1
|
Asselah T. What is the Path Forward to Treat Hepatitis Delta Virus?: Old Treatments and New Options. Clin Liver Dis 2023; 27:985-995. [PMID: 37778781 DOI: 10.1016/j.cld.2023.05.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
HDV use the cell enzymes for its own replication, and the HBsAg as an envelope. There is an urgent need to develop new drugs for chronic hepatitis D (CHD). Pegylated interferon alpha (PEG-IFNα) (direct-antiviral and immune modulator) has been used and recommended by scientific guidelines, although not approved, with moderate efficacy and poor tolerability. There are several drugs in development which target the host: bulevirtide (BLV), lonafarnib (LNF), nucleic acid polymer, and others.
Collapse
Affiliation(s)
- Tarik Asselah
- University of Paris-Cité, Hôpital Beaujon, Service d'hépatologie AP-HP & INSERM UMR1149, Clichy, France.
| |
Collapse
|
2
|
Lok J, Guerra Veloz MF, Agarwal K. Overview of New Targets for Hepatitis B Virus: Immune Modulators, Interferons, Bifunctional Peptides, Therapeutic Vaccines and Beyond. Clin Liver Dis 2023; 27:857-876. [PMID: 37778774 DOI: 10.1016/j.cld.2023.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Nucleos(t)ide analogs are the cornerstone of treatment against hepatitis B virus; however, they have no direct effect on its transcriptional template (ie, covalently closed circular DNA) and so functional cure is rarely achieved. Over recent years, there has been a significant improvement in our understanding of the viral life cycle and its mechanisms of immune evasion. In this review article, we will explore novel therapeutic targets, discuss the latest data from clinical trials, and highlight future research priorities.
Collapse
Affiliation(s)
- James Lok
- Institute of Liver Studies, King's College Hospital, London, SE5 9RS, UK
| | | | - Kosh Agarwal
- Institute of Liver Studies, King's College Hospital, London, SE5 9RS, UK.
| |
Collapse
|
3
|
Olenginski LT, Attionu SK, Henninger EN, LeBlanc RM, Longhini AP, Dayie TK. Hepatitis B Virus Epsilon (ε) RNA Element: Dynamic Regulator of Viral Replication and Attractive Therapeutic Target. Viruses 2023; 15:1913. [PMID: 37766319 PMCID: PMC10534774 DOI: 10.3390/v15091913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 09/01/2023] [Accepted: 09/05/2023] [Indexed: 09/29/2023] Open
Abstract
Hepatitis B virus (HBV) chronically infects millions of people worldwide, which underscores the importance of discovering and designing novel anti-HBV therapeutics to complement current treatment strategies. An underexploited but attractive therapeutic target is ε, a cis-acting regulatory stem-loop RNA situated within the HBV pregenomic RNA (pgRNA). The binding of ε to the viral polymerase protein (P) is pivotal, as it triggers the packaging of pgRNA and P, as well as the reverse transcription of the viral genome. Consequently, small molecules capable of disrupting this interaction hold the potential to inhibit the early stages of HBV replication. The rational design of such ligands necessitates high-resolution structural information for the ε-P complex or its individual components. While these data are currently unavailable for P, our recent structural elucidation of ε through solution nuclear magnetic resonance spectroscopy marks a significant advancement in this area. In this review, we provide a brief overview of HBV replication and some of the therapeutic strategies to combat chronic HBV infection. These descriptions are intended to contextualize our recent experimental efforts to characterize ε and identify ε-targeting ligands, with the ultimate goal of developing novel anti-HBV therapeutics.
Collapse
Affiliation(s)
- Lukasz T. Olenginski
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA (R.M.L.)
- Department of Biochemistry, University of Colorado, Boulder, CO 80309, USA
| | - Solomon K. Attionu
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA (R.M.L.)
| | - Erica N. Henninger
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA (R.M.L.)
| | - Regan M. LeBlanc
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA (R.M.L.)
| | - Andrew P. Longhini
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA (R.M.L.)
