & AIMS

Genotype 6 chronic hepatitis C (HCV) is encountered predominantly in Southeast Asia and data on optimal treatment strategy is limited. This study was aimed at assessing the rate and predictors of sustained virological response (SVR) in genotype 6 chronic HCV following 48 and 24 weeks of pegylated interferon and ribavirin therapy.

METHODS

This investigator-initiated, open-label randomized trial was conducted in Vietnam between 2008 and 2010. One hundred and five treatment-naïve HCV genotype 6 patients were randomized to either 48-week (N=70) or 24-week (N=35) duration of pegylated interferon (PEG-IFN) alfa-2a 180 mcg/week and ribavirin (RBV) 15mg/kg/day; 92 patients completed the study (63 in the 48-week and 29 in the 24-week group, respectively). Primary outcome was sustained virological response (SVR) as intention-to-treat analysis.

RESULTS

There was no statistical difference in SVR between 48-week and 24-week treated groups (71% vs. 60%, respectively; p=0.24). In the 48-week and 24-week treatment groups, 81% and 80% of cases achieved rapid virological response (RVR) (p=0.86), and 86% and 80% achieved complete early virological response (p=0.45). Among those patients with RVR, SVR was in 86% (48-weeks), and 75% (24-weeks) of cases, whereas following non-RVR, only 8% of cases had an SVR with 48-week treatment duration.

CONCLUSIONS

Overall, RVR was achieved in the majority of genotype 6 patients and, in those patients, similar and high rates of SVR were noted following 24-week and 48-week therapy. This observation, however, needs validation in a larger study to demonstrate non-inferiority of the shorter duration therapy. In non-RVR patients, even 48-week therapy achieved low SVR rates.

APASL consensus statements and management algorithms for hepatitis C virus infection

The Asian Pacific Association for the Study of the Liver (APASL) convened an international working party on the "APASL Consensus Statements and Management Algorithms for Hepatitis C Virus Infection" in December, 2010, in order to revise "Asian Pacific Association for the Study of the Liver consensus statements on the diagnosis, management and treatment of hepatitis C virus infection (J Gastroenterol Hepatol 22:615-633, 2007)". The working party consisted of expert hepatologists from the Asian-Pacific region gathered at Makuhari, Chiba, Japan on 19 December 2010. New data were presented, discussed and debated to draft a revision. Participants of the consensus meeting assessed the quality of cited studies. Finalized recommendations are presented in this review.

Twenty-four weeks of pegylated interferon plus ribavirin effectively treat patients with HCV genotype 6a

The optimal duration of treatment and expected response rate for hepatitis C virus genotype (HCV-6)-infected patients have not been determined. Our aims were to determine the treatment outcome with pegylated interferon (PEG-IFN) plus ribavirin for HCV-6a-infected patients at Southwest Hospital and assess the association of the on-treatment virological response with the sustained virological response (SVR). Medical records were reviewed retrospectively. Twenty-two HCV-6a-infected patients were treated for 24 weeks, and 21 (95.5%) achieved an early virological response (EVR), 20 (90.9%) an end-of-treatment response (ETR) and 18 (81.8%) a SVR. However, only 18 of the 22 HCV-6a-infected patients were tested for serum HCV RNA level at week 4 of treatment and 15 (83.3%) achieved a rapid virological response (RVR). The rates of SVR, RVR, EVR and ETR in these patients were all similar to those in HCV-2/3 treated for 24 weeks and higher than those in HCV-1b-infected patients treated for 48 weeks. A lower relapse rate (10.0%) was seen in HCV-6a compared with HCV-2/3 (12.5%) or HCV-1b-infected patients (23.3%). The positive predictive values of RVR and EVR for HCV-6a were comparable with those for HCV-2/3-infected patients (86.7%vs 90.9%, P = 0.683 and 85.7%vs 86.8%, P = 0.904, respectively). Of the 3 HCV-6a-infected patients who did not achieve a RVR, 2 achieved an EVR and went on to achieve a SVR. The patient who did not achieve an EVR did not achieve a SVR. In summary, our results indicate that 24 weeks of PEG-IFN plus ribavirin can effectively treat patients with HCV-6a chronic infection.

