O224: What is in the pipeline for treatment of Hepatitis B? (IFN-lambda, TLR-agonists, entry inhibitors etc.)

Human hepatic bile acid transporter Na+/taurocholate co-transporting polypeptide (NTCP) represents the liver-specific entry receptor for the Hepatitis B and D Viruses (HBV/HDV). Chronic hepatitis B and D affect several million people worldwide, but treatment options are limited. Recently, HBV/HDV entry inhibitors targeting NTCP have emerged as promising novel drug candidates. Nevertheless, the exact molecular mechanism that NTCP uses to mediate virus binding and entry into hepatocytes is still not completely understood. It is already known that human NTCP mRNA expression is down-regulated under cholestasis. Furthermore, incubation of rat hepatocytes with the secondary bile acid taurolithocholic acid (TLC) triggers internalization of the rat Ntcp protein from the plasma membrane. In the present study, the long-term inhibitory effect of TLC on transport function, HBV/HDV receptor function and membrane expression of human NTCP were analyzed in HepG2 and HEK293 cells stably overexpressing NTCP. Even after short pulse preincubation, TLC had a significant long-lasting inhibitory effect on the transport function of NTCP, but the NTCP protein was still present at the plasma membrane. Furthermore, binding of the HBV/HDV myr-preS1 peptide and susceptibility for in vitro HDV infection were significantly reduced by TLC preincubation. We hypothesize that TLC rapidly accumulates in hepatocytes and mediates long-lasting trans-inhibition of the transport and receptor function of NTCP via a particular TLC binding site at an intracellularly accessible domain of NTCP. Physiologically, this trans-inhibition might protect hepatocytes from toxic overload of bile acids. Pharmacologically, it provides an interesting novel NTCP target site for potential long-acting HBV/HDV entry inhibitors.

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Establishment of a monoclonal antibody against human NTCP that blocks HBV infection

Journal of Virology ◽

10.1128/jvi.01686-21 ◽

2022 ◽

Author(s):

Toshitada Takemori ◽

Akiko Sugimoto-Ishige ◽

Hironori Nishitsuji ◽

Yushi Futamura ◽

Michishige Harada ◽

...

Keyword(s):

Monoclonal Antibody ◽

Chronic Hepatitis ◽

Bile Acid ◽

Hepatitis B ◽

Inhibitory Effect ◽

Hbv Infection ◽

Current Therapy ◽

Entry Inhibitors ◽

Hdv Infection

Hepatitis B virus (HBV) infects 240 million people worldwide. Current therapy profoundly suppresses HBV replication but requires long-term maintenance therapy. Therefore there is still a medical need for an efficient HBV cure. HBV enters host cells by binding via the preS1-domain of the viral L protein to the Na + /Taurocholate Cotransporting Polypeptide (NTCP). Thus, NTCP should be a key target for the development of anti-HBV therapeutics. Indeed, Myrcludex B, a synthetic form of the myristoylated preS1 peptide, effectively reduces HBV/HDV infection and has been approved as Hepcludex® in Europe for the treatment of patients with chronic hepatitis D virus (HDV) infection. We established a monoclonal antibody (mAb) N6HB426-20 that recognizes the extracellular domain of human NTCP and blocks HBV entry in vitro into human liver cells but has much less of an inhibitory effect on bile acid uptake. In vivo , administration of the N6HB426-20 mAb prevented HBV viremia for an extended period of time after HBV inoculation in a mouse model system without strongly inhibiting bile acid absorption. Among the extracellular loops (ECLs) of NTCP, regions of amino acids (aa) 84-87 in ECL1 and aa 157-165 near ECL2 of transmembrane domain 5 are critically important for HBV/HDV infection. Epitope-mapping and the 3D model of the NTCP structure suggested that the N6HB426-20 mAb may recognize aa 276/277 at the tip of ECL4 and interfere with an binding of HBV to the aa 84-87 region. In summary, we identified an in vivo neutralizing NTCP-targeting antibody capable of preventing HBV infection. Further improvements in efficacy of this drug will pave the way for its clinical applications. IMPORTANCE A number of entry inhibitors are being developed to enhance the treatment of HBV patients with oral nucleos(t)ide analogues (NA). To amplify the effectiveness of NA therapy, several efforts have been made to develop therapeutic mAbs with neutralizing activity against HBs antigens. However, the neutralizing effect of these mAbs may be muted by a large excess of HBsAg-positive noninfectious particles in the blood of infected patients. The advantage of NTCP-targeted HBV entry inhibitors is that they remain effective regardless of viral genotype, viral mutations and the presence of subviral particles. Although N6HB426-20 requires a higher dose than Myrcludex to obtain equivalent suppression of HBV in a model mouse system, it maintained the inhibitory effect for a long time post administration in proportion to the half-life of an IgG mAb. We believe that further improvements will make this antibody a promising treatment option for patients with chronic hepatitis B.

