Ledipasvir-sofosbuvir in patients with hepatitis C virus genotype 5 infection: an open-label, multicentre, single-arm, phase 2 study

Contemporary Insights into Hepatitis C Virus: A Comprehensive Review

Hepatitis C virus (HCV) remains a significant global health challenge. Approximately 50 million people were living with chronic hepatitis C based on the World Health Organization as of 2024, contributing extensively to global morbidity and mortality. The advent and approval of several direct-acting antiviral (DAA) regimens significantly improved HCV treatment, offering potentially high rates of cure for chronic hepatitis C. However, the promising aim of eventual HCV eradication remains challenging. Key challenges include the variability in DAA access across different regions, slightly variable response rates to DAAs across diverse patient populations and HCV genotypes/subtypes, and the emergence of resistance-associated substitutions (RASs), potentially conferring resistance to DAAs. Therefore, periodic reassessment of current HCV knowledge is needed. An up-to-date review on HCV is also necessitated based on the observed shifts in HCV epidemiological trends, continuous development and approval of therapeutic strategies, and changes in public health policies. Thus, the current comprehensive review aimed to integrate the latest knowledge on the epidemiology, pathophysiology, diagnostic approaches, treatment options and preventive strategies for HCV, with a particular focus on the current challenges associated with RASs and ongoing efforts in vaccine development. This review sought to provide healthcare professionals, researchers, and policymakers with the necessary insights to address the HCV burden more effectively. We aimed to highlight the progress made in managing and preventing HCV infection and to highlight the persistent barriers challenging the prevention of HCV infection. The overarching goal was to align with global health objectives towards reducing the burden of chronic hepatitis, aiming for its eventual elimination as a public health threat by 2030.

Therapeutic manipulation of IKBKAP mis-splicing with a small molecule to cure familial dysautonomia

Approximately half of genetic disease-associated mutations cause aberrant splicing. However, a widely applicable therapeutic strategy to splicing diseases is yet to be developed. Here, we analyze the mechanism whereby IKBKAP-familial dysautonomia (FD) exon 20 inclusion is specifically promoted by a small molecule splice modulator, RECTAS, even though IKBKAP-FD exon 20 has a suboptimal 5' splice site due to the IVS20 + 6 T > C mutation. Knockdown experiments reveal that exon 20 inclusion is suppressed in the absence of serine/arginine-rich splicing factor 6 (SRSF6) binding to an intronic splicing enhancer in intron 20. We show that RECTAS directly interacts with CDC-like kinases (CLKs) and enhances SRSF6 phosphorylation. Consistently, exon 20 splicing is bidirectionally manipulated by targeting cellular CLK activity with RECTAS versus CLK inhibitors. The therapeutic potential of RECTAS is validated in multiple FD disease models. Our study indicates that small synthetic molecules affecting phosphorylation state of SRSFs is available as a new therapeutic modality for mechanism-oriented precision medicine of splicing diseases.

Discovery and Optimization of a 4-Aminopiperidine Scaffold for Inhibition of Hepatitis C Virus Assembly

The majority of FDA-approved HCV therapeutics target the viral replicative machinery. An automated high-throughput phenotypic screen identified several small molecules as potent inhibitors of hepatitis C virus replication. Here, we disclose the discovery and optimization of a 4-aminopiperidine (4AP) scaffold targeting the assembly stages of the HCV life cycle. The original screening hit (1) demonstrates efficacy in the HCVcc assay but does not show potency prior to or during viral replication. Colocalization and infectivity studies indicate that the 4AP chemotype inhibits the assembly and release of infectious HCV. Compound 1 acts synergistically with FDA-approved direct-acting antiviral compounds Telaprevir and Daclatasvir, as well as broad spectrum antivirals Ribavirin and cyclosporin A. Following an SAR campaign, several derivatives of the 4AP series have been identified with increased potency against HCV, reduced in vitro toxicity, as well as improved in vitro and in vivo ADME properties.

Current treatment for hepatitis C virus/human immunodeficiency virus coinfection in adults

Hepatitis C virus (HCV)/human immunodeficiency virus (HIV) coinfection is a major problem among HIV-infected patients, resulting in increased morbidity and mortality rates due to the acceleration of liver fibrosis progression by HIV, leading to liver cirrhosis and hepatocellular carcinoma. Although the efficacy of direct-acting antiviral therapy in patients with HIV/HCV coinfection and HCV monoinfection are similar in terms of sustained virologic response rate, there are some additional complications that arise in the treatment of patients with HIV/HCV coinfection, including drug-drug interactions and HCV reinfection due to the high risk behavior of these patients. This review will summarize the current management of HIV/HCV coinfection.

Hepatitis C Virus Treatment: Simplifying the Simple and Optimizing the Difficult

The availability of safe, efficacious, oral direct-acting antivirals (DAAs) have ushered in a new era of hepatitis C treatment with potential to eliminate hepatitis C as a public health threat. To achieve population-level effectiveness of these oral DAAs, hepatitis C treatment by a wide range of providers in different settings will be essential to increase the number of persons treated. We provide a clinical review of hepatitis C treatment with a focus on practical tools for management of hepatitis C in majority of currently infected individuals who can be easily cured and optimization of treatment for those in whom treatment may not be as simple.

Efficacy and safety of glecaprevir/pibrentasvir in patients with HCV genotype 5/6: An integrated analysis of phase 2/3 studies

BACKGROUND & AIMS

Hepatitis C virus (HCV) has high genetic diversity with six major genotypes (GT) GT1-6 and global distribution. HCV GT5 and 6 are rare with < 10 million people infected worldwide. Data on direct-acting antiviral use in these rare HCV genotypes are limited. The study aimed to evaluate the efficacy and safety of glecaprevir/pibrentasvir (G/P) in a pooled analysis of phase 2/3 trials in HCV GT5 or 6-infected patients without cirrhosis or with compensated cirrhosis.

METHODS

Patients with chronic HCV GT5 or 6 infection received oral G/P (300 mg/120 mg) once daily for 8 or 12 weeks. The primary efficacy endpoint was sustained virological response at post-treatment week 12 (SVR12) in the intention-to-treat population.

