Hepatitis C virus: the 25-year journey from discovery to cure

Immunological crossroads: The intriguing dance between hepatitis C and autoimmune hepatitis

Delving into the immunological crossroads of liver diseases, this editorial explores the dynamic interplay between hepatitis C virus (HCV) and autoimmune hepatitis (AIH). While HCV primarily manifests as a viral infection impacting the liver, previous studies unveil a captivating connection between HCV and the emergence of AIH. The dance of the immune system in response to HCV appears to set the stage for an intriguing phenomenon-an aberrant autoimmune response leading to the onset of AIH. Evidence suggests a heightened presence of autoimmune markers in individuals with chronic HCV infection, hinting at a potential overlap between viral and autoimmune liver diseases. Navigating the intricate terrain of viral replication, immune response dynamics, and genetic predisposition, this editorial adds a layer of complexity to our understanding of the relationship between HCV and AIH. In this immunological crossroads, we aim to unearth insights into the complex interplay, using a compelling case where AIH and primary sclerosing cholangitis overlapped following HCV treatment with direct-acting antivirals as background.

Milestones in the discovery of hepatitis C

The discovery of hepatitis C has been a landmark in public health as it brought the opportunity to save millions of lives through the diagnosis, prevention and cure of the disease. The combined work of three researchers, Alter H, Houghton M and Rice C, which set the basis for the diagnosis, treatment and prevention of hepatitis C apart from laying the ground work for a new approach to study infections in general and developing new antiviral agents. This is a story of a transfusion-associated infection. A series of clinical studies demonstrated the existence of an infectious agent associated with hepatitis. That was followed by the identification of what was later known to be the hepatitis C virus (HCV) and the development of diagnostic tests. It all preceded the full molecular identification and demonstration of a causal effect. Finally it ended up with the development and discovery of a new class of therapeutic drugs, the direct acting antivirals, which are now used not only to cure the disease but most probably, to eliminate the problem. This work started with Dr Alter H who demonstrated that a new virus was responsible for the majority of post-transfusion hepatitis followed by Houghton M who cloned the virus and developed the blood test to identify those cases that carried the virus. Finally, the work of Rice C demonstrated that a cloned HCV produced after applying molecular biology techniques could cause long-standing infection and cause the same disease as the one observed in humans.

Discovery of Hepatitis C Virus: 2020 Nobel Prize in Medicine

Hepatitis C virus (HCV) accounts for hepatitis, cirrhosis, hepatocellular carcinoma, and liver transplantation. Every year, millions of people develop chronic liver diseases. This article provides novel insights into the major breakthroughs in the discovery of hepatitis C virus. 2020 Nobel Prize in Medicine was awarded to Michael Houghton, Harvey Alter, and Charles Rice for their outstanding contribution in the discovery of HCV. Also, this article deals with current findings, challenges, and future prospects in the diagnosis of HCV infection. DAA, along with protease inhibitors, is found to have higher SVR and is a promising drug to treat HCV infection. However, with regard to the emergence of resistance to DAAs, CRISPR-Cas can be the future technique in preventing resistance. Although the current knowledge of molecular mechanisms associated with HCV infection is insufficient, the better understanding of it provides better hope in the treatment of HCV.

Lymphoma

A cancer causing infection on lymphocytes.

Fulminant hepatitis

A decrease in the size of the liver accompanied even by the death of liver parenchyma with the onset of infection with hepatitis virus.

Transfection

The process of introducing nucleic acids into eukaryotic cells without using viral methods.

Huh-7 cells

A type of liver cells grown in the laboratory for research purposes.

Immunoscreening

A biomedical method that helps to detect a protein produced from a cloned gene after it undergoes transcription, followed by the translation process within the cell.

cDNA library

A group of only the genes that are encoded into proteins by an organism.

Sustained virologic response

Absence of any evidence of the presence of HCV in the blood of patients with chronic HCV infection after undergoing antiviral treatment.

