New drugs for chronic hepatitis B: a review. Am J Ther. 2008;15:167-172. [PMID: 18356637 DOI: 10.1097/MJT.0b013e318155a191]

Antiviral Therapy with Entecavir following Antituberculosis Therapy Alleviates Liver Injury and Restores Innate Immunity in Tuberculosis Patients Coinfected with Hepatitis B Virus

Objective

Coinfection of tuberculosis (TB) and viral hepatitis may increase the risk of antituberculosis treatment-induced hepatotoxicity, which is regarded as a common cause of termination of the first-line antituberculosis drugs. The study aimed at investigating the protective effects of antiviral therapy on the liver and innate immunity in patients with TB-HBV coinfection.

Methods

A total of 100 patients with TB-HBV coinfection were recruited and split into antituberculosis and antiviral groups, 50 per group, according to odd or even date of hospital admission from December 2019 to October 2020. The patients in the anti-TB group received antituberculosis therapy, and those in the antiviral group received antiviral therapy. The clinical effectiveness; HBV-DNA negative conversion rate; liver function assessment involving alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total bilirubin (TBIL); immune function evaluation including CD4⁺, CD8⁺, CD4⁺/CD8⁺, and CD3⁺ T cells; inflammatory cytokines containing tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interferon-γ (IFN-γ); and intestinal microflora including bifidobacterium, lactobacillus, enterobacterium, enterococcus, and clostridium were main outcome measures after treatment.

Results

It was found that the total response rate in the antiviral group was significantly higher than the anti-TB group after treatment (χ ² = 3.157, P=0.017). There was a significant difference in HBV-DNA negative conversion rates between the antiviral group and anti-TB group (82% vs. 58%, χ ² = 6.384, P=0.001). The ALT, AST, and TBIL in the two groups were all increased after treatment (P < 0.05), but the antiviral group indicated a rise of the above indices compared to the anti-TB group (P < 0.05). The two groups showed a rise on the concentration of CD3⁺, CD4⁺, and CD4⁺/CD8⁺ T cells and a decline on the CD8⁺ T cells after treatment (P < 0.05), but these changes in the antiviral group were more evident to those in the anti-TB group (P < 0.05). There was an increase on the IFN-γ level and decrease on the TNF-α and IL-6 levels in both groups after treatment (P < 0.05), but the antiviral group revealed a higher level of IFN-γ with lower levels of TNF-α and IL-6 compared to the anti-TB group (P < 0.05). After treatment, the number of bifidobacteria and lactobacilli was increased, and the number of enterobacteria, enterococci, and clostridium were decreased in the two groups (P < 0.05), while these changes in the antiviral group were more remarkable compared to the anti-TB group (P < 0.05). There was no significant difference in the incidence of adverse reactions between the two groups (χ2 = 0.267, P=0.731).

Conclusion

Antiviral therapy for tuberculosis-HBV coinfected patients could inhibit HBV replication, providing protection against liver damage, improving innate immunity, and balancing intestinal microflora.

Analysis of Clinical Trials of New Drugs for Liver Diseases in China

Background

Liver diseases are a major public health concern worldwide, and the development of novel therapeutic drugs is an important research focus. But no overview has been conducted so far on the current research and development for liver-specific drugs in China, and the actual situation regarding the development and evaluation of new drugs in clinical trials.

Methods

The information of all clinical trials on liver diseases were obtained through the "Pharmaceutical Clinical Trial Registration and Information Disclosure Platform" before December 31, 2020.

Results

A total of 751 clinical trials on liver disease-related drugs were published on the above platform, including 574 chemical drugs, 128 biological products, and 49 traditional Chinese medicine (TCM)/natural drugs. The number of annual registrations has increased on an annual basis. The main indications for these clinical trials are viral hepatitis, liver malignancies, liver abscess, liver transplantation, congenital liver metabolic disease, and other hepatitis-related diseases. Hepatitis B, hepatitis C and liver cancer accounted for 72.4% of the total clinical trials, and the majority are related to generic drug research. There are 103 innovative drugs currently in clinical testing, mainly for hepatitis B, hepatitis C and hepatocellular carcinoma.