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Theodore K. Dayie
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA (R.M.L.)
| |
Collapse
|
4
|
Kamzeeva PN, Aralov AV, Alferova VA, Korshun VA. Recent Advances in Molecular Mechanisms of Nucleoside Antivirals. Curr Issues Mol Biol 2023; 45:6851-6879. [PMID: 37623252 PMCID: PMC10453654 DOI: 10.3390/cimb45080433] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 08/12/2023] [Accepted: 08/14/2023] [Indexed: 08/26/2023] Open
Abstract
The search for new drugs has been greatly accelerated by the emergence of new viruses and drug-resistant strains of known pathogens. Nucleoside analogues (NAs) are a prospective class of antivirals due to known safety profiles, which are important for rapid repurposing in the fight against emerging pathogens. Recent improvements in research methods have revealed new unexpected details in the mechanisms of action of NAs that can pave the way for new approaches for the further development of effective drugs. This review accounts advanced techniques in viral polymerase targeting, new viral and host enzyme targeting approaches, and prodrug-based strategies for the development of antiviral NAs.
Collapse
Affiliation(s)
| | | | | | - Vladimir A. Korshun
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (P.N.K.); (A.V.A.); (V.A.A.)
| |
Collapse
|
5
|
Salama II, Sami SM, Salama SI, Abdel-Latif GA, Shaaban FA, Fouad WA, Abdelmohsen AM, Raslan HM. Current and novel modalities for management of chronic hepatitis B infection. World J Hepatol 2023; 15:585-608. [PMID: 37305370 PMCID: PMC10251278 DOI: 10.4254/wjh.v15.i5.585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 03/13/2023] [Accepted: 04/12/2023] [Indexed: 05/24/2023] Open
Abstract
Over 296 million people are estimated to have chronic hepatitis B viral infection (CHB), and it poses unique challenges for elimination. CHB is the result of hepatitis B virus (HBV)-specific immune tolerance and the presence of covalently closed circular DNA as mini chromosome inside the nucleus and the integrated HBV. Serum hepatitis B core-related antigen is the best surrogate marker for intrahepatic covalently closed circular DNA. Functional HBV “cure” is the durable loss of hepatitis B surface antigen (HBsAg), with or without HBsAg seroconversion and undetectable serum HBV DNA after completing a course of treatment. The currently approved therapies are nucleos(t)ide analogues, interferon-alpha, and pegylated-interferon. With these therapies, functional cure can be achieved in < 10% of CHB patients. Any variation to HBV or the host immune system that disrupts the interaction between them can lead to reactivation of HBV. Novel therapies may allow efficient control of CHB. They include direct acting antivirals and immunomodulators. Reduction of the viral antigen load is a crucial factor for success of immune-based therapies. Immunomodulatory therapy may lead to modulation of the host immune system. It may enhance/restore innate immunity against HBV (as toll-like-receptors and cytosolic retinoic acid inducible gene I agonist). Others may induce adaptive immunity as checkpoint inhibitors, therapeutic HBV vaccines including protein (HBsAg/preS and hepatitis B core antigen), monoclonal or bispecific antibodies and genetically engineered T cells to generate chimeric antigen receptor-T or T-cell receptor-T cells and HBV-specific T cells to restore T cell function to efficiently clear HBV. Combined therapy may successfully overcome immune tolerance and lead to HBV control and cure. Immunotherapeutic approaches carry the risk of overshooting immune responses causing uncontrolled liver damage. The safety of any new curative therapies should be measured in relation to the excellent safety of currently approved nucleos(t)ide analogues. Development of novel antiviral and immune modulatory therapies should be associated with new diagnostic assays used to evaluate the effectiveness or to predict response.