Systematic review: epidemiology of hepatitis C genotype 6 and its management

BACKGROUND

Hepatitis C virus (HCV) genotype 6 is common among patients from Southeast Asia and the surrounding regions, where HCV prevalence is also high. HCV genotype 6 has great genetic diversity and different response to antiviral therapy compared with the more commonly known genotype 1.

AIM

Our goal was to provide a systematic review of the current literature on the epidemiology, classification and treatment of HCV genotype 6.

METHODS

A search using PubMed for 'hepatitis C' AND 'genotype 6' produced a total of 47 articles, of which 33 articles were found to be relevant and included in this review. Additional articles were identified using the reference lists of these 33 primary articles.

RESULTS

The prevalence of HCV genotype 6 is estimated to be as high as 50% in some regions of Southeast Asia with demonstrated significance among intravenous drug users and thalassemia major patients. Although previous line probe assays may have misclassified HCV genotype 6 as genotype 1, newer line probe assays can more accurately and reliably determine HCV genotype. Patients infected with HCV genotype 6 respond better to interferon-based therapy compared with those infected with genotype 1, although patient baseline clinical characteristics and side effect profiles are similar between HCV genotype 6 and other HCV genotypes.

CONCLUSIONS

Future studies should seek to clarify issues regarding early predictors for treatment response in patients with HCV genotype 6, and the impact of ethnic and genotypic factors to treatment response in HCV genotype 6 patients.

Randomized controlled trial of pegylated interferon-alfa 2a and ribavirin in treatment-naive chronic hepatitis C genotype 6

Hepatitis C virus (HCV) genotype is an important criteria in determining duration of therapy and predictor of sustained virologic response (SVR) to pegylated interferon (PEG IFN) and ribavirin (RBV) therapy. Optimal duration of therapy for patients with HCV genotype 6 is not known. We conducted a multicenter, open-label randomized controlled trial of patients with HCV genotype 6 at five gastroenterology clinics in the western U.S. Patients were stratified by viral load and histologic stage and assigned to receive PEG IFN-α2a 180 μg subcutaneously weekly and weight-based oral RBV 800 to 1,200 mg daily for 24 or 48 weeks. Primary outcome measurement was SVR rate by intention-to-treat analysis. From February 2005 to October 2007 a total of 60 patients (age 51 ± 10 years, 47% male, log HCVRNA 6.3 ± 1.1 IU/mL) were enrolled: 27 patients to 24 weeks and 33 patients to 48 weeks of therapy. In the 24-week and 48-week groups, 96% and 97% achieved early virologic response (P = 0.90); 89% versus 94% achieved end of therapy virologic response (P = 0.48). SVR was achieved in 70% versus 79% of patients assigned to 24 weeks versus 48 weeks (P = 0.45). Rapid virologic response (RVR) was a significant predictor of SVR in the 48-week group and trending towards significance in the 24-week group: 82% and 83% of those with RVR achieved SVR versus 33% and 29% for the 24-week and 48-week groups, respectively (P = 0.07 and P = 0.02).

CONCLUSION

There was no significant difference in SVR rates in patients with HCV genotype 6 treated with PEG IFN-α2a and RBV for 24 versus 48 weeks.

Response to pegylated interferon and ribavirin in Asian American patients with chronic hepatitis C genotypes 1 vs 2/3 vs 6

