Nature of Host Immunity during Hepatitis B Virus Infection and designing Immune Therapy

Design and Synthesis of Hepatitis B Virus (HBV) Capsid Assembly Modulators and Evaluation of Their Activity in Mammalian Cell Model

Capsid assembly modulators (CAMs) have emerged as a promising class of antiviral agents. We studied the effects of twenty-one newly designed and synthesized CAMs including heteroaryldihydropyrimidine compounds (HAPs), their analogs and standard compounds on hepatitis B virus (HBV) capsid assembly. Cytoplasmic expression of the HBV core (HBc) gene driven by the exogenously delivered recombinant alphavirus RNA replicon was used for high level production of the full-length HBc protein in mammalian cells. HBV capsid assembly was assessed by native agarose gel immunoblot analysis, electron microscopy and inhibition of virion secretion in HepG2.2.15 HBV producing cell line. Induced fit docking simulation was applied for modelling the structural relationships of the synthesized compounds and HBc. The most efficient were the HAP class compounds—dihydropyrimidine 5-carboxylic acid n-alkoxyalkyl esters, which induced the formation of incorrectly assembled capsid products and their accumulation within the cells. HBc product accumulation in the cells was not detected with the reference HAP compound Bay 41-4109, suggesting different modes of action. A significant antiviral effect and substantially reduced toxicity were revealed for two of the synthesized compounds. Two new HAP compounds revealed a significant antiviral effect and a favorable toxicity profile that allows these compounds to be considered promising leads and drug candidates for the treatment of HBV infection. The established alphavirus based HBc expression approach allows for the specific selection of capsid assembly modulators directly in the natural cell environment.

Comparative role of tenofovir versus entecavir for treating patients with hepatitis B virus-related acute on chronic liver failure

INTRODUCTION

The aim of the study was to compare the safety and efficacy of tenofovir versus entecavir for treatment of naive acute on chronic liver failure (ACLF) due to hepatitis B virus (HBV) (ACLF-B).

METHODS

Thirty-two patients aged 14-65 years were enrolled in the study. Diagnosis of ACLF was confirmed by clinical condition, biochemical analysis, and virological data. The causes of both chronic liver damages and acute insult in all patients were HBV. They were expressing HBV DNA in the sera, positive for IgM anti-HBc, had increased levels of serum bilirubin, compromised prothrombin time; and more than 50% patients had encephalopathy. The standard dose of tenofovir and entecavir was given.

RESULTS

The antiviral effects of tenofovir and entecavir were evident as most patients became negative for HBV DNA in the sera after 90 days of therapy. Also, the levels of serum bilirubin, CTP (Child-Turcotte-Pugh) and MELD (model for end-stage liver disease) score exhibited significant improvement due to antiviral therapy. Although the improvement of liver functions, and liver damages were detected in patients receiving both tenofovir and entecavir, the survival of the patients was significantly higher in those receiving tenofovir compared to entecavir-treated patients.

CONCLUSION

This prospective study with limited number patients provides a challenge to assess the real potential of tenofovir over entecavir as therapeutic option for ACLF-B by conducting a multicenter clinical trial enrolling patient of different races and background.

Role of tenofovir and telbivudine in treatment of hepatitis B related acute on chronic liver failure

INTRODUCTION

ACLF is characterized by acute deterioration of liver function in patients with chronic liver disease. HBV is one of the most important causes of both acute insult and underlying chronic liver disease in ACLF. Reactivation of HBV is one of the common causes of ACLF in our region. ACLF requires multiple organ support and is associated with high short and medium term mortality. This is the reason why early, rapid reduction of HBV DNA is essential in treating ACLF-B.

METHODS

Consecutive patients of ACLF-B due to spontaneous reactivation of HBV (ALT> 5xULN or >2 x baseline and HBV DNA >20,000 IU/ml) were randomized into tenofovir group (300mg/day) and telbivudine group (600mg/day) along with standard medical treatment. Clinical and laboratory parameters were evaluated at baseline, day-7, day-14, day-30 and day-90. HBV DNA was evaluated at baseline and after three months of therapy. Primary end point was survival or death at three months. Secondary end point was improvement of liver function assessed by Child-Turcotte Pugh score and MELD score at three months.