Collapse
Affiliation(s)
- Iman Ibrahim Salama
- Department of Community Medicine Research, National Research Centre, Giza 12411, Dokki, Egypt
| | - Samia M Sami
- Department of Child Health, National Research Centre, Giza 12411, Dokki, Egypt
| | - Somaia I Salama
- Department of Community Medicine Research, National Research Centre, Giza 12411, Dokki, Egypt
| | - Ghada A Abdel-Latif
- Department of Community Medicine Research, National Research Centre, Giza 12411, Dokki, Egypt
| | - Fatma A Shaaban
- Department of Child Health, National Research Centre, Giza 12411, Dokki, Egypt
| | - Walaa A Fouad
- Department of Community Medicine Research, National Research Centre, Giza 12411, Dokki, Egypt
| | - Aida M Abdelmohsen
- Department of Community Medicine Research, National Research Centre, Giza 12411, Dokki, Egypt
| | - Hala M Raslan
- Department of Internal Medicine, National Research Centre, Giza 12411, Dokki, Egypt
| |
Collapse
|
6
|
Ranga A, Gupta A, Yadav L, Kumar S, Jain P. Advancing beyond reverse transcriptase inhibitors: The new era of hepatitis B polymerase inhibitors. Eur J Med Chem 2023; 257:115455. [PMID: 37216809 DOI: 10.1016/j.ejmech.2023.115455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 05/03/2023] [Accepted: 05/03/2023] [Indexed: 05/24/2023]
Abstract
Hepatitis B virus (HBV) is a genetically diverse blood-borne virus responsible for chronic hepatitis B. The HBV polymerase plays a key role in viral genome replication within the human body and has been identified as a potential drug target for chronic hepatitis B therapeutics. However, available nucleotide reverse transcriptase inhibitors only target the reverse transcriptase domain of the HBV polymerase; they also pose resistance issues and require lifelong treatment that can burden patients financially. In this study, various chemical classes are reviewed that have been developed to target different domains of the HBV polymerase: Terminal protein, which plays a vital role in the formation of the viral DNA; Reverse transcriptase, which is responsible for the synthesis of the viral DNA from RNA, and; Ribonuclease H, which is responsible for degrading the RNA strand in the RNA-DNA duplex formed during the reverse transcription process. Host factors that interact with the HBV polymerase to achieve HBV replication are also reviewed; these host factors can be targeted by inhibitors to indirectly inhibit polymerase functionality. A detailed analysis of the scope and limitations of these inhibitors from a medicinal chemistry perspective is provided. The structure-activity relationship of these inhibitors and the factors that may affect their potency and selectivity are also examined. This analysis will be useful in supporting the further development of these inhibitors and in designing new inhibitors that can inhibit HBV replication more efficiently.
Collapse
Affiliation(s)
- Abhishek Ranga
- Department of Pharmacology, Delhi Institute of Pharmaceutical Sciences and Research, Delhi Pharmaceutical Sciences and Research University, Pushp Vihar, MB Road, New Delhi, 110017, India
| | - Aarti Gupta
- Department of Pharmaceutical Biotechnology, Delhi Pharmaceutical Sciences and Research University, Pushp Vihar, MB Road, New Delhi, 110017, India
| | - Laxmi Yadav
- Department of Pharmacology, Delhi Institute of Pharmaceutical Sciences and Research, Delhi Pharmaceutical Sciences and Research University, Pushp Vihar, MB Road, New Delhi, 110017, India
| | - Sachin Kumar
- Department of Pharmacology, Delhi Institute of Pharmaceutical Sciences and Research, Delhi Pharmaceutical Sciences and Research University, Pushp Vihar, MB Road, New Delhi, 110017, India.
| | - Priti Jain
- Department of Pharmaceutical Chemistry, Delhi Pharmaceutical Sciences and Research University, Pushp Vihar, MB Road, New Delhi, 110017, India.
| |
Collapse
|
7
|
Emerging Therapies for Chronic Hepatitis B and the Potential for a Functional Cure. Drugs 2023; 83:367-388. [PMID: 36906663 DOI: 10.1007/s40265-023-01843-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/01/2023] [Indexed: 03/13/2023]
Abstract
Worldwide, an estimated 296 million people are living with chronic hepatitis B virus (HBV) infection, with a significant risk of morbidity and mortality. Current therapy with pegylated interferon (Peg-IFN) and indefinite or finite therapy with nucleoside/nucleotide analogues (Nucs) are effective in HBV suppression, hepatitis resolution, and prevention of disease progression. However, few achieve hepatitis B surface antigen (HBsAg) loss (functional cure), and relapse often occurs after the end of therapy (EOT) because these agents have no direct effect on durable template: covalently closed circular DNA (cccDNA) and integrated HBV DNA. Hepatitis B surface antigen loss rate increases slightly by adding or switching to Peg-IFN in Nuc-treated patients and this loss rate greatly increases up to 39% in 5 years with finite Nuc therapy with currently available Nuc(s). For this, great effort has been made to develop novel direct-acting antivirals (DAAs) and immunomodulators. Among the DAAs, entry inhibitors and capsid assembly modulators have little effect on reducing HBsAg levels; small interfering RNA, antisense oligonucleotides, and nucleic acid polymers in combination with Peg-IFN and Nuc may reduce HBsAg levels significantly, even a rate of HBsAg loss sustained for > 24 weeks after EOT up to 40%. Novel immunomodulators, including T-cell receptor agonists, check-point inhibitors, therapeutic vaccines, and monoclonal antibodies may restore HBV-specific T-cell response but not sustained HBsAg loss. The safety issues and the durability of HBsAg loss warrant further investigation. Combining agents of different classes has the potential to enhance HBsAg loss. Compounds directly targeting cccDNA would be more effective but are still in the early stage of development. More effort is required to achieve this goal.
