Efficacy and Safety of Bepirovirsen in Chronic Hepatitis B Infection

Therapeutic effects of reduced glutathione on liver function, fibrosis, and HBV DNA clearance in chronic hepatitis B patients

OBJECTIVE

To evaluate the therapeutic impact of reduced glutathione combined with entecavir on liver function, fibrosis, and HBV-DNA clearance in chronic hepatitis B patients.

METHODS

This was a randomized controlled trial. This study included 90 patients diagnosed with chronic hepatitis B, who were randomly divided into two groups (observation group and control group) using a random number table, with 45 patients in each group. The control group received standard entecavir treatment (0.5 mg/time, once a day, continuous treatment for 3 months), while the observation group received a combination therapy of reduced glutathione and the standard entecavir treatment. Liver function markers (ALT, TBIL, AST, ALB), fibrosis markers (HA, PC III, LN), and liver fibrosis grades were assessed pre-and post-treatment. HBV-DNA negative conversion rates were recorded at 4, 12, 24, and 48 weeks. The incidence of adverse reactions, including nausea, vomiting, headache, and mild gastric discomfort, was recorded and compared between the two groups during the treatment period.

RESULTS

ALT decreased from 348.96 ± 31.47 U/L to 31.11 ± 9.78 U/L in the observation group and from 347.90 ± 31.40 U/L to 56.90 ± 16.32 U/L in the control group (P < 0.05). TBIL decreased from 61.78 ± 4.94 µmol/L to 18.82 ± 2.93 µmol/L in the observation group and from 61.32 ± 4.93 µmol/L to 26.70 ± 4.44 µmol/L in the control group (P < 0.05). ALB increased from 29.65 ± 0.94 g/L to 48.76 ± 4.85 g/L in the observation group and from 29.77 ± 0.90 g/L to 34.12 ± 0.84 g/L in the control group (P < 0.05). The observation group showed greater reductions in HA, PC III, and LN, and improved liver fibrosis grades (P < 0.05). HBV-DNA negative conversion rates in the observation group were 15.56%, 35.56%, 60.00%, and 68.89% at 4, 12, 24, and 48 weeks, respectively, compared to 2.22%, 6.67%, 17.78%, and 42.22% in the control group (P < 0.05). Adverse reaction rates were 8.89% in the observation group and 20.00% in the control group (P > 0.05).

CONCLUSION

Reduced glutathione combined with entecavir significantly improves liver function, reduces liver fibrosis, and enhances HBV-DNA clearance in chronic hepatitis B patients without increasing adverse reactions.

Sequential Peg-IFN after bepirovirsen may reduce post-treatment relapse in chronic hepatitis B

BACKGROUND & AIMS

Bepirovirsen, an antisense oligonucleotide, induces sustained reductions in hepatitis B surface antigen (HBsAg) and HBV DNA to below the lower limit of quantification (

METHODS

In this phase IIb, multicentre, open-label trial, participants on stable nucleos(t)ide analogue (NA) therapy were randomised 1:1 to bepirovirsen 300 mg once weekly (plus loading dose on Days 4 and 11) for 24 (Arm 1) or 12 (Arm 2) weeks followed by Peg-IFN 180 μg once weekly for up to 24 weeks, with up to 36 weeks follow-up. Participants continued NA therapy throughout. The primary outcome was the proportion of participants with HBsAg <0.05 IU/ml and HBV DNA

RESULTS

The intent-to-treat population included 108 participants (Arm 1, n = 55; Arm 2, n = 53). The primary outcome was achieved by 5 (9%) participants in Arm 1 and 8 (15%) in Arm 2. All responders had baseline HBsAg ≤3,000 IU/ml. Indirect comparison with the phase IIb study B-Clear indicates that sequential addition of Peg-IFN may reduce the relapse rates previously observed with bepirovirsen alone. The proportions of participants with adverse events and treatment-related adverse events in both treatment windows were similar between treatment arms.

CONCLUSIONS

Sequential therapy with bepirovirsen followed by Peg-IFN is tolerable and effective in participants with chronic HBV infection on stable NA therapy. This proof-of-concept trial demonstrates a potential strategy to extend responses to bepirovirsen by reducing relapse.

IMPACT AND IMPLICATIONS

This phase IIb study investigated whether sequential therapy with bepirovirsen followed by Peg-IFN could improve off-treatment response rates to bepirovirsen alone by converting partial bepirovirsen responders to full responders and/or reducing relapse rates in participants with chronic HBV. These data show that sequential therapy with bepirovirsen followed by Peg-IFN is tolerable and effective; in patients with a bepirovirsen response, sequential treatment with Peg-IFN may help to reduce off-treatment relapses in participants on stable NA. Participants had a similar response during bepirovirsen treatment as seen in B-Clear, with increased response rates in participants with lower baseline HBsAg; all responders to the sequential regimen had baseline HBsAg <3000 IU/mL. As the first study of antisense oligonucleotide-mediated RNA silencing followed by interferon immunomodulation in patients with chronic HBV infection, this study is an important proof-of-concept for sequential therapy, shedding light on the therapeutic potential of utilising immunomodulators following suppression of HBV antigens.

CLINICAL TRIAL NUMBER

NCT04676724.

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Key Words

• Hepatitis B
• antisense oligonucleotide
• bepirovirsen
• pegylated interferon-α-2a
• sequential therapy

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MESH Headings

• Humans
• Hepatitis B, Chronic/drug therapy
• Polyethylene Glycols/administration & dosage
• Polyethylene Glycols/therapeutic use
• Male
• Female
• Antiviral Agents/therapeutic use
• Antiviral Agents/administration & dosage
• Adult
• Middle Aged
• Interferon-alpha/administration & dosage
• Interferon-alpha/therapeutic use
• Recombinant Proteins/administration & dosage
• Recombinant Proteins/therapeutic use
• Recurrence
• Drug Therapy, Combination/methods
• Hepatitis B Surface Antigens/blood
• DNA, Viral/blood
• Hepatitis B virus/genetics
• Hepatitis B virus/drug effects
• Hepatitis B virus/immunology
• Treatment Outcome

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Affiliation(s)

Maria Buti Liver Unit, Hospital Vall d'Hebrón, Barcelona and CIBER-EHD del Instituto Carlos III, Barcelona, Spain.
Jeong Heo Department of Internal Medicine, College of Medicine, Pusan National University, Busan, Republic of Korea; Biomedical Research Institute, Pusan National University Hospital, Busan, Republic of Korea.
Yasuhito Tanaka Department of Gastroenterology and Hepatology, Kumamoto University Hospital, Kumamoto, Japan
Pietro Andreone Medicina Interna a indirizzo Metabolico-Nutrizionale, Ospedale Clinicizzato di Baggiovara, AOU di Modena, Modena, Italy; Dipartimento SMECHIMAI, Università di Modena e Reggio Emilia, Modena, Italy
Masanori Atsukawa Nippon Medical School Hospital, Tokyo, Japan
Joaquín Cabezas Gastroenterology and Hepatology Department, University Hospital Marques de Valdecilla, Santander, Spain; Clinical and Translational Research in Digestive Diseases, Valdecilla Research Institute (IDIVAL), Santander, Spain
Eric Chak UC Davis, Sacramento, California, USA
Carla S Coffin Department of Medicine, Cumming School of Medicine, University of Calgary, Alberta, Calgary, Canada
Kei Fujiwara Nagoya City University Hospital, Aichi, Japan
Natalya Gankina Krasnojarsk Regional Center of AIDS prevention, Krasnojarsk, Russian Federation
Stuart C Gordon Henry Ford Health and Wayne State University School of Medicine, Detroit, MI, USA
Ewa Janczewska Department of Basic Medical Sciences, Faculty of Public Health in Bytom, Medical University of Silesia, Myslowice, Poland
Atsumasa Komori National Hospital Organization, NHO Nagasaki Medical Center, Nagasaki, Japan
Pietro Lampertico Division of Gastroenterology and Hepatology, Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy; CRC "A. M. and A. Migliavacca" Center for Liver Disease, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
Stuart McPherson Hepatology and Newcastle NIHR Biomedical Research Centre, The Newcastle Upon Tyne Hospitals NHS Foundation Trust, Freeman Hospital, Newcastle-upon-Tyne, UK
Vyacheslav Morozov Hepatologist Medical Company, Samara, Russian Federation
Robert Plesniak University of Rzeszow Centrum Medyczne w Lancucie Sp. z o.o., Lancut, Poland
Sébastien Poulin Clinique Médecine Urbaine du Quartier Latin, Montréal, Québec, Canada
Pablo Ryan Hospital Infanta Leonor and CIBERINFEC, del Instituto Carlos III., Madrid, Spain
Olga Sagalova South Ural State Medical University, Chelyabinsk, Russian Federation
Guoping Sheng Department of Infectious Disease, Shulan (Hangzhou) Hospital Affiliated to Zhejiang Shuren University, Shulan International Medical College, Hangzhou, Zhejiang, China
Natalya Voloshina Medical Centre Healthy Family, Novosibirsk, Russian Federation
Qing Xie Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
Hyung Joon Yim Korea University Ansan Hospital, Ansan, Republic of Korea
Susan Dixon GSK, London, UK
Melanie Paff GSK, Collegeville, PA, USA
Leigh Felton GSK, London, UK
Maximilian Lee GSK, Collegeville, PA, USA
Thomas Greene GSK, Collegeville, PA, USA
Jessica Lim GSK, Collegeville, PA, USA
Divya Lakshminarayanan GSK, Collegeville, PA, USA
Grant McGonagle GSK, London, UK
Helene Plein GSK, London, UK
Amir S Youssef GSK, Collegeville, PA, USA
Rob Elston GSK, Stevenage, UK
Stuart Kendrick GSK, Stevenage, UK
Dickens Theodore GSK, Durham, NC, USA

