Advances in therapeutics for chronic hepatitis B

Availability, price, and affordability of anti-hepatitis B virus drugs: a cross-sectional study in China

BACKGROUND

The global prevalence of hepatitis B virus (HBV) has presented a persistent challenge for public health prevention and treatment. However, studies that assess the public's access to anti-HBV drugs are absent.

AIM

To examine the availability, pricing, and affordability of anti-HBV drugs in Jiangsu province, China and provide recommendations for improvement.

METHOD

An enhanced methodology developed by the World Health Organization (WHO) and Health Action International was applied in a cross-sectional study that included 1026 healthcare facilities distributed in 13 prefectural-level cities in Jiangsu province.

RESULTS

Since almost all drugs had an availability of less than 30%, the accessibility of anti-HBV drugs was notably low. Primary healthcare facilities had the lowest availability, reporting 1.4% for Original Brands (OBs) and 1.7% for lowest-priced generics (LPGs). Furthermore, the northern Jiangsu region recorded the lowest availability at 0.7%. LPGs demonstrated higher availability than OBs, with median availability probabilities of 2.6% and 1.4%, respectively. The drugs listed on the WHO Essential Medicines List exhibited higher availability than those on other lists. The median price ratios for OBs, LPGs, and volume-based purchasing drugs were 0.83, 0.50, and 0.27, respectively, less than 1.5 times the international reference price. Despite favorable pricing, affordability rate was 23% for urban residents and 0% for rural residents, which was discouraging.

CONCLUSION

Low availability and affordability of anti-HBV drugs were observed. Policy recommendations should emphasize the improvement of LPG availability by incentivizing priority prescribing. Healthcare subsidies should be provided more effectively and equitably.

Activation of distinct antiviral T-cell immunity: A comparison of bi- and trispecific T-cell engager antibodies with a chimeric antigen receptor targeting HBV envelope proteins

Despite the availability of an effective prophylactic vaccine, 820,000 people die annually of hepatitis B virus (HBV)-related liver disease according to WHO. Since current antiviral therapies do not provide a curative treatment for the 296 million HBV carriers around the globe, novel strategies to cure HBV are urgently needed. A promising approach is the redirection of T cells towards HBV-infected hepatocytes employing chimeric antigen receptors or T-cell engager antibodies. We recently described the effective redirection of T cells employing a second-generation chimeric antigen receptor directed against the envelope protein of hepatitis B virus on the surface of infected cells (S-CAR) as well as bispecific antibodies that engage CD3 or CD28 on T cells employing the identical HBV envelope protein (HBVenv) binder. In this study, we added a trispecific antibody comprising all three moieties to the tool-box. Cytotoxic and non-cytolytic antiviral activities of these bi- and trispecific T-cell engager antibodies were assessed in co-cultures of human PBMC with HBV-positive hepatoma cells, and compared to that of S-CAR-grafted T cells. Activation of T cells via the S-CAR or by either a combination of the CD3- and CD28-targeting bispecific antibodies or the trispecific antibody allowed for specific elimination of HBV-positive target cells. While S-CAR-grafted effector T cells displayed faster killing kinetics, combinatory treatment with the bispecific antibodies or single treatment with the trispecific antibody was associated with a more pronounced cytokine release. Clearance of viral antigens and elimination of the HBV persistence form, the covalently closed circular (ccc) DNA, through cytolytic as well as cytokine-mediated activity was observed in all three settings with the combination of bispecific antibodies showing the strongest non-cytolytic, cytokine-mediated antiviral effect. Taken together, we demonstrate that bi- and trispecific T-cell engager antibodies can serve as a potent, off-the-shelf alternative to S-CAR-grafted T cells to cure HBV.

Fuzheng Huayu Recipe and its active compounds inhibited HBeAg production by promoting TOMM34 gene expression in HBV-infected hepatocytes

Background and aim: Fuzheng Huayu Recipe (FZHY) is a Chinese patent medicine (approval No. Z20020074) included in the national medical insurance catalogue, which is mainly used for anti-hepatic fibrosis treatment of hepatitis B virus (HBV) induced liver fibrosis and liver cirrhosis. In clinical practice, we discovered that FZHY might also have a direct anti-HBV effect on inhibiting HBeAg production, but the mechanism underlying was unclear. This study aimed to clarify the molecular mechanism of the inhibition effect of FZHY on HBeAg production.

