scholarly journals Preclinical Profile of AB-423, an Inhibitor of Hepatitis B Virus Pregenomic RNA Encapsidation

2018 ◽  
Vol 62 (6) ◽  
Author(s):  
Nagraj Mani ◽  
Andrew G. Cole ◽  
Janet R. Phelps ◽  
Andrzej Ardzinski ◽  
Kyle D. Cobarrubias ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Antiviral Activity ◽  
De Novo ◽  
Infection Model ◽  
Pharmacokinetic Studies ◽  
Circular Dna ◽  
B Virus ◽  
Combination Studies

ABSTRACTAB-423 is a member of the sulfamoylbenzamide (SBA) class of hepatitis B virus (HBV) capsid inhibitors in phase 1 clinical trials. In cell culture models, AB-423 showed potent inhibition of HBV replication (50% effective concentration [EC50] = 0.08 to 0.27 μM; EC90= 0.33 to 1.32 μM) with no significant cytotoxicity (50% cytotoxic concentration > 10 μM). Addition of 40% human serum resulted in a 5-fold increase in the EC50s. AB-423 inhibited HBV genotypes A through D and nucleos(t)ide-resistant variantsin vitro. Treatment of HepDES19 cells with AB-423 resulted in capsid particles devoid of encapsidated pregenomic RNA and relaxed circular DNA (rcDNA), indicating that it is a class II capsid inhibitor. In ade novoinfection model, AB-423 prevented the conversion of encapsidated rcDNA to covalently closed circular DNA, presumably by interfering with the capsid uncoating process. Molecular docking of AB-423 into crystal structures of heteroaryldihydropyrimidines and an SBA and biochemical studies suggest that AB-423 likely also binds to the dimer-dimer interface of core protein.In vitrodual combination studies with AB-423 and anti-HBV agents, such as nucleos(t)ide analogs, RNA interference agents, or interferon alpha, resulted in additive to synergistic antiviral activity. Pharmacokinetic studies with AB-423 in CD-1 mice showed significant systemic exposures and higher levels of accumulation in the liver. A 7-day twice-daily administration of AB-423 in a hydrodynamic injection mouse model of HBV infection resulted in a dose-dependent reduction in serum HBV DNA levels, and combination with entecavir or ARB-1467 resulted in a trend toward antiviral activity greater than that of either agent alone, consistent with the results of thein vitrocombination studies. The overall preclinical profile of AB-423 supports its further evaluation for safety, pharmacokinetics, and antiviral activity in patients with chronic hepatitis B.

scholarly journals Preclinical Profile and Characterization of the Hepatitis B Virus Core Protein Inhibitor ABI-H0731

2020 ◽  
Vol 64 (11) ◽  
Author(s):  
Qi Huang ◽  
Dawei Cai ◽  
Ran Yan ◽  
Lichun Li ◽  
Yuhua Zong ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Dna Replication ◽  
Hepatitis B ◽  
Mechanism Of Action ◽  
De Novo ◽  
Core Protein ◽  
Protein Inhibitor ◽  
Circular Dna ◽  
B Virus

ABSTRACT ABI-H0731, a first-generation hepatitis B virus (HBV) core protein inhibitor, has demonstrated effective antiviral activity in chronic hepatitis B (CHB) patients in a phase 1b clinical trial and is currently being further evaluated in phase 2 clinical trials. Here, we report the preclinical profile of ABI-H0731. In in vitro cell culture systems (HepG2-derived cell lines HepAD38 and HepG2-NTCP and primary human hepatocytes [PHHs]), ABI-H0731 exhibited selective inhibition of HBV DNA replication (50% effective concentration [EC50] from 173 nM to 307 nM). Most importantly, ABI-H0731 suppressed covalently closed circular DNA (cccDNA) formation in two de novo infection models with EC50s from 1.84 μM to 7.3 μM. Mechanism-of-action studies indicated that ABI-H0731 is a direct-acting antiviral that targets HBV core protein, preventing HBV pregenomic RNA (pgRNA) encapsidation and subsequent DNA replication. The combination of ABI-H0731 with entecavir appears to decrease viral DNA faster and deeper than nucleoside/nucleotide analogue (NrtI) therapy alone. In addition, ABI-H0731 disrupts incoming nucleocapsids, causing the premature release of relaxed circular DNA (rcDNA) before delivery to the nucleus, and thus prevents new cccDNA formation. ABI-H0731 exhibits pangenotypic activity and is additive to moderately synergistic when combined with an NrtI. In addition to its potency and novel mechanism of action, ABI-H0731 possesses drug-like properties and a preclinical pharmacokinetic profile supportive of once-daily dosing in patients with CHB. Taken together, these data support the ongoing clinical development of ABI-H0731 as a treatment for HBV.

