Direct-acting antiviral (DAA) regimens are safe and effective at eradicating hepatitis C virus (HCV) infection. Unfortunately, DAAs remain expensive, so treatment of all HCV-infected patients would ...substantially affect health care costs. It is therefore important to continue to assess the hepatic and extrahepatic benefits of a DAA-induced sustained virologic response (SVR). A DAA-induced SVR reduces a patient’s risk of cirrhosis and hepatocellular carcinoma and extrahepatic manifestations of HCV infection; there are also data to indicate that an SVR can reduce mortality. SVR is a relevant clinical end point, but further analyses are required to confirm its importance among diverse HCV-infected populations and to document the public health benefits of HCV elimination at the population level. We review the evidence for the benefits associated with SVRs in different clinical settings and challenges to data collection.
The treatment of HCV infection has evolved at an extremely rapid pace over the past few years. The development of direct-acting antiviral agents, which potently inhibit different stages in the viral ...life cycle, has led to the replacement of interferon with well-tolerated oral therapies with cure rates of >90% in most patient populations. Understanding the mechanisms of action of the various agents as well as related issues, including the molecular basis for resistance, helps to guide drug development and clinical use. In this Review, we provide a mechanistic description of NS3/4A protease inhibitors, nucleotide and non-nucleotide inhibitors of the NS5B viral polymerase and inhibitors of the NS5A protein, followed by a summary of clinical data from studies of each drug class alone and in combination. Remaining challenges in drug development efforts are also discussed.
Despite remarkable therapeutic advances, hepatitis C virus (HCV) infection continues to be a major global problem. While the development of highly effective direct-acting antivirals has ensured that ...almost all those who are treated achieve viral cure, progress toward HCV elimination globally has stalled due to challenges upstream of treatment in the cascade of care, namely diagnosis and linkage to care. The major challenge continues to be the relative complexity of HCV diagnosis with the current requirement for a confirmatory HCV RNA test after an initial antibody-positive result. In this review, challenges with the current paradigm are highlighted with a focus on new technologies, as well as simple strategies using existing tools, which may simplify diagnosis and improve linkage to care and treatment. To achieve HCV elimination, improvements in the HCV diagnostics field to allow for a simple single-step diagnosis are required.
The next decade will be a crucial period in the public health response to hepatitis C virus (HCV) infection. The rapid development of direct-acting antiviral (DAA) therapy for HCV infection has ...brought considerable optimism to the HCV sector, with the realistic hope that therapeutic intervention will soon provide near-optimal efficacy with well-tolerated short-duration, all-oral regimens. As the zenith in HCV therapeutic development approaches, there remain several key obstacles to the broad implementation of interferon-free DAA regimens. The extent of HCV screening and disease assessment, global and national public health prioritization, and drug pricing will determine the potential impact on disease burden derived from introduction of these exciting new HCV therapies. Public health partnerships and advocacy will be crucial to remove barriers to enhanced HCV treatment access.
To evaluate screening and treatment strategies, large-scale real-world data on liver disease-related outcomes are needed. We sought to validate health administrative data for identification of ...cirrhosis, decompensated cirrhosis and hepatocellular carcinoma among patients with known liver disease.
Primary patient data were abstracted from patients of the Toronto Center for Liver Disease with viral hepatitis (2006-2014), and all patients with liver disease from the Kingston Health Sciences Centre Hepatology Clinic (2013). We linked clinical information to health administrative data and tested a range of coding algorithms against the clinical reference standard.
A total of 6,714 patients had primary chart data abstracted. A single physician visit code for cirrhosis was sensitive (98-99%), and a single hospital diagnostic code for cirrhosis was specific (91-96%). The most sensitive algorithm for decompensated cirrhosis was one cirrhosis code with any of: a hospital diagnostic code, death code, or procedure code for decompensation (range 88-99% across groups). The most specific was one cirrhosis code and one hospital diagnostic code (range 89-98% across groups). Two physician visit codes or a single hospital diagnostic code, death code, or procedure code combined with a code for cirrhosis were sensitive and specific for hepatocellular carcinoma (sensitivity 94-96%, specificity 93-98%).
These sensitive and specific algorithms can be used to define patient cohorts or detect clinical outcomes using health administrative data. Our results will facilitate research into the adequacy of screening and treatment for patients with chronic viral hepatitis or other liver diseases.
