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

Change in treatment paradigm in people who previously injected drugs with chronic hepatitis C in the era of direct-acting antiviral therapy

BACKGROUND

Chronic hepatitis C virus (HCV) infection is highly prevalent among people who inject drugs but is often undiagnosed. The treatment paradigm for HCV patients has been changing since the availability of direct-acting antiviral (DAA) treatment. We aimed to evaluate the change in treatment paradigm of people who previously injected drugs (ex-PWID) in Hong Kong before and after the availability of DAA.

METHOD

Consecutive ex-PWID referred from various nongovernmental organizations attended education talks at rehabilitation centers and received point-of-care rapid test for HCV antibody (anti-HCV) at the same session. Subjects tested positive for anti-HCV were invited to undergo further assessment. Afterwards, the patients were referred to the regional hospitals for follow-up and/or treatment.

RESULTS

Three hundred sixty-five ex-PWID received HCV rapid test; 268 (73.4%) were found to be anti-HCV positive. Among these 268 HCV-positive ex-PWID, 234 (87.3%) attended the assessment session (mean age 52 years, 90.2% male, 45.5% genotype 1b, 41.1% genotype 6a, and median liver stiffness 5.9 kPa); 187 (69.8%) attended follow-up visits at regional hospitals. Seventy-one patients received antiviral treatment for HCV; 69 first received peginterferon and ribavirin (PegIFN/RBV), whereas 10 patients (eight PegIFN/RBV-treated patients) received DAA treatment. Fifty-two patients achieved sustained virologic response at 12 or 24 weeks. Treatment uptake rates of PegIFN/RBV and DAA treatment in the pre-DAA versus post-DAA era were 22.3% versus 48.5% and 0% versus 15.6%, respectively.

CONCLUSIONS

Targeted screening in ex-PWID is effective in identifying patients with HCV infection in the community. To improve treatment uptake, further improvements in the referral system and treatment regimens are needed.

Liver disease burden and required treatment expenditures for hepatitis C virus (HCV) infection in Thailand: Implications for HCV elimination in the new therapeutic era, a population-based study

The prevalence of hepatitis C virus (HCV) infection has been decreasing globally, but the growing effects of HCV-related morbidity and mortality remain of concern. Advances in curative medicine, involving direct-acting antivirals (DAAs), have led many countries to aim to eradicate HCV. Information on epidemiology and disease burden is essential for national policy development. Thus, this study aimed to determine the HCV-related hepatic disease burden in areas of Thailand with high and average HCV prevalence in order to extrapolate the viral burden across Thailand. Patients previously diagnosed as positive for anti-HCV antibodies were recruited to assess chronic HCV infection (CHC) status, liver function, HCV-RNA level and hepatic fibrosis. The number of patients eligible for Universal Health Coverage (UC) scheme and the approximately required expenditure on interferon (IFN)-based treatment were estimated. In areas of both high (12%) and average (2%) HCV viremic prevalence, over half of the patients (52.2% to 62.5%) had advanced liver fibrosis (F3 and F4). A striking percentage of patients with F4 (38.9%) were found in the high-prevalence area, while comparable proportions of advanced liver fibrosis presented in the two areas and disease burden peaked at 50–59 years. Under the current UC program treatment scenario, 78–83% of CHC patients with stage F2–F4 fibrosis were eligible for treatment. The estimated expenditure required for overall CHC treatment across the whole country was 1,240 million USD at this current status, but the declining cost of generic DAA-based therapy may reduce the requirement to <90 million USD. This study provides information on the estimated number of CHC patients, liver disease burden and expenditure requirements for Thailand. To eliminate HCV by 2030, proactive government strategies raising public health to minimize transmission and emphasizing targeted screen-and-treatment programs, novel therapeutic guideline development for decentralizing treatment, and effective budget allocation are urgently needed.

[Prevalence, risk factors and clinical characteristics in patients with genotype 6 chronic hepatitis C: a single institute experience]

BACKGROUND/AIMS

Hepatitis C genotypes 1 and 2 are widely distributed globally. In contrast, genotype 6 is found mainly in Southeast Asia, while genotype 6 is rare in Korea. This study aims to investigate the prevalence, risk factors and clinical characteristics of patients with genotype 6 chronic hepatitis C.