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Hepatitis B virus infection and its treatment in Eastern Ethiopia

Hepatitis B virus (HBV) infection causes acute and chronic hepatitis, compensated and decompensated cirrhosis, and hepatocellular carcinoma worldwide. The actual status of HBV infection and its treatment in certain regions of Asian and African countries, including Ethiopia, has not been well-documented thus far. Antiviral therapy for HBV infection can prevent the progression of HBV-related liver diseases and decrease the HBV-related symptoms, such as abdominal symptoms, fatigue, systemic symptoms and others. In Eastern Ethiopia, HBV-infected patients with cirrhosis were found to be positive for the HBV e antigen and to have a higher viral load than those without cirrhosis. Notably, 54.4% of patients practiced khat chewing and 18.1% consumed excessive amounts of alcohol. Tenofovir disoproxil fumarate effectively suppressed HBV DNA in those infected with HBV. It is important to elucidate the actual status of HBV infection in Eastern Ethiopia to eliminate HBV infection worldwide by 2030. HBV vaccination and the educational programs for Health Science students that provide practical strategies could help to reduce HBV infection in Eastern Ethiopia.

Evaluation of a next generation sequencing assay for Hepatitis B antiviral drug resistance on the oxford nanopore system

BACKGROUND

Next-generation sequencing (NGS) for Hepatitis B virus (HBV) antiviral resistance (AVR) testing is a highly sensitive diagnostic method, able to detect low-level mutant subpopulations. Our clinical virology laboratory previously transitioned from DNA hybridization (INNO-LiPA) to NGS, initially with the GS Junior System and subsequently the MiSeq. The Oxford Nanopore Technology (ONT) sequencing system was evaluated for HBV resistance testing, with regards to sequencing accuracy and turn-around time.

METHODS

We performed amplicon sequencing of the HBV polymerase gene from patient plasma and external quality assessment (EQA) samples on the MiSeq Reagent Nano Kit v2 and GridION ONT with R10.4.1 flowcells. Mutational analysis and genotyping were performed by DeepChek®Assay-HBV (version 2.0).

RESULTS

A total of 49 patient samples and 15 EQA samples were tested on both the MiSeq and ONT. There was high agreement for both patient and EQA samples between the MiSeq and ONT systems, with regards to total drug resistance mutations detected and total patient sample agreement, 68/70 (97 %) and 47/49 (96 %), respectively.

CONCLUSION

The ONT NGS platform provided accurate HBV AVR results, with improved turn-around times. Sequencing error rates at AVR codons were below 1 %.

Investigational RNA Interference Agents for Hepatitis B

Functional cure of chronic hepatitis B (CHB)-defined as sustained seroclearance of hepatitis B surface antigen (HBsAg) with unquantifiable hepatitis B virus (HBV) DNA at 24 weeks off treatment, is an optimal treatment endpoint. Nonetheless, it cannot be consistently attained by current treatment modalities. RNA interference (RNAi) is a novel treatment strategy using small-interfering RNA (siRNA) or antisense oligonucleotide (ASO) to target HBV post-transcriptional RNA, in turn suppressing viral protein production and replication. Hence, RNAi has indirect effects in promoting host immune reconstitution against HBV. Multiple RNAi therapeutics have entered phase II/III clinical trials, demonstrating potent, dose-dependent, and sustainable effects in suppressing HBsAg. Incidences of HBsAg seroclearance, particularly with the use of ASO, have also been documented. The combination of RNAi with other antivirals/immunomodulators (e.g. pegylated interferon), have shown promising results in potentiating RNAi effects and enhancing treatment durability. Further research will be required to establish predictors of response, optimal treatment protocols, and long-term outcomes in patients on RNAi. RNAi therapeutics have shown promising results and will likely be the keystone of future HBV treatment.

Functional cure of hepatitis B in patients with cancer undergoing immune checkpoint inhibitor therapy

BACKGROUND & AIMS

Immune checkpoint inhibitors (ICIs) can restore exhausted T-cell immunity not only for cancer treatment but also potentially to cure chronic hepatitis B (CHB). Thus, we aimed to determine the previously unclear impact of ICIs on hepatitis B surface antigen (HBsAg) seroclearance in patients with cancer.

METHODS

Consecutive patients with cancer from 2016 to 2020 (cohort 1, n = 118), and hepatocellular carcinoma from 2020 to 2022 (cohort 2, n = 44, as validation) receiving ICIs and positive for HBsAg were retrospectively recruited. An additional HBV-HCC cohort (cohort 3, n = 85) not receiving ICIs served as a control group. Factors associated with HBsAg loss or a HBsAg decline >1 log were analyzed.

RESULTS

With median follow-up of 17.5 months, 8 (6.8%) patients in cohort 1 and 4 (9.1%) in cohort 2 achieved HBsAg seroclearance, and an additional four in cohort 1 and one in cohort 2 had a HBsAg decline >1 log. In multivariate analysis, HBsAg <100 IU/ml was associated with HBsAg seroclearance (hazard ratio 6.274, p = 0.028). In the validation cohort, the cumulative incidences of HBsAg loss at months 12 and 24 were 13.0% and 38.4%, respectively, for baseline HBsAg <100 IU/ml, which were significantly higher than those in the control group (p = 0.0267). No case in cohort 3 achieved HBsAg loss within 24 months. Of the 17 cases who achieved HBsAg loss or a decline >1 log, 16 (94.1%) received nucleos(t)ide analogue treatment. The median time to HBsAg loss or HBsAg decline was 16.5 (range 9.6 to 27.5) months.

CONCLUSIONS

ICIs may accelerate HBsAg seroclearance in patients with cancer and baseline HBsAg <100 IU/ml. This finding provides important information for the design of future trials evaluating the ability of ICIs to induce functional cure in patients with CHB.

IMPACT AND IMPLICATIONS

Immune checkpoint inhibitors (ICIs) can restore exhausted T-cell immunity not only for cancer treatment but also potentially to cure chronic hepatitis B. Functional cure of hepatitis B was observed in patients with cancer or HCC undergoing ICI treatment, and the cumulative incidence of HBsAg loss was higher compared with controls without ICIs. ICIs may accelerate the HBsAg loss in patients with baseline HBsAg levels <100 IU/ml. This finding provides important information for the design of future ICI trials evaluating the ability of ICIs to induce functional cure in patients with CHB.

Epigenetic regulation and its therapeutic potential in hepatitis B virus covalently closed circular DNA

Human hepatitis B virus (HBV) infection is the major cause of acute and chronic hepatitis B, liver cirrhosis, and hepatocellular carcinoma. Although the application of prophylactic vaccination programs has successfully prevented the trend of increasing HBV infection prevalence, the number of HBV-infected people remains very high. Approved therapeutic management efficiently suppresses viral replication; however, HBV infection is rarely completely resolved. The major reason for therapeutic failure is the persistence of covalently closed circular DNA (cccDNA), which forms viral minichromosomes by combining with histone and nonhistone proteins in the nucleus. Increasing evidence indicates that chromatin-modifying enzymes, viral proteins, and noncoding RNAs are essential for modulating the function of cccDNA. Therefore, a deeper understanding of the regulatory mechanism underlying cccDNA transcription will contribute to the development of a cure for chronic hepatitis B. This review summarizes the current knowledge of cccDNA biology, the regulatory mechanisms underlying cccDNA transcription, and novel anti-HBV approaches for eliminating cccDNA transcription.