Methods: The decrease degree of serum HBeAg titer in FZHY + entecavir (ETV) group patients were analyzed through clinical data. C57BL/6N-Tg (1.28HBV)/Vst HBV transgenic mice were used for in vivo experiments. HepG2. 2.15 cells (wild-type HBV replication cells) were used for in vitro experiments.

Results: The clinical study results showed that the decrease degree of serum HBeAg titer in FZHY+ETV group was significantly higher than that in ETV group after 48 weeks treatment. In vivo experiments results showed that FZHY could significantly reduce the serum HBeAg titer in HBV transgenic mice, and promote HBeAg seroconversion. In vitro experiments results showed that FZHY could reduce HBeAg titer dependently, but it did not significantly inhibit the expression of HBsAg and HBV-DNA. Further cell experiments in vitro discovered that TOMM34 might be the key target for FZHY to inhibit HBeAg production. The subsequent pharmacological screening experiment of 20 active compounds in FZHY showed that quercetin, baicalin and cordycepin could promote the expression of TOMM34 gene and reduce the production of HBeAg.

Conclusion: In conclusion, FZHY and its active compounds quercetin, baicalin and cordycepin could inhibit HBeAg production by promoting the expression of TOMM34 gene in HBV-infected hepatocytes.

Clinical Efficacy and Safety of Tenofovir in the Treatment of Patients with Chronic Hepatitis B

The negative rate of serum HBV DNA, HBeAg, and ALT in the tenofovir group was significantly higher than that in the entecavir group (86.67%, 3.33%, and 80.00%) (all P < 0.05). In the tenofovir group, 2cases were considered. Objective. The aim of this study is to analyze the clinical effect and safety of tenofovir in the treatment of chronic hepatitis B (CHB) patients. Methods. A total of 60 patients with CHB who were admitted and treated in Anqing First People's Hospital Affiliated to Anhui Medical University from January 2019 to July 2020 were randomly assigned at a ratio of 1 : 1 into the tenofovir group (treated with tenofovir) and the entecavir group (treated with entecavir) via the random number table method. The clinical therapeutic effect and safety of the two groups were compared. Results. The serum hepatitis B virus (HBV) DNA levels in the two groups decreased after treatment, but there was no significant difference. Ths (2.50%) had nausea, 1 (1.25%) had headache, and 0 had an elevated creatine kinase. In the tenofovir group,1(3.33%) had nausea, 0 had headache, and 0 had an elevated creatine kinase. In the entecavir group, there were 3 (10.00%) cases of nausea, 2 (6.67%) cases of headache, and 1 (3.33%) case of elevated creatine kinase. The overall incidence of adverse reactions in the tenofovir group (3.33%) was significantly lower than that in the entecavir group (20.00%) (all P < 0.05). Conclusion. Tenofovir is more effective than entecavir in the treatment of patients with CHB due to low incidence of adverse events and a good safety profile.

Effect of Hepatocyte Targeting Nanopreparation Syringopicroside on Duck Hepatitis B Virus and Evaluation of Its Safety

Syringopicroside is a kind of iridoid monomer compound isolated from Syringa oblata exhibiting a potent effect against hepatitis B virus (HBV). The therapeutic effect and safety of syringopicroside-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (SYR-NP) were studied on the model of HBV-infected ducklings and on cultured HepG2.2.15 cells. HBV DNA in ducklings was assessed by fluorescence quantitative PCR. In HepG2.2.15 cells, the content of HBsAg and HBeAg were assayed. Acute toxicity of SYR-NP was studied in ICR mice in 12 h and 7 days after SYR-NP administration. The serum levels of HBV DNA in ducklings treated with SYR-NP in a high dose was significantly lower than in the control. In HepG2.2.15 cells treated with different doses of SYR-NP, the concentrations of HBsAg and HBeAg were significantly below the control. Acute toxicity test showed high safety of SYR-NP. Thus, SYR-NP can inhibit replication of HBV DNA and protect the liver tissue.

