Direct-acting antiviral therapies for hepatitis C infection: global registration, reimbursement, and restrictions

Trends in viral hepatitis liver-related morbidity and mortality in New South Wales, Australia

Background

Monitoring hepatitis B virus (HBV) and hepatitis C virus (HCV) liver-related morbidity and mortality is key to evaluate progress towards elimination targets.

Methods

HBV and HCV notifications in NSW, Australia (1995-2022) were linked to hospital and mortality records. Temporal trends in decompensated cirrhosis (DC), hepatocellular carcinoma (HCC), and mortality were evaluated among people notified for HBV and HCV. Segmented Poisson regression models were used to assess the impact of the viral hepatitis elimination era (1 January 2015-31 December 2022) on advanced liver disease and mortality.

Findings

During 1995-2022, there were 64,865 people with an HBV notification and 112,277 people with an HCV notification in NSW. Between 2002 and 2022, there were significant reductions in age-adjusted HBV- and HCV-related DC, HCC, and liver-related mortality. Among those with HBV, age-standardised incidence per 1000 person-years (py) in 2002, 2015, and 2022 was 3.08, 1.47, and 1.16 for DC (p < 0.001); 2.97, 1.45, and 0.75 for HCC (p < 0.001); and 2.84, 1.93, and 1.40 for liver-related mortality (p < 0.001). Among those with HCV, age-standardised incidence per 1000 py in 2002, 2015, and 2022, was 5.53, 4.57, and 2.31 for DC (p < 0.001); 2.22, 2.59, and 1.87 for HCC (p < 0.001); and 3.89, 4.73, and 3.16 for liver-related mortality (p < 0.001). In 2022, absolute liver-related mortality per 100,000 population was 0.95 for HBV and 3.56 for HCV. In adjusted analyses, older age, comorbidity, and a history of alcohol use disorder were associated with increased liver-related mortality among those with HBV and HCV.

Interpretation

This population-level study demonstrated declining risks of DC, HCC, and mortality, with HBV-related declines commencing well before elimination era while HCV-related declines were mostly during elimination era. Population liver mortality indicates elimination target achieved for combined viral hepatitis and HBV, but not HCV.

Funding

The Kirby Institute, UNSW Sydney, and New South Wales Ministry of Health, Australia.

HCV infection activates the proteasome via PA28γ acetylation and heptamerization to facilitate the degradation of RNF2, a catalytic component of polycomb repressive complex 1

We previously reported that hepatitis C virus (HCV) infection or HCV core protein expression induces HOX gene expression by impairing histone H2A monoubiquitination via a proteasome-dependent reduction in the level of RNF2, a key catalytic component of polycomb repressive complex 1 (H. Kasai, K. Mochizuki, T. Tanaka, A. Yamashita, et al., J Virol 95:e01784-20, 2021, https://doi.org/10.1128/jvi.01784-20). In this study, we aimed to investigate the mechanism by which HCV infection accelerates RNF2 degradation. Yeast two-hybrid screening and an immunoprecipitation assay revealed that RNF2 is a PA28γ-binding protein. The proteasome activator PA28γ destabilized the RNF2 protein in a proteasome-dependent manner, since RNF2 degradation was impaired by PA28γ knockout or MG132 treatment. HCV infection or core protein expression reduced the levels of RNF2 and histone H2A K119 monoubiquitination and induced the expression of HOX genes in the presence of PA28γ, while PA28γ knockout reversed these changes. Treatment with a lysine acetyltransferase inhibitor inhibited the acetylation of PA28γ at K195 and the degradation of the RNF2 protein, while treatment with a lysine deacetylase inhibitor accelerated these events in a PA28γ-dependent manner. RNF2 protein degradation was increased by expression of the acetylation mimetic PA28γ mutant but not by expression of the acetylation-defective mutant or the proteasome activation-defective mutant. Furthermore, HCV infection or core protein expression facilitated the interaction between PA28γ and the lysine acetyltransferase CBP/p300 and then accelerated PA28γ acetylation and heptazmerization to promote RNF2 degradation. These data suggest that HCV infection accelerates the acetylation-dependent heptamerization of PA28γ to increase the proteasomal targeting of RNF2.IMPORTANCEHCV is a causative agent of HCV-related liver diseases, including hepatic steatosis, cirrhosis, and hepatocellular carcinoma. PA28γ, which, in heptameric form, activates the 20S core proteasome for the degradation of PA28γ-binding proteins, is responsible for HCV-related liver diseases. HCV core protein expression or HCV infection accelerates RNF2 degradation, leading to the induction of HOX gene expression via a decrease in the level of H2Aub on HOX gene promoters. However, the mechanism of RNF2 degradation in HCV-infected cells has not been clarified. The data presented in this study suggest that PA28γ acetylation and heptamerization are promoted by HCV infection or by core protein expression to activate the proteasome for the degradation of RNF2 and are responsible for HCV propagation. This study provides novel insights valuable for the development of therapies targeting both HCV propagation and HCV-related diseases.