RESULTS

One hundred eighty-one patients were evaluated; 56 with HCV GT5 and 125 with HCV GT6. The majority were treatment-naïve (88%) and non-cirrhotic (85%). Overall SVR12 rate with 8- or 12-week G/P treatment was 98% (178/181). Eight-week treatment with G/P yielded SVR12 rates of 95% (21/22) in HCV GT5- and 99% (69/70) in HCV GT6-infected non-cirrhotic patients. Eight- and 12-week treatment of patients with compensated cirrhosis achieved SVR12 rates of 100% (10/10) and 94% (17/18) respectively. The G/P regimen was well-tolerated; 3% (6/181) Grade 3 or higher adverse events, and no serious adverse events were attributed to G/P or led to study drug discontinuation.

CONCLUSIONS

This integrated dataset demonstrates a high SVR12 rate following 8-week G/P treatment in patients with HCV GT5 (96%) or GT6 (99%) infection without cirrhosis or with compensated cirrhosis.

2020 Taiwan consensus statement on the management of hepatitis C: part (I) general population

Hepatitis C virus (HCV) infection remains a major public health issue with high prevalence in Taiwan. Recently, the advent of direct-acting antiviral (DAA) agents, with higher efficacy, excellent safety profile, and truncated treatment duration, has revolutionized the paradigm of hepatitis C treatment and made HCV elimination possible. To provide timely guidance for optimal hepatitis C management, the Taiwan Association for the Study of the Liver (TASL) established an expert panel to publish a 2-part consensus statement on the management of hepatitis C in the DAA era. After comprehensive literature review and a consensus meeting, patient-oriented, genotype-guided recommendations on hepatitis C treatment for the general and special populations have been provided based on the latest indications and scientific evidence. In the first part of this consensus, we present the epidemiology and treatment situation of hepatitis C in Taiwan, the development of DAA, pre-treatment evaluation, post sustained virologic response (SVR) monitoring, and most importantly the treatment recommendations for the general population with compensated liver disease. The second part will focus on the treatment recommendations for the special populations.

Screening for Hepatitis C Virus Infection in Adolescents and Adults: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE

A 2013 review for the US Preventive Services Task Force (USPSTF) of hepatitis C virus (HCV) screening found interferon-based antiviral therapy associated with increased likelihood of sustained virologic response (SVR) and an association between achieving an SVR and improved clinical outcomes. New direct-acting antiviral (DAA) regimens are available.

OBJECTIVE

To update the 2013 review on HCV screening to inform the USPSTF.

DATA SOURCES

Ovid MEDLINE, the Cochrane Central Register of Controlled Trials, and the Cochrane Database of Systematic Reviews through February 2019, with surveillance through September 2019.

STUDY SELECTION

Randomized clinical trials (RCTs) and nonrandomized treatment studies of HCV screening and DAA therapy; cohort studies on screening, antiviral therapy, and the association between an SVR after antiviral therapy and clinical outcomes.

DATA EXTRACTION AND SYNTHESIS

One investigator abstracted data; a second checked accuracy. Two investigators independently rated study quality.

MAIN OUTCOMES AND MEASURES

Mortality, morbidity, quality of life, screening and treatment harms, and screening diagnostic yield.

RESULTS

Eight RCTs of DAA therapy vs placebo or an outdated antiviral regimen, 48 other treatment studies, and 33 cohort studies, with a total of 179 230 participants, were included. No study evaluated effects of HCV screening vs no screening. One new study since the 2013 review (n = 5917) found similar diagnostic yield of risk-based screening (sensitivity, 82%; number needed to screen to identify 1 HCV case, 15) and birth cohort screening (sensitivity, 76%; number needed to screen, 29), assuming perfect implementation. Ten open-label studies (n = 3292) reported small improvements in some quality-of-life and functional outcomes (eg, less than 3 points on the 0 to 100 36-Item Short Form Health Survey physical and mental component summary scales) after DAA treatment compared with before treatment. Two cohort studies (n = 24 686) found inconsistent associations of antiviral therapy vs no therapy with risk of hepatocellular carcinoma. Forty-nine treatment studies (n = 10 181) found DAA regimens associated with pooled SVR rates greater than 95% across genotypes, and low short-term rates of serious adverse events (1.9%) and withdrawal due to adverse events (0.4%). An SVR after antiviral therapy was associated with decreased adjusted risk of all-cause mortality (13 studies, n = 36 986; pooled hazard ratio [HR], 0.40 [95% CI, 0.28-0.56) and hepatocellular carcinoma (20 studies, n = 84 491; pooled HR, 0.29 [95% CI, 0.23 to 0.38]) vs no SVR.

CONCLUSIONS AND RELEVANCE

Direct evidence on the effects of HCV screening on clinical outcomes remains unavailable, but DAA regimens were associated with SVR rates greater than 5% and few short-term harms relative to older antiviral therapies. An SVR after antiviral therapy was associated with improved clinical outcomes compared with no SVR.

Eradicating hepatitis C virus: The APRN's role

Chronic hepatitis C virus (HCV) infection is a leading cause of liver disease. The World Health Organization has called for the global elimination of HCV by 2030. NPs can significantly expand the availability of community-based providers and bridge gaps in HCV treatment to assist in eradicating this curable virus.

Systematic Review with Meta-Analysis: Efficacy and Safety of Direct-Acting Antivirals for Chronic Hepatitis C Genotypes 5 and 6

Direct-acting antivirals (DAAs) are modern treatments for chronic hepatitis C infection, but majority of available evidence on its treatment effect covers genotypes 1 to 4. Therefore, the efficacy and safety of DAAs for genotypes 5 and 6 need to be analysed. Studies were identified from Medline, Scopus, and CENTRAL and a Chinese database CNKI, from inception until Dec 4, 2018. Clinical trials were included if they enrolled patients with genotypes 5 and/or 6 infection, any type of second-generation DAAs was studied, and sustained virological response was assessed at the 12^th week after treatment (SVR12) as outcome measure. Meta-analysis using metaprop statistical program was applied for pooling proportions if data were sufficient (i.e., at least 2 studies). Thirteen studies were included in the analysis. Four studies assessed the efficacy of four DAA regimens in genotype 5 patients, which were mainly sofosbuvir (SOF) plus pegylated-interferon/ribavirin (PR) or other DAAs, with SVR12 ranging from 94.4% to 100%. Twelve studies assessed the efficacy of seven DAA regimens among genotype 6 patients, but only two DAA regimens (i.e., SOF + PR and SOF/ledipasvir) had sufficient data for pooling. The pooled SVR12 rates (95% CI) were 99.6% (92.2 to 100) for SOF + PR and 99.2% (96.5 to 100) for SOF/ledipasvir. No treatment-related serious adverse event was reported, while the nonserious adverse events were comparable to other genotypes. In conclusion, DAAs are effective and may be safe for the treatment of chronic hepatitis C genotypes 5 and 6. However, our evidence is based on noncomparative studies; hence, further larger-scale randomized controlled trials in these genotypes are still required.