Pegylated interferon

A covalent conjugate of recombinant interferon and polyethylene glycol, used as an antiviral and antineoplastic agent.

Immunoelectron microscopy

A technique to localize ultrastructure antigens or antibodies in cells or tissues for the diagnosis of viral infections.

Stellate cells

A major type of liver cell involved in liver cirrhosis.

Hepatitis C virus (HCV) accounts for hepatitis, liver cirrhosis, hepatocellular carcinoma, and liver transplantation. This virus is a single-stranded RNA virus that belongs to the Flaviviridae family. According to the WHO, about 71 million people have chronic HCV infections around the globe in 2020, and hence, it is a plague of humankind. The credit of discovery of HCV goes to Michael Houghton, Harvey Alter, and Charles Rice for which they are awarded 2020 Nobel Prize in Medicine. Their contribution has given better hope to mankind to cure HCV for the first time in the history. With the use of pegylated interferon and ribavirin jointly, higher SVR has been found comparatively, even in patients with chronic liver diseases. However, due to excessive pain tolerated by patients, interferon (IFN)-based therapy is rapidly being replaced with IFN-free DAA regimens. With the onset of resistance to DAA drugs, CRISPR-Cas system can be used to modify the viral genome to impair their ability to develop resistance.

How to cite this article: Laugi H. Discovery of Hepatitis C Virus: 2020 Nobel Prize in Medicine. Euroasian J Hepato-Gastroenterol 2020;10(2): 105–108.

Competition between on-patent medicines in Europe

There is widespread concern regarding the high price of innovative medicines and their impact on the sustainability of healthcare systems. However, the debate rarely accounts for the evolution of prices over the lifetime of the medicine and the impact of competitive forces. This article uses the experience of hepatitis C (HCV), during the years 2010-2017 to examine the impact of in-class competition and implications for policies that enable competition. To study the HCV market, we focused on European countries and applied a two-step approach involving a comprehensive literature review and an analysis of monthly sales data in US$ across seven European countries from July 2011 until July 2017. We find that competition to address the unmet medical need has led to significant treatment improvements to the benefit of patients, payers and the wider healthcare system and society. Competitive launches have led to innovative agreements, lowering the cost per treatment and improving patient access to treatment. For innovators, intense competition does not only impact the price set and their market share but in many cases shortens the economic life of the product to only a fraction of the patented period. This has an impact on future research decisions, focusing efforts on areas where unmet need is greatest. Sustainable innovation requires a well-balanced policy framework that provides the appropriate incentives and encourages competition.

"Hep C, where art thou": What are the remaining (fundable) questions in hepatitis C virus research?

Hepatitis C virus (HCV) has dominated the field of hepatology for the past 25 years, and its cure in the majority of treated patients is one of the greatest achievements in all of medicine. However, the latter has led to the belief by some that HCV research should be shelved for other, more pressing areas. The mission for HCV eradication is far from accomplished. As a historical reference, we should consider that disease elimination has required vaccination with all previously controlled infections including smallpox and polio and that simple, effective treatment is not sufficient in most infections to lead to substantial control. Syphilis is the best example, for which a single dose of penicillin (which literally costs pennies and that we have had since 1945) is curative in early stages. Not only have we not eradicated syphilis, rates of infection have increased in many places within the United States in recent years. Most HCV-infected subjects are unaware of their infection, remaining at risk for transmission to others and disease progression, including cirrhosis and hepatocellular carcinoma. In the era of highly effective direct-acting antivirals (DAAs), many questions pertaining to HCV remain, but they are more complex and difficult to answer. Here, I provide my perspective on some of these salient issues: the residual risk for disease progression after sustained virologic response, the optimal approach to current DAA failures, the impact of targeting people who inject drugs with DAAs, vaccine prospects, and application of neutralizing HCV glycoprotein antibodies. (Hepatology 2017;65:341-349).