Benefits of Hepatitis C Viral Eradication: A Real-World Nationwide Cohort Study in Taiwan

BACKGROUND

Chronic hepatitis C (CHC) increases the risk of liver cirrhosis (LC) and hepatocellular carcinoma (HCC). This nationwide cohort study assessed the effectiveness of viral eradication of CHC.

METHODS

The Taiwanese chronic hepatitis C cohort and Taiwan hepatitis C virus (HCV) registry are nationwide HCV registry cohorts incorporating data from 23 and 53 hospitals in Taiwan, respectively. This study included 27,577 individuals from these cohorts that were given a diagnosis of CHC and with data linked to the Taiwan National Health Insurance Research Database. Patients received either pegylated interferon and ribavirin or direct-acting antiviral agent therapy for > 4 weeks for new-onset LC and liver-related events.

RESULTS

Among the 27,577 analyzed patients, 25,461 (92.3%) achieved sustained virologic response (SVR). The mean follow-up duration was 51.2 ± 48.4 months, totaling 118,567 person-years. In the multivariable Cox proportional hazard analysis, the hazard ratio (HR) for incident HCC was 1.39 (95% confidence interval [CI]: 1.00-1.95, p = 0.052) among noncirrhotic patients without SVR compared with those with SVR and 1.82 (95% CI 1.34-2.48) among cirrhotic patients without SVR. The HR for liver-related events, including HCC and decompensated LC, was 1.70 (95% CI 1.30-2.24) among cirrhotic patients without SVR. Patients with SVR had a lower 10-year cumulative incidence of new-onset HCC than those without SVR did (21.7 vs. 38.7% in patients with LC, p < 0.001; 6.0 vs. 18.4% in patients without LC, p < 0.001).

CONCLUSION

HCV eradication reduced the incidence of HCC in patients with and without LC and reduced the incidence of liver-related events in patients with LC.

The Impact of Biliary Injury on the Recurrence of Biliary Cancer and Benign Disease after Liver Transplantation: Risk Factors and Mechanisms

Liver transplantation is known to generate significant inflammation in the entire organ based on the metabolic profile and the tissue's ability to recover from the ischemia-reperfusion injury (IRI). This cascade contributes to post-transplant complications, affecting both the synthetic liver function (immediate) and the scar development in the biliary tree. The new occurrence of biliary strictures, and the recurrence of malignant and benign liver diseases, such as cholangiocarcinoma (CCA) and primary sclerosing cholangitis (PSC), are direct consequences linked to this inflammation. The accumulation of toxic metabolites, such as succinate, causes undirected electron flows, triggering the releases of reactive oxygen species (ROS) from a severely dysfunctional mitochondrial complex 1. This initiates the inflammatory IRI cascade, with subsequent ischemic biliary stricturing, and the upregulation of pro-tumorigenic signaling. Such inflammation is both local and systemic, promoting an immunocompromised status that can lead to the recurrence of underlying liver disease, both malignant and benign in nature. The traditional treatment for CCA was resection, when possible, followed by cytotoxic chemotherapy. Liver transplant oncology is increasingly recognized as a potentially curative approach for patients with intrahepatic (iCCA) and perihilar (pCCA) cholangiocarcinoma. The link between IRI and disease recurrence is increasingly recognized in transplant oncology for hepatocellular carcinoma. However, smaller numbers have prevented similar analyses for CCA. The mechanistic link may be even more critical in this disease, as IRI causes the most profound damage to the intrahepatic bile ducts. This article reviews the underlying mechanisms associated with biliary inflammation and biliary pathology after liver transplantation. One main focus is on the link between transplant-related IRI-associated inflammation and the recurrence of cholangiocarcinoma and benign liver diseases of the biliary tree. Risk factors and protective strategies are highlighted.