Hepatitis C

Hepatitis C is a global health problem, and an estimated 71·1 million individuals are chronically infected with hepatitis C virus (HCV). The global incidence of HCV was 23·7 cases per 100 000 population (95% uncertainty interval 21·3-28·7) in 2015, with an estimated 1·75 million new HCV infections diagnosed in 2015. Globally, the most common infections are with HCV genotypes 1 (44% of cases), 3 (25% of cases), and 4 (15% of cases). HCV transmission is most commonly associated with direct percutaneous exposure to blood, via blood transfusions, health-care-related injections, and injecting drug use. Key high-risk populations include people who inject drugs, men who have sex with men, and prisoners. Approximately 10-20% of individuals who are chronically infected with HCV develop complications, such as cirrhosis, liver failure, and hepatocellular carcinoma over a period of 20-30 years. Direct-acting antiviral therapy is now curative, but it is estimated that only 20% of individuals with hepatitis C know their diagnosis, and only 15% of those with known hepatitis C have been treated. Increased diagnosis and linkage to care through universal access to affordable point-of-care diagnostics and pangenotypic direct-acting antiviral therapy is essential to achieve the WHO 2030 elimination targets.

Consensus recommendations for resistance testing in the management of chronic hepatitis C virus infection: Public Health England HCV Resistance Group

The treatment of hepatitis C virus (HCV) infection has been revolutionised by the advent of oral, well-tolerated, direct acting antiviral therapies (DAA), with high cure rates. However, in some scenarios, HCV resistance to antiviral therapies may have an impact on treatment success. Public Health England's HCV Resistance Group was established to support clinicians treating people with HCV, where the issue of resistance may be a factor in clinical decision-making, and this review includes the Group's current recommendations on the use of HCV resistance testing. The authors describe the principles behind and approach to HCV resistance testing and consider evidence from in vitro studies, clinical trials and real world cohorts on the impact of HCV resistance on treatment outcomes for particular DAA regimens. Five scenarios are identified in the UK and similar settings, where, in the Group's opinion, resistance testing should be performed.

Viral Hepatitis C Therapy: Pharmacokinetic and Pharmacodynamic Considerations: A 2019 Update

It has been estimated by the World Health Organization (WHO) that over 71 million people were infected with the hepatitis C virus (HCV) in 2015. Since then, a number of highly effective direct-acting antiviral (DAA) regimens have been licensed for the treatment of chronic HCV infection: sofosbuvir/daclatasvir, sofosbuvir/ledipasvir, elbasvir/grazoprevir, sofosbuvir/velpatasvir, glecaprevir/pibrentasvir, and sofosbuvir/velpatasvir/voxilaprevir. With these treatment regimens, almost all chronic HCV-infected patients, even including prior DAA failures, can be treated effectively and safely. It is therefore likely that further development of DAAs will be limited. In this descriptive review we provide an overview of the clinical pharmacokinetic characteristics of currently available DAAs by describing their absorption, distribution, metabolism, and excretion. Potential drug-drug interactions with the DAAs are briefly discussed. Furthermore, we summarize what is known about the pharmacodynamics of the DAAs in terms of efficacy and safety. We briefly discuss the relationship between the pharmacokinetics of the DAAs and efficacy or toxicity in special populations, such as hard to cure patients and patients with liver cirrhosis, liver transplantation, renal impairment, hepatitis B virus or HIV co-infection, bleeding disorders, and children. The aim of this overview is to educate/update prescribers and pharmacists so that they are able to safely and effectively treat HCV-infected patients even in the presence of underlying co-infections or co-morbidities.

International Liver Transplantation Society Asian Consensus on the Management of Hepatitis C Virus Infection in Resource Limited Setting-From Noncirrhotic to Decompensated Disease and After Liver Transplantation

BACKGROUND

The population of Asia exceeds 4.4 billion people. Chronic hepatitis C virus (HCV) infection in Asia is characterized by specific distribution of genotypes, lack of access to specific therapeutic agents, relatively high cost of treatment, and lack of experienced healthcare providers. Clear consensus on the diagnosis, management, and monitoring of HCV infection specific to the Asian region is a major unmet need. The consensus guidelines documents that have been published to date by major medical societies presume access to an array of direct acting antiviral agents and diagnostic tests that are not broadly applicable to resource limited settings, including Asia.

METHODS

To address the lack of an Asia-specific set of HCV treatment guidelines, we assembled a panel of 15 HCV experts in the field of hepatology from India, Indonesia, Myanmar, Vietnam, Pakistan, Philippines, and Mongolia convened in April 2017 to review the updated literature and provide recommendations on the diagnosis and management of chronic HCV infection that reflects local conditions.

RESULTS

An evidence-based comprehensive compilation of the literature supported by the graded recommendations from the expert panel for the optimization of the diagnosis, pretreatment, on treatment, and posttreatment assessments, and management of chronic HCV infection has been presented in this article.

CONCLUSIONS

With the evolving treatment landscape and addition of several new direct-acting antiviral agents and combination regimens into the therapeutic armamentarium, the current article may serve as a guide to the clinicians in optimizing the diagnosis and treatment selection for the management of chronic HCV infection in resource-limited settings.

Consensus on management of hepatitis C virus infection in resource-limited Ukraine and Commonwealth of Independent States regions

Globally, 69.6 million individuals were infected with hepatitis C virus (HCV) infection in 2016. Of the six major HCV genotypes (GT), the most predominant one is GT1, worldwide. The prevalence of HCV in Central Asia, which includes most of the Commonwealth of Independent States (CIS), has been estimated to be 5.8% of the total global burden. The predominant genotype in the CIS and Ukraine regions has been reported to be GT1, followed by GT3. Inadequate HCV epidemiological data, multiple socio-economic barriers, and the lack of region-specific guidelines have impeded the optimal management of HCV infection in this region. In this regard, a panel of regional experts in the field of hepatology convened to discuss and provide recommendations on the diagnosis, treatment, and pre-, on-, and posttreatment assessment of chronic HCV infection and to ensure the optimal use of cost-effective antiviral regimens in the region. A comprehensive evaluation of the literature along with expert recommendations for the management of GT1-GT6 HCV infection with the antiviral agents available in the region has been provided in this review. This consensus document will help guide clinical decision-making during the management of HCV infection, further optimizing treatment outcomes in these regions.