Conclusion

The stronger macro-control is required for the clinical trials conducted in China, and it is necessary to identify new therapeutic targets and develop novel drugs for the key liver diseases, as well as preventive hepatitis C vaccines, and targeted therapy, TCM/natural drugs and immunotherapy for liver cancer.

Effects of Fuzheng Huayu recipe on entecavir pharmacokinetics in normal and dimethylnitrosamine-induced hepatic fibrosis rats

Context: Fuzheng Huayu recipe (FZHY) combined with entecavir (ETV) is used to treat the cirrhosis caused by chronic hepatitis B (CHB) infection.Objective: To investigate the effect of FZHY on ETV pharmacokinetics under different conditions.Materials and methods: A model of liver fibrosis was created by intraperitoneal injection of dimethylnitrosamine (DMN; 10 μg/kg) for 4 weeks in Wistar rats. Ultra-high-performance liquid chromatography-tandem mass spectrometry was used to determine the blood concentration of ETV. Pharmacokinetic characteristics of ETV (0.9 mg/kg) were investigated after co-administration with FZHY (0.55 g/kg) at certain time intervals in normal and model rats.Results: The analytical method for ETV was validated at 0.5-50 μg/L with a correlation coefficient = 0.9996, lower limit of quantitation of 0.5 μg/L and mean accuracy of 104.18 ± 9.46%. Compared with the ETV-N group, the pharmacokinetic parameters of the EF-2 group did not change significantly, but that of the EF-0 group decreased in C_max to 27.38 μg/L, in AUC_0-t from 323.84 to 236.67 μg/h/L, and a delay in T_max from 0.75 to 6.00 h; that of the EF-0 group presented a decrease in C_max of 61.92%, delay in t_1/2 of 2.45 h and delay in T_max of 2.92 h. The t_1/2e and V_d/F of ETV were increased significantly to 8.01 h and 24.38 L/kg in the ETV-M group.Conclusions: The effects of FZHY on ETV pharmacokinetics were diminished with an increase of interval time. The best time to administer both drugs is >2 h apart.

Hepatoprotective and inhibiting HBV effects of polysaccharides from roots of Sophora flavescens

Roots of Sophora flavescens is an important herbal medicine for treatment of HBV and hepatic carcinoma in China. Alkaloids in the root were well known for exhibiting good hepato-protective and anti-HBV effects. However, polysaccharides as main components in the root remained unknown. In the studies, we investigated the chemical features and hepatoprotective effects of Sophora flavescens polysaccharides (SFP-100 and its active fractions) with ConA-induced hepatitis mice, human liver LO2 cells and HepG2.2.15 cells. The results showed that SFP-100 was composed of arabinose, glucose, galactose and galacturonic acid, SFP-100-A mainly contained glucose. SFP-100-B and SFP-100-C were acidic polysaccharides. SFP-100 significantly decreased hepatocytes apoptosis, inhibited the infiltration of neutrophils and macrophages into liver, and improved the production of IFN-γ and IL-6 of splenocytes in ConA-induced hepatitis mice. SFP-100 and its two sugar fractions increased LO2 cell proliferation and reduced cell apoptosis induced by ConA. SFP-100, SFP-100-A and SFP-100-C remarkedly inhibited the secretion of HBsAg and HBeAg by HepG2.2.15 cells.These results suggested Sophora flavescens polysaccharides exerts significant hepatoprotective and anti-HBV roles, and further is used for treatment of immune-mediated liver disease in the future.

Current progress in antiviral strategies

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Antiviral agents function as either viral targets or host factors.

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Virus-targeting antivirals (VTAs) function through a direct (DVTAs) or an indirect (InDVTAs) method in the viral life cycle.

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Host-targeting antivirals (HTAs) include reagents that target the host proteins that are involved in the viral life cycle.