Characterization of Hepatitis B Virus Transcripts in Chronically HBV-Infected Chimpanzees and Patients Treated with ARC-520 siRNA Demonstrates Transcriptional Silencing of cccDNA

Full-length hepatitis B virus (HBV) transcripts of chimpanzees and patients treated with multidose (MD) HBV siRNA ARC-520 and entecavir (ETV) were characterized by single-molecule real-time (SMRT) sequencing, identifying multiple types of transcripts with the potential to encode HBx, HBsAg, HBeAg, core, and polymerase, as well as transcripts likely to be derived from dimers of dslDNA, and these differed between HBeAg-positive (HBeAg+) and HBeAg-negative (HBeAg-) individuals. HBV transcripts from the last follow-up ~30 months post-ARC-520 treatment were categorized from one HBeAg+ (one of two previously highly viremic patients that became HBeAg- upon treatment and had greatly reduced cccDNA products) and four HBeAg- patients. The previously HBeAg+ patient received a biopsy that revealed that he had 3.4 copies/cell cccDNA (two to three orders of magnitude more cccDNA than HBeAg- chimpanzees) but expressed primarily truncated X and HBsAg from iDNA, like two patients that were HBeAg- at the start of the study and had one copy/cell cccDNA. No HBV transcripts were detected in two other HBeAg- patients that had ~0.3 copies/cell cccDNA, one of which had seroconverted for HBsAg. The paucity of cccDNA-derived transcripts in the presence of high cccDNA demonstrates the transcriptional silencing of HBV following MD siRNA treatment with ETV.

Xalnesiran with or without an Immunomodulator in Chronic Hepatitis B

BACKGROUND

Xalnesiran, a small interfering RNA molecule that targets a conserved region of the hepatitis B virus (HBV) genome and silences multiple HBV transcripts, may have efficacy, with or without an immunomodulator, in patients with chronic HBV infection.

METHODS

We conducted a phase 2, multicenter, randomized, controlled, adaptive, open-label platform trial that included the evaluation of 48 weeks of treatment with xalnesiran at a dose of 100 mg (group 1), xalnesiran at a dose of 200 mg (group 2), xalnesiran at a dose of 200 mg plus 150 mg of ruzotolimod (group 3), xalnesiran at a dose of 200 mg plus 180 μg of pegylated interferon alfa-2a (group 4), or a nucleoside or nucleotide analogue (NA) alone (group 5) in participants with chronic HBV infection who had virologic suppression with NA therapy. The primary efficacy end point was hepatitis B surface antigen (HBsAg) loss (HBsAg level, <0.05 IU per milliliter) at 24 weeks after the end of treatment. Safety was also assessed.

RESULTS

Among 159 participants (30, 30, 34, 30, and 35 in groups 1 through 5, respectively), the primary end-point event occurred in 7% (95% confidence interval [CI], 1 to 22) of those in group 1, in 3% (95% CI, 0 to 17) of those in group 2, in 12% (95% CI, 3 to 28) of those in group 3, in 23% (95% CI, 10 to 42) of those in group 4, and in none (95% CI, 0 to 10) of those in group 5. In groups 1 through 5, respectively, HBsAg seroconversion occurred in 3%, none, 3%, 20%, and none of the participants at 24 weeks after the end of treatment. HBsAg loss with or without seroconversion occurred only in participants with a screening HBsAg level below 1000 IU per milliliter. In groups 1 through 5, respectively, grade 3 or 4 adverse events occurred in 17%, 10%, 18%, 50%, and 6% of the participants, with the most frequent event being an elevated alanine aminotransferase level.

CONCLUSIONS

Among participants with chronic HBV infection who had virologic suppression with NA therapy, treatment with xalnesiran plus an immunomodulator resulted in HBsAg loss at 24 weeks after the end of treatment in a substantial percentage of participants. Grade 3 or 4 adverse events were not uncommon. (Funded by F. Hoffmann-La Roche; Piranga ClinicalTrials.gov number, NCT04225715.).

Current trends and advances in antiviral therapy for chronic hepatitis B

ABSTRACT

Chronic hepatitis B virus (HBV) infection is a global public health concern. Existing antiviral drugs, including nucleos(t)ide analogs and interferon-α, can suppress HBV replication and improve the prognosis. However, the persistence of covalently closed circular DNA (cccDNA), the integration of HBV-DNA into the host genome, and compromised immune responses impede the successful treatment of hepatitis B. While achieving a functional cure of HBV remains elusive with the current treatment methods, this is the goal of new therapeutic approaches. Therefore, developing novel antiviral drugs is necessary for achieving a functional or complete cure for chronic hepatitis B. In recent years, substantial progress has been made in drug discovery and development for HBV infection. Direct-acting antiviral agents such as entry inhibitors, capsid assembly modulators, subviral particle release inhibitors, cccDNA silencers, and RNA interference molecules have entered clinical trials. In addition, several immunomodulatory agents, including toll-like receptor agonists, therapeutic vaccines, checkpoint inhibitors, and monoclonal antibodies, are also making their way toward clinical use. In this review, we summarize the recent progress and limitations of chronic hepatitis B treatment and discuss perspectives on approaches to achieving functional cure. Although it will take some time for these new antiviral drugs to be widely used in clinical practice, combination therapy may become a preferable treatment option in the future.

Hepatitis B virus DNA integration: Implications for diagnostics, therapy, and outcome

Hepatitis B virus (HBV) DNA integration - originally recognised as a non-functional byproduct of the HBV life cycle - has now been accepted as a significant contributor to HBV pathogenesis and hepatitis D virus (HDV) persistence. Integrated HBV DNA is derived from linear genomic DNA present in viral particles or produced from aberrantly processed relaxed circular genomic DNA following an infection, and can drive expression of hepatitis B surface antigen (HBsAg) and HBx. DNA integration events accumulate over the course of viral infection, ranging from a few percent during early phases to nearly 100 percent of infected cells after prolonged chronic infections. HBV DNA integration events have primarily been investigated in the context of hepatocellular carcinoma development as they can activate known oncogenes and other growth promoting genes, cause chromosomal instability and, presumably, induce epigenetic alterations, promoting tumour growth. More recent evidence suggests that HBsAg expression from integrated DNA might contribute to HBV pathogenesis by attenuating the immune response. Integrated DNA provides a source for envelope proteins required for HDV replication and hence represents a means for HDV persistence. Because integrated DNA is responsible for persistence of HBsAg in the absence of viral replication it impacts established criteria for the resolution of HBV infection, which rely on HBsAg as a diagnostic marker. Integrated HBV DNA has been useful in assessing the turnover of infected hepatocytes which occurs during all phases of chronic hepatitis B including the initial phase of infection historically termed immune tolerant. HBV DNA integration has also been shown to impact the development of novel therapies targeting viral RNAs.

VIR-2218 (elebsiran) plus pegylated interferon-alfa-2a in participants with chronic hepatitis B virus infection: a phase 2 study

BACKGROUND

Chronic hepatitis B virus (HBV) remains a global concern, with current treatments achieving low rates of HBsAg seroclearance. VIR-2218 (elebsiran), a small interfering RNA agent against HBV transcripts, reduces HBsAg concentrations. We aimed to evaluate the safety and antiviral activity of VIR-2218 with and without pegylated interferon-alpha-2a treatment in participants with chronic HBV.

METHODS

This open-label, phase 2 study was conducted at 23 sites in six countries (New Zealand, Australia, Hong Kong, Thailand, South Korea, and Malaysia). Adults (aged 18-65 years) with chronic HBV infection without cirrhosis and with HBsAg more than 50 IU/mL and HBV DNA less than 90 IU/mL who were on continued nucleoside or nucleotide reverse transcriptase inhibitor (NRTI) therapy for 2 months or longer were eligible. Participants were enrolled into one of six cohorts to receive VIR-2218 200 mg subcutaneously every 4 weeks, with or without 180 μg subcutaneous pegylated interferon-alfa-2a once per week. Cohort 1 received six doses of VIR-2218 (total 20 weeks); cohort 2 received six doses of VIR-2218 starting at day 1, plus 12 doses of pegylated interferon-alfa-2a starting at week 12 (total 24 weeks); cohort 3 received six doses of VIR-2218 and 24 doses of pegylated interferon-alfa-2a (total 24 weeks); cohort 4 received six doses of VIR-2218 and up to 48 doses of pegylated interferon-alfa-2a (total 48 weeks); cohort 5 received up to 13 doses of VIR-2218 and up to 44 doses of pegylated interferon-alfa-2a (total 48 weeks); and cohort 6 received three doses of VIR-2218 and 12 doses of pegylated interferon-alfa-2a (total 12 weeks). The primary endpoints were the incidence of adverse events and clinical assessments (including results of laboratory tests). Secondary endpoints were the mean maximum reduction of serum HBsAg at any timepoint; the proportion of participants with serum HBsAg seroclearance at any timepoint and for more than 6 months after the end of treatment; and the proportion of participants with anti-HBs seroconversion at any timepoint. For patients who were HBeAg-positive, we also assessed the proportion with HBeAg seroclearance or anti-HBe seroconversion at any timepoint. This study is registered with ClinicalTrials.gov, NCT03672188, and is ongoing.