Overview of Direct-Acting Antiviral Drugs and Drug Resistance of Hepatitis C Virus

The advent of direct-acting antivirals (DAAs) has brought about a sudden renaissance in the treatment of chronic hepatitis C virus (HCV) infection with SVR rates now routinely >90%. However, due to the error-prone nature of the HCV RNA polymerase, resistance-associated substitutions (RASs) to DAAs may be present at baseline and can result in a significant effect on treatment outcomes and hamper the achievement of sustained virologic response. By further understanding the patterns and nature of these RASs, it is anticipated that the incidence of treatment failure will continue to decrease in frequency with the development of drug regimens with increasing potency, barrier to resistance, and genotypic efficacy. This review summarizes our current knowledge of RASs associated with HCV infection as well as the clinical effect of RASs on treatment with currently available DAA regimens.

Sofosbuvir, velpatasvir and voxilaprevir: a new triple combination for hepatitis C virus treatment. One pill fits all? Is it the end of the road?

The advent of oral direct-acting antiviral agents (DAAs) has dramatically improved the hepatitis C virus (HCV) treatment landscape in the last 4 years, providing cure rates over 95% with a shorter duration of treatment and a very good safety profile. This has enabled access to treatment in nearly all HCV infected patients. The launch of two pangenotypic fixed dose combinations (FDCs) in 2017 made a new step forward in HCV treatment by slightly increasing efficacy and more importantly allowing the treatment of patients without HCV genotyping, and in some cases without fibrosis assessment. However, retreatment of the few DAA failure patients was still an issue for some HCV genotypes. The launch of the triple regimen FDC, sofosbuvir/velpatasvir/voxilaprevir, solves this issue by providing a cure rate over 96% regardless of HCV genotype. In this review, we describe the current HCV treatment landscape and focus on the development of this triple FDC either in treatment-naïve or treatment-experienced patients with previous failure on a DAA regimen.

Efficacy and safety of glecaprevir/pibrentasvir in patients with chronic hepatitis C virus genotype 5 or 6 infection (ENDURANCE-5,6): an open-label, multicentre, phase 3b trial

BACKGROUND

The pangenotypic direct-acting antiviral regimen of glecaprevir coformulated with pibrentasvir is approved to treat chronic hepatitis C virus (HCV) genotype 1-6 infection in adults. In registrational studies, 84 (99%) of 85 patients with HCV genotype 5 or 6 infection achieved a sustained virological response (SVR) with glecaprevir/pibrentasvir, with no virological failures. To increase the body of data for these less prevalent genotypes, ENDURANCE-5,6 evaluated the efficacy and safety of glecaprevir/pibrentasvir exclusively in patients infected with HCV genotype 5 or 6.

METHODS

ENDURANCE-5,6 was a phase 3b, single-arm, open-label, multicentre trial done in 24 hospitals or clinics in Europe, Oceania, North America, South Africa, and southeast Asia. Adults with chronic HCV genotype 5 or 6 infection who were previously untreated or treatment-experienced were eligible to be enrolled. Glecaprevir/pibrentasvir (300 mg/120 mg) was given orally once daily for 8 weeks (for patients without cirrhosis) or 12 weeks (for patients with compensated cirrhosis). The primary efficacy endpoint was SVR12 (ie, HCV RNA <15 IU/mL at 12 weeks post-treatment), assessed within each HCV genotype, and analysed in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT02966795.

FINDINGS

Between Feb 9, 2017, and Aug 28, 2018, 84 patients were enrolled: 23 with genotype 5 infection and 61 with genotype 6 infection. Overall, 82 (97·6%, 95% CI 94·4-100·0) of the 84 patients achieved SVR12. 22 (95·7%, 95% CI 87·3-100·0) of 23 patients with genotype 5 infection achieved SVR12, as did 60 (98·4%, CI 95·2-100·0) of 61 with genotype 6 infection. One patient with an HCV genotype 6f infection and cirrhosis had on-treatment virological failure at treatment week 12, and one patient with HCV genotype 5a without cirrhosis who had achieved SVR at post-treatment week 4 relapsed at post-treatment week 12. Five (6%) patients had serious adverse events, none of which were deemed related to glecaprevir/pibrentsavir or led to discontinuation. Fatigue (11 [13%] patients) and headache (11 [13%]) were the only adverse events that occurred in 10% or more of patients. No post-baseline grade 3 or higher increases in aminotransferase concentrations were reported.

INTERPRETATION

Glecaprevir/pibrentasvir achieved high SVR12 rates, comparable with data reported in registrational studies, and was well tolerated in patients with HCV genotype 5 or 6 infection with compensated liver disease.

FUNDING

AbbVie.

Hepatitis C Guidance 2018 Update: AASLD-IDSA Recommendations for Testing, Managing, and Treating Hepatitis C Virus Infection

Recognizing the importance of timely guidance regarding the rapidly evolving field of hepatitis C management, the American Association for the Study of Liver Diseases (AASLD) and the Infectious Diseases Society of America (IDSA) developed a web-based process for the expeditious formulation and dissemination of evidence-based recommendations. Launched in 2014, the hepatitis C virus (HCV) guidance website undergoes periodic updates as necessitated by availability of new therapeutic agents and/or research data. A major update was released electronically in September 2017, prompted primarily by approval of new direct-acting antiviral agents and expansion of the guidance's scope. This update summarizes the latest release of the HCV guidance and focuses on new or amended recommendations since the previous September 2015 print publication. The recommendations herein were developed by volunteer hepatology and infectious disease experts representing AASLD and IDSA and have been peer reviewed and approved by each society's governing board.