The prevalence of chronic viral infectious diseases, such as human immunodeficiency virus (HIV), hepatitis C virus (HCV), and influenza virus; the emergence and re-emergence of new viral infections, such as picornaviruses and coronaviruses; and, particularly, resistance to currently used antiviral drugs have led to increased demand for new antiviral strategies and reagents. Increased understanding of the molecular mechanisms of viral infection has provided great potential for the discovery of new antiviral agents that target viral proteins or host factors. Virus-targeting antivirals can function directly or indirectly to inhibit the biological functions of viral proteins, mostly enzymatic activities, or to block viral replication machinery. Host-targeting antivirals target the host proteins that are involved in the viral life cycle, regulating the function of the immune system or other cellular processes in host cells. Here we review key targets and considerations for the development of both antiviral strategies.

Structural features and biological activities of the polysaccharides from Astragalus membranaceus

Recently, a great deal of interest has been developed to isolate and investigate novel bioactive components with health benefit effects from natural resources. The dried root of Astragalus membranaceus, one of the most popular health-promoting herbal medicines, has been used historically as an immunomodulating agent for the treatment of common cold, diarrhea, fatigue and anorexia for more than 2000 years. Modern phytochemistry and pharmacological experiments have proved that polysaccharide is one of the major active ingredients in the root of A. membranaceus with various important bioactivities, such as immunomodulation, antioxidant, antitumor, anti-diabetes, antiviral, hepatoprotection, anti-inflammation, anti-atherosclerosis, hematopoiesis and neuroprotection. The aim of the present review is to summarize previous and current references and give a comprehensive summary regarding the structural features and biological activities of A. membranaceus polysaccharides in order to provide new insight for further development of these macromolecules.

Comparison of clevudine and entecavir for treatment-naive patients with chronic hepatitis B virus infection: two-year follow-up data

BACKGROUND/AIM

Clevudine and entecavir are highly potent antiviral agents being used in treatment of chronic hepatitis B. However, no data comparing clinical efficacy and safety of these 2 drugs over a long-term period is available. The aims of this study are to compare virologic, biochemical, and serologic response rates of clevudine and entecavir, as well as treatment failure rates up to 2 years.

METHODS

Data of patients who started clevudine (n = 86) or entecavir (n = 159) as a primary treatment for chronic hepatitis B at Korea University Ansan or Guro Hospital between January 2007 and June 2008 were analyzed.

RESULTS

Treatment responses were compared at 3-month intervals up to 24 months. Per protocol analysis showed no difference in virologic responses between the 2 groups at all time points, except at 18 months. When analyzed on intention-to-treat basis for virologic response at 24 months, the response rates were 45.3% in the clevudine group and 72.3% in the entecavir group, which are significantly different (P < 0.001). Rates of biochemical response and HBeAg seroconversion were not significantly different between the groups at all time points. Up to 24 months, antiviral resistance developed in 18 patients (24.4%) in the clevudine group. Clevudine was discontinued owing to muscle-related problems in 10 patients (11.6%).

CONCLUSIONS

Although both drugs showed potent antiviral activity, entecavir showed better virologic response at 24 months, primarily owing to treatment failures in the clevudine group that were associated with development of drug resistance and muscle-related problems.

Antiviral treatment of chronic hepatitis B virus (HBV) infections

While 25 compounds have been formally licensed for the treatment of HIV infection (AIDS), only seven licensed products are currently available for the treatment of chronic hepatitis B virus (HBV) infection: interferon-α, pegylated interferon-α, lamivudine, adefovir (dipivoxil), entecavir, telbivudine and tenofovir (disoproxil fumarate). In contrast to the treatment of HIV infections where the individual drugs are routinely used in combination, for the treatment of chronic HBV infection the individual drugs are generally used in monotherapy. In principle, combination drug therapy should allow reducing the likelihood of drug-resistant development.

Forecasting drug utilization and expenditure in a metropolitan health region

BACKGROUND

New pharmacological therapies are challenging the healthcare systems, and there is an increasing need to assess their therapeutic value in relation to existing alternatives as well as their potential budget impact. Consequently, new models to introduce drugs in healthcare are urgently needed. In the metropolitan health region of Stockholm, Sweden, a model has been developed including early warning (horizon scanning), forecasting of drug utilization and expenditure, critical drug evaluation as well as structured programs for the introduction and follow-up of new drugs. The aim of this paper is to present the forecasting model and the predicted growth in all therapeutic areas in 2010 and 2011.