FINDINGS

Between July 2, 2020, and Nov 2, 2021, 124 individuals were screened for eligibility, 84 of whom were enrolled (15 in cohort 1, 15 in cohort 2, 18 in cohort 3, 18 in cohort 4, 13 in cohort 5, and five in cohort 6). Participants were predominantly HBeAg-negative, Asian, and male (66 [79%] participants were male and 18 [21%] were female). Most treatment emergent adverse events were grades 1-2. Three (20%) participants in cohort 1, four (27%) in cohort 2, eight (44%) in cohort 3, seven (39%) in cohort 4, six (46%) in cohort 5, and two (40%) in cohort 6 reported treatment-emergent adverse events related to VIR-2218. 12 (80%) participants in cohort 2, 12 (67%) in cohort 3, 14 (78%) in cohort 4, 13 (100%) in cohort 5, and three (60%) in cohort 6 reported treatment-emergent adverse events related to pegylated interferon-alfa-2a. Two (13%) participants in cohort 1 had elevations in alanine aminotransferase, compared with 13 (87%) participants in cohort 2, 15 (83%) in cohort 3, 17 (94%) in cohort 4, 11 (85%) in cohort 5, and three (60%) in cohort 6. The mean maximum change from baseline at any timepoint in HBsAg concentration was -2·0 log10 IU/mL (95% CI -2·1 to -1·8) in cohort 1, -2·2 log10 IU/mL (-2·5 to -1·8) in cohort 2, -2·5 log10 IU/mL (-2·8 to -2·1) in cohort 3, -2·4 log10 IU/mL (-3·1 to -1·8) in cohort 4, -3·0 log10 IU/mL (-3·7 to -2·3) in cohort 5, and -1·7 log10 IU/mL (-2·1 to -1·4) in cohort 6. 11 participants (one in cohort 2, one in cohort 3, five in cohort 4, and four in cohort 5) receiving VIR-2218 plus pegylated interferon-alfa-2a had HBsAg seroclearance at any timepoint. Of these, ten (91%; one in cohort 2, five in cohort 4, and four in cohort 5) had anti-HBs seropositivity. Six participants (one in cohort 2, three in cohort 4, and two in cohort 5) had sustained HBsAg seroclearance through to 24 weeks after the end of treatment. No participants receiving VIR-2218 monotherapy (cohort 1) or VIR-2218 plus pegylated interferon-alfa-2a 12-week regimen (cohort 6) had HBsAg seroclearance. 12 (42%) of 26 participants (one of four in cohort 1, two of six in cohort 2, four of seven in cohort 3, four of six in cohort 4, and one of three in cohort 5) who were HBeAg positive at baseline had HBeAg seroclearance or anti-HBe seroconversion.

INTERPRETATION

The results of this phase 2 study support further development of VIR-2218 as a potential therapy for patients with chronic HBV infection. Additional clinical trials of VIR-2218 with and without pegylated interferon-alfa-2a in combination with an HBsAg-targeting monoclonal antibody are ongoing.

FUNDING

Vir Biotechnology.

Global and Chinese trends in oligonucleotide drug clinical development: A comparative analysis

Oligonucleotide drugs are anticipated to mark the new wave of pharmaceutical innovation, succeeding the eras of small molecule drugs and monoclonal antibodies. This review assessed a decade of global and Chinese clinical advancements in this field. Since 2013, there has been a notable surge in the development of oligonucleotide drugs, although a considerable majority of these candidates are still in the nascent stages of clinical trials. Antisense oligonucleotides (ASOs) and small interfering RNAs (siRNAs) represent two pivotal classes both on global scale and within China. Rare diseases have been the main therapeutic target for oligonucleotide drugs, with a less pronounced focus in China's pipeline relative to the global trend. Concurrently, these drugs are broadening their scope to encompass a variety of indications, potentially revolutionizing treatment approaches for chronic conditions. While China's clinical development in this sector is in its infancy compared to the global stage, technological progress and favorable policies are expected to foster a new landscape of oligonucleotide drug development in the future.

Nucleic acid drugs: recent progress and future perspectives

High efficacy, selectivity and cellular targeting of therapeutic agents has been an active area of investigation for decades. Currently, most clinically approved therapeutics are small molecules or protein/antibody biologics. Targeted action of small molecule drugs remains a challenge in medicine. In addition, many diseases are considered 'undruggable' using standard biomacromolecules. Many of these challenges however, can be addressed using nucleic therapeutics. Nucleic acid drugs (NADs) are a new generation of gene-editing modalities characterized by their high efficiency and rapid development, which have become an active research topic in new drug development field. However, many factors, including their low stability, short half-life, high immunogenicity, tissue targeting, cellular uptake, and endosomal escape, hamper the delivery and clinical application of NADs. Scientists have used chemical modification techniques to improve the physicochemical properties of NADs. In contrast, modified NADs typically require carriers to enter target cells and reach specific intracellular locations. Multiple delivery approaches have been developed to effectively improve intracellular delivery and the in vivo bioavailability of NADs. Several NADs have entered the clinical trial recently, and some have been approved for therapeutic use in different fields. This review summarizes NADs development and evolution and introduces NADs classifications and general delivery strategies, highlighting their success in clinical applications. Additionally, this review discusses the limitations and potential future applications of NADs as gene therapy candidates.

New Insights on Hepatitis B Virus Viral Transcription in Single Hepatocytes

The hepatitis B virus (HBV) infects approximately 290 million people globally, with chronic infection sustained by persistent viral gene expression. Recent single-cell analyses of HBV viral transcripts have uncovered novel features of HBV transcription and provided fresh insights into its regulation at the single-cell level. In this review, we summarize the latest advancements in understanding HBV viral transcription in individual hepatocytes and highlight emerging technologies that hold promise for future research.

Understanding and Targeting HBV Transcription and Post-Transcriptional Regulation

Chronic hepatitis B (CHB) affects approximately 300 million people worldwide and current therapies rarely cure it [...].

CRISPR-Cas13b-mediated suppression of HBV replication and protein expression

BACKGROUND & AIMS

New antiviral approaches that target multiple aspects of the HBV replication cycle to improve rates of functional cure are urgently required. HBV RNA represents a novel therapeutic target. Here, we programmed CRISPR-Cas13b endonuclease to specifically target the HBV pregenomic RNA and viral mRNAs in a novel approach to reduce HBV replication and protein expression.

METHODS

Cas13b CRISPR RNAs (crRNAs) were designed to target multiple regions of HBV pregenomic RNA. Mammalian cells transfected with replication competent wild-type HBV DNA of different genotypes, a HBV-expressing stable cell line, a HBV infection model and a hepatitis B surface antigen (HBsAg)-expressing stable cell line were transfected with PspCas13b-BFP (blue fluorescent protein) and crRNA plasmids, and the impact on HBV replication and protein expression was measured. Wild-type HBV DNA, PspCas13b-BFP and crRNA plasmids were simultaneously hydrodynamically injected into mice, and serum HBsAg was measured. PspCas13b mRNA and crRNA were also delivered to a HBsAg-expressing stable cell line via lipid nanoparticles and the impact on secreted HBsAg determined.

RESULTS

Our HBV-targeting crRNAs strongly suppressed HBV replication and protein expression in mammalian cells by up to 96% (p <0.0001). HBV protein expression was also reduced in a HBV-expressing stable cell line and in the HBV infection model. CRISPR-Cas13b crRNAs reduced HBsAg expression by 50% (p <0.0001) in vivo. Lipid nanoparticle-encapsulated PspCas13b mRNA reduced secreted HBsAg by 87% (p = 0.0168) in a HBsAg-expressing stable cell line.