Collapse
|
8
|
Squires KE, Ogilvie L, Jucov A, Anastasiy I, Ghicavii N, Huguet J, Melara R, Constantineau M, De La Rosa A, Mayers DL. A randomized phase 1b trial of the active site polymerase inhibitor nucleotide ATI-2173 in patients with chronic hepatitis B virus infection. J Viral Hepat 2023; 30:19-28. [PMID: 36201354 PMCID: PMC10092119 DOI: 10.1111/jvh.13753] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 09/13/2022] [Accepted: 09/13/2022] [Indexed: 01/15/2023]
Abstract
ATI-2173 is an active site polymerase inhibitor nucleotide in development as part of a potentially curative regimen for chronic hepatitis B virus (HBV) infection. This study evaluated the safety, tolerability, pharmacokinetics (PK) and antiviral activity of ATI-2173. This was a phase 1b, randomized, double-blind, placebo-controlled trial in treatment-naive adults with chronic HBV infection conducted in the Republic of Moldova and Ukraine (ClinicalTrials.gov: NCT04248426). Patients positive for hepatitis B surface antigen were randomized 6:2 to receive once-daily oral doses of ATI-2173 10, 25, or 50 mg (n = 6 per dose) or placebo (n = 7) for 28 days, with off-treatment monitoring for 24 weeks. Endpoints included PK parameters of ATI-2173 and its metabolite clevudine, maximum reduction from baseline in HBV DNA, and safety and tolerability. Treatment-emergent adverse events occurred in eight patients (47%) receiving ATI-2173 and five (71%) receiving placebo; headache was the most common (n = 4). ATI-2173 PK was generally dose proportional. Systemic clevudine exposure with ATI-2173 dosing was substantially reduced compared with historical values observed with clevudine administration. On Day 28, mean changes from baseline in HBV DNA were -2.72 to -2.78 log10 IU/ml with ATI-2173 and +0.17 log10 IU/ml with placebo. Off-treatment sustained viral suppression and decreases in covalently closed circular DNA biomarkers were observed in most patients; one maintained undetectable HBV DNA at 24 weeks off treatment. In this 28-day monotherapy study, ATI-2173 demonstrated safety and antiviral activity, with sustained off-treatment effects and substantially reduced systemic clevudine exposure. These results support evaluation of ATI-2173 with tenofovir disoproxil fumarate in phase 2 studies.
Collapse
Affiliation(s)
| | | | - Alina Jucov
- ARENSIA Exploratory Medicine, Republican Clinical Hospital, Chisinau, Moldova.,Department of Infectious Diseases, Nicolae Testemitanu State University of Medicine and Pharmacy, Chisinau, Moldova
| | - Igor Anastasiy
- Department of Infectious Diseases, Nicolae Testemitanu State University of Medicine and Pharmacy, Chisinau, Moldova.,ARENSIA Exploratory Medicine, Kiev, Ukraine
| | - Nelli Ghicavii
- ARENSIA Exploratory Medicine, Republican Clinical Hospital, Chisinau, Moldova
| | | | | | | | | | | |
Collapse
|
9
|
Yardeni D, Chang KM, Ghany MG. Current Best Practice in Hepatitis B Management and Understanding Long-term Prospects for Cure. Gastroenterology 2023; 164:42-60.e6. [PMID: 36243037 PMCID: PMC9772068 DOI: 10.1053/j.gastro.2022.10.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 09/25/2022] [Accepted: 10/04/2022] [Indexed: 02/03/2023]
Abstract
The hepatitis B virus (HBV) is a major cause of cirrhosis and hepatocellular carcinoma worldwide. Despite an effective vaccine, the prevalence of chronic infection remains high. Current therapy is effective at achieving on-treatment, but not off-treatment, viral suppression. Loss of hepatitis B surface antigen, the best surrogate marker of off-treatment viral suppression, is associated with improved clinical outcomes. Unfortunately, this end point is rarely achieved with current therapy because of their lack of effect on covalently closed circular DNA, the template of viral transcription and genome replication. Major advancements in our understanding of HBV virology along with better understanding of immunopathogenesis have led to the development of a multitude of novel therapeutic approaches with the prospect of achieving functional cure (hepatitis B surface antigen loss) and perhaps complete cure (clearance of covalently closed circular DNA and integrated HBV DNA). This review will cover current best practice for managing chronic HBV infection and emerging novel therapies for HBV infection and their prospect for cure.