Era of direct acting anti-viral agents for the treatment of hepatitis C

Hepatitis C infection is universal and the most common indication of liver transplantation in the United States. The period of less effective interferon therapy with intolerable side effects has gone. Now we have stepped into the era of direct acting anti-viral agents (DAAs) against hepatitis C virus. Treatment of hepatitis C is now extremely effective, tolerable and requires a short duration of intake of oral agents. Less monitoring is required with the current therapy and drug-drug interactions are less than the previous regimen. The current treatment options of chronic hepatitis C with various DAAs are discussed in this article.

Molecular and Biological Characterization of a Prepared Recombinant Human Interferon Alpha 2b Isoform

Recombinant human interferon alpha2b (rhIFN-α2b) protein is FDA approved for treatment of many tumors and viral diseases. A rhIFN-α2b isoform has been produced and purified from the refolding reaction using high-resolution anion ion exchange chromatography. This isoform has a proper MW (19 kDa) and high purity and homogeneity. The conservation of native linear and conformational epitopes in this isoform was immunologically confirmed by Western blot and ELISA. Mass spectrometry assessment of its intact mass showed average mass (19,337 Da) equivalent to that of the expressed rhIFN-α2b protein without any chemical modification and without the first methionine. Peptide mapping of rhIFN-α2b through tryptic digestion of reductive/alkylated protein using urea as a denaturing agent gave the best pattern. The rhIFN-α2b had a high specific antiviral activity (2.5 × 10⁸ ± 1.1 × 10⁸IU/mg protein). In vivo clearance study of rhIFN-α2b in female SD rats (500 μg/kg, intramuscularly) revealed rapid clearance (elimination half-life 0.54 h with a maximum plasma concentration of 33,792 pg/ml) compared with the commercial rhIFN-α2 (elimination half-life 0.75-0.96 h). In conclusion, the prepared rhIFN-α2b isoform has high purity, homogeneity, native like chemical and structural composition, high antiviral activity, and proper biological stability, which reduce its immunogenicity and raise its therapeutic efficiency.

Patients with chronic hepatitis C receiving sofosbuvir and ribavirin-based treatment, with or without interferon in Zhejiang, China: An observational study

Hepatitis C virus (HCV) is one of the most important virus as the cause of liver disease in China. The aim of the present study was to explore whether sofosbuvir and ribavirin-based treatment can cure patients with chronic hepatitis C in eastern China. We examined a cohort of HCV-monoinfected patients and 9 patients agreed to participate in our treatment and research. The patients were diagnosed with chronic hepatitis C with or without cirrhosis. Nine patients including 4 female and 5 male met the requirements for selection and were willing to participate in this experiment. Sofosbuvir and ribavirin-based treatment with or without interferon was given to the patients. Viral loads, cytokines, and chemokines were recorded during treatment and after treatment. After 2 weeks of sofosbuvir and ribavirin-based treatment, the viral load of patients decreased to limits of detection. Eight patients were cured. Patients had rapid virological response (RVR) with undetectable viral load at week 4 and sustained virological response (SVR). The interferon-inducible protein-10 (IP-10) decreased after the treatment. However, the patient with cirrhosis failed, as the virus reappeared during SVR4. At the same time, the IP-10 dramatically increased as the relapse of the HCV virus. In summary, the IP-10 has the potential to be the biomarker for the prognostic of HCV.

Recent update of the 2017 Korean Association for the Study of the Liver (KASL) treatment guidelines of chronic hepatitis C: Comparison of guidelines from other continents, 2017 AASLD/IDSA and 2016 EASL

The paradigm for the treatment of chronic hepatitis C (CHC) has been changed due to the development of direct acting antivirals (DAAs) of hepatitis C virus (HCV). The high sustained virologic response rate and ease of administration makes the DAAs approach ideal to contribute to the complete eradication of HCV. Currently, treatment options for individual patients vary depending on the genotype or subtype of HCV, presence or absence of liver cirrhosis, previous experience of antiviral treatment or resistance associated substitutions. Because of drug avalilability, cost-effectiveness, preference, compliance and greater possibility of desirable effects and presumed patient-important outcomes may vary between countries, treatment options for individual patients are different. The review focuses on the comparing the current treatment options for CHC in other continents with the 2017 Korea Association for the Study of the Liver guidelines.

HCV genotype 4, 5 and 6: Distribution of viral subtypes and sustained virologic response rates in clinical trials of approved direct-acting antiviral regimens

Multiple direct-acting antiviral (DAA)-based regimens are now available for all hepatitis C virus (HCV) genotypes (GTs). Because HCV GT 4, 5 and 6 are less common in the United States (US) and worldwide, relatively small numbers of participants with these GTs were evaluated in individual clinical trials. To provide a comprehensive description of subtype diversity and treatment outcomes in clinical trials for these less common GTs, we analysed data from 744 participants with HCV GT4 (n = 573), GT5 (n = 81), or GT6 (n = 90) across 18 clinical trials of DAA regimens. These data are from US New Drug Applications submitted between 2014 and 2017, and our analyses included only approved regimens. Excluding unresolved or mixed subtypes, the distribution of reported GT4 subtypes was 49% 4a, 31% 4d and 16% for one of 14 other subtypes. The distribution of GT6 subtypes was 39% 6a, 27% 6e, 8% 6 L and 23% for one of 11 other subtypes. Across approved regimens, sustained virologic response rates 12 weeks post-treatment (SVR12) for GT 4, 5 and 6 ranged from 91% to 100%, 93% to 97% and 96% to 100%, respectively. SVR12 by GT4 subtype ranged from 96% to 100% for 4a and 81% to 100% for 4d. Virologic failures occurred in GT 4a, 4b, 4d and 4r. For GT6, SVR12 was 100% for all subtypes except 6 L, for which 1 of 7 participants experienced virologic failure. To our knowledge, this is the largest compilation of HCV GT 4, 5 or 6 clinical trial data. These analyses may be useful for clinicians treating HCV GT 4, 5 or 6.

Clinical utility of ledipasvir/sofosbuvir in the treatment of adolescents and children with hepatitis C

Chronic infection with hepatitis C virus (HCV) affects an estimated 0.1%–2% of the pediatric population in the United States. While the clinical course in young children is indolent, adolescents who contract HCV have a disease course similar to adults, with a 26-fold increased risk of chronic liver disease-associated mortality, hepatocellular carcinoma, and need for curative liver transplantation. Furthermore, adolescent patients are entering childbearing age and carry a risk of passing HCV to their offspring via vertical transmission. Pegylated-interferon (PEG-IFN) with ribavirin was previously the only treatment option for pediatric patients with chronic hepatitis C (CHC), but the high likelihood of adverse reactions and subcutaneous route of administration limited its use and efficacy. Recently, the direct-acting antivirals (DAAs) ledipasvir (LDV) and sofosbuvir (SOF) were approved for adolescents with CHC. This review discusses the natural history of CHC in pediatric patients, data supporting LDV/SOF in adolescents, and ongoing studies evaluating DAAs in pediatric patients.