CONCLUSIONS

Together, these results show that CRISPR-Cas13b can be programmed to specifically target and degrade HBV RNAs to reduce HBV replication and protein expression, demonstrating its potential as a novel therapeutic option for chronic HBV infection.

IMPACT AND IMPLICATIONS

Owing to the limitations of current antiviral therapies for hepatitis B, there is an urgent need for new treatments that target multiple aspects of the HBV replication cycle to improve rates of functional cure. Here, we present CRISPR-Cas13b as a novel strategy to target HBV replication and protein expression, paving the way for its development as a potential new treatment option for patients living with chronic hepatitis B.

SMC5/6-Mediated Transcriptional Regulation of Hepatitis B Virus and Its Therapeutic Potential

Cells have developed various mechanisms to counteract viral infections. In an evolutionary arms race, cells mobilize cellular restriction factors to fight off viruses, targeted by viral factors to facilitate their own replication. The hepatitis B virus (HBV) is a small dsDNA virus that causes acute and chronic infections of the liver. Its genome persists in the nuclei of infected hepatocytes as a covalently closed circular DNA (cccDNA) minichromosome, thus building up an episomal persistence reservoir. The chromosomal maintenance complex SMC5/6 acts as a restriction factor hindering cccDNA transcription, whereas the viral regulatory protein HBx targets SMC5/6 for proteasomal degradation, thus relieving transcriptional suppression of the HBV minichromosome. To date, no curative therapies are available for chronic HBV carriers. Knowledge of the factors regulating the cccDNA and the development of therapies involving silencing the minichromosome or specifically interfering with the HBx-SMC5/6 axis holds promise in achieving sustained viral control. Here, we summarize the current knowledge of the mechanism of SMC5/6-mediated HBV restriction. We also give an overview of SMC5/6 cellular functions and how this compares to the restriction of other DNA viruses. We further discuss the therapeutic potential of available and investigational drugs interfering with the HBx-SMC5/6 axis.

A Phase 1, Single-Dose Study to Evaluate the Pharmacokinetics and Safety of Bepirovirsen in Adults with Hepatic Impairment and Healthy Participants (B-Assured)

Bepirovirsen is a developmental antisense oligonucleotide (ASO) for treatment of chronic hepatitis B virus infection. No pharmacokinetic (PK) studies comparing participants with hepatic impairment (HI) and healthy participants (HPs) have been conducted with ASOs. Given the target patient population, characterization of bepirovirsen PK in HI was imperative. This phase 1, nonrandomized, open-label study (NCT04971928) evaluated the PKs of a single 300-mg dose of bepirovirsen in participants with HI and matched HPs, enrolled in 2 parts (Part 1: moderate HI; Part 2: mild HI). If no predefined difference in the area under the concentration-time curve from time 0 (predose) to infinite time (AUC0-∞) and maximum observed concentration (Cmax; geometric mean ratio [GMR] 0.5-1.5) was identified in Part 1, findings were applied to mild HI, eliminating Part 2. Participants were monitored for 50 days post-treatment and noncompartmental analysis estimated PK parameters. Twenty-four participants (moderate HI, n = 12; HP, n = 12) received bepirovirsen and completed Part 1. AUC0-∞ and Cmax were lower in participants with moderate HI (GMR 0.69 and 0.67, respectively) than in HPs, while apparent clearance (CL/F) and apparent terminal phase volume of distribution (Vz/F) were higher (GMR 1.44 and 1.64, respectively), but fell within the predefined thresholds of difference for this study. Part 2 was omitted. Adverse events were mild. Moderate HI did not have a clinically relevant impact on bepirovirsen PK or safety.

Functional cure of chronic hepatitis B-hope or hype?

Chronic hepatitis B constitutes a substantial disease burden worldwide. The steps advocated by the World Health Organization in 2016 to eradicate hepatitis B by 2030 has failed to achieve significant progress, especially with respect to immunization coverage and linkage to care. The lack of governmental and public awareness regarding the long-term implications of hepatitis B burden cause underfunding of developmental projects. The presently approved treatment modalities have limited efficacy in complete viral eradication, hence the need for newer molecules to achieve functional cure (sustained undetectable hepatitis B surface antigen (HBsAg) and hepatitis B virus DNA in peripheral blood after a finite period of therapy). However, preliminary results from trials of novel therapies show their inadequacy to achieve this end by themselves but better performance with a low baseline serum HBsAg with nucleos(t)ide analogues (NA) treatment which need to be combined with/without pegylated interferon as an immunomodulator. Such therapy is limited by cost and adverse events and need to show incremental benefit over the standard of care (long-term NA therapy) with respect to efficacy and drug toxicities, making the development process tenuous. Thus, while such therapies continue to be tested, strategies should still focus on prevention of transmission by non-pharmaceutical measures, vaccination and increasing linkage to care.

High accuracy model for HBsAg loss based on longitudinal trajectories of serum qHBsAg throughout long-term antiviral therapy

OBJECTIVE

Hepatitis B surface antigen (HBsAg) loss is the optimal outcome for patients with chronic hepatitis B (CHB) but this rarely occurs with currently approved therapies. We aimed to develop and validate a prognostic model for HBsAg loss on treatment using longitudinal data from a large, prospectively followed, nationwide cohort.

DESIGN

CHB patients receiving nucleos(t)ide analogues as antiviral treatment were enrolled from 50 centres in China. Quantitative HBsAg (qHBsAg) testing was prospectively performed biannually per protocol. Longitudinal discriminant analysis algorithm was used to estimate the incidence of HBsAg loss, by integrating clinical data of each patient collected during follow-up.

RESULTS

In total, 6792 CHB patients who had initiated antiviral treatment 41.3 (IQR 7.6-107.6) months before enrolment and had median qHBsAg 2.9 (IQR 2.3-3.3) log10IU/mL at entry were analysed. With a median follow-up of 65.6 (IQR 51.5-84.7) months, the 5-year cumulative incidence of HBsAg loss was 2.4%. A prediction model integrating all qHBsAg values of each patient during follow-up, designated GOLDEN model, was developed and validated. The AUCs of GOLDEN model were 0.981 (95% CI 0.974 to 0.987) and 0.979 (95% CI 0.974 to 0.983) in the training and external validation sets, respectively, and were significantly better than those of a single qHBsAg measurement. GOLDEN model identified 8.5%-10.4% of patients with a high probability of HBsAg loss (5-year cumulative incidence: 17.0%-29.1%) and was able to exclude 89.6%-91.5% of patients whose incidence of HBsAg loss is 0. Moreover, the GOLDEN model consistently showed excellent performance among various subgroups.

CONCLUSION

The novel GOLDEN model, based on longitudinal qHBsAg data, accurately predicts HBsAg clearance, provides reliable estimates of functional hepatitis B virus (HBV) cure and may have the potential to stratify different subsets of patients for novel anti-HBV therapies.

Elimination of the hepatitis B virus: A goal, a challenge

The hepatitis B elimination is a goal proposed by the WHO to be achieved by 2030 through the adoption of synergistic measures for the prevention and chronic HBV infection treatment. Complete cure is characterized by the HBV elimination from the body and is the goal of the chronic hepatitis B treatment, which once achieved, will enable the hepatitis B elimination. This, today, has been a scientific challenge. The difficulty in achieving a complete cure is due to the indefinite maintenance of a covalently closed episomal circular DNA (cccDNA) reservoir and the maintenance and persistence of an insufficient and dysfunctional immune response in chronically infected patients. Among the measures adopted to eliminate hepatitis B, two have the potential to directly interfere with the virus cycle, but with limited effect on HBV control. These are conventional vaccines-blocking transmission and antiviral therapy-inhibiting replication. Vaccines, despite their effectiveness in protecting against horizontal transmission and preventing mother-to-child vertical transmission, have no effect on chronic infection or potential to eliminate the virus. Treatment with antivirals suppresses viral replication, but has no curative effect, as it has no action against cccDNA. Therapeutic vaccines comprise an additional approach in the chronic infection treatment, however, they have only a modest effect on the immune system, enhancing it temporarily. This manuscript aims to address (1) the cccDNA persistence in the hepatocyte nucleus and the immune response dysfunction in chronically infected individuals as two primary factors that have hampered the treatment and HBV elimination from the human body; (2) the limitations of antiviral therapy and therapeutic vaccines, as strategies to control hepatitis B; and (3) the possibly promising therapeutic approaches for the complete cure and elimination of hepatitis B.