Collapse
Affiliation(s)
- David Yardeni
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Kyong-Mi Chang
- Medical Research, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania; Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Marc G Ghany
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland.
| |
Collapse
|
10
|
Asselah T. Beyond bulevirtide: Alternative therapeutic options for the management of hepatitis delta virus. J Viral Hepat 2022; 30 Suppl 1:33-38. [PMID: 36529713 DOI: 10.1111/jvh.13789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 12/08/2022] [Indexed: 01/06/2023]
Abstract
Hepatitis delta virus (HDV) is a small RNA virus which needs Hepatitis B Surface Antigen for its envelope, for entry into hepatocytes and secretion. HDV chronic infection affects around 12 million people worldwide. HDV infection is believed to be the most severe form of viral hepatitis, with a high risk of developing cirrhosis and hepatocellular carcinoma. Pegylated interferons has been used and recommended by guidelines, although not approved, with low efficacy and poor tolerability. Bulevirtide (entry inhibitor) has been recently conditionally approved by the European Medicines Agency. These treatments have many advantages, but they have also limitations since there are non-responders to these previous therapies. There is an urgent need to develop new drugs. In this article, we review antiviral treatments under development for HDV chronic infection (except bulevirtide reviewed in a specific article), including those in the HBV cure programme, outlining their respective mechanisms-of-action.
Collapse
Affiliation(s)
- Tarik Asselah
- Université de Paris-Cité, Department of Hepatology, Hôpital Beaujon, AP-HP, CRI, INSERM UMR 1149, Clichy, France
| |
Collapse
|
11
|
Mak LY, Cheung KS, Fung J, Seto WK, Yuen MF. New strategies for the treatment of chronic hepatitis B. Trends Mol Med 2022; 28:742-757. [PMID: 35780008 DOI: 10.1016/j.molmed.2022.06.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 06/03/2022] [Accepted: 06/06/2022] [Indexed: 10/17/2022]
Abstract
Functional cure, as defined by seroclearance of hepatitis B surface antigen (HBsAg), is the desired treatment endpoint for chronic hepatitis B (CHB) infection, yet is rarely achieved with the currently approved therapy. Novel treatments currently in the clinical phase of development act by inhibiting viral replication/antigen reduction and/or by restoring host immune control. Although some agents are effective in reducing the viral antigen load, a greater magnitude of suppression is required to achieve functional cure. Compounds that target the covalently closed circular DNA (cccDNA) pool, hepatitis B X (HBx) protein inhibition, and mRNA destabilization are also in the preclinical phase of development. Challenges which remain include the clinical implications, immunological perturbations, and safety of these novel compounds to be used in the real-life setting.
Collapse
Affiliation(s)
- Lung-Yi Mak
- Department of Medicine, School of Clinical Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Ka-Shing Cheung
- Department of Medicine, School of Clinical Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong; Department of Medicine, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
| | - James Fung
- Department of Medicine, School of Clinical Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Wai-Kay Seto
- Department of Medicine, School of Clinical Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong; Department of Medicine, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
| | - Man-Fung Yuen
- Department of Medicine, School of Clinical Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong.