Chronic hepatitis C is generally underappreciated in Asian Americans, and most pivotal studies were conducted in western countries and only included a small numbers of Asian patients. Our goal was to examine and compare treatment outcomes in these patients with genotypes 1 vs 2/3 vs 6. We performed a retrospective cohort study of 167 consecutive treatment-naïve Asian American patients treated with pegylated interferon (PEG IFN) plus ribavirin (RBV) at two community clinics in Northern California from 12/00 to 1/08. Primary outcome was sustained virological response rate by intention-to-treat analysis. The overall completion rate was 76%, and treatment adherence (completion of ≥ 75-80% PEG IFN + RBV dose for ≥ 75-80% of intended duration) was 74%. Significant depression was noted in only 4% of patients. Sustained virologic response in patients with genotype 6 treated for 48 weeks was similar to that seen in those with genotype 2/3 (74%vs 75%, P = 0.89) and significantly higher than those with genotype 1 (74%vs 49%, P = 0.016). On multivariate analysis inclusive of sex, age, body mass index (≤ 25 vs > 25) and viral load, only treatment adherence and genotype (2/3 and 6 treated for 48 weeks) were found to be significant predictors of sustained virologic response. We conclude that significant depression is rare in Asian American patients (4%). Patients with genotype 6 treated for 48 weeks appear to have a similar treatment response rate as patients with genotype 2/3 and a significantly higher response rate than those with genotype 1.

Hepatitis C virus genotyping using an oligonucleotide microarray based on the NS5B sequence

The genotype of the hepatitis C virus (HCV) is essential for determining treatment duration in clinical practice and for epidemiological and clinical studies. Currently, few genotyping assays that determine the HCV subtype are available. This report describes a microarray-based molecular technique for identifying the HCV genotype and subtype. It uses low-density hydrogel-based biochips containing genotype- and subtype-specific oligonucleotides based on the sequences of the NS5B region of the HCV genome. The biochip contains 120 oligonucleotides that identify genotypes 1 to 6 and 36 (1a, 1b, 1c, 1d, 1e, 2a, 2b, 2c, 2d, 2i, 2j, 2k, 2l, 2m, 3a, 3b, 3k, 4a, 4c, 4d, 4f, 4h, 4i, 4k, 4n, 4o, 4p, 4r, 4t, 5a, 6a, 6b, 6d, 6g, 6h, and 6k) subtypes. The procedure included amplification of a 380-nucleotide (nt) fragment of NS5B and its hybridization on the biochip. Tests on 345 HCV-positive samples showed that the assay agreed with NS5B sequencing 100% for the genotype and 99.7% for the subtype. The hybridization on the microarray and the NS5B sequence were in 100% agreement for identifying the most common subtypes, 1a, 1b, 4a, 4d, and 3a. This approach is a promising tool for HCV genotyping, especially for implementing the new anti-HCV drugs that require accurate identification of clinically relevant subtypes.

Natural history of chronic hepatitis C: genotype 1 versus genotype 6

BACKGROUND & AIMS

Data on the natural history of chronic hepatitis C virus (HCV) genotype 6 is lacking.

METHODS

We compared the natural history of 138 HCV genotype 1 patients (median age: 50) with 78 HCV genotype 6 patients (median age: 46.5). Baseline demographic data including gender, route of transmission, liver biochemistry, HCV RNA levels, and serial alanine aminotransferase (ALT) levels were compared. The rate of development of complications and mortality were also analyzed.

RESULTS

A total of 71.7% and 8.7% of genotype 1 patients were infected through blood transfusion and intravenous drug addiction, respectively, compared with 56.4% and 28.2% for genotype 6 patients, respectively (p<0.05). There were no differences in the baseline liver biochemistry in terms of ALT, albumin, bilirubin, alpha-fetoprotein (AFP), and HCV RNA levels between the two groups. Comparison of the proportion of normal and abnormal ALT levels between the two groups showed no statistical difference (p=0.121). There was also no statistical difference in the cumulative rate of development of cirrhotic complications and hepatocellular carcinoma (p=0.358) and mortality (p=0.649) between the two groups.

CONCLUSIONS

HCV genotype 1 patients were largely infected through blood transfusion, while a statistically larger proportion of genotype 6 patients were infected through intravenous drug injection. Both genotypes have comparable liver biochemistry, HCV viral load, and similar rates of development of cirrhotic complications and mortality.