Investigating the role of GTPase in inhibiting HBV replication and enhancing interferon therapy efficacy in chronic hepatitis B patients

BACKGROUND

Interferon-alpha (IFNα) is a common treatment for chronic hepatitis B virus (HBV) infection, but its efficacy varies widely among patients. GTPASE, an interferon-stimulated gene (ISG), has recently been identified as a factor in antiviral immunity, though its role in HBV infection is not fully understood.

OBJECTIVE

This study investigates the role of GTPASE in enhancing the antiviral effects of IFNα against HBV and elucidates its mechanism of action.

METHODS

We analyzed the impact of GTPASE overexpression and silencing on HBV replication and clearance in HBV-infected cells. Molecular docking studies assessed the interaction between GTPASE and HBV surface antigens (HBs). Clinical samples from HBV patients undergoing Peg-IFNα treatment were also evaluated for GTPASE expression and its correlation with treatment efficacy.

RESULTS

Overexpression of GTPASE led to significant inhibition of HBV replication, increased HBeAg seroconversion, and enhanced HBsAg clearance. GTPASE directly bound to HBs proteins, reducing their levels and affecting viral particle formation. Silencing GTPASE reduced these effects, while combined treatment with Peg-IFNα and GTPASE overexpression further improved antiviral outcomes. Mutational analysis revealed that specific sites in GTPASE are crucial for its antiviral activity.

CONCLUSIONS

GTPASE acts as a positive regulator in IFNα-induced antiviral immunity against HBV. It enhances the therapeutic efficacy of IFNα by targeting HBs and modulating viral replication. GTPASE levels may serve as a predictive biomarker for response to Peg-IFNα therapy, highlighting its potential for improving individualized treatment strategies for chronic HBV infection.

Recent advances in the molecular design and applications of viral RNA-targeting antiviral modalities

Pathogenic viruses are a profound threat to global public health, underscoring the urgent need for the development of efficacious antiviral therapeutics. The advent of RNA-targeting antiviral strategies has marked a significant paradigm shift in the management of viral infections, offering a potent means of control and potential cure. In this review, we delve into the cutting-edge progress in RNA-targeting antiviral agents, encompassing antisense oligonucleotides (ASOs), small interfering RNAs (siRNAs), small and bifunctional molecules. We provide an in-depth examination of their strategic molecular design and elucidate the underlying mechanisms of action that confer their antiviral efficacy. By synthesizing recent findings, we shed light on the innovative potential of RNA-targeting approaches and their pivotal role in advancing the frontiers of antiviral drug discovery.

Optimal Treatment Based on Interferon No Longer Makes Clinical Cure of Chronic Hepatitis B Far Away: An Evidence-Based Review on Emerging Clinical Data

Chronic hepatitis B (CHB) remains a major global public health problem. The functional cure is the ideal therapeutic target recommended by the latest guidelines, and pursuing a functional cure has become the key treatment end point of current therapy and for upcoming clinical trials. In this review, based on the latest published clinical research evidence, we analyzed the concept and connotation of clinical cures and elaborated on the benefits of clinical cures in detail. Secondly, we have summarized various potential treatment methods for achieving clinical cures, especially elaborating on the latest research progress of interferon-based optimized treatment strategies in achieving clinical cures. We also analyzed which populations can achieve clinical cures and conducted a detailed analysis of relevant virological and serological markers in screening clinical cure advantage populations and predicting clinical cure achievement. In addition, we also introduced the difficulties that may be encountered in the current pursuit of achieving a clinical cure.

Predictive models for functional cure in patients with CHB receiving PEG-IFN therapy based on HBsAg quantification through meta-analysis

BACKGROUND AND AIMS

The efficacy of achieving HBsAg clearance through pegylated interferon (PEG-IFNα) therapy in patients with chronic hepatitis B (CHB) remains uncertain, especially regarding the probability of achieving functional cure among patients with varying baseline HBsAg levels. We aimed to investigate the predictive value of HBsAg quantification for HBsAg seroclearance in CHB patients undergoing PEG-IFNα treatment.

METHODS

A systematic search was conducted in PubMed, Embase, and the Cochrane Library up to January 11, 2022. Subgroup analyses were performed for HBeAg-positive and HBeAg-negative patients, PEG-IFNα monotherapy and PEG-IFNα combination therapy, treatment-naive and treatment-experienced patients, and patients with or without liver cirrhosis.

RESULTS

This predictive model incorporated 102 studies. The overall HBsAg clearance rates at the end of treatment (EOT) and the end of follow-up (EOF) were 10.6% (95% CI 7.8-13.7%) and 11.1% (95% CI 8.4-14.1%), respectively. Baseline HBsAg quantification was the most significant factor. According to the model, it is projected that when baseline HBsAg levels are 100, 500, 1500, and 10,000 IU/ml, the HBsAg clearance rates at EOF could reach 53.9% (95% CI 40.4-66.8%), 32.1% (95% CI 24.8-38.7%), 14.2% (95% CI 9.8-18.8%), and 7.9% (95% CI 4.2-11.8%), respectively. Additionally, treatment-experienced patients with HBeAg-negative status, and without liver cirrhosis exhibited higher HBsAg clearance rates after PEG-IFNα treatment.

CONCLUSION

A successful predictive model has been established to predict the achievement of functional cure in CHB patients receiving PEG-IFNα therapy.

Toward a Functional Cure for Hepatitis B

Current treatment of chronic hepatitis B virus (HBV) infection, pegylated interferon-α (pegIFN-α) and nucleos(t)ide analogue (NA), can suppress HBV replication, reverse liver inflammation and fibrosis, and decrease risks of cirrhosis and hepatocellular carcinoma, but hepatitis B surface antigen (HBsAg) loss is rare. Functional HBV cure is defined as undetectable HBsAg and unquantifiable serum HBV DNA for at least 24 weeks after a finite course of therapy. This requires suppression of HBV replication and viral protein production as well as restoration of immune response to HBV. Direct-acting antivirals targeting virus entry, capsid assembly, viral protein production and secretion are in clinical trials. In parallel, immune modulatory therapies to stimulate HBV-specific immune response and to remove immune blockade are being tested. Clinical trials of direct-acting antivirals alone or immune modulatory therapies alone have not been successful in achieving HBV cure. Recent combinations of direct-acting antivirals and immune modulatory therapies have shown promising results particularly with combinations that included pegIFN-α. These results need to be confirmed in larger studies with longer follow-up, and further work is needed to develop simpler regimens with fewer drugs that can be administered orally and safely. While there is a strong desire to develop finite therapies that can achieve HBV cure, safety is paramount and new therapies must provide incremental value compared to standard of care, which is predominantly long-term NA therapy.

Lipid-nanoparticle-enabled nucleic acid therapeutics for liver disorders

Inherited genetic disorders of the liver pose a significant public health burden. Liver transplantation is often limited by the availability of donor livers and the exorbitant costs of immunosuppressive therapy. To overcome these limitations, nucleic acid therapy provides a hopeful alternative that enables gene repair, gene supplementation, and gene silencing with suitable vectors. Though viral vectors are the most efficient and preferred for gene therapy, pre-existing immunity debilitating immune responses limit their use. As a potential alternative, lipid nanoparticle-mediated vectors are being explored to deliver multiple nucleic acid forms, including pDNA, mRNA, siRNA, and proteins. Herein, we discuss the broader applications of lipid nanoparticles, from protein replacement therapy to restoring the disease mechanism through nucleic acid delivery and gene editing, as well as multiple preclinical and clinical studies as a potential alternative to liver transplantation.

Population Pharmacokinetics of Bepirovirsen in Healthy Participants and Participants with Chronic Hepatitis B Virus Infection: Results from Phase 1, 2a, and 2b Studies

INTRODUCTION

Bepirovirsen is a novel antisense oligonucleotide in development for chronic hepatitis B virus (HBV) infection therapy. Understanding the impact that clinical characteristics may have on bepirovirsen exposure is important for determining efficacious and well-tolerated dosing regimens. This analysis evaluated demographics and clinical characteristics associated with bepirovirsen exposure using a population pharmacokinetic (PK) analysis.

METHODS

Population PK analyses were conducted using pooled data from three phase 1/2 clinical studies (NCT03020745/NCT02981602/NCT04449029) to construct a structural PK model for bepirovirsen that adequately described plasma concentration-time profiles and identify covariates that affect systemic exposure. The final population PK model was used to simulate bepirovirsen exposure measures to inform exposures at different dose levels and within different subpopulations.