The Mexican consensus on the treatment of hepatitis C

The aim of the Mexican Consensus on the Treatment of HepatitisC was to develop clinical practice guidelines applicable to Mexico. The expert opinion of specialists in the following areas was taken into account: gastroenterology, infectious diseases, and hepatology. A search of the medical literature was carried out on the MEDLINE, EMBASE, and CENTRAL databases through keywords related to hepatitisC treatment. The quality of evidence was subsequently evaluated using the GRADE system and the consensus statements were formulated. The statements were then voted upon, using the modified Delphi system, and reviewed and corrected by a panel of 34 voting participants. Finally, the level of agreement was classified for each statement. The present guidelines provide recommendations with an emphasis on the new direct-acting antivirals, to facilitate their use in clinical practice. Each case must be individualized according to the comorbidities involved and patient management must always be multidisciplinary.

Ledipasvir + Sofosbuvir for Liver Transplant Recipients With Recurrent Hepatitis C: A Systematic Review and Meta-analysis

INTRODUCTION

Studies focusing on the efficacy and safety of ledipasvir (LDV) + sofosbuvir (SOF) therapy in liver transplant (LT) recipients with hepatitis C virus (HCV) recurrence are still limited. Therefore, the aim of our work was to perform a systematic review and meta-analysis to evaluate outcome data of LDV + SOF therapy in LT recipients.

METHODS

Multiple databases were systematically searched for eligible studies. We included studies reporting sustained virological response 12 weeks after treatment (SVR12) and treatment-related adverse events (AEs) in LT recipients treated with LDV + SOF ± ribavirin (RBV) for HCV recurrence. All statistical analyses were conducted by using R version 3.3.1 (The R Foundation for Statistical Computing, Vienna, Austria).

RESULTS

Twelve studies with a total of 994 LT recipients were included, most of which were diagnosed with HCV genotype 1 infection. The overall SVR12 reached 96.3% (95% confidence interval [CI]: 94.9%-97.5%) and no significant heterogeneity was observed (Q statistic = 10.63, P = .47; I² = 0%). No difference was found in SVR12 between treatments for 12 weeks and 24 weeks (P = .18). Patients treated with LDV + SOF + RBV (n = 525) exhibited an SVR12 rate of 95.1% (95% CI 92.8%-96.6%), which showed no difference from the findings in the LDV + SOF treatment group (n = 314) with an SVR12 reaching 94.9% (95% CI 91.5%-97.0%; P = .92). There was a tendency for a higher SVR12 in patients without cirrhosis than those with cirrhosis (P < .05). The most common AEs were listed as following: anemia 41.9% (n = 203 of 484), fatigue 39.1% (n = 207 of 530), headache 24.2% (n = 128 of 530), nausea 21.9% (n = 106 of 484), and diarrhea 19.0% (n = 92 of 484).

CONCLUSION

LDV + SOF-based treatment is highly effective and well tolerated in LT recipients with HCV reinfection.

Eliminating hepatitis C within low-income countries - The need to cure genotypes 4, 5, 6

Around 70 to 100 million people are chronically infected with HCV worldwide. HCV antiviral drug development has revolutionised the treatment of HCV, with several direct-acting antiviral agents offering patients the chance of cure after only 8-12 weeks of treatment. Drug development was initially focussed on HCV genotype 1 (GT1) infection, since this was the most prevalent worldwide, although clinical trials included all genotypes prevalent in the US and Europe. Because the earliest in vitro assays utilised the GT1b and 2 replicons, the initial classes of direct-acting antivirals (protease inhibitors, non-nucleotide polymerase inhibitors) were GT1-specific, albeit they had an effect on other less prevalent genotypes. Epidemiological data has shown the regional importance of other HCV genotypes. More than 50% of all HCV infections around the globe are not with GT1. The prevalence of HCV genotype 4 (GT4), 5 (GT5), and 6 (GT6) is increasing in North America and Europe due to migration from the Middle East, Africa and South-East Asia. With the successful development of the multi and pan-genotypic non-structural protein 5A inhibitors, second generation protease inhibitors and nucleotide non-structural protein 5B inhibitors comes a unique opportunity to achieve global HCV elimination. The goal of this review is to summarise the available information pertaining to GT4, GT5 and GT6, with a specific focus on direct-acting antiviral agents.

Retreatment Options Following HCV Direct Acting Antiviral Failure

Despite the excellent efficacy of direct acting antivirals (DAA) for hepatitis C virus (HCV), treatment failures do occur. Until recently, retreatment decisions after DAA failure were influenced by the number of available agents, concerns about HCV drug resistance, and lack of data regarding retreatment. Recommended treatment approaches previously depended on limited clinical trials and expert opinion. In this article, we review the current state of the evidence for HCV retreatment after DAA failure. Based on recent clinical trial data, most patients who fail HCV treatment with DAA agents now have excellent retreatment options. While some patients may benefit from resistance testing after DAA therapy failure to select the optimal treatment and duration, newly approved salvage therapies are not significantly impacted by common mutations and have been approved by the Food and Drug Administration for HCV retreatment without regard for the presence of resistance associated substitutions. While prior retreatment efforts were limited to longer courses of therapy, the addition of ribavirin, or novel combinations of approved therapies based on expert guidance, current DAA options make HCV retreatment in the DAA era more streamlined and evidence-based.