New antiviral therapies for chronic hepatitis C

Chronic hepatitis C is an important health issue worldwide. The current standard therapy is based on a combination of pegylated-interferon (pegIFN) and ribavirin (RBV), but this treatment leads to only ~50% sustained virological response (SVR) in patients with HCV genotype 1 and high viral loads, who were mostly null-responders or relapsers. Among HCV genotypes other than HCV genotype 1, especially HCV genotype 4 patients show only 40-70% SVR by this treatment. Although new drugs also depend on the combination of pegIFN and RBV, it appears that these drugs improve not only rapid virological response (RVR) but also early virological response, leading to SVR in these patients. In the near future, we predict higher SVR rates in chronic hepatitis C patients treated with these new drugs.

Superior response to pegylated interferon and ribavirin in Asians with chronic hepatitis C

PURPOSE

Reported sustained virological response (SVR) rates in Asians with chronic hepatitis C (CHC) exceed those of other ethnic groups, but differences in body weight across races potentially confound this observed superior response. Our aim was to determine whether Asian race independently predicts SVR within a multicultural clinic setting.

METHODS

Patients with genotype 1, 2 and 3 CHC prescribed peginterferon and weight-based ribavirin were included in this retrospective study. Logistic regression was performed to identify factors associated with SVR.

RESULTS

Three-hundred ninety-two patients (BMI 26.9 ± 5.0 kg/m(2), genotype 1 66%, viral load 5.9 ± 0.66 log(10) IU/ml, advanced fibrosis 53%) were included in this study. Caucasians comprised 81%, South Asians 9% and Asians (Non-South) 10%. SVR was achieved by 54% overall, but was highest amongst Asians (Non-South) (79%) compared with South Asians (56%, P = 0.04) and Caucasians (50%, P < 0.001) despite a predominance of genotype 3 infection amongst the South Asians. Asians (Non-South) had the highest SVR rate even amongst those infected with genotype 1 (75%) and those with advanced fibrosis (77%). Independent of viral genotype, Asian (Non-South) race was a strong predictor of SVR (OR 5.10 vs. Caucasians, 95% CI 1.72-17.71, OR 7.84 vs. South Asians, 95% CI 1.62-37.84), as were treatment naïve status (OR 3.85, 95% CI 1.76-8.89), non-diabetic status (OR 3.70, 95% CI 1.30-11.11), non-obesity (OR 2.13, 95% CI 1.06-4.35), peginterferon α2a (2.08 vs. α2b, 95% CI 1.16-3.85), steatosis <10% (OR 2.0, 95% CI 1.05-3.85) and ribavirin exposure (mg/kg/day) (OR 1.13, 95% CI 1.01-1.28).

CONCLUSION

Asian (Non-South) race is a strong independent predictor of SVR.

Individualisation of antiviral therapy for chronic hepatitis C

The combination of pegylated-interferon (PEG-IFN)/ribavirin is currently the standard of care antiviral treatment for chronic hepatitis C (CHC), but optimal results require an individual approach. Key issues are to deliver doses that confer optimal antiviral efficacy against hepatitis C virus (HCV) for a time sufficient to minimise relapse. Viral monitoring during therapy guides the subsequent treatment course, particularly HCV RNA results at 4 weeks (rapid viral response [RVR]) and 12 weeks (complete early viral response [cEVR]). There is strong evidence that for most patients with genotypes 2 or 3 HCV infection, RVR allows truncation of treatment to 16 weeks, provided ribavirin dose is weight-based. However, those patients with cirrhosis, insulin resistance/diabetes or older than 50 years need 6-12 months treatment. For "difficult-to-treat" CHC (genotypes 1 and 4), RVR is infrequent (approximately 15% in European studies), but allows treatment to be truncated from 48 to 24 weeks. Without RVR, there is some evidence that longer treatment (72 weeks) improves sustained viral response (SVR). However, "induction dosing" first 12 weeks of PEG-IFN clearly does not improve SVR. To prevent dose reductions and complete therapy, it is critical to detect and treat depression and other disabling side-effects, including judicious use of growth factors for severe anemia or neutropenia and possibly, thrombocytopenia. Another potentially important aspect may be attempts to counter central obesity and insulin resistance, which confer suboptimal antiviral response with any HCV genotype. Treatment partnerships with specialist nurses, psychological therapists and other healthcare workers are also essential for optimal individual management of patients with CHC.