METHODS

Linear regression analysis was applied to aggregate sales data on hospital sales and dispensed drugs in ambulatory care, including both reimbursed expenditure and patient co-payment. The linear regression was applied on each pharmacological group based on four observations 2006-2009, and the crude predictions estimated for the coming two years 2010-2011. The crude predictions were then adjusted for factors likely to increase or decrease future utilization and expenditure, such as patent expiries, new drugs to be launched or new guidelines from national bodies or the regional Drug and Therapeutics Committee. The assessment included a close collaboration with clinical, clinical pharmacological and pharmaceutical experts from the regional Drug and Therapeutics Committee.

RESULTS

The annual increase in total expenditure for prescription and hospital drugs was predicted to be 2.0% in 2010 and 4.0% in 2011. Expenditures will increase in most therapeutic areas, but most predominantly for antineoplastic and immune modulating agents as well as drugs for the nervous system, infectious diseases, and blood and blood-forming organs.

CONCLUSIONS

The utilisation and expenditure of drugs is difficult to forecast due to uncertainties about the rate of adoption of new medicines and various ongoing healthcare reforms and activities to improve the quality and efficiency of prescribing. Nevertheless, we believe our model will be valuable as an early warning system to start developing guidance for new drugs including systems to monitor their effectiveness, safety and cost-effectiveness in clinical practice.

Drug delivery systems and liver targeting for the improved pharmacotherapy of the hepatitis B virus (HBV) infection

In spite of the progress made in vaccine and antiviral therapy development, hepatitis B virus (HBV) infection is still the most common cause of liver cirrhosis and hepatocellular carcinoma, with more than 400 million people chronically infected worldwide. Antiviral therapy with nucleos(t)ide analogues and/or immunomodulating peptides is the only option to control and prevent the progression of the disease in chronic hepatitis B (CHB)-infected patients. So far, the current antiviral monotherapy remains unsatisfactory because of the low efficacy and the development of drug resistance mutants. Moreover, viral rebound is frequently observed following therapy cessation, since covalent closed circular DNA (cccDNA) is not removed from hepatocytes by antiviral therapy. First, this review describes the current pharmacotherapy for the management of CHB and the new drug candidates being investigated. Then, the challenges in the development of drug delivery systems for the targeting of antiviral drugs to the liver parenchyma are discussed. Finally, perspectives in the design of a more efficient pharmacotherapy to eradicate the virus from the host are addressed.

Inhibitory effect of emodin and Astragalus polysaccharide on the replication of HBV

AIM: To evaluate the anti-viral effect of emodin plus Astragalus polysaccharide (APS) in hepatitis B virus (HBV) transgenic mice.

METHODS: Sixty HBV transgenic mice (HBV TGM) whose weight varied between 18 and 24 g were randomly divided into 3 groups, with 20 mice in each group. Group A was the normal control, where the mice were treated with physiological saline; group B was the positive control where the mice were treated with lamivudine solution (100 mL/kg per day). Group C was the experimental group where the mice were treated with physiological saline containing emodin and APS (57.59 mg/kg per day and 287.95 mg/kg per day, respectively). The mice were treated daily for 3 wk. After 1 wk recovery time, the mice were sacrificed and serum as well as liver tissues were collected for ELISA and histological examination.

RESULTS: After 21 d treatment, HBV DNA levels in group B and group C significantly declined when compared with group A (P < 0.05). However, a significant increase in HBV DNA content was observed in group B, whereas this phenomenon was not observed in group C. A reduction in the contents of HBsAg, HBeAg and HBcAg in the mice from group B and C was observed when compared with group A.

CONCLUSION: Emodin and APS have a weak but persistent inhibitory effect on HBV replication in vivo, which may function as a supplementary modality in the treatment of hepatitis B infection.