Recommendations for the treatment of hepatitis C virus infection in chronic kidney disease: a position statement by the Spanish association of the liver and the kidney

Hepatitis C virus (HCV) infection is one of the main causes of liver cirrhosis worldwide. The long-term impact of HCV infection is highly variable, ranging from minimal histological changes to extensive fibrosis with hepatocellular carcinoma. The development of HCV drugs has increased dramatically in recent years, even in special populations such as chronic kidney disease patients. Classical treatment of chronic hepatitis C was based on the administration of interferon and ribavirin for 24-48 weeks, which was associated with a poor viral response and a high rate of side effects, especially in patients with a lower estimated glomerular filtration rate. The current high availability of the new direct-acting antivirals renders the classification of these agents for this special population necessary. The Spanish Association of the Liver and the Kidney has produced a position statement on the treatment of HCV infection in chronic kidney disease patients since the evidence to guide this treatment is scant and what evidence does exist is weak. The recommendations are based on the results of clinical trials and controlled studies conducted to date, with data published hitherto by the authors of these studies. Since the indications for treatment have been evaluated by other societies or are dependent on internal clinical protocols, the main goal of this position statement is to assist in decision-making when choosing a therapeutic option.

Direct antiviral agents (DAAs) - A new age in the treatment of hepatitis C virus infection

Hepatitis C virus (HCV) is a global health problem, because infection frequently leads to chronic hepatitis C eventually progressing to liver cirrhosis and liver cancer. Improved insights into the HCV replication cycle and the role of HCV non-structural proteins have recently enabled to identify drugs directly acting on specific HCV target structures. Agents from three drug classes have been developed and approved by the health authorities. Combinations of two or more drugs from different classes achieve high (>90%) HCV clearance rates and are well tolerated. This interferon-free DAA (direct antiviral agent) therapy has revolutionized antiviral therapy in hepatitis C so that successful hepatitis C treatment can be offered to virtually all patients irrespective of their co-morbidity. This review provides an overview over currently approved regimens and outlines their use in clinical practice. In addition potential short-comings of the current therapeutic options such as drug-drug interactions and selection of viral resistance are addressed. DAA combination therapy has the potential to obtain global control over hepatitis C. However, easy access to DAAs, availability of reliable HCV diagnostics, and affordable costs remain still important goals, which must be reached to globally eliminate hepatitis C.

Hepatitis C treatment from "response-guided" to "resource-guided" therapy in the transition era from interferon-containing to interferon-free regimens

Peginterferon/ribavirin has been the standard-of-care for chronic hepatitis C virus (HCV) infections: 48 weeks for genotype 1 or 4 (HCV-1/4) and 24 weeks for HCV-2/3. Response-guided therapy recommended shorter 24- and 16-week regimens for HCV-1 with lower baseline viral loads (< 400 000-800 000 IU/mL) and rapid virological response (RVR, undetectable HCV RNA at week 4) and HCV-2/3 with RVR, respectively; and extending to 72 and 48 weeks for HCV-1 slower responders and HCV-2 non-RVR patients, respectively, to improve the efficacy. The progress of directly acting antivirals (DAA), moving from interferon-containing regimens in 2011 to interferon-free regimens in 2013, has greatly improved the treatment success. Interferon-containing regimens include boceprevir or telaprevir or simeprevir or daclatasvir plus peginterferon/ribavirin, 24-48 weeks, for HCV-1 or 4. However, adding these DAA has no benefit for HCV-1 with lower baseline viral loads/RVR. Instead, 12-week sofosbuvir plus peginterferon/ribavirin attained sustained virological response rates of > 90% for HCV-1/3-6. Interferon-free regimens include two main categories: NS5B nucleotide inhibitor (sofosbuvir)-based regimens and NS3/4A inhibitor/NS5A inhibitor-based regimens (daclatasvir/asunaprevir, paritaprevir/r/ombitasvir/dasabuvir and grazoprevir/elbasvir). About 8-24 weeks interferon-free regimens could achieve sustained virological response rates of 82-99% for corresponding HCV genotypes. Although the newly DAA interferon-free regimens have high efficacy and safety, the huge budget impact increases the treatment barriers. The current recommendation should, therefore, base on the availability, indication, and cost-effectiveness in the transition era of DAA. Based on the concept of "resource-guided therapy," peginterferon/ribavirin might be applied for easy-to-treat interferon-eligible patients in resource-constrained areas. Prioritizing patients for interferon-free regimens according to "time-degenerative factors" (age and fibrosis) is justified before the regimens becoming available and affordable.

Determinants of Infection Outcome in HCV-Genotype 4

Hepatitis C virus (HCV) infection represents a worldwide health problem and has been for long an attractive point of research due to diversity among different genotypes regarding unique geographical distribution and diverse treatment outcome. HCV is considered a major cause of chronic liver disease and cirrhosis, which leads to liver failure and hepatocellular carcinoma requiring liver transplantation. Of the HCV genotypes identified, HCV genotype 4 (HCV-4) is the least studied. HCV-4 is responsible for ∼10% of HCV infections and is common in the Middle East and Africa; recently it is increasingly prevalent in European Countries. HCV-4 is a continuing epidemic in Egypt, having the highest prevalence of HCV worldwide. "Know your epidemic, know your response" concept necessitates better understanding of HCV-4 characteristics to control disease dissemination and progression, which compromises the life quality of chronic HCV-infected patients. In this review, we discuss the epidemiology, natural history, and treatment options for patients with HCV-4 infection.

The emergence of NS5B resistance associated substitution S282T after sofosbuvir-based treatment

S282T in NS5B is the primary amino acid substitution associated with resistance to sofosbuvir (SOF) but has rarely been detected in patients treated with a SOF‐based regimen. Here, the emergence and fitness of the S282T substitution in virologic failure patients administered SOF‐based regimens across the SOF and ledipasvir (LDV)/SOF phase 2 and 3 programs was evaluated. Plasma samples collected at baseline and at virologic failure were amplified and deep sequenced (1% cutoff). To date, over 12,000 patients have been treated in SOF or LDV/SOF phase 2 and 3 studies. Of these, deep sequencing was available at baseline in 8598 patients (62.4% genotype [GT] 1, 10.7% GT2, 20.9% GT3, and 6.0% GT4‐6) and at virologic failure in 901 patients. In the 8598 patients, no S282T substitution was detected at baseline; at virologic failure, 10 of the 901 (1%) patients had S282T detected. The SOF‐based regimen associated with treatment‐emergent S282T was SOF monotherapy in two patients, retreatment with LDV/SOF in prior LDV/SOF failures in three patients, LDV/SOF for 8 weeks in 1 GT1 patient, LDV/SOF for 12 weeks in 1 patient each with GT3, GT4, and GT5, and LDV/SOF + ribavirin for 12 weeks in 1 GT6 patient. Nine of 10 patients with emergent S282T received an SOF‐based retreatment regimen, eight of whom achieved sustained virologic response 12 weeks after treatment and one of whom failed retreatment. Conclusion: The emergence of S282T substitution was rare in patients who fail SOF‐based regimens. Successful retreatment of prior SOF failure patients is possible in the presence of S282T substitution with SOF in combination with various direct‐acting antiviral agents. (Hepatology Communications 2017;1:538–549)

Oral Direct-Acting Agent Therapy for Hepatitis C Virus Infection: A Systematic Review

BACKGROUND

Rapid improvements in hepatitis C virus (HCV) therapy have led to the approval of multiple oral direct-acting antiviral (DAA) regimens by the U.S. Food and Drug Administration (FDA) for treatment of chronic HCV infection.