METHODS

We retrospectively identified 133 HCV-infected patients who underwent HCV genotype analysis between January 2012 and December 2012, and analyzed the prevalence, risk factors and clinical characteristics of patients diagnosed with genotype 6 chronic hepatitis C.

RESULTS

Among 133 patients, 53 patients (39.8%) were infected with genotype 1, 62 patients (46.6%) with genotype 2, 2 patients (1.5%) with genotype 3, 14 patients (10.5%) with genotype 6, and 2 patients (1.5%) with mixed genotypes (genotype 1 and 6). The risk factors associated with genotype 6 were acupuncture (n=4, 28.6%), intravenous drug use (n=3, 21.4%), tattoo (n=2, 14.3%), and transfusion (n=2, 14.3%). Of the 14 patients with genotype 6, 6 patients were treated with pegylated interferon and ribavirin. Five patients had reached the end of treatment. All patients reaching end of treatment for genotype 6 showed early virological response and sustained virological response.

CONCLUSIONS

The prevalence of genotype 6 is 10.5% and mixed infections of genotype 1 and 6 are 1.5% in patients with chronic hepatitis C. A major potential risk factor is intravenous drug use and the treatment response rate to pegylated interferon plus ribavirin is high in patients with genotype 6 chronic hepatitis C. Large scale multicenter studies are needed.

Economic evaluation of pegylated interferon plus ribavirin for treatment of chronic hepatitis C in Thailand: genotype 1 and 6

Background

Pegylated interferon alpha 2a, alpha 2b and ribavirin have been included to the National List of Essential Medicines (NLEM) for treatment of only chronic hepatitis C genotypes 2 and 3 in Thailand. This reimbursement policy has not covered for other genotypes of hepatitis C virus infection (HCV) especially for genotypes 1 and 6 that account for 30-50 % of all HCV infection in Thailand. Therefore, this research determined whether pegylated interferon alpha 2a or alpha 2b plus ribavirin is more cost-effective than a palliative care for treatment of HCV genotype 1 and 6 in Thailand.

Methods

A cost-utility analysis using a model-based economic evaluation was conducted based on a societal perspective. A Markov model was developed to estimate costs and quality-adjusted life years (QALYs) comparing between the combination of pegylated interferon alpha 2a or alpha 2b and ribavirin with a usual palliative care for genotype 1 and 6 HCV patients. Health-state transition probabilities, virological responses, and utility values were obtained from published literatures. Direct medical and direct non-medical costs were included and retrieved from published articles and Thai Standard Cost List for Health Technology Assessment. The incremental cost-effectiveness ratio (ICER) was presented as costs in Thai baht per QALY gained.

Results

HCV treatment with pegylated interferon alpha 2a or alpha 2b plus ribavirin was dominant or cost-saving in Thailand compared to a palliative care. The ICER value was negative with lower in total costs (peg 2a- 747,718vs. peg 2b- 819,921 vs. palliative care- 1,169,121 Thai baht) and more in QALYs (peg 2a- 13.44 vs. peg 2b- 13.14 vs. palliative care- 11.63 years) both in HCV genotypes 1 and 6.

Conclusion

As cost-saving results, the Subcommittee for Development of the NLEM decided to include both pegylated interferon alpha 2a and alpha 2b into the NLEM for treatment of HCV genotype 1 and 6 recently. Economic evaluation for these current drugs can be further applied to other novel medications for HCV treatment.

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.

Impact of IL28B and PNPLA3 polymorphisms on treatment outcomes in patients infected with genotype 6 hepatitis C virus

BACKGROUND/AIMS

Interleukin-28B (IL28B) and patatin-like phospholipase domain containing 3 (PNPLA3) gene polymorphisms are associated with hepatitis C virus (HCV) clearance and fatty liver, respectively. We aimed to test if their polymorphisms are associated with virologic responses in Chinese chronic hepatitis C (CHC) patients.

METHODS

This was a retrospective-prospective cohort study. Consecutive patients infected by genotype 1 and 6 HCV received antiviral therapy were included. Host IL-28B rs12979860/rs8099917 and PNPLA3 rs738409 genotype were tested. The primary outcome was sustained virologic response (sustained virologic response [SVR]: undetectable HCV RNA 24 weeks post-treatment).