| |
Collapse
|
12
|
Hui RWH, Mak LY, Seto WK, Yuen MF. Assessing the developing pharmacotherapeutic landscape in hepatitis B treatment: A spotlight on drugs at phase II clinical trials. Expert Opin Emerg Drugs 2022; 27:127-140. [PMID: 35511483 DOI: 10.1080/14728214.2022.2074977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Functional cure, defined as sustained HBsAg seroclearance, is associated with favorable outcomes in chronic hepatitis B (CHB). While nucleos(t)ide analogues (NAs) are effective in suppressing HBV replication, NAs are unable to induce functional cure at high rates. A range of novel HBV antivirals, aiming to induce functional cure, are currently under development. AREAS COVERED This article covered novel hepatitis B virus (HBV) antivirals that have entered phase II trials. Virus-directing agents covered include entry inhibitors, transcription inhibitors, RNA silencers, core protein allosteric modulators, non-competitive polymerase inhibitors, and viral protein export inhibitors. Immunomodulators covered include innate immune stimulators, T-cell modulators, therapeutic vaccines, and monoclonal antibodies. Upcoming developmental directions would also be discussed. EXPERT OPINION Among novel HBV antivirals, RNA silencers, viral protein export inhibitors (with pegylated interferon) and entry inhibitors (with pegylated interferon) appear to be effective in suppressing HBsAg and may even induce functional cure. The other virus-targeting agents have variable effects on HBV DNA, HBsAg, HBeAg and HBcrAg. Immunomodulators have modest effects on HBsAg, but may have important roles in combination therapy. Upcoming trials will answer important questions on ideal dosing, long-term drug effects, and efficacy of combination regimens.
Collapse
Affiliation(s)
- Rex Wan-Hin Hui
- Department of Medicine, The University of Hong Kong, Hong Kong
| | - Lung Yi Mak
- Department of Medicine, The University of Hong Kong, Hong Kong.,State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Wai-Kay Seto
- Department of Medicine, The University of Hong Kong, Hong Kong.,State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Man-Fung Yuen
- Department of Medicine, The University of Hong Kong, Hong Kong.,State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| |
Collapse
|
13
|
Yardeni D, Ghany MG. Review article: hepatitis B-current and emerging therapies. Aliment Pharmacol Ther 2022; 55:805-819. [PMID: 35224760 DOI: 10.1111/apt.16828] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 01/17/2022] [Accepted: 02/04/2022] [Indexed: 12/12/2022]
Abstract
BACKGROUND The hepatitis B virus (HBV) affects an estimated 290 million individuals worldwide and is responsible for approximately 900 000 deaths annually, mostly from complications of cirrhosis and hepatocellular carcinoma. Although current treatment is effective at preventing complications of chronic hepatitis B, it is not curative, and often must be administered long term. There is a need for safe, effective, finite duration curative therapy. AIM Our aim was to provide a concise, up to date review of all currently available and emerging treatment options for chronic hepatitis B. METHODS We conducted a search of PubMed, clinicaltrials.gov, major meeting abstracts and pharmaceutical websites for publications and communications on current and emerging therapies for HBV. RESULTS Currently approved treatment options for chronic hepatitis B include peginterferon alpha-2a and nucleos(t)ide analogues. Both options do not offer a 'complete cure' (clearance of covalently closed circular DNA (cccDNA) and integrated HBV DNA) and rarely achieve a 'functional cure' (hepatitis B surface antigen (HBsAg) loss). An improved understanding of the viral lifecycle, immunopathogenesis and recent advances in drug delivery technologies have led to many novel therapeutic approaches that are currently being evaluated in clinical trials including targeting of viral entry, cccDNA, viral transcription, core protein, and release of HBsAg and HBV polymerase. Additionally, novel immunological approaches that include targeting the innate and adaptive immune system and therapeutic vaccination are being pursued. CONCLUSION The breadth and scope of novel therapies in development hold promise for regimen/s that will achieve functional cure.
Collapse
Affiliation(s)
- David Yardeni
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Marc G Ghany
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| |
Collapse
|
14
|
Nečasová I, Stojaspal M, Motyčáková E, Brom T, Janovič T, Hofr C. Transcriptional regulators of human oncoviruses: structural and functional implications for anticancer therapy. NAR Cancer 2022; 4:zcac005. [PMID: 35252867 PMCID: PMC8892037 DOI: 10.1093/narcan/zcac005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 02/04/2022] [Accepted: 02/15/2022] [Indexed: 11/26/2022] Open
Abstract
Transcription is often the first biosynthetic event of viral infection. Viruses produce preferentially viral transcriptional regulators (vTRs) essential for expressing viral genes and regulating essential host cell proteins to enable viral genome replication. As vTRs are unique viral proteins that promote the transcription of viral nucleic acid, vTRs interact with host proteins to suppress detection and immune reactions to viral infection. Thus, vTRs are promising therapeutic targets that are sequentially and structurally distinct from host cell proteins. Here, we review vTRs of three human oncoviruses: HBx of hepatitis B virus, HBZ of human T-lymphotropic virus type 1, and Rta of Epstein–Barr virus. We present three cunningly exciting and dangerous transcription strategies that make viral infections so efficient. We use available structural and functional knowledge to critically examine the potential of vTRs as new antiviral-anticancer therapy targets. For each oncovirus, we describe (i) the strategy of viral genome transcription; (ii) vTRs’ structure and binding partners essential for transcription regulation; and (iii) advantages and challenges of vTR targeting in antiviral therapies. We discuss the implications of vTR regulation for oncogenesis and perspectives on developing novel antiviral and anticancer strategies.