scholarly journals In Vitro Characterization of the Anti-Hepatitis B Virus Activity and Cross-Resistance Profile of 2′,3′-Dideoxy-3′-Fluoroguanosine

2006 ◽  
Vol 50 (3) ◽  
pp. 955-961 ◽  
Author(s):  
A.-C. Jacquard ◽  
M.-N. Brunelle ◽  
C. Pichoud ◽  
D. Durantel ◽  
S. Carrouée-Durantel ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Antiviral Activity ◽  
Drug Resistant ◽  
Free System ◽  
Hbv Replication ◽  
Duck Hepatitis ◽  
Huh7 Cells ◽  
B Virus

ABSTRACT The fluorinated guanosine analog 2′,3′-dideoxy-3′-fluoroguanosine (FLG) was shown to inhibit wild-type (wt) hepatitis B virus (HBV) replication in a human hepatoma cell line permanently expressing HBV. Experiments performed in the duck model of HBV infection also showed its in vivo antiviral activity. In this study, we investigated the mechanism of inhibition of FLG on HBV replication and its profile of antiviral activity against different HBV or duck hepatitis B virus (DHBV) drug-resistant mutants. We found that FLG-triphosphate inhibits weakly the priming of the reverse transcription compared to adefovir-diphosphate in a cell-free system assay allowing the expression of an enzymatically active DHBV reverse transcriptase. It inhibits more potently wt DHBV minus-strand DNA synthesis compared to lamivudine-triphosphate and shows a similar activity compared to adefovir-diphosphate. FLG-triphosphate was most likely a competitive inhibitor of dGTP incorporation and a DNA chain terminator. In Huh7 cells transiently transfected with different HBV constructs, FLG inhibited similarly the replication of wt, lamivudine-resistant, adefovir-resistant, and lamivudine-plus-adefovir-resistant HBV mutants. These results were consistent with those obtained in the DHBV polymerase assay using the same drug-resistant polymerase mutants. In conclusion, our data provide new insights in the mechanism of action of FLG-triphosphate on HBV replication and demonstrate its inhibitory activity on drug-resistant mutant reverse transcriptases in vitro. Furthermore, our results provide the rationale for further clinical evaluation of FLG in the treatment of drug-resistant virus infection and in the setting of combination therapy to prevent or delay drug resistance.

scholarly journals Preclinical Characterization of NVR 3-778, a First-in-Class Capsid Assembly Modulator against Hepatitis B Virus

2018 ◽  
Vol 63 (1) ◽  
Author(s):  
Angela M. Lam ◽  
Christine Espiritu ◽  
Robert Vogel ◽  
Suping Ren ◽  
Vincent Lau ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Antiviral Activity ◽  
Viral Replication ◽  
De Novo ◽  
Hbv Dna ◽  
Cross Resistance ◽  
Capsid Assembly ◽  
B Virus