HCV 5-Methylcytosine Enhances Viral RNA Replication through Interaction with m5C Reader YBX1

Hepatitis C virus (HCV) is a positive-stranded RNA virus that mainly causes chronic hepatitis, cirrhosis and hepatocellular carcinoma. Recently we confirmed m5C modifications within NS5A gene of HCV RNA genome. However, the roles of the m5C modification and its interaction with host proteins in regulating HCV's life cycle, remain unexplored. Here, we demonstrate that HCV infection enhances the expression of the host m5C reader YBX1 through the transcription factor MAX. YBX1 acts as an m5C reader, recognizing the m5C-modified NS5A C7525 site in the HCV RNA genome and significantly enhancing HCV RNA stability. This m5C-modification is also required for YBX1 colocalization with lipid droplets and HCV Core protein. Moreover, YBX1 facilitates HCV RNA replication, as well as viral assembly/budding. The tryptophan residue at position 65 (W65) of YBX1 is critical for these functions. Knockout of YBX1 or the application of YBX1 inhibitor SU056 suppresses HCV RNA replication and viral protein translation. To our knowledge, this is the first report demonstrating that the interaction between host m5C reader YBX1 and HCV RNA m5C methylation facilitates viral replication. Therefore, hepatic-YBX1 knockdown holds promise as a potential host-directed strategy for HCV therapy.

Applying a stigma and time framework to facilitate equitable access to hepatitis C care among women who inject drugs: The ETHOS Engage Study

BACKGROUND

Women who inject drugs are significantly less likely to initiate hepatitis C virus (HCV) treatment than men. Concerted efforts are needed to minimise gender-based inequalities in care. The study aim was to use a stigma and time framework to investigate how women who inject drugs experienced HCV care in healthcare settings.

METHODS

Semi-structured, in-depth interviews were conducted with 34 participants from the ETHOS Engage Cohort (n = 1,443) in Australia. Inclusion criteria were aged ≥18 years, history of injection drug use, and persons who injected in the prior six months or were currently receiving opioid agonist treatment. Drawing on the original qualitative dataset (n = 34), we conducted a secondary analysis focused on women participants' experiences of receiving HCV related care (n = 21/34). Utilising thematic analysis, we applied Earnshaw's theoretical framework, which incorporates time into stigma and health research via three "timescales" - historical context, human development, and status course.

RESULTS

Among the 21 women interviewed (mean age 42 years, 5 are Aboriginal, 11 received HCV treatment), the majority were currently receiving opioid agonist treatment and over half injected drugs in the past month. For historical context, most participants were diagnosed with HCV during the interferon era (1990s-2014). Participants had to navigate a sociomedical landscape not only largely bereft of adequate HCV medical knowledge, appropriate support, and adequate treatments, but were also generally assessed as "unsuitable" for treatment based on their perceived personhood as people who inject drugs. For human development, many participants reported encountering overlapping stigmatizing experiences (layered stigma) while receiving their HCV diagnosis in prenatal care and early postpartum. Under status course, participants acutely recognised the intersection of HCV infection, injection drug use, and gender, and reported concerns about being judged more harshly from healthcare providers as a result.

CONCLUSION

A stigma and time framework illuminated multiple overlapping stigmatizing experiences for women who inject drugs in HCV care and in turn, can help to inform tools and interventions to counter their impact.

Viral Hepatitis C: From Unraveling the Nature of Disease to Cure and Global Elimination

BACKGROUND

The discovery of the hepatitis C virus (HCV) and direct-acting antiviral (DAA) drugs is one of the major milestones in the last 3 decades of medicine. These discoveries encouraged the World Health Organization (WHO) to set an ambitious goal to eliminate HCV by 2030, meaning "a 90% reduction in new cases of chronic HCV, a 65% reduction in HCV deaths, and treatment of 80% of eligible people with HCV infections."

SUMMARY

This review summarizes the key achievements from the discovery of HCV to the development of effective treatment and global elimination strategies. A better understanding of HCV structure, enzymes, and lifecycle led to the introduction of new drug targets and the discovery of DAA. Massive public health interventions are required, such as screening, access to care, treatment, and post-care follow-up, to make the most of DAA's potential. Screening must be supported by fast, accessible, sensitive, specific HCV diagnostic tests and noninvasive methods to determine the stage of liver disease. Linkage to care and treatment access are critical components of a comprehensive HCV elimination program, and decentralization plays a key role in ensuring their effectiveness.

KEY MESSAGES

Effective and simple screening strategies, rapid diagnostic tools, linkage to health care, and accessible treatment are key elements to achieving the WHO's goal. Incorporating treatment as prevention strategies into elimination programs together with preventive education and harm reduction interventions can have a profound and lasting impact on reducing both the incidence and prevalence of HCV. However, WHO's goal can be challenging to implement because of the need for high financial resources and strong political commitment.