Kushenin Combined with Adefovir Dipivoxil or Entecavir for Chronic Hepatitis B: A Systematic Review and Meta-Analysis

Kushenin (KS) has become a traditional Chinese medicine preparation that plays an important role in treating chronic hepatitis B (CHB). Many clinical studies have discussed its curative effect and safety in combination with adefovir dipivoxil (ADV) or entecavir (ETV) for treating CHB, but there is still a lack of a systematic analysis. Therefore, this study evaluated the efficacy and safety of KS through a meta-analysis to better guide clinical treatment. Seven databases were searched to identify randomized controlled trials (RCTs) concerning KS combined with ADV or ETV for treating CHB. The primary outcomes included serum viral indices and adverse events, and the secondary outcomes were liver function indices. The risk of bias of the included RCTs was appraised by Cochrane software. STATA 15.1 and Review Manager 5.3 software were used for the meta-analysis. Thirty-two RCTs recruiting 3343 patients with CHB were collected for this meta-analysis. KS combined with ETV or ADV led to an amelioration of the CHB index to various degrees. In short, the meta-analysis indicated that the combination group, compared to the single group, showed great improvement in HBeAg seroconversion, frequency of undetectable HBV-DNA levels, loss of serum HBeAg, and loss of serum HBsAg. The combination treatment also decreased serum HBV-DNA levels when compared to the levels after the single treatment. However, KS combined with ADV or ETV displayed no remarkable difference in the incidence of adverse events or in serum ALT levels. Current evidence showed that, compared with the use of either drug alone, KS combined with ADV or ETV can improve the clinical efficacy of CHB treatment.

Prevention of Hepatitis B Virus Infection and Liver Cancer

Hepatocellular carcinoma (HCC) is one of the five leading causes of cancer death in human. Hepatitis B virus (HBV) is the most common etiologic agent of HCC in the world. Prevention is the best way to control cancer. There are three levels of liver cancer prevention, i.e., primary prevention by HBV vaccination targeting the general population starting from birth dose, secondary prevention by antiviral agent for high-risk subjects with chronic HBV infection, and tertiary prevention by antiviral agent to prevent recurrence for patients who have been successfully treated for liver cancer. Primary prevention by hepatitis B vaccination is most cost effective, the cancer preventive efficacy support it as the first successful example of cancer preventive vaccine in human. Addition of hepatitis B immunoglobulin immediately after birth and antiviral agent during the third trimester of pregnancy to block mother-to-infant transmission of HBV are existing or possible emerging strategies to enhance the prevention efficacy of HBV infection and its related liver cancer. Secondary prevention with current antiviral agents may reduce the risk or delay the onset of HCC development, but could not eradicate HBV infection and HCC. Better antiviral therapeutic agents are needed for better secondary prevention.

EGF receptor inhibitors comprehensively suppress hepatitis B virus by downregulation of STAT3 phosphorylation

Current antiviral therapy can not cure chronic hepatitis B virus (HBV) infection or eliminate the risk of hepatocellular carcinoma. The licensed epidermal growth factor receptor (EGFR) inhibitors have found to inhibit hepatitis C virus replication via downregulation of signal transducers and activators of transcription 3 (STAT3) phosphorylation. Since STAT3 is also involved in HBV replication, we further studied the anti-HBV efficacy of the EGFR inhibitors in this study. HBV-transfected HepG2.2.15 cells and HBV-infected HepG2-NTCP cells were used as cell models, and HBV replication, the syntheses of viral antigens and the magnitude of the covalently closed circular DNA (cccDNA) reservoir were used as indictors to test the anti-HBV effects of EGFR inhibitors erlotinib and gefitinib. Erlotinib inhibited HBV replication with a half-maximal inhibitory concentration of 1.05 μM. It also reduced the syntheses of viral antigens at concentrations of 2.5 μM or higher. The underlying mechanism was possibly correlated with its inhibition on STAT3 phosphorylation via up-regulation of suppressor of cytokine signaling 3. Gefitinib also inhibited HBV replication and antigen syntheses. Compared with the commonest antiviral drug entecavir, these EGFR inhibitors additionally reduced hepatitis B e antigen and erlotinib also marginally affected the cccDNA reservoir in HBV-infected HepG2-NTCP cells. Interestingly, these promising anti-HBV effects were significantly enhanced by extension of treatment duration. In conclusion, EGFR inhibitors demonstrated a comprehensive anti-HBV potential, highlighting a new strategy to cure HBV infection and suggesting animal model-related studies or clinical try in the future.