ABSTRACT NVR 3-778 is the first capsid assembly modulator (CAM) that has demonstrated antiviral activity in hepatitis B virus (HBV)-infected patients. NVR 3-778 inhibited the generation of infectious HBV DNA-containing virus particles with a mean antiviral 50% effective concentration (EC50) of 0.40 µM in HepG2.2.15 cells. The antiviral profile of NVR 3-778 indicates pan-genotypic antiviral activity and a lack of cross-resistance with nucleos(t)ide inhibitors of HBV replication. The combination of NVR 3-778 with nucleos(t)ide analogs in vitro resulted in additive or synergistic antiviral activity. Mutations within the hydrophobic pocket at the dimer-dimer interface of the core protein could confer resistance to NVR 3-778, which is consistent with the ability of the compound to bind to core and to induce capsid assembly. By targeting core, NVR 3-778 inhibits pregenomic RNA encapsidation, viral replication, and the production of HBV DNA- and HBV RNA-containing particles. NVR 3-778 also inhibited de novo infection and viral replication in primary human hepatocytes with EC50 values of 0.81 µM against HBV DNA and between 3.7 and 4.8 µM against the production of HBV antigens and intracellular HBV RNA. NVR 3-778 showed favorable pharmacokinetics and safety in animal species, allowing serum levels in excess of 100 µM to be achieved in mice and, thus, enabling efficacy studies in vivo. The overall preclinical profile of NVR 3-778 predicts antiviral activity in vivo and supports its further evaluation for safety, pharmacokinetics, and antiviral activity in HBV-infected patients.

scholarly journals Identification of Disubstituted Sulfonamide Compounds as Specific Inhibitors of Hepatitis B Virus Covalently Closed Circular DNA Formation

2012 ◽  
Vol 56 (8) ◽  
pp. 4277-4288 ◽  
Author(s):  
Dawei Cai ◽  
Courtney Mills ◽  
Wenquan Yu ◽  
Ran Yan ◽  
Carol E. Aldrich ◽  
...  
Keyword(s):  
Cell Culture ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Polymerase Activity ◽  
Circular Dna ◽  
Drug Candidates ◽  
Covalently Closed Circular Dna ◽  
Hbv Cccdna ◽  
B Virus

ABSTRACTHepatitis B virus (HBV) covalently closed circular DNA (cccDNA) plays a central role in viral infection and persistence and is the basis for viral rebound after the cessation of therapy, as well as the elusiveness of a cure even after extended treatment. Therefore, there is an urgent need for the development of novel therapeutic agents that directly target cccDNA formation and maintenance. By employing an innovative cell-based cccDNA assay in which secreted HBV e antigen is a cccDNA-dependent surrogate, we screened an in-house small-molecule library consisting of 85,000 drug-like compounds. Two structurally related disubstituted sulfonamides (DSS), termed CCC-0975 and CCC-0346, emerged and were confirmed as inhibitors of cccDNA production, with low micromolar 50% effective concentrations (EC50s) in cell culture. Further mechanistic studies demonstrated that DSS compound treatment neither directly inhibited HBV DNA replication in cell culture nor reduced viral polymerase activity in thein vitroendogenous polymerase assay but synchronously reduced the levels of HBV cccDNA and its putative precursor, deproteinized relaxed circular DNA (DP-rcDNA). However, DSS compounds did not promote the intracellular decay of HBV DP-rcDNA and cccDNA, suggesting that the compounds interfere primarily with rcDNA conversion into cccDNA. In addition, we demonstrated that CCC-0975 was able to reduce cccDNA biosynthesis in duck HBV-infected primary duck hepatocytes. This is the first attempt, to our knowledge, to identify small molecules that target cccDNA formation, and DSS compounds thus potentially serve as proof-of-concept drug candidates for development into therapeutics to eliminate cccDNA from chronic HBV infection.

Enhanced oral absorption and antiviral activity of 1-O-octadecyl-sn-glycero-3-phospho-acyclovir and related compounds in hepatitis b virus infection, in vitro

1997 ◽  
Vol 53 (12) ◽  
pp. 1815-1822 ◽  
Author(s):  
Karl Y. Hostetler ◽  
James R. Beadle ◽  
Ganesh D. Kini ◽  
Michael F. Gardner ◽  
Kristine N. Wright ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Virus Infection ◽  
Hepatitis B ◽  
Antiviral Activity ◽  
Oral Absorption ◽  
Hepatitis B Virus Infection ◽  
B Virus ◽  
Related Compounds

scholarly journals Inhibitory Effect of Adefovir on Viral DNA Synthesis and Covalently Closed Circular DNA Formation in Duck Hepatitis B Virus-Infected Hepatocytes In Vivo and In Vitro