RESULTS

From 305 patients had positive antibody to HCV, 52 and 31 patients infected by genotype 1 and 6 HCV, respectively were recruited. Mean age was 58 ± 11 years; 70% were male. Mean baseline HCV RNA was 6.8 ± 2.7 log IU/ml. The SVR for patients infected by genotype 1 and 6 HCV was 67.3% and 90.3%, respectively. The proportions of IL28B genotypes were 78%, 21%, and 1% for TT/TG/GG at rs8099917, and 81%, 18%, and 1% for CC/TC/TT at rs12979860, respectively. The proportions of PNPLA3 rs738409 genotypes were 16%, 36%, and 48% for GG/GC/CC. IL28B genotype was significantly associated with SVR in patients infected by genotype 1 but not genotype 6 HCV, with 80% versus 38% of patients infected by genotype 1 achieved SVR carried TT versus TG/GG at rs8099917, respectively (P=0.003). PNPLA3 genotype was not associated with SVR.

CONCLUSIONS

IL28B gene with rs8099917 T allele as an independent predictor of SVR in Chinese CHC patients infected by genotype 1 but not genotype 6 HCV.

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.

Failed triple therapy in a treatment-experienced patient with genotype 6 hepatitis C infection

PURPOSE

The first published report of the use of triple therapy in a patient with hepatitis C virus (HCV) genotype 6 infection-a treatment that was prescribed due to incorrect HCV genotyping and which ultimately failed-is presented.

SUMMARY

A 70-year-old male U.S. resident of Vietnamese descent requested treatment for chronic HCV infection acquired decades earlier. He reported experiencing hepatitis C treatment failures twice before-13 years prior (interferon alfa monotherapy for six months) and 7 years prior (standard dual therapy with pegylated interferon alfa-2b and ribavirin for nine months). Initial viral genotyping indicated infection with HCV genotypes 1a and 6c (a form of mixed HCV disease amenable to triple therapy), and treatment with pegylated interferon alfa-2a, ribavirin, and boceprevir was initiated. By week 8 of triple therapy, the patient's viral load had decreased from 15,700,000 (7.20 log) to 462,882 (5.67 log) IU/mL, but the viral load subsequently rebounded to baseline levels, and treatment was discontinued at week 16. When repeat HCV genotyping was performed, it was discovered that initial genotyping was incorrect and that the man's infection involved not mixed genotypes but only genotype 6; he was not an appropriate candidate for triple therapy. The case emphasizes the need for clinicians to be cognizant of potential HCV genotyping errors, particularly with regard to patients of Southeast Asian descent.

CONCLUSION

Three courses of interferon-based treatment, including triple therapy with boceprevir, failed to produce a sustained therapeutic response in a 70-year-old ethnic Vietnamese man with genotype 6 HCV infection.

Early viral kinetics during hepatitis C virus genotype 6 treatment according to IL28B polymorphisms

AIM

To investigate the early viral kinetics and interleukin-28B (IL28B) polymorphisms of hepatitis C genotype 6 during pegylated interferon and ribavirin therapy.

METHODS

Sixty-five patients with chronic hepatitis C virus (HCV) infection treated with pegylated interferon and ribavirin (PEG-IFN/RBV) were included, of whom 15 (23.1%), 16 (24.6%) and 34 (52.3%) patients were infected with hepatitis C genotype 1 (HCV-1), genotype 3 (HCV-3) and genotype 6 (HCV-6), respectively. Serum HCV-RNA levels were measured frequently during the first 4-wk of therapy. DNA extracted from samples was analyzed for the IL28B single nucleotide polymorphism (SNP) rs12979860 by polymerase chain reaction and direct sequencing.