HBV Reactivation in Patients Undergoing Hematopoietic Stem Cell Transplantation: A Narrative Review

HBV reactivation (HBVr) can occur due to the ability of HBV to remain latent in the liver as covalently closed circular DNA and by the capacity of HBV to alter the immune system of the infected individuals. HBVr can occur in patients undergoing hematopoietic stem cell transplantation (HSCT) with a clinical spectrum that ranges from asymptomatic infection to fulminant hepatic failure. The risk of HBVr is determined by a complex interplay between host immunity, virus factors, and immunosuppression related to HSCT. All individuals who undergo HSCT should be screened for HBV. HSCT patients positive for HBsAg and also those HBcAb-positive/HBsAg-negative are at high risk of HBV reactivation (HBVr) due to profound and prolonged immunosuppression. Antiviral prophylaxis prevents HBVr, decreases HBVr-related morbidity and mortality in patients with chronic or previous HBV. The optimal duration of antiviral prophylaxis remains to be elucidated. The vaccination of HBV-naïve recipients and their donors against HBV prior to HSCT has an important role in the prevention of acquired HBV infection. This narrative review provides a comprehensive update on the current concepts, risk factors, molecular mechanisms, prevention, and management of HBVr in HSCT.

An OX40/OX40L interaction directs successful immunity to hepatitis B virus

Depending on age of acquisition, hepatitis B virus (HBV) can induce a cell-mediated immune response that results in either cure or progressive liver injury. In adult-acquired infection, HBV antigens are usually cleared, whereas in infancy-acquired infection, they persist. Individuals infected during infancy therefore represent the majority of patients chronically infected with HBV (CHB). A therapy that can promote viral antigen clearance in most CHB patients has not been developed and would represent a major health care advance and cost mitigator. Using an age-dependent mouse model of HBV clearance and persistence in conjunction with human blood and liver tissue, we studied mechanisms of viral clearance to identify new therapeutic targets. We demonstrate that age-dependent expression of the costimulatory molecule OX40 ligand (OX40L) by hepatic innate immune cells is pivotal in determining HBV immunity, and that treatment with OX40 agonists leads to improved HBV antigen clearance in young mice, as well as increased strength of T cell responses in young mice and adult mice that were exposed to HBV when they were young and developed a CHB serological profile. Similarly, in humans, we show that hepatic OX40L transcript expression is age-dependent and that increased OX40 expression on peripheral CD4⁺ T cells in adults is associated with HBV clearance. These findings provide new mechanistic understanding of the immune pathways and cells necessary for HBV immunity and identify potential therapeutic targets for resolving CHB.

Harnessing CRISPR/Cas 9 System for manipulation of DNA virus genome

The recent development of the Clustered Regularly Interspaced Palindromic Repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) system, a genome editing system, has many potential applications in virology. The possibility of introducing site specific breaks has provided new possibilities to precisely manipulate viral genomics. Here, we provide diagrams to summarize the steps involved in the process. We also systematically review recent applications of the CRISPR/Cas9 system for manipulation of DNA virus genomics and discuss the therapeutic potential of the system to treat viral diseases.

Interferon-α inhibits cell migration and invasion and induces the expression of antiviral proteins in Huh-7 cells transfected with hepatitis B virus X gene-expressing lentivirus

Hepatitis B virus (HBV) X protein (HBx) serves an important role in HBV infection and the development of HBV-related liver cancer. Interferon-α (IFN-α) is used to treat patients with HBV; however, the role of IFN-α in the development of HBV-related liver cancer remains unclear. The present study established a new HBV-related liver cancer model (Huh-7-HBx) by transfecting the hepatoma cell line Huh-7, with HBx-expressing lentivirus. Following IFN-α treatment, cell viability, migration and invasion, as well as the expression of antiviral proteins in Huh-7-HBx, were subsequently determined. The results demonstrated that HBx-expressing lentivirus had no significant effect on cell viability but promoted the migration and invasion of Huh-7 cells. The expression of the antiviral genes IFN α and β receptor subunit 1 (IFNAR1), IFNAR2, IFN-stimulated gene factor 3, double-stranded RNA-activated protein kinase and ribonuclease L, was also increased. Following treatment of Huh-7-HBx cells with IFN-α, the expression of antiviral genes was increased at the level of transcription and translation, whereas cell migration and invasion was decreased. The present study suggests that IFN-α may attenuate the development of HBV-related liver cancer by reducing cell migration and invasion and promoting the expression of antiviral proteins.