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Toll-Like Receptor Response to Hepatitis B Virus Infection and Potential of TLR Agonists as Immunomodulators for Treating Chronic Hepatitis B: An Overview

International Journal of Molecular Sciences ◽

10.3390/ijms221910462 ◽

2021 ◽

Vol 22 (19) ◽

pp. 10462

Author(s):

Mohammad Enamul Hoque Kayesh ◽

Michinori Kohara ◽

Kyoko Tsukiyama-Kohara

Keyword(s):

Chronic Hepatitis ◽

Hepatitis B ◽

Immune Responses ◽

Chronic Hepatitis B ◽

Innate Immune ◽

Hbv Infection ◽

Innate Immune Responses ◽

Tlr Agonists ◽

B Virus ◽

Host Innate Immunity

Chronic hepatitis B virus (HBV) infection remains a major global health problem. The immunopathology of the disease, especially the interplay between HBV and host innate immunity, is poorly understood. Moreover, inconsistent literature on HBV and host innate immunity has led to controversies. However, recently, there has been an increase in the number of studies that have highlighted the link between innate immune responses, including Toll-like receptors (TLRs), and chronic HBV infection. TLRs are the key sensing molecules that detect pathogen-associated molecular patterns and regulate the induction of pro- and anti-inflammatory cytokines, thereby shaping the adaptive immunity. The suppression of TLR response has been reported in patients with chronic hepatitis B (CHB), as well as in other models, including tree shrews, suggesting an association of TLR response in HBV chronicity. Additionally, TLR agonists have been reported to improve the host innate immune response against HBV infection, highlighting the potential of these agonists as immunomodulators for enhancing CHB treatment. In this study, we discuss the current understanding of host innate immune responses during HBV infection, particularly focusing on the TLR response and TLR agonists as immunomodulators.

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Development of a mass spectrometric screening assay for hepatitis B virus entry inhibitors

Journal of Pharmaceutical and Biomedical Analysis ◽

10.1016/j.jpba.2019.112959 ◽

2020 ◽

Vol 178 ◽

pp. 112959 ◽

Cited By ~ 2

Author(s):

Byoungsook Goh ◽

Jieun Choi ◽

Jung-Ah Kang ◽

Sung-Gyoo Park ◽

Jiwon Seo ◽

...

Keyword(s):

Hepatitis B Virus ◽

Hepatitis B ◽

Virus Entry ◽

Mass Spectrometric ◽

Screening Assay ◽

Entry Inhibitors ◽

B Virus ◽

Virus Entry Inhibitors

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Selective hepatitis B and D virus entry inhibitors from the group of pentacyclic lupane-type betulin-derived triterpenoids

Scientific Reports ◽

10.1038/s41598-020-78618-2 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Michael Kirstgen ◽

Kira Alessandra Alicia Theresa Lowjaga ◽

Simon Franz Müller ◽

Nora Goldmann ◽

Felix Lehmann ◽

...

Keyword(s):

Bile Acid ◽

Hepatitis B ◽

Treatment Options ◽

Receptor Function ◽

Acid Transport ◽

Virus Binding ◽

Virus Receptor ◽

Bile Acid Transport ◽

Entry Inhibitors

AbstractCurrent treatment options against hepatitis B and D virus (HBV/HDV) infections have only limited curative effects. Identification of Na+/taurocholate co-transporting polypeptide (NTCP) as the high-affinity hepatic receptor for both viruses in 2012 enables target-based development of HBV/HDV cell-entry inhibitors. Many studies already identified appropriate NTCP inhibitors. However, most of them interfere with NTCP’s physiological function as a hepatic bile acid transporter. To overcome this drawback, the present study aimed to find compounds that specifically block HBV/HDV binding to NTCP without affecting its transporter function. A novel assay was conceptualized to screen for both in parallel; virus binding to NTCP (measured via binding of a preS1-derived peptide of the large HBV/HDV envelope protein) and bile acid transport via NTCP. Hits were subsequently validated by in vitro HDV infection studies using NTCP-HepG2 cells. Derivatives of the birch-derived pentacyclic lupane-type triterpenoid betulin revealed clear NTCP inhibitory potency and selectivity for the virus receptor function of NTCP. Best performing compounds in both aspects were 2, 6, 19, and 25. In conclusion, betulin derivatives show clear structure–activity relationships for potent and selective inhibition of the HBV/HDV virus receptor function of NTCP without tackling its physiological bile acid transport function and therefore are promising drug candidates.

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Advances in hepatitis B therapeutics

Therapeutic Advances in Infectious Disease ◽

10.1177/2049936120965027 ◽

2020 ◽

Vol 7 ◽

pp. 204993612096502

Author(s):

Vicente Soriano ◽

Pablo Barreiro ◽

Edward Cachay ◽

Shyamasundaran Kottilil ◽

José V. Fernandez-Montero ◽

...

Keyword(s):

Hepatitis B ◽

Significant Proportion ◽

Clinical Development ◽

Drug Discontinuation ◽

Virus Eradication ◽

Immune Modulators ◽

Entry Inhibitors ◽

Hbsag Loss ◽

Treatment Benefits ◽

Advanced Stages

Despite the availability of both effective preventive vaccines and oral antivirals, over 250 million people are chronically infected with the hepatitis B virus (HBV). Globally, chronic hepatitis B is the leading cause of hepatocellular carcinoma, which represents the third cause of cancer mortality, accounting for nearly 1 million annual deaths. Current oral nucleos(t)ide therapy with tenofovir or entecavir suppresses serum HBV-DNA in most treated patients, but rarely is accompanied by HBsAg loss. Thus, treatment has to be given lifelong to prevent viral rebound. A broad spectrum of antivirals that block the HBV life cycle at different steps are in clinical development, including entry inhibitors, cccDNA disrupters/silencers, translation inhibitors, capsid assembly modulators, polymerase inhibitors and secretion inhibitors. Some of them exhibit higher potency than current oral nucleos(t)ides. Drugs in more advanced stages of clinical development are bulevirtide, JNJ-6379, ABI-H0731, ARO-HBV and REP-2139. To date, only treatment with ARO-HBV and with REP-2139 have resulted in HBsAg loss in a significant proportion of patients. Combination therapies using distinct antivirals and/or immune modulators are expected to maximize treatment benefits. The current goal is to achieve a ‘functional cure’, with sustained serum HBsAg after drug discontinuation. Ultimately, the goal of HBV therapy will be virus eradication, an achievement that would require the elimination of the cccDNA reservoir within infected hepatocytes.

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