Viral Infections

Although influenza remains indisputably the most significant viral pathogen in adults, other viruses such as respiratory syncytial virus, parainfluenza viruses, and human metapneumovirus are now recognized as significant pathogens in older populations.

Oseltamivir and zanamivir are antiviral agents that are effective for the treatment and prophylaxis of influenza A and B. For treatment and for optimal effect, therapy should be initiated within 48 h of symptom onset.

Infection with hepatitis viruses may be more severe in older adults with more fulminate disease as observed with acute hepatitis A and a more rapid progression to cirrhosis with hepatitis C.

Outbreaks of viral gastroenteritis are common in long-term care facilities, and infection may lead to death due to dehydration and oliguria.

The incidence of herpes zoster increases with advancing age and carries with it a significant risk of post herpetic neuralgia. The use of antiviral medications and corticosteroids may reduce the incidence and severity of chronic pain.

Understanding the molecular basis of HBV drug resistance by molecular modeling

Despite the significant successes in the area of anti-HBV agents, resistance and cross-resistance against available therapeutics are the major hurdles in drug discovery. The present investigation is to understand the molecular basis of drug resistance conferred by the B and C domain mutations of HBV-polymerase on the binding affinity of five anti-HBV agents [lamivudine (3TC, 1), adefovir (ADV, 2), entecavir (ETV, 3), telbivudine (LdT, 4) and clevudine (l-FMAU, 5)]. In this regard, homology modeled structure of HBV-polymerase was used for minimization, conformational search and induced fit docking followed by binding energy calculation on wild-type as well as on mutant HBV-polymerases (L180M, M204V, M204I, L180M+M204V, L180M-M204I). Our studies suggest a significant correlation between the fold resistances and the binding affinity of anti-HBV nucleosides. The binding mode studies reveals that the domain C residue M204 is closely associated with sugar/pseudosugar ring positioning in the active site. The positioning of oxathiolane ring of 3TC (1) is plausible due the induced fit orientation of the M204 residue in wild-type, and further mutation of M204 to V204 or I204 reduces the final binding affinity which leads to the drug resistance. The domain B residue L180 is not directly close ( approximately 6A) to the nucleoside/nucleoside analogs, but indirectly associated with other active-site hydrophobic residues such as A87, F88, P177 and M204. These five hydrophobic residues can directly affect on the incoming nucleoside analogs in terms of its association and interaction that can alter the final binding affinity. There was no sugar ring shifting observed in the case of adefovir (2) and entecavir (3), and the position of sugar ring of 2 and 3 is found similar to the sugar position of natural substrate dATP and dGTP, respectively. The exocyclic double bond of entecavir (3) occupied in the backside hydrophobic pocket (made by residues A87, F88, P177, L180 and M204), which enhances the overall binding affinity. The active site binding of LdT (4) and l-FMAU (5) showed backward shifting along with upward movement without enforcing M204 residue and this significant different binding mode makes these molecules as polymerase inhibitors, without being incorporated into the growing HBV-DNA chain. Structural results conferred by these l- and d-nucleosides, explored the molecular basis of drug resistance which can be utilized for future anti-HBV drug discovery.

New antiviral choice for chronic hepatitis B: tenofovir disoproxil fumarate

Tenofovir disoproxil fumarate (TDF) is an oral prodrug of tenofovir, a novel, acyclic nucleotide analogue with in vitro activity against HIV-1 and HIV-2. TDF is licensed by American Food and Drug Administration (FDA) in 2001 for the treatment of HIV infection. TDF is currently one of the most widely used nucleotide reverse transcriptase inhibitors (NRTIs) for the treatment of HIV infection. Its efficacy, favorable toxicity profile, and convenient dosing have made this drug one of the most popular first-line treatment. Numerous studies have demonstrated the use of TDF in the treatment of HIV infection. It also has been shown to be effective in HIV/HBV coinfected patients and in patients with wild-type and lamivudine-resistant strains. Accumulating evidence suggests that TDF is more potent in suppressing HBV replication. In this review, we summarize the study progress of TDF in treating HBV infection.