RESULTS

30 patients were enrolled in the study and 15 of them received tenofovir and 15 patients received telbivudine. Most of the baseline parameters showed no difference except serum AST and serum creatinine level that showed statistically significant difference between two groups. After antiviral therapy both groups showed significant clinical improvement along with CTP and MELD scores. However statistically significant improvement between tenofovir and telbivudine groups was only seen with MELD score. Survival rate was 80% in tenofovir group and 60% in telbivudine group, but this was not statistically significant. Low serum albumin at baseline was predictor of mortality.

CONCLUSION

In patients of ACLF-B, antiviral therapy with both tenofovir and telbivudine improve liver function, but there is no statistically significant difference in survival between tenofovir and telbivudine.

Observational study on the response of tenofovir monotherapy versus tenofovir plus telbivudine dual therapy in patients with hepatitis B virus related acute on chronic liver failure

INTRODUCTION

HBV is major health problem globally due to complications, including ACLF, cirrhosis and hepa¬tocellular carcinoma. ACLF due to exacerbation of CHB is associate with 30%-70% mortality. Reduction of HBV-DNA is therefore a target of therapy in ACLF-B.

METHODS

Patients with spontaneous reactivation of HBV [(ALT >5×ULN or >2× baseline) and HBV-DNA >20,000 IU/ml] were randomized to Tenofovir mono therapy (300 mg/day) or Tenofovir plus Telbivudine (600 mg/day) dual therapy with standard care. Clinical and biochemical parameters were evaluated at baseline, 1 week, 4 weeks and at 3 months. Virological evaluation was done at baseline and at 3 months. Primary end points were reduction of HBV-DNA and resolution of ascites, as applied. Secondary end point was reduction of liver related complications, therapy related adverse effects and survival at 3 months.

RESULTS

27 patients were enrolled. 15 received mono therapy with Tenofovir and 12 received dual therapy (Tenofovir plus Telbivudine). Baseline parameters in 2 groups had no significant difference. In both groups there was significant improvement of S. bilirubin, ALT, INR, CTP score and MELD score. Only MELD score showed significant improvement in patient with dual therapy at 3 months in comparison to mono therapy. 11 patients on Tenofovir mono therapy (n=15) showed undetected HBV-DNA (91.7%) at 3 months and one patient had detectable HBV-DNA (<2,000 IU/ml). 10 patients on dual therapy (n=12) had undetectable HBV-DNA (100%). Ascites resolved in 3 patients in both groups. Patients receiving dual therapy showed significant improvement in AKI on follow up compared to those on Tenofovir mono therapy. Among 5 deaths, 3 received mono therapy with Tenofovir and 2 dual therapy. Predictors of mortality had high S. bilirubin, HBV-DNA, MELD score and CTP score.

CONCLUSION

In spontaneous reactivation of HBV presenting as ACLF, combination of Telbivudine plus Tenofovir is safer with less nephrotoxicity and better outcomes.

Role of Pegylated Interferon in Patients with Chronic Liver Diseases in the Context of SARS-CoV-2 Infection

The coronavirus 2019 (COVID-19) pandemic has resulted in 168 million cases and about 3.5 million deaths (as of May 26, 2021) during the last 18 months. These 18 months of the COVID-19 pandemic have been characterized by phases or waves of new cases, the emergence of new variants of the deadly virus, and several new complications. After providing emergency approval to several drugs and adherence to several public health measures with frequent full and partial lockdowns, the incidence of new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) could not be contained till now on a global basis. Although prophylactic vaccines have inspired optimism, the scarcity of vaccines and several vaccine-related regulations indicate that the vaccine's benefit would not be reaching the people of developing countries anytime soon. In the course of our clinical practice, we used pegylated interferon (Peg-IFN) in 35 patients with chronic liver diseases (CLD), and we found that only two of them were infected with SARS-CoV-2 that was mild in nature. These two patients with CLD have a mild course of disease cured without any specific therapy. Patients with CLD are usually immune-compromised. However, three CLD patients remained free of SARS-CoV-2 although they had COVID-19 patients among their family members. Next, we accomplished two studies for assessing the immune-modulatory capacities of Peg-IFN, 1 and 12 injections following administration of Peg-IFN. The data revealed that peripheral blood mononuclