Treatment of hepatitis B virus-infected patients: utility of therapeutic recommendations in developing countries

Cellular and Molecular Mechanisms Underlying Scope and Limitation of Ongoing and Innovative Therapies for Treating Chronic Hepatitis B

Millions of people of the world suffer from chronic hepatitis B (CHB), a pathological entity in which the patients are chronically infected with hepatitis B virus (HBV) and express hepatitis B surface antigen (HBsAg) and HBV DNA, as well as evidence of liver damages. Considerable numbers of CHB patients develop cirrhosis of the liver and hepatocellular carcinoma if untreated. Two groups of drugs (interferons and nucleoside analogs) are used to treat CHB patients, but both are endowed with considerable adverse effects, increased costs, extended duration of therapy, and limited efficacy. Thus, there is a pressing need to develop new and innovative therapeutics for CHB patients, and many such drugs have been developed during the last four decades. Some of these drugs have inspired considerable optimism to be a game-changer for the treatment of CHB. Here, we first discuss why ongoing therapeutics such as interferon and nucleoside analogs could not stand the test of time. Next, we dissect the scope and limitation of evolving therapies for CHB by dissecting the cellular and molecular mechanisms of some of these innovative therapeutics.

Exploring evidence-based innovative therapy for the treatment of chronic HBV infection: experimental and clinical

With the advent of various vaccines and antimicrobial agents during the 20th century, the control and containment of infectious diseases appeared to be a matter of time. However, studies unveiled the diverse natures of microbes, their lifestyle, and pathogenetic potentials. Since the ground-breaking discovery of the hepatitis B virus (HBV) by Baruch Blumberg and the subsequent development of a vaccine in the early 1980s, the main task of the scientific community has been to develop a proper management strategy for HBV-induced chronic liver diseases. In the early 1980’s, standard interferon (IFN) induced a reduction of HBV DNA levels, followed by the normalization of serum transaminases (alanine aminotransferase, ALT), in some chronic hepatitis B (CHB) patients. However, in the course of time, the limitations of standard IFN became evident, and the search for an alternative began. In the late 1980’s, nucleoside analogs entered the arena of CHB treatment as oral drugs with potent antiviral capacities. At the beginning of the 21st century, insights were developed into the scope and limitations of standard IFN, pegylated-IFN as well as nucleoside analogs for treating CHB. Considering the non-cytopathic nature of the HBV, the presence of covalently closed circular DNA (cccDNA) in the nucleus of the infected hepatocytes and HBV-induced immune-mediated liver damages, a new field of CHB management was initiated by modulating the hosts’ immune system through immune therapy. This review will discuss the nature and design of innovative immune therapy for CHB.

Hepatitis B Core Antigen in Hepatocytes of Chronic Hepatitis B: Comparison between Indirect Immunofluorescence and Immunoperoxidase Method

Background

Hepatitis B virus (HBV) infection has many faces. Precore and core promoter mutants resemble inactive carrier status. The identification of hepatitis B core antigen (HBcAg) in hepatocytes may have variable clinical significance. The present study was undertaken to detect HBcAg in chronic hepatitis B (CHB) patients and to assess the efficacy of detection system by indirect immunofluorescence (IIF) and indirect immunoperoxidase (IIP).

Materials and methods

The study was done in 70 chronic HBV-infected patients. Out of 70 patients, eight (11.4%) were hepatitis B e antigen (HBeAg) positive and 62 (88.57%) were HBeAg negative. Hepatitis B core antigen was detected by indirect immunofluorescence (IIF) and indirect immunoperoxidase (IIP) methods in liver tissue.

Results

All HBeAg positive patients expressed HBcAg by both IIF and IIP methods. Out of 62 patients with HBeAg-negative CHB, HBcAg was detected by IIF in 55 (88.7%) patients and by IIP in 51 (82.26%) patients. A positive relation among viral load and HBcAg detection was also found. This was more evident in the case of HBeAg negative patients and showed a positive relation with HBV DNA levels.

Conclusion

Hepatitis B core antigen can be detected using the IIF from formalin fixed paraffin block preparation and also by IIP method. This seems to reflect the magnitudes of HBV replication in CHB.

How to cite this article

Raihan R, Tabassum S, Al-Mahtab M, Nessa A, Jahan M, Kabir CMS, Kamal M, Aguilar JC. Hepatitis B Core Antigen in Hepatocytes of Chronic Hepatitis B: Comparison between Indirect Immunofluorescence and Immunoperoxidase Method. Euroasian J Hepato-Gastroenterol 2015;5(1):7-10.

HBsAg, HBcAg, and combined HBsAg/HBcAg-based therapeutic vaccines in treating chronic hepatitis B virus infection

BACKGROUND

As the host immunity is diminished in patients with chronic hepatitis B (CHB), different approaches have been used to up-regulate their immune responses to produce therapeutic effects. But, cytokines, growth factors and polyclonal immune modulators could not exhibit sufficient therapeutic effects in these patients. Immune therapy with HBV-related antigens (vaccine therapy) has been used in CHB patients. But there is a paucity of information about the design of HBV antigen-based immune therapy in these patients.

DATA SOURCE

Preclinical and clinical studies on immune therapy with HBsAg-based vaccine, HBcAg and combination of HBsAg/HBcAg-based vaccines have been discussed.

RESULTS

HBsAg-based prophylactic vaccine was used as an immune therapeutic agent in CHB patients; however, monotherapy with HBsAg-based immune therapy could not lead to sustained control of HBV replication and/or liver damages. HBsAg-based vaccine was used as a combination therapy with cytokines, growth factors, and antiviral drugs. HBsAg-based vaccine was also used for cell-based therapy. However, satisfactory therapeutic effects of HBsAg-based vaccine could not be documented in CHB patients. In the mean time, evidences have supported that HBcAg-specific immunity is endowed with antiviral and liver protecting capacities in CHB patients. Recent data concentrate on the clinical use of combined HBsAg- and HBcAg-based vaccines in CHB patients.