2015 Philip S. Portoghese Medicinal Chemistry Lectureship. Curing Hepatitis C Virus Infection with Direct-Acting Antiviral Agents: The Arc of a Medicinal Chemistry Triumph

The development of direct-acting antiviral agents that can cure a chronic hepatitis C virus (HCV) infection after 8-12 weeks of daily, well-tolerated therapy has revolutionized the treatment of this insidious disease. In this article, three of Bristol-Myers Squibb's HCV programs are summarized, each of which produced a clinical candidate: the NS3 protease inhibitor asunaprevir (64), marketed as Sunvepra, the NS5A replication complex inhibitor daclatasvir (117), marketed as Daklinza, and the allosteric NS5B polymerase inhibitor beclabuvir (142), which is in late stage clinical studies. A clinical study with 64 and 117 established for the first time that a chronic HCV infection could be cured by treatment with direct-acting antiviral agents alone in the absence of interferon. The development of small molecule HCV therapeutics, designed by medicinal chemists, has been hailed as "the arc of a medical triumph" but may equally well be described as "the arc of a medicinal chemistry triumph".

Association of Hepatitis C Virus With Alcohol Use Among U.S. Adults: NHANES 2003-2010

INTRODUCTION

Excessive alcohol use exacerbates morbidity and mortality among hepatitis C virus (HCV)-infected people. The purpose of this study was to describe self-reported patterns of alcohol use and examine the association with HCV infection and other sociodemographic and health-related factors.

METHODS

Data from 20,042 participants in the 2003-2010 National Health and Nutrition Examination Survey were analyzed in 2014. Estimates were derived for self-reported demographic characteristics, HCV-RNA (indicative of current HCV infection) status, and alcohol use at four levels: lifetime abstainers, former drinkers, non-excessive current drinkers, and excessive current drinkers.

RESULTS

Former drinkers and excessive current drinkers had a higher prevalence of HCV infection (2.2% and 1.5%, respectively) than never or non-excessive current drinkers (0.4% and 0.9%, respectively). HCV-infected adults were estimated to ever drink five or more drinks/day almost every day at some time during their lifetime about 3.3 times more often (43.8% vs 13.7%, p<0.001) than those who were never infected with HCV. Controlling for age, sex, race/ethnicity, education, and having a usual source of health care, HCV infection was significantly associated with excessive current drinking (adjusted prevalence ratio, 1.3; 95% CI=1.1, 1.6) and former drinking (adjusted prevalence ratio, 1.3; 95% CI=1.1, 1.6).

CONCLUSIONS

Chronic HCV infection is associated with both former and excessive current drinking. Public health HCV strategies should implement interventions with emphasis on alcohol abuse, which negatively impacts disease progression for HCV-infected individuals.

High Hepatitis C Infection Rate Among Baby Boomers in an Urban Primary Care Clinic: Results from the HepTLC Initiative

OBJECTIVE

CDC recommends that all people born between 1945 and 1965 be tested for hepatitis C virus (HCV). We hypothesized that HCV testing in a large, urban primary care clinic would reveal higher rates of HCV infection than previously published.

METHODS

Through the Hepatitis Testing and Linkage to Care initiative, the primary care clinic at MedStar Washington Hospital Center in Washington, DC, provided HCV antibody (anti-HCV) testing and linkage to care from October 2012 through September 2013 for patients born between 1945 and 1965 without previously noted risk factors. We collected data on age, race/ethnicity, sex, anti-HCV and HCV ribonucleic acid (RNA) results, risk factors in those who tested anti-HCV positive, and health insurance type and made comparisons using c(2) and Student's t-tests.

