Worldwide, some 240 million people have chronic hepatitis B virus (HBV), with the highest rates of infection in Africa and Asia. Our understanding of the natural history of HBV infection and the potential for therapy of the resultant disease is continuously improving. New data have become available since the previous APASL guidelines for management of HBV infection were published in 2012. The objective of this manuscript is to update the recommendations for the optimal management of chronic HBV infection. The 2015 guidelines were developed by a panel of Asian experts chosen by the APASL. The clinical practice guidelines are based on evidence from existing publications or, if evidence was unavailable, on the experts' personal experience and opinion after deliberations. Manuscripts and abstracts of important meetings published through January 2015 have been evaluated. This guideline covers the full spectrum of care of patients infected with hepatitis B, including new terminology, natural history, screening, vaccination, counseling, diagnosis, assessment of the stage of liver disease, the indications, timing, choice and duration of single or combination of antiviral drugs, screening for HCC, management in special situations like childhood, pregnancy, coinfections, renal impairment and pre- and post-liver transplant, and policy guidelines. However, areas of uncertainty still exist, and clinicians, patients, and public health authorities must therefore continue to make choices on the basis of the evolving evidence. The final clinical practice guidelines and recommendations are presented here, along with the relevant background information.

/pdf/asian-pacific-clinical-practice-guidelines-on-the-management-za5qxgu5i6.pdf

Asian-Pacific clinical practice guidelines on the management of hepatitis B: a 2015 update.

The liver is a central immunological organ with a high exposure to circulating antigens and endotoxins from the gut microbiota, particularly enriched for innate immune cells (macrophages, innate lymphoid cells, mucosal-associated invariant T (MAIT) cells). In homeostasis, many mechanisms ensure suppression of immune responses, resulting in tolerance. Tolerance is also relevant for chronic persistence of hepatotropic viruses or allograft acceptance after liver transplantation. The liver can rapidly activate immunity in response to infections or tissue damage. Depending on the underlying liver disease, such as viral hepatitis, cholestasis or NASH, different triggers mediate immune-cell activation. Conserved mechanisms such as molecular danger patterns (alarmins), Toll-like receptor signalling or inflammasome activation initiate inflammatory responses in the liver. The inflammatory activation of hepatic stellate and Kupffer cells results in the chemokine-mediated infiltration of neutrophils, monocytes, natural killer (NK) and natural killer T (NKT) cells. The ultimate outcome of the intrahepatic immune response (for example, fibrosis or resolution) depends on the functional diversity of macrophages and dendritic cells, but also on the balance between pro-inflammatory and anti-inflammatory T-cell populations. As reviewed here, tremendous progress has helped to understand the fine-tuning of immune responses in the liver from homeostasis to disease, indicating promising targets for future therapies in acute and chronic liver diseases.

Immunology in the liver — from homeostasis to disease

At least 250 million people worldwide are chronically infected with HBV, a small hepatotropic DNA virus that replicates through reverse transcription. Chronic infection greatly increases the risk for terminal liver disease. Current therapies rarely achieve a cure due to the refractory nature of an intracellular viral replication intermediate termed covalently closed circular (ccc) DNA. Upon infection, cccDNA is generated as a plasmid-like episome in the host cell nucleus from the protein-linked relaxed circular (RC) DNA genome in incoming virions. Its fundamental role is that as template for all viral RNAs, and in consequence new virions. Biosynthesis of RC-DNA by reverse transcription of the viral pregenomic RNA is now understood in considerable detail, yet conversion of RC-DNA to cccDNA is still obscure, foremostly due to the lack of feasible, cccDNA-dependent assay systems. Conceptual and recent experimental data link cccDNA formation to cellular DNA repair, which is increasingly appreciated as a critical interface between cells and viruses. Together with new in vitro HBV infection systems, based on the identification of the bile acid transporter sodium taurocholate cotransporting polypeptide as an HBV entry receptor, this offers novel opportunities to decipher, and eventually interfere with, formation of the HBV persistence reservoir. After a brief overview of the role of cccDNA in the HBV infectious cycle, this review aims to summarise current knowledge on cccDNA molecular biology, to highlight the experimental restrictions that have hitherto hampered faster progress and to discuss cccDNA as target for new, potentially curative therapies of chronic hepatitis B.

https://gut.bmj.com/content/gutjnl/64/12/1972.full.pdf

HBV cccDNA: viral persistence reservoir and key obstacle for a cure of chronic hepatitis B

Hepatitis B cure: From discovery to regulatory approval

Chronic hepatitis B virus (HBV) infection is a common cause of liver disease globally, with a disproportionately high burden in South-East Asia. Vaccines and nucleoside or nucleotide drugs are available and reduce both new infection rates and the development of liver disease in HBV-positive persons who adhere to long-term suppressive treatment. Although there is still considerable value in optimizing access to virus-suppressing regimens, the scientific and medical communities have embarked on a concerted journey to identify new antiviral drugs and immune interventions aimed at curing infection. The mechanisms and drug targets being explored are diverse; however, the field universally recognizes the importance of addressing the persistence of episomal covalently closed circular DNA, the existence of integrated HBV DNA in the host genome and the large antigen load, particularly of hepatitis B surface antigen. Another major challenge is to reinvigorate the exhausted immune response within the liver microenvironment. Ultimately, combinations of new drugs will be required to cure infection. Here we critically review the recent literature that describes the rationale for curative therapies and the resulting compounds that are being tested in clinical trials for hepatitis B.

Therapeutic strategies for hepatitis B virus infection: towards a cure

https://www.natap.org/2013/HBV/PIIS0016508513001698.pdf

GS-9620, an Oral Agonist of Toll-Like Receptor-7, Induces Prolonged Suppression of Hepatitis B Virus in Chronically Infected Chimpanzees

BackgroundGS-9620 is a novel oral agonist of Toll-like receptor 7 (TLR7) in development for the treatment of chronic viral hepatitis. TLR7 is a highly conserved innate immune receptor expressed pri...

Christian R. Frey

Papers

GS-9620, an Oral Agonist of Toll-Like Receptor-7, Induces Prolonged Suppression of Hepatitis B Virus in Chronically Infected Chimpanzees

Safety, pharmacokinetics and pharmacodynamics of GS-9620, an oral Toll-like receptor 7 agonist.