RESULTS

During the first 4-wk of therapy, the mean viral decline for patients with HCV-6 (5.55 ± 1.82 log₁₀IU/mL) was comparable to that of patients with HCV-3 (5.55 ± 1.82 log₁₀IU/mL vs 5.86 ± 1.02 log₁₀IU/mL, P = 0.44) and was significantly higher than patients with HCV-1 (5.55 ± 1.82 log₁₀IU/mL vs 4.23 ± 1.99 log₁₀IU/mL, P = 0.04). In the HCV-6 group, the first phase (days 0-2) viral decline was significantly higher in patients with the favorable rs12979860 CC than non-CC genotypes (2.46 ± 1.01 log₁₀IU/mL/wk vs 1.70 ± 0.67 log₁₀IU/mL, respectively, P = 0.045). A statistically insignificant decrease in the second-phase (days 7-28) decline was also found in patients with the CC genotype than those with the non-CC genotype, though not significantly different (1.24 ± 0.64 log₁₀IU/mL/wk vs 0.80 ± 0.65 log₁₀IU/mL/wk, respectively, P = 0.172). At baseline, the SNP genotype was an independent predictor of rapid virological response but not of sustained virological response.

CONCLUSION

The IL28B genotype was linked to an impact on early viral kinetics in response to PEG-IFN/RBV therapy in HCV-6 infected patients.

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.

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.

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.

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.

Clinical and epidemiological characteristics of Korean patients with hepatitis C virus genotype 6

Background/Aims

The distribution of hepatitis C virus (HCV) genotypes varies geographically. In Korea, genotypes 1 and 2 comprise more than 90% of HCV infections, while genotype 6 is very rare. This study compared the clinical and epidemiological characteristics of patients with genotype 6 HCV infection with those infected with HCV genotypes 1 and 2.

Methods

This was a prospective, multicenter HCV cohort study that enrolled 1,173 adult patients, of which 930 underwent HCV genotype analysis, and only 9 (1.0%) were found to be infected with genotype 6 HCV. The clinical and epidemiological parameters of the genotypes were compared.

Results

The patients with genotype 6 HCV had a mean age of 41.5 years, 77.8% were male, and they had no distinct laboratory features. A sustained virologic response (SVR) was observed in four (67%) of six patients who received antiviral therapy. Risk factors such as the presence of a tattoo (n=6, 66.7%), more than three sexual partners (n=3, 33.3%), and injection drug use (n=3, 33.3%) were more common among genotype 6 patients than among genotypes 1 or 2.

Conclusions

The epidemiology and treatment response of patients infected with genotype 6 HCV differed significantly from those with genotypes 1 or 2, warranting continuous monitoring.

Treatment indication and response to standard of care with peginterferon and ribavirin in acute and chronic HCV infection

Great strides have been made in the treatment of hepatitis C virus (HCV) infection in the past decade. Although there is much focus on the development of new direct-acting antivirals (DAA), interferon and ribavirin remain the backbone of therapy for both acute and chronic HCV infections. While DAA therapy will likely eventually largely replace interferon, in much of the world and for genotype non-1 patients, peginterferon and ribavirin remain first-line therapy. Interferon-based therapy is highly effective in acute HCV with high response rates with short courses of therapy. Unfortunately once infection progresses to chronicity, treatment success rates drop off considerably. The indications, pre-treatment evaluation and efficacy of peginterferon and ribavirin therapy in the treatment of acute and chronic HCV infection are discussed with strategies to improve outcomes and manage adverse events.

Hepatitis C therapy in non-genotype 1 patients: the near future

Worldwide, 50-70 million subjects are infected with an hepatitis C virus (HCV) genotype 2, 3, 4, 5 or 6. In these patients, the combination of PEG-INF-α and ribavirin remains the currently approved standard-of-care treatment. The identification of different potential therapeutic targets in the HCV life cycle has led to the development of both direct antiviral agents (DAAs) and reagents targeting host functions essential for viral replication. DAAs comprise so far first-generation, second-wave and second-generation NS3/4A protease inhibitors (PIs), nucleos(t)ide (NIs) and non-nucleoside inhibitors of the NS5B RNA polymerase and NS5A complex inhibitors. The main host-protein-directed antiviral agents are cyclophilin inhibitors and silibinin. Whereas the launch of first-generation PIs was a major landmark in the management of genotype 1 (GT-1)-infected patients, these drugs are inactive in most non-GT-1-infected patients. Several of these and other drugs have now reached phase II and even phase III clinical stage development. The purpose of this article is to provide an overview of the clinical results recently reported for the treatment for non-GT-1 HCV infection with a focus on the most promising new compounds and combinations.