Collapse
Affiliation(s)
- Ivona Nečasová
- Institute of Biophysics of the Czech Academy of Sciences, Scientific Incubator, Královopolská 135, Brno 612 65, Czech Republic
| | - Martin Stojaspal
- Institute of Biophysics of the Czech Academy of Sciences, Scientific Incubator, Královopolská 135, Brno 612 65, Czech Republic
| | - Edita Motyčáková
- Institute of Biophysics of the Czech Academy of Sciences, Scientific Incubator, Královopolská 135, Brno 612 65, Czech Republic
| | - Tomáš Brom
- LifeB, Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 753/5, Brno 625 00, Czech Republic
| | - Tomáš Janovič
- LifeB, Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 753/5, Brno 625 00, Czech Republic
| | - Ctirad Hofr
- Institute of Biophysics of the Czech Academy of Sciences, Scientific Incubator, Královopolská 135, Brno 612 65, Czech Republic
| |
Collapse
|
15
|
Hui RWH, Mak LY, Seto WK, Yuen MF. RNA interference as a novel treatment strategy for chronic hepatitis B infection. Clin Mol Hepatol 2022; 28:408-424. [PMID: 35172540 PMCID: PMC9293617 DOI: 10.3350/cmh.2022.0012] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 02/16/2022] [Indexed: 11/26/2022] Open
Abstract
Chronic hepatitis B (CHB) is a major cause of liver-related morbidity and mortality. Functional cure of CHB, defined as sustainable hepatitis B surface antigen (HBsAg) seroclearance, is associated with improved clinical outcomes. However, functional cure is rarely attainable by current treatment modalities. RNA interference (RNAi) by small-interfering RNA (siRNA) and anti-sense oligonucleotide (ASO) has been studied as a novel treatment strategy for CHB. RNAi targets post-transcriptional messenger RNAs and pregenomic RNAs to reduce hepatitis B virus (HBV) antigen production and viral replication. By reducing viral antigens, host immune reconstitution against HBV may also be attained. Phase I/II trials on siRNAs have demonstrated them to be safe and well-tolerated. siRNA is effective when given in monthly doses with different total number of doses according to different trial design, and can lead to sustainable dose-dependent mean HBsAg reduction by 2–2.5 log. Incidences of HBsAg seroclearance after siRNA therapy have also been reported. ASOs have also been studied in early phase trials, and a phase Ib study using frequent dosing regimen within 4 weeks could achieve similar HBsAg reduction of 2 log from baseline. Given the established efficacy and safety of nucleos(t) ide analogues (NAs), future RNAi regimens will likely include NA backbone. While the current evidence on RNAi appears promising, it remains undetermined whether the potent HBsAg reduction by RNAi can result in a high rate of HBsAg seroclearance with durability. Data on RNAi from phase IIb/III trials are keenly anticipated.