RESULTS

Bepirovirsen PK data were well-described by a linear, three-compartment model with first-order absorption and absorption delay. Chronic HBV infection status, body weight, and Asian versus non-Asian race were key covariates included in the final model. Visual inspection of correlation scatter plots confirmed general agreement between observed and predicted data from the studies. In simulations, bepirovirsen systemic exposure was dosed proportionally and predicted to be almost completely washed out by 12 weeks following the final 300-mg dose. Differences in body weight, Asian race, or disease status did not result in clinically relevant differences in exposure.

CONCLUSIONS

This analysis demonstrated that the linear three-compartmental model accurately described bepirovirsen PK data. The lack of clinically relevant differences seen in exposure indicate that dose adjustments are not recommended for bepirovirsen based on demographics or clinical characteristics.

Clinical significance of serum Ck18-M65 and M30 levels in patients with chronic hepatitis B combined with nonalcoholic steatohepatitis and liver fibrosis

In this study, we aimed to explore the clinical significance of serum CK18-M65 and CK18-M30 levels in patients with chronic hepatitis B (CHB) complicated by nonalcoholic steatohepatitis (NASH) and liver fibrosis. The observation and control groups comprised 133 patients with CHB complicated by NASH and 50 healthy patients from our hospital, respectively. Liver function indices, including alanine aminotransferase, glutamic aminotransferase, γ-glutamyltransferase, total bilirubin, total protein, and total cholesterol, were determined using an automatic biochemical analyzer. Hyaluronic acid, type III procollagen, type IV collagen, laminin, and CK18-M65 and M30 levels were detected using ELISA. Serum CK18-M65 and M30 levels in patients with CHB complicated by NASH were positively correlated with the liver fibrosis stage (P < .05). While serum CK18-M65 demonstrated a low diagnostic value for liver fibrosis in the S0-1 stage, it exhibited good diagnostic value for S2-3 stage liver fibrosis. Serum CK18-M30 displayed good diagnostic value for S0-1 and S2-3 hepatic fibrosis, particularly for S2-3 hepatic fibrosis. Elevated serum CK18-M65 and CK18-M30 levels in patients with CHB complicated with NASH suggest their potential utility in evaluating the progression of liver fibrosis in this population. In particular, CK18-M30 exhibits superior diagnostic efficiency.

Predictors of HBsAg seroclearance in patients with chronic HBV infection treated with pegylated interferon-α: a systematic review and meta-analysis

BACKGROUND AND AIMS

The identification of reliable predictors for hepatitis B surface antigen (HBsAg) seroclearance remains controversial. We aimed to summarize potential predictors for HBsAg seroclearance by pegylated interferon-α (PegIFNα) in patients with chronic HBV infection.

METHODS

A systematic search of the Cochrane Library, Embase, PubMed, and Web of Science databases was conducted from their inception to 28 September 2022. Meta-analyses were performed following the PRISMA statement. Predictors of HBsAg seroclearance were evaluated based on baseline characteristics and on-treatment indicators.

RESULTS

This meta-analysis encompasses 27 studies, including a total of 7913 patients. The findings reveal several factors independently associated with HBsAg seroclearance induced by PegIFNα-based regimens. These factors include age (OR = 0.961), gender (male vs. female, OR = 0.537), genotype (A vs. B/D; OR = 7.472, OR = 10.738), treatment strategy (combination vs. monotherapy, OR = 2.126), baseline HBV DNA (OR = 0.414), baseline HBsAg (OR = 0.373), HBsAg levels at week 12 and 24 (OR = 0.384, OR = 0.294), HBsAg decline from baseline to week 12 and 24 (OR = 6.689, OR = 6.513), HBsAg decline from baseline ≥ 1 log10 IU/ml and ≥ 0.5 log10 IU/ml at week 12 (OR = 18.277; OR = 4.530), and ALT elevation at week 12 (OR = 3.622). Notably, subgroup analysis suggests no statistical association between HBsAg levels at week 12 and HBsAg seroclearance for treatment duration exceeding 48 weeks. The remaining results were consistent with the overall analysis.

CONCLUSIONS

This is the first meta-analysis to identify predictors of HBsAg seroclearance with PegIFNα-based regimens, including baseline and on-treatment factors, which is valuable in developing a better integrated predictive model for HBsAg seroclearance to guide individualized treatment and achieve the highest cost-effectiveness of PegIFNα.

Perspective on Emerging Therapies to Achieve Functional Cure of Chronic Hepatitis B

Purpose of Review

Advancements in our understanding of the hepatitis B viral (HBV) life cycle have paved the way for novel approaches to treat HBV infection. This review summarizes the various strategies being pursued to achieve a functional cure, defined as loss of hepatitis B surface antigen (HBsAg) and absence of viral replication 6 months off-therapy.

Recent Findings

Direct acting antiviral, host targeting antiviral, and immunological approaches are in various stages of development as treatment for chronic HBV infection.

Summary

Novel treatments are being developed in pursuit of a cure for HBV. Current evidence suggests a single therapeutic agent alone may be insufficient, necessitating the need for combination therapy targeting HBV and the host immune response. Ongoing research focused on identifying the best therapeutic combination holds promise in achieving functional cure for HBV.

The lack of HBsAg secretion does neither facilitate induction of antiviral T cell responses nor Hepatitis B Virus clearance in mice

Immune tolerance to the hepatitis B virus (HBV) is crucial for developing chronic hepatitis B, and the HBV surface antigen (HBsAg) produced and secreted in high amounts is regarded as a key contributor. HBsAg is expressed in HBV-infected hepatocytes and those carrying an HBV integration. Whether either HBsAg secretion or the high antigen amount expressed in the liver determines its immunomodulatory properties, however, remains unclear. We, therefore, developed a novel HBV animal model that allowed us to study the role of secreted HBsAg. We introduced a previously described HBs mutation, C65S, abolishing HBsAg secretion into a replication-competent 1.3-overlength HBV genome and used adeno-associated virus vectors to deliver it to the mouse liver. The AAV-HBV established a carrier state of wildtype and C65S mutant HBV, respectively. We investigated antiviral B- and T-cell immunity in the HBV-carrier mice after therapeutic vaccination. Moreover, we compared the effect of a lacking HBsAg secretion with that of an antiviral siRNA. While missing HBsAg secretion allowed for higher levels of detectable anti-HBs antibodies after therapeutic vaccination, it did neither affect antiviral T-cell responses nor intrahepatic HBV gene expression, irrespective of the starting level. A treatment with HBV siRNA restricting viral antigen expression within hepatocytes, however, improved the antiviral efficacy of therapeutic vaccination, irrespective of the ability of HBV to secrete HBsAg. Our data indicate that clearing HBsAg from blood cannot significantly impact HBV persistence or T-cell immunity. This indicates that a restriction of hepatic viral antigen expression will be required to break HBV immunotolerance.

A mutual regulatory loop between transcription factor Yin Yang 1 and hepatitis B virus replication influences chronic hepatitis B

Hepatitis B virus (HBV) infections pose a major threat to human health. HBV can upregulate the expression of the transcription factor Yin Yang 1 (YY1) in in vitro cytological experiments, suggesting an association between YY1 and HBV infection. However, data on YY1 expression in chronic hepatitis B (CHB) patients are lacking. In this study, we aimed to assess the correlation between YY1 expression and HBV infection. We detected serum YY1 levels in 420 patients with chronic HBV infection, 30 patients with chronic hepatitis C virus infection, and 32 healthy controls using an enzyme-linked immunosorbent assay. The correlation between YY1 levels and clinical parameters was analyzed. Meanwhile, the changes of YY1 before and after interferon or entecavir treatment were analyzed. YY1 levels in the liver tissues were detected using immunofluorescence staining. The expression of YY1 in HBV-expressing cells was detected through western blotting. Meanwhile, we explored the effects of YY1 on HBV replication and gene expression. We found that YY1 was highly expressed in the serum and liver tissues of CHB patients. Serum YY1 levels positively correlated with HBV DNA and hepatitis B surface antigen (HBsAg). Additionally, HBV DNA levels increased but HBsAg levels decreased after HBV-expressing cells overexpress YY1. In conclusion, our study demonstrates that YY1 plays an important role in HBV replication and gene expression, providing a potential target for the treatment of CHB.