Chronic hepatitis C virus (HCV) infection is associated with several extrahepatic manifestations. Patients with HCV may develop mixed cryoglobulinemia and its sequelae, ranging from cutaneous and ...visceral vasculitis to glomerulonephritis and B-cell non-Hodgkin lymphoma. HCV-infected patients have increased rates of insulin resistance, diabetes, and atherosclerosis, which may lead to increased cardiovascular morbidity and mortality. Neurological manifestations of HCV infection include fatigue and cognitive impairment. The mechanisms causing the extrahepatic effects of HCV infection are likely multifactorial and may include endocrine effects, HCV replication in extrahepatic cells, or a heightened immune reaction with systemic effects. Successful eradication of HCV with interferon alfa and ribavirin was shown to improve some of these extrahepatic effects; sustained virological response is associated with resolution of complications of cryoglobulinemia, reduced levels of insulin resistance, reduced incidence of diabetes and stroke, and improved fatigue and cognitive functioning. The availability of new interferon-free, well-tolerated anti-HCV treatment regimens is broadening the spectrum of patients available for therapy, including those in whom interferon was contraindicated, and will likely result in greater improvements in the extrahepatic manifestations of HCV. If these regimens are shown to confer significant benefit in the metabolic, cardiovascular, or neuropsychiatric conditions associated with HCV infection, extrahepatic manifestations of HCV may become a major indication for treatment even in the absence of liver disease.
Since the identification of the hepatitis C virus, great strides have been made in the development of an antiviral therapy. As a crucial mediator of the innate antiviral immune response, ...interferon-alpha (IFN-alpha) was a natural choice for treatment. Whereas treatment with IFN-alpha alone achieved only modest success, the addition of the broad-spectrum antiviral agent ribavirin greatly improved responses. However, half of the infected individuals with chronic disease do not achieve sustained clearance of hepatitis C virus. To optimize current therapeutic strategies and to develop new therapies, a better understanding of the mechanism of action of IFN and ribavirin will be essential.
Summary The hepatitis C virus (HCV) was discovered in the late 1980s. Interferon (IFN)-α was proposed as an antiviral treatment for chronic hepatitis C at about the same time. Successive improvements ...in IFN-α-based therapy (dose finding, pegylation, addition of ribavirin) increased the rates of sustained virologic response, i.e. the rates of curing HCV infection. These rates were further improved by adding the first available direct-acting antiviral (DAA) drugs to the combination of pegylated IFN-α and ribavirin. An IFN-free era finally started in 2014, yielding rates of sustained virologic response over 90% in patients treated for 8 to 24 weeks with all-oral regimens. Major challenges however remain in implementation of these new treatment strategies, not only in low- to middle-income countries, but also in high-income countries where the price of these therapies is still prohibitive. Elimination of HCV infection through treatment in certain areas is possible but raises major public health issues.
Summary
Background
Treatment of hepatitis B virus (HBV) infection with current therapy suppresses HBV DNA, but loss of hepatitis B surface antigen (HBsAg; functional cure), is rare. Multiple ...compounds are under investigation.
Aims
To describe the pharmacology, including drug interactions, efficacy, safety and mechanisms of action of investigational compounds for HBV infection.
Methods
Descriptive review using PubMed and Google to identify literature/conference papers on investigational compounds (≥Phase 2) with data on efficacy and safety in HBV‐infected patients.
Results
Bulevirtide, JNJ‐56136379, ABI‐H0731, REP‐2139, and inarigivir decrease HBV DNA/RNA, with greater potency than current nucleos(t)ide analogues. REP‐2139 (25%‐75% of patients, 20‐48 weeks treatment) and inarigivir (26% of patients, 12‐24 weeks treatment) induce HBsAg loss. ARO‐HBV reduced (>1.5 log10 UI/mL) HBsAg in 85% of patients (12 weeks treatment). There are some safety concerns with investigational agents (e.g., increased bile acids with bulevirtide, and liver enzyme flares with REP‐2139) which will require a risk benefit assessment compared with current therapies. Single and multidose pharmacokinetic data are available for bulevirtide, JNJ‐56136379, ABI‐H0731; no such data are available for REP‐2139, ARO‐HBV, inarigivir. Initial drug interaction assessments have been performed with bulevirtide and inarigivir (only in vitro).
Conclusions
There are promising investigational therapies for HBV infection. Increasing the potential for HBsAg loss may result in more patients achieving functional cure. However, many knowledge gaps remain such as pharmacokinetics in those with HBV, cirrhosis and renal impairment but also the interaction potential between investigational therapies, risk‐benefit profiles, and potential for drug interactions with medications used to treat comorbidities associated with aging.
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