PURPOSE

To summarize published literature on the efficacy and safety of oral DAAs for treatment of persons with chronic HCV infection.

DATA SOURCES

MEDLINE and EMBASE from inception through 1 November 2016.

STUDY SELECTION

42 English-language studies from controlled and single-group registered clinical trials of adults with HCV infection that evaluated at least 8 weeks of an FDA-approved interferon-free HCV regimen that included at least 2 DAAs.

DATA EXTRACTION

Two investigators abstracted data on study design, patient characteristics, and virologic and safety outcomes sequentially and assessed quality independently.

DATA SYNTHESIS

Six DAA regimens showed high sustained virologic response (SVR) rates (>95%) in patients with HCV genotype 1 infection without cirrhosis, including those with HIV co-infection. Effective treatments for HCV genotype 3 infection are limited (2 DAA regimens). Patients with hepatic decompensation, particularly those with Child-Turcotte-Pugh class C disease, had lower SVR rates (78% to 87%) than other populations. The addition of ribavirin was associated with increased SVR rates for certain DAA regimens and patient groups. Overall rates of serious adverse events and treatment discontinuation were low (<10% in the general population); regimens that included ribavirin had more mild or moderate adverse events than those without.

LIMITATIONS

Twenty-three studies had moderate risk of bias (10 were open-label single-group trials, 11 had limited information on concealment of the allocation scheme, and 5 had selective outcome reporting). All but 1 of the studies were industry-funded. Heterogeneity of interventions precluded pooling.

CONCLUSION

Multiple oral DAA regimens show high rates of safety, tolerability, and efficacy for treatment of HCV genotype 1 infection, particularly among persons without cirrhosis.

PRIMARY FUNDING SOURCE

Patient-Centered Outcomes Research Institute. (PROSPERO: CRD42014009711).

Current therapy for chronic hepatitis C: The role of direct-acting antivirals

One of the most exciting developments in antiviral research has been the discovery of the direct-acting antivirals (DAAs) that effectively cure chronic hepatitis C virus (HCV) infections. Based on more than 100 clinical trials and real-world studies, we provide a comprehensive overview of FDA-approved therapies and newly discovered anti-HCV agents with a special focus on drug efficacy, mechanisms of action, and safety. We show that HCV drug development has advanced in multiple aspects: (i) interferon-based regimens were replaced by interferon-free regimens; (ii) genotype-specific drugs evolved to drugs for all HCV genotypes; (iii) therapies based upon multiple pills per day were simplified to a single pill per day; (iv) drug potency increased from moderate (∼60%) to high (>90%) levels of sustained virologic responses; (v) treatment durations were shortened from 48 to 12 or 8 weeks; and (vi) therapies could be administered orally regardless of prior treatment history and cirrhotic status. However, despite these remarkable achievements made in HCV drug discovery, challenges remain in the management of difficult-to-treat patients.

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HCV genotype-specific drugs evolve to pan-genotypic drugs.

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Drug potency increases from moderate (∼60%) to high (>90%) levels of sustained virologic response.

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Treatment durations are shortened from a 48-week to 12-week or 8-week period.

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HCV therapies based upon multiple pills per day are simplified to a single pill per day.

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HCV therapies are administered orally regardless of prior treatment history and cirrhotic status.

HCV management in resource-constrained countries

With the arrival of all-oral directly acting antiviral (DAA) therapy with high cure rates, the promise of hepatitis C virus (HCV) eradication is within closer reach. The availability of generic DAAs has improved access to countries with constrained resources. However, therapy is only one component of the HCV care continuum, which is the framework for HCV management from identifying patients to cure. The large number of undiagnosed HCV cases is the biggest concern, and strategies to address this are needed, as risk factor screening is suboptimal, detecting <20% of known cases. Improvements in HCV confirmation through either reflex HCV RNA screening or ideally a sensitive point of care test are needed. HCV notification (e.g., Australia) may improve diagnosis (proportion of HCV diagnosed is 75%) and may lead to benefits by increasing linkage to care, therapy and cure. Evaluations for cirrhosis using non-invasive markers are best done with a biological panel, but they are only moderately accurate. In resource-constrained settings, only generic HCV medications are available, and a combination of sofosbuvir, ribavirin, ledipasvir or daclatasvir provides sufficient efficacy for all genotypes, but this is likely to be replaced with pangenetypic regimens such as sofosbuvir/velpatasvir and glecaprevir/pibrentaasvir. In conclusion, HCV management in resource-constrained settings is challenging on multiple fronts because of the lack of infrastructure, facilities, trained manpower and equipment. However, it is still possible to make a significant impact towards HCV eradication through a concerted effort by individuals and national organisations with domain expertise in this area.

Hepatitis C treatment: where are we now?

Chronic hepatitis C infection affects millions of people worldwide and confers significant morbidity and mortality. Effective treatment is needed to prevent disease progression and associated complications. Previous treatment options were limited to interferon and ribavirin (RBV) regimens, which gave low cure rates and were associated with unpleasant side effects. The era of direct-acting antiviral (DAA) therapies began with the development of first-generation NS3/4A protease inhibitors in 2011. They vastly improved outcomes for patients, particularly those with genotype 1 infection, the most prevalent genotype globally. Since then, a multitude of DAAs have been licensed for use, and outcomes for patients have improved further, with fewer side effects and cure rates approaching 100%. Recent regimens are interferon-free, and in many cases, RBV-free, and involve a combination of DAA agents. This review summarizes the treatment options currently available and discusses potential barriers that may delay the global eradication of hepatitis C.