Similar treatment response to peginterferon and ribavirin in Asian and Caucasian patients with chronic hepatitis C

OBJECTIVES

Previous studies have found ethnicity to be an important predictor of outcomes of treatment with peginterferon (PEG-IFN) and ribavirin (RBV) in chronic hepatitis C. Although the expected sustained virological response (SVR) rates of Hispanics and African Americans are lower than those of Caucasians, SVR rates in Asians appear to be more favorable. However, in some of these studies, hepatitis C virus (HCV) genotype was identified by INNO-LiPA assay, which can mistype the easier-to-treat HCV genotype 6 as genotype 1. Our goal was to compare SVR rates among Caucasian and Asian-American patients with genotype 1 and 2/3 infection whose HCV genotypes were accurately classified by core sequencing testing.

METHODS

A cohort of 269 consecutive treatment-naive HCV-infected patients with genotype 1 or 2/3 (157 Caucasians and 112 Asians) treated with PEG-IFN+RBV from January 2001 to November 2007 at four community-based gastroenterology clinics in Northern California were studied. The analysis of data was by intention-to-treat.

RESULTS

The SVR rates for patients with genotype 1 were 45% for Caucasians and 52% for Asians (P=0.37). The SVR rates for patients with genotype 2/3 infection was 77% for Asians and 74% for Caucasians (P=0.7). On multivariate logistic regression analyses adjusting for age, alanine aminotransferase (ALT), baseline viral load, HCV genotype, and treatment adherence, we did not find Asian ethnicity to predict SVR. On a separate analysis, we found that Asians who had HCV genotype 1 or 1b by the less accurate INNO-LiPA assay had significantly higher SVR rates than Caucasians with genotype 1 (64% vs. 45%, respectively, P=0.03).

CONCLUSIONS

SVR rates were similar in Asian Americans and Caucasians infected with HCV genotype 1 or 2/3 when HCV genotype classification was accurately determined.

Risk factors, genotype 6 prevalence, and clinical characteristics of chronic hepatitis C in Southeast Asian Americans

PURPOSE

Although infection with hepatitis C virus (HCV) affects 32 million individuals from Southeast Asia, little is known about the mode of HCV acquisition and the epidemiology of chronic hepatitis C (CHC) in these individuals. Our goal was to examine risk factors for HCV acquisition, prevalence, and clinical characteristics of HCV genotype 6 compared with genotypes 1 and 2/3 in Southeast Asian (SEA) patients.

METHODS

We performed a cross-sectional study of 308 consecutive SEA Americans with CHC evaluated by five gastroenterologists from January 2000 to December 2008 at two community clinics in northern California via medical record review, using a case report form.

RESULTS

A significant proportion of patients (41%) could not recall any specific risk factors for HCV acquisition. The most commonly reported risk factor in patients who reported at least one risk factor was history of surgeries (34%), followed by blood transfusion (25%) and acupuncture (13%). Among patients with core sequence testing for HCV genotype (n = 181), the most common HCV genotypes were genotype 1 (42%) and genotype 6 (41%), followed by genotype 2/3 (17%). There were no major differences in the clinical and virological characteristics between the different genotype groups (1 vs. 2/3 vs. 6).

CONCLUSION

HCV genotype 6 is as common as genotype 1 in SEAs. Commonly known risk factors for HCV acquisition were not readily identifiable in a large proportion of SEA Americans (41%) and may not be useful in identifying at-risk individuals for HCV screening in this population.

Chronic hepatitis C genotype 6 responds better to pegylated interferon and ribavirin combination therapy than genotype 1

BACKGROUND AND AIMS

Chronic hepatitis C genotype 6 is common in Hong Kong, especially among i.v. drug abusers. Responses of these patients to combination of pegylated interferon and ribavirin treatment were inconsistent and the numbers of patients involved in previous studies were small. We performed a retrospective study to compare the therapeutic responses of this regimen in patients infected with genotype 6 and genotype 1.