Collapse
Affiliation(s)
- Rex Wan-Hin Hui
- Department of Medicine, The University of Hong Kong, Hong Kong
| | - Lung-Yi Mak
- Department of Medicine, The University of Hong Kong, Hong Kong.,State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Wai-Kay Seto
- Department of Medicine, The University of Hong Kong, Hong Kong.,State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Man-Fung Yuen
- Department of Medicine, The University of Hong Kong, Hong Kong.,State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| |
Collapse
|
16
|
Gish RG, Asselah T, Squires K, Mayers D. Active site polymerase inhibitor nucleotides (ASPINs): Potential agents for chronic HBV cure regimens. Antivir Chem Chemother 2022; 30:20402066221138705. [PMID: 36423233 PMCID: PMC9703507 DOI: 10.1177/20402066221138705] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 10/06/2022] [Indexed: 10/03/2023] Open
Abstract
Chronic hepatitis B virus (HBV) infection affects 240 to 300 million people worldwide. In the nucleus of infected hepatocytes, the HBV genome is converted to covalently closed circular DNA (cccDNA), which persists and serves as a transcriptional template for viral progeny. Therefore, a long-term cure for chronic HBV infection will require elimination of cccDNA. Although currently available nucleos(t)ide analogues (eg, tenofovir disoproxil fumarate, tenofovir alafenamide, entecavir) effectively control HBV replication, they are seldom curative (functional cure rate ∼10%) and require lifelong treatment for most patients. As such, antiviral agents with novel mechanisms of action are needed. Active site polymerase inhibitor nucleotides (ASPINs) noncompetitively distort the HBV polymerase active site to completely inhibit all polymerase functions, unlike traditional chain-terminating nucleos(t)ide analogues, which only target select polymerase functions and are consumed in the process. Clevudine, a first-generation ASPIN, demonstrated potent and prolonged HBV suppression in phase 2 and 3 clinical studies, but long-term treatment was associated with reversible myopathy in a small number of patients. ATI-2173, a novel next-generation ASPIN, is structurally similar to clevudine but targets the liver and demonstrates potent anti-HBV activity on and off treatment, and may ultimately demonstrate an improved pharmacokinetic and safety profile by significantly reducing systemic clevudine exposure. Thus, ATI-2173 is currently in clinical development as an agent for HBV cure. Here, we review the mechanism of action and preclinical and clinical profiles of clevudine and ATI-2173 to support the role of ASPINs as part of curative regimens for chronic HBV infection.
Collapse
Affiliation(s)
- Robert G Gish
- Hepatitis B Foundation, Doylestown, PA, USA
- Robert G. Gish Consultants, LLC, La Jolla, CA, USA
| | - Tarik Asselah
- Université de Paris, Inserm U1149, Centre de Recherche sur l’inflammation, Paris, France
- Department of Hepatology, AP-HP, Hôpital Beaujon, Clichy, France
| | | | | |
Collapse
|
17
|
Tremblay T, Alcée JB, Giguère D. Protecting-group-free synthesis of clevudine ( l-FMAU), a treatment of the hepatitis B virus. Org Biomol Chem 2022; 20:8859-8863. [DOI: 10.1039/d2ob01814d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A new strategy for the synthesis of unnatural 2′-deoxy-2′-fluoro-l-nucleoside is described.
Collapse
Affiliation(s)
- Thomas Tremblay
- Département de Chimie, 1045 av. De la Médecine, Université Laval, Québec City, Qc, Canada G1V 0A6
| | - Jessica B. Alcée
- Département de Chimie, 1045 av. De la Médecine, Université Laval, Québec City, Qc, Canada G1V 0A6
| | - Denis Giguère
- Département de Chimie, 1045 av. De la Médecine, Université Laval, Québec City, Qc, Canada G1V 0A6
| |
Collapse
|
18
|
Bassit L, Ono SK, Schinazi RF. Moving Fast Toward Hepatitis B Virus Elimination. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1322:115-138. [PMID: 34258739 DOI: 10.1007/978-981-16-0267-2_5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Currently, there are two safe and effective therapeutic strategies for chronic hepatitis B treatment, namely, nucleoside analogs and interferon alpha (pegylated or non-pegylated). These treatments can control viral replication and improve survival; however, they do not eliminate the virus and therefore require long-term continued therapy. In addition, there are significant concerns about virus rebound on discontinuation of therapy and the development of fibrosis and hepatocellular carcinoma despite therapy. Therefore, the search for new, more effective, and safer antiviral agents that can cure hepatitis B virus (HBV) continues. Anti-HBV drug discovery and development is fundamentally impacted by our current understanding of HBV replication, disease physiopathology, and persistence of HBV covalently closed circular DNA (cccDNA). Several HBV replication targets are the basis for novel anti-HBV drug development strategies. Many of them are already in clinical trial phase 1 or 2, while others with promising results are still in preclinical stages. As research intensifies, potential HBV curative therapies and modalities in the pipeline are now on the horizon.
Collapse
Affiliation(s)
- Leda Bassit
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, and Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Suzane Kioko Ono
- Department of Gastroenterology, University of Sao Paulo School of Medicine, Sao Paulo, SP, Brazil
| | - Raymond F Schinazi
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, and Children's Healthcare of Atlanta, Atlanta, GA, USA.
| |
Collapse
|