CONCLUSION

Antigen-based immune therapy with HBV-related antigens may be an alternative method for the treatment of CHB patients but proper designs of antigens, types of adjuvants, dose of vaccinations, and routes of administration need further analyses for the development of an effective regimen of immune therapy against HBV.

Non-antigen-specific and antigen-specific immune therapies for chronic hepatitis B: evidences from laboratory benches and patient's bedsides

INTRODUCTION

Due to unsatisfactory therapeutic efficacy and considerable side effects of antiviral drugs in patients with chronic hepatitis B (CHB), immunotherapy has emerged as an alternative approach. CHB immunotherapy may be categorized into two main types: i) non-antigen-specific immune therapy and ii) hepatitis B virus (HBV) antigen-specific immune therapy. Although different immune modulators have been used in CHB patients for the last two to three decades, the nature and design of ongoing regimens of immunotherapeutic approaches need considerable modifications.

AREAS COVERED

In this review, the authors have outlined the relevant immunotherapies for CHB patients that have been used for the last two to three decades. The mechanisms underlying the limited therapeutic efficacy of available therapeutic agents for CHB patients have been discussed to aid in the development of an effective therapeutic approach for these patients.

EXPERT OPINION

Circumstantial evidence indicates that a better regimen of immunotherapy may be developed using different HBV-related antigens or combinations of two or more HBV-related antigens, or combinations of HBV-related antigens and antiviral drugs. However, the capacity of 'inducible immunity' by immune modulators to cure or block progression of liver diseases in CHB patients needs to be addressed.

Sulfamoylbenzamide derivatives inhibit the assembly of hepatitis B virus nucleocapsids

Chronic hepatitis B virus (HBV) infection, a serious public health problem leading to cirrhosis and hepatocellular carcinoma, is currently treated with either pegylated alpha interferon (pegIFN-α) or one of the five nucleos(t)ide analogue viral DNA polymerase inhibitors. However, neither pegIFN-α nor nucleos(t)ide analogues are capable of reliably curing the viral infection. In order to develop novel antiviral drugs against HBV, we established a cell-based screening assay by using an immortalized mouse hepatocyte-derived stable cell line supporting a high level of HBV replication in a tetracycline-inducible manner. Screening of a library consisting of 26,900 small molecules led to the discovery of a series of sulfamoylbenzamide (SBA) derivatives that significantly reduced the amount of cytoplasmic HBV DNA. Structure-activity relationship studies have thus far identified a group of fluorine-substituted SBAs with submicromolar antiviral activity against HBV in human hepatoma cells. Mechanistic analyses reveal that the compounds dose dependently inhibit the formation of pregenomic RNA (pgRNA)-containing nucleocapsids of HBV but not other animal hepadnaviruses, such as woodchuck hepatitis virus (WHV) and duck hepatitis B virus (DHBV). Moreover, heterologous genetic complementation studies of capsid protein, DNA polymerase, and pgRNA between HBV and WHV suggest that HBV capsid protein confers sensitivity to the SBAs. In summary, SBAs represent a novel chemical entity with superior activity and a unique antiviral mechanism and are thus warranted for further development as novel antiviral therapeutics for the treatment of chronic hepatitis B.

Future aspects of therapy for hepatitis B virus infection: value of surrogate markers, innovative therapy, and global collaboration

Both optimism and frustration exist regarding therapy for patients with chronic hepatitis B virus infection. Due to the recent advent of several drugs with potent antiviral capacities and comparatively low rates of adverse effects, considerable optimism has developed regarding the treatment of these patients. Chronic hepatitis B is now a treatable disease, and suppression of hepatitis B virus replication, normalization of alanine aminotransferase levels, seronegativity/seroconversion of hepatitis B e antigen and hepatitis B surface antigen, and decreased hepatic inflammation and liver fibrosis have been documented in chronic hepatitis B virus-infected patients treated with antiviral therapy. In contrast, many frustrations regarding antiviral therapy for chronic hepatitis B have arisen, because the disease, although treatable, is not curable. The present regimens of antiviral therapy modulate some intermediate parameters or so-called surrogate markers in chronic hepatitis B virus-infected patients, but usually fail to improve all intermediate parameters or ultimate clinical outcomes. In addition, major concerns remain about the applicability and use of antiviral drugs in developing and resource-constrained countries in which healthcare delivery systems do not support the proper use of antiviral therapy. New and more effective therapeutic regimens for chronic hepatitis B patients are needed that take into account potential surrogate markers of treatment outcomes and allow for effective collaboration between resource-constrained and advanced countries.

Alginate-chitosan-PLGA composite microspheres enabling single-shot hepatitis B vaccination

Hepatitis B vaccination typically requires a multi-dose administration protocol over a course of 3-6 months. Aiming at developing a single-shot formulation for hepatitis B vaccine (hepatitis B surface antigen (HBsAg)), a novel vaccine delivery system, the composite microspheres of alginate-chitosan-poly(lactic-co-glycolic acid) (PLGA), was synthesized by a two-step preparation. The composite microspheres showed distinct advantages over the conventional PLGA microspheres in aspects of the high loading capacity and the elimination of lyophilizing process. The loading capacity of the composite microspheres was about seven times higher than those in the conventional PLGA microspheres, due to the protein-friendly microenvironment created by the hydrophilic alginate-chitosan cores of the composite microspheres. This vaccine delivery system was shown to be able to induce robust immune responses by single injection and display no significant difference in HBsAg-specific antibody levels compared to the double-injection method.