Impact of etiological treatment on prognosis

Portal hypertension (PHT) is a frequent and severe complication of cirrhosis. PHT may lead to the development of various complications with high mortality. Liver transplantation is the gold standard as a surgical curative treatment for end-stage liver disease. Theoretically, etiological treatment focusing on the pathophysiology of the underlying disease should be the objective of the nonsurgical management of cirrhotic PHT. Chronic viral hepatitis is the major etiology of cirrhosis and PHT. In cirrhotic patients with chronic hepatitis B virus infection, antiviral therapies can suppress viral replication, ameliorate hepatic inflammation, regress fibrosis, and restore liver functional reserve. Moreover, they can delay the progression of liver cirrhosis and ameliorate the severity of PHT. In patients with hepatitis C virus-induced liver cirrhosis, interferon and ribavirin combination therapy provide a favorable long-term prognosis, including lower rates of liver-related and non-liver-related deaths, hepatic decompensation, and hepatocellular carcinoma, particularly in those who have successful eradication of the virus after therapy. In patients with PHT, direct antivirals (DAAs) for hepatitis C virus infection have good safety profiles and excellent viral suppression. Moreover, DAAs can reduce hepatic venous pressure gradient. However, these effects are stronger during the earlier stage of liver cirrhosis. Abstinence is the cornerstone of etiological treatment for alcoholic liver disease. The effects of pharmacological treatments are not satisfactory, and additional studies are mandatory.

The state of gene therapy research in Africa, its significance and implications for the future

Gene therapy has made impressive recent progress and has potential for treating a wide range of diseases, many of which are important to Africa. However, as a result of lack of direct public funding and skilled personnel, direct research on gene therapy in Africa is currently limited and resources to support the endeavor are modest. A strength of the technology is that it is based on principles of rational design, and the tools of gene therapy are now highly versatile. For example gene silencing and gene editing may be used to disable viral genes for therapeutic purposes. Gene therapy may thus lead to cure from infections with HIV-1, hepatitis B virus and Ebola virus, which are of significant public health importance in Africa. Although enthusiasm for gene therapy is justified, significant challenges to implementing the technology remain. These include ensuring efficient delivery of therapeutic nucleic acids to target cells, limiting unintended effects, cost and complexity of treatment regimens. In addition, implementation of effective legislation that will govern gene therapy research will be a challenge. Nevertheless, it is an exciting prospect that gene therapy should soon reach the mainstream of medical management. Participation of African researchers in the exciting developments is currently limited, but their involvement is important to address health problems, develop capacity and enhance economic progress of the continent.

Sustained Inhibition of HBV Replication In Vivo after Systemic Injection of AAVs Encoding Artificial Antiviral Primary MicroRNAs

Chronic infection with hepatitis B virus (HBV) remains a problem of global significance and improving available treatment is important to prevent life-threatening complications arising in persistently infected individuals. HBV is susceptible to silencing by exogenous artificial intermediates of the RNA interference (RNAi) pathway. However, toxicity of Pol III cassettes and short duration of silencing by effectors of the RNAi pathway may limit anti-HBV therapeutic utility. To advance RNAi-based HBV gene silencing, mono- and trimeric artificial primary microRNAs (pri-miRs) derived from pri-miR-31 were placed under control of the liver-specific modified murine transthyretin promoter. The sequences, which target the X sequence of HBV, were incorporated into recombinant hepatotropic self-complementary adeno-associated viruses (scAAVs). Systemic intravenous injection of the vectors into HBV transgenic mice at a dose of 1 × 10¹¹ per animal effected significant suppression of markers of HBV replication for at least 32 weeks. The pri-miRs were processed according to the intended design, and intrahepatic antiviral guide sequences were detectable for 40 weeks after the injection. There was no evidence of toxicity, and innate immunostimulation was not detectable following the injections. This efficacy is an improvement on previously reported RNAi-based inhibition of HBV replication and is important to clinical translation of the technology.