Guanylate-Binding Protein 1 (GBP1) Enhances IFN-α Mediated Antiviral Activity against Hepatitis B Virus Infection

Interferon-alpha (IFN-α) is a first-line drug for treating chronic hepatitis B (CHB). Guanylate-binding protein 1 (GBP1) is one of the interferon-stimulating factors, which participates in the innate immunity of the host and plays an antiviral and antibacterial role. In this study, we explored how GBP1 is involved in IFN-α antiviral activity against HBV. Before being gathered, HepG2-NTCP and HepG2 2.15 cells were transfected with the wild-type hGBP1 plasmid or si-GBP1, respectively, and followed by stimulation with Peg-IFNα-2b. We systematically explored the role of GBP1 in regulating HBV infection in cell models. Additionally, we also examined GBP1 levels in CHB patients. GBP1 activity increased, and its half-life was prolonged after HBV infection. Overexpression of GBP1 inhibited the production of HBsAg and HBeAg, as well as HBs protein and HBV total RNA levels, whereas silencing of GBP1 inhibited its ability to block viral infections. Interestingly, overexpressing GBP1 co-treatment with Peg-IFNα-2b further increased the antiviral effect of IFN-α, while GBP1 silencing co-treatment with Peg-IFNα-2b partly restored its inhibitory effect on HBV. Mechanistically, GBP1 mediates the anti-HBV response of Peg-IFNα-2b by targeting HBs. Analysis of clinical samples revealed that GBP1 was elevated in CHB patients and increased with Peg-IFNα-2b treatment, while GBP1 showed good stability in the interferon response group. Our study demonstrates that GBP1 inhibits HBV replication and promotes HBsAg clearance. It is possible to achieve antiviral effects through the regulation of IFN-α induced immune responses in response to HBV.

Targeted delivery strategies: The interactions and applications of nanoparticles in liver diseases

In recent years, nanoparticles have been broadly utilized in various drugs delivery formulations. Nanodelivery systems have shown promise in solving problems associated with the distribution of hydrophobic drugs and have promoted the accumulation of nanomedicines in the circulation or in organs. However, the injection dose of nanoparticles (NPs) is much greater than that needed by diseased tissues or organs. In other words, most of the NPs are localized off-target and do not reach the desired tissue or organs. With the rapid development of biodegradable and biosafety nanomaterials, the nanovectors represent assurance of safety. However, the off-target effects also induce concerns about the application of NPs, especially in the delivery of gene editing tools. Therefore, a complete understanding of the biological responses to NPs in the body will clearly guide the design of targeted delivery of NPs. The different properties of various nanodelivery systems may induce diverse interactions between carriers and organs. In this review, we describe the relationship between the liver, the most influenced organ of systemic administration of NPs, and targeted delivery nanoplatforms. Various transport vehicles have adopted multiple delivery strategies for the targeted delivery to the cells in the homeostasis liver and in diseased liver. Additionally, nanodelivery systems provide a novel strategy for treating incurable diseases. The appearance of a targeted delivery has profoundly improved the application of NPs to liver diseases.

The Coming Age of Antisense Oligos for the Treatment of Hepatic Ischemia/Reperfusion (IRI) and Other Liver Disorders: Role of Oxidative Stress and Potential Antioxidant Effect

Imbalances in the redox state of the liver arise during metabolic processes, inflammatory injuries, and proliferative liver disorders. Acute exposure to intracellular reactive oxygen species (ROS) results from high levels of oxidative stress (OxS) that occur in response to hepatic ischemia/reperfusion injury (IRI) and metabolic diseases of the liver. Antisense oligonucleotides (ASOs) are an emerging class of gene expression modulators that target RNA molecules by Watson-Crick binding specificity, leading to RNA degradation, splicing modulation, and/or translation interference. Here, we review ASO inhibitor/activator strategies to modulate transcription and translation that control the expression of enzymes, transcription factors, and intracellular sensors of DNA damage. Several small-interfering RNA (siRNA) drugs with N-acetyl galactosamine moieties for the liver have recently been approved. Preclinical studies using short-activating RNAs (saRNAs), phosphorodiamidate morpholino oligomers (PMOs), and locked nucleic acids (LNAs) are at the forefront of proof-in-concept therapeutics. Future research targeting intracellular OxS-related pathways in the liver may help realize the promise of precision medicine, revolutionizing the customary approach to caring for and treating individuals afflicted with liver-specific conditions.

Intracellular Host Restriction of Hepatitis B Virus Replication

The hepatitis B virus (HBV) infects hepatocytes and hijacks host cellular mechanisms for its replication. Host proteins can be frontline effectors of the cell's defense and restrict viral replication by impeding multiple steps during its intracellular lifecycle. This review summarizes many of the well-described restriction factors, their mechanisms of restriction, and counteractive measures of HBV, with a special focus on viral transcription. We discuss some of the limitations and knowledge gaps about the restriction factors, highlighting how these factors may be harnessed to facilitate therapeutic strategies against HBV.

Hepatitis B: Model Systems and Therapeutic Approaches

Hepatitis B virus (HBV) infection is a major global health issue and ranks among the top causes of liver cirrhosis and hepatocellular carcinoma. Although current antiviral medications, including nucleot(s)ide analogs and interferons, could inhibit the replication of HBV and alleviate the disease, HBV cannot be fully eradicated. The development of cellular and animal models for HBV infection plays an important role in exploring effective anti-HBV medicine. During the past decades, advancements in several cell culture systems, such as HepG2.2.15, HepAD38, HepaRG, hepatocyte-like cells, and primary human hepatocytes, have propelled the research in inhibiting HBV replication and expression and thus enriched our comprehension of the viral life cycle and enhancing antiviral drug evaluation efficacy. Mouse models, in particular, have emerged as the most extensively studied HBV animal models. Additionally, the present landscape of HBV therapeutics research now encompasses a comprehensive assessment of the virus's life cycle, targeting numerous facets and employing a variety of immunomodulatory approaches, including entry inhibitors, strategies aimed at cccDNA, RNA interference technologies, toll-like receptor agonists, and, notably, traditional Chinese medicine (TCM). This review describes the attributes and limitations of existing HBV model systems and surveys novel advancements in HBV treatment modalities, which will offer deeper insights toward discovering potentially efficacious pharmaceutical interventions.

Advances in the Pharmacological Management of Chronic Hepatitis B

BACKGROUND

Hepatitis B, a vaccine-preventable liver infection, remains a global public health problem. Dedicated groups of experts and funding are focusing on achieving a functional cure to eradicate this disease by 2030.

AREAS OF UNCERTAINTY

With more than 40 molecules available or under investigation as new treatments for hepatitis B virus (HBV) infection, none of them is curative so far. Available treatments are effective in suppressing HBV replication and in decreasing the risk of developing cirrhosis, liver failure, hepatocellular carcinoma, and death, but do not eliminate the virus, and the risk of hepatocellular carcinoma remains. Nucleoside/nucleotide analogs are recommended as first-line therapy for patients with chronic hepatitis B infection to inhibit viral replication and lower the HBV DNA values, but long-term therapy is usually needed to maintain suppression. Cessation of the therapy in accordance with clinical guidelines can result in virological and clinical relapse.

DATA SOURCES

PubMed, Web of Science, clinicaltrials.gov , and gray literature sources were searched for articles discussing HBV management and new therapies.

RESULTS

With current nucleoside/nucleotide analog therapies, fewer than 5% of patients lose hepatitis B surface antigen after 12 months, which underscores the need for new drugs that can achieve a functional cure. New therapies are being developed, including small interfering RNAs. Bepirovirsen, a modified antisense oligonucleotide, shows promising results and a good safety profile, but requires further exploration in larger number of patients to determine whether a functional cure is possible.

CONCLUSIONS

Eradication of HBV infection with currently available therapies is not yet possible. Experts are developing innovative treatments, such as bepirovirsen, to achieve functional cure for this disease and to reduce morbidity and mortality associated with hepatic cirrhosis and hepatocellular carcinoma.

Chronic Hepatitis B Finite Treatment: Similar and Different Concerns With New Drug Classes

Chronic hepatitis B, a major cause of liver disease and cancer, affects >250 million people worldwide. Currently there is no cure, only suppressive therapies. Efforts to develop finite curative hepatitis B virus (HBV) therapies are underway, consisting of combinations of multiple novel agents with or without nucleos(t)ide reverse-transcriptase inhibitors. The HBV Forum convened a webinar in July 2021, along with subsequent working group discussions to address how and when to stop finite therapy for demonstration of sustained off-treatment efficacy and safety responses. Participants included leading experts in academia, clinical practice, pharmaceutical companies, patient representatives, and regulatory agencies. This Viewpoints article outlines areas of consensus within our multistakeholder group for stopping finite therapies in chronic hepatitis B investigational studies, including trial design, patient selection, outcomes, biomarkers, predefined stopping criteria, predefined retreatment criteria, duration of investigational therapies, and follow-up after stopping therapy. Future research of unmet needs are discussed.