RESULTS

Of 1,123 patients tested, the mean age was 57 years, 742 (66.1%) were women, 969 (86.3%) were black/African American, and 654 (58.2%) had public health insurance. Of the 99 (8.8%) patients who tested anti-HCV positive, the mean age was 58 years, 54 were men, and 93 were black/African American; 41 of 74 anti-HCV-positive patients were intravenous drug users. Of 82 anti-HCV-positive patients, 51 were HCV RNA positive. Of the black/African American patients tested, 49 of 317 men (15.5%) and 44 of 652 women (6.7%) were anti-HCV positive (p,0.001). The HCV prevalence rate in the birth cohort (8.8%) was significantly higher than the U.S. (3.3%) and DC (2.5%) rates (p,0.001), and the HCV prevalence rate among black/African American men in DC (15.5%) was substantially higher than the prevalence rate reported by CDC (8.1%).

CONCLUSION

Testing initiatives in primary care settings need to be more rigorously upheld, and internal champions are needed to advocate for increased screening to ensure linkage to care and engagement in the HCV care cascade.

Characterization of Samples Identified as Hepatitis C Virus Genotype 1 without Subtype by Abbott RealTime HCV Genotype II Assay Using the New Abbott HCV Genotype Plus RUO Test

Hepatitis C virus (HCV) genotyping continues to be relevant for therapeutic strategies. Some samples are reported as genotype 1 (gt 1) without subtype by the Abbott RealTime HCV Genotype II (GT II) test. To characterize such samples further, the Abbott HCV Genotype Plus RUO (Plus) assay, which targets the core region for gt 1a, gt 1b, and gt 6 detection, was evaluated as a reflex test in reference to NS5B or 5′-untranslated region (UTR)/core region sequencing. Of 3,626 routine samples, results of gt 1 without subtype were received for 171 samples (4.7%), accounting for 11.5% of gt 1 specimens. The Plus assay and sequencing were applied to 98 of those samples. NS5B or 5′-UTR/core region sequencing was successful for 91/98 specimens (92.9%). Plus assay and sequencing results were concordant for 87.9% of specimens (80/91 samples). Sequencing confirmed Plus assay results for 82.6%, 85.7%, 100%, and 89.3% of gt 1a, gt 1b, gt 6, and non-gt 1a/1b/6 results, respectively. Notably, 12 gt 6 samples that had been identified previously as gt 1 without subtype were assigned correctly here; for 25/28 samples reported as “not detected” by the Plus assay, sequencing identified the samples as gt 1 with subtypes other than 1a/1b. The genetic variability of HCV continues to present challenges for the current genotyping platforms regardless of the applied methodology. Samples identified by the GT II assay as gt 1 without subtype can be further resolved and reliably characterized by the new Plus assay.

Hepatitis C Virus Treatment Revolution: Eastern European Story

Hepatitis C can be cured and even eradicated by new "revolutionary" treatments. However, at present exorbitant prices, Eastern European countries cannot afford the new treatments, while in western rich and developed countries (e.g. Germany and France) they are already available. Concerted efforts of governments, public health officials, and the community at large, are needed to negotiate agreements with pharmaceuticals companies to make the new treatments accessible and affordable. When science has demonstrated that hepatitis C can be cured, it would be unforgivable if millions of infected patients from eastern parts of the continent were denied access to new treatment on grounds of high prices and financial constraints.

Chronic hepatitis B: A wave of new therapies on the horizon

This year marks the 50th anniversary of the discovery of the Australia antigen (Blumberg et al., 1965), which in 1967 was identified to be the hepatitis B virus (HBV) surface antigen. Even though several antiviral medications have been in use for the management of chronic HBV infection for more than 20years, sustained clearance of HBsAg, similar to the sustained viral response (SVR) or cure in chronic hepatitis C, occurs in only a minority of treated patients. Moreover, even after 10years of effective suppression of HBV viremia with current therapy, there is only a 40-70% reduction in deaths from liver cancer. Recent success in developing antivirals for hepatitis C that are effective across all genotypes has renewed interest in a similar cure for chronic HBV infection. In this article, we review a wave of newly identified drug targets, investigational compounds and experimental strategies that are now under clinical evaluation or in preclinical development. The paper forms part of a symposium in Antiviral Research on "An unfinished story: From the discovery of the Australia antigen to the development of new curative therapies for hepatitis B."