2002 ◽  
Vol 46 (2) ◽  
pp. 425-433 ◽  
Author(s):  
Julien Delmas ◽  
Olivier Schorr ◽  
Catherine Jamard ◽  
Craig Gibbs ◽  
Christian Trépo ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Dna Synthesis ◽  
Dna Amplification ◽  
Viral Dna ◽  
Circular Dna ◽  
Covalently Closed Circular Dna ◽  
B Virus

ABSTRACT The elimination of viral covalently closed circular DNA (CCC DNA) from the nucleus of infected hepatocytes is an obstacle to achieving sustained viral clearance during antiviral therapy of chronic hepatitis B virus (HBV) infection. The aim of our study was to determine whether treatment with adefovir, a new acyclic nucleoside phosphonate, the prodrug of which, adefovir dipivoxil, is in clinical evaluation, is able to suppress viral CCC DNA both in vitro and in vivo using the duck HBV (DHBV) model. First, the effect of adefovir on viral CCC DNA synthesis was examined with primary cultures of DHBV-infected fetal hepatocytes. Adefovir was administered for six consecutive days starting one day before or four days after DHBV inoculation. Dose-dependent inhibition of both virion release in culture supernatants and synthesis of intracellular viral DNA was observed. Although CCC DNA amplification was inhibited by adefovir, CCC DNA was not eliminated by antiviral treatment and the de novo formation of CCC DNA was not prevented by pretreatment of the cells. Next, preventive treatment of experimentally infected ducklings with lamivudine or adefovir revealed that both efficiently suppressed viremia and intrahepatic DNA. However, persistence of viral DNA even when detectable only by PCR was associated with a recurrence of viral replication following drug withdrawal. Taken together, our results demonstrate that adefovir is a potent inhibitor of DHBV replication that inhibits CCC DNA amplification but does not effectively prevent the formation of CCC DNA from incoming viral genomes.

scholarly journals Alkoxyalkyl Esters of 9-(S)-(3-Hydroxy-2-Phosphonomethoxypropyl) Adenine Are Potent and Selective Inhibitors of Hepatitis B Virus (HBV) Replication In Vitro and in HBV Transgenic Mice In Vivo

2009 ◽  
Vol 53 (7) ◽  
pp. 2865-2870 ◽  
Author(s):  
John D. Morrey ◽  
Brent E. Korba ◽  
James R. Beadle ◽  
David L. Wyles ◽  
Karl Y. Hostetler
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Antiviral Activity ◽  
Transgenic Mice ◽  
Adefovir Dipivoxil ◽  
Murine Cytomegalovirus ◽  
Cross Resistance ◽  
B Virus

ABSTRACT Alkoxyalkyl esters of acyclic nucleoside phosphonates have previously been shown to have increased antiviral activity when they are administered orally in animal models of viral diseases, including lethal infections with vaccinia virus, cowpox virus, ectromelia virus, murine cytomegalovirus, and adenovirus. 9-(S)-(3-Hydroxy-2-phosphonomethoxypropyl)adenine [(S)-HPMPA] was previously shown to have activity against hepatitis B virus (HBV) in vitro. To assess the effect of alkoxyalkyl esterification of (S)-HPMPA, we prepared the hexadecyloxypropyl (HDP), 15-methyl-hexadecyloxypropyl (15M-HDP), and octadecyloxyethyl (ODE) esters and compared their activities with the activity of adefovir dipivoxil in vitro and in vivo. Alkoxyalkyl esters of (S)-HPMPA were 6 to 20 times more active than unmodified (S)-HPMPA on the basis of their 50% effective concentrations in 2.2.15 cells. The increased antiviral activity appeared to be due in part to the increased uptake and conversion of HDP-(S)-HPMPA to HPMPA diphosphate observed in HepG2 cells in vitro. HDP-(S)-HPMPA retained full activity against HBV mutants resistant to lamivudine (L180M, M204V), but cross-resistance to a mutant resistant to adefovir (N236T) was detected. HDP-(S)-HPMPA is orally bioavailable and provides excellent liver exposure to the drug. Oral treatment of HBV transgenic mice with HDP-(S)-HPMPA, 15M-HDP-(S)-HPMPA, and ODE-(S)-HPMPA for 14 days reduced liver HBV DNA levels by roughly 1.5 log units, a response equivalent to that of adefovir dipivoxil.

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