METHODS

Seventy patients with either genotype 6 or genotype 1 were recruited. Both groups received 800-1200 mg of ribavirin daily plus either 180 mg of pegylated alpha-interferon-2a or 1.5 mg/kg pegylated alpha-interferon-2b weekly for 48 weeks. Their responses to treatments were compared.

RESULTS

The early virological response to combination therapy of patients with genotype 6 was significantly better than that of genotype 1 (88.6% vs 74.3%, P = 0.03). Significant difference was also identified in the end of treatment response of the two genotypes (60% vs 81.4% for genotype 1 and 6, respectively; P = 0.005). The sustained virological response (SVR) to treatment in patients with genotype 6 was also significantly superior to that of patients with genotype 1 (75.7% vs 57.1%, P = 0.02). Multiple logistic regression analysis demonstrated that age of 55 years or less, genotypes of hepatitis C virus, liver biopsy staging and baseline hepatitis C virus RNA of 200,000 IU/mL or less were independent predictors for better SVR in this cohort.

CONCLUSION

Patients with chronic hepatitis C genotype 6 respond better to pegylated interferon and ribavirin combination treatment than patients with genotype 1.

Individualized treatment of chronic hepatitis C with pegylated interferon and ribavirin

Chronic infection with hepatitis C virus (HCV) is a major public health problem, with perhaps 180 million people infected worldwide. A significant proportion of these will eventually develop clinical complications, such as cirrhosis, liver decompensation and hepatocellular carcinoma. Sustained virological response (SVR) to antiviral therapy is associated with improvement in liver histology and survival free of liver-related complications. Great effort has been made to improve SVR rate by adapting the duration of therapy according to HCV genotype and to on-treatment response. Rapid virological response (RVR, undetectable HCV RNA at week 4) usually has a high positive predictive value for achieving SVR and early virological response (EVR, ≥ 2 log reduction or undetectable HCV RNA at week 12) exhibits a high negative predictive value for non-response. Individualized approach can improve cost-effectiveness of HCV antiviral therapy by reducing side effects and the costs of therapy associated with unnecessary exposure to treatment and through extending therapy for those with unfavorable features. This article summarizes recent data on strategies of individualized treatment in naïve patients with mono-infection by the different HCV genotypes. The management of common side effects, the impact of HCV infection on health-related quality of life and the potential applications of host genomics in HCV therapy are also briefly discussed.

The neglected hepatitis C virus genotypes 4, 5 and 6: an international consensus report

Abstract Hepatitis C virus (HCV) genotypes 4, 5 and 6 represent >20% of all HCV cases worldwide. HCV-4 is mainly seen in Egypt, where it represents 90% of all HCV cases. Antischistosomal therapy was the main cause of contamination there, followed by procedures performed by informal providers and traditional healers such as dental care, wound treatment, circumcision, deliveries, excision and scarification. It is also highly prevalent in sub-Saharan Africa and in the Middle East. In Europe, its prevalence has recently increased particularly among intravenous drug users and in immigrants. HCV-5 is mainly found in South Africa, where it represents 40% of all HCV genotypes, but four pockets of HCV-5 were found in France, Spain, Syria and Belgium and sporadic cases were found elsewhere. The mode of transmission is mainly iatrogenic and transfusion. HCV-6 is found in Hong Kong, Vietnam, Thailand and Myanmar and also in American and Australian from Asian origin. The response to treatment in HCV-4 is intermediate between HCV-1 and HCV-2 and HCV-3. A sustained viral response is achieved in 43-70% with pegylated interferon and ribavirin. It is higher in Egyptians than Europeans and Africans and is negatively related to insulin resistance and to the severity of fibrosis. It increases to >80% with 24 weeks of therapy only if a rapid virological response is achieved. In HCV-5, a sustained virological response is achieved in >60% with 48 weeks of therapy. HCV-6 is also considered an easy-to-treat genotype, leading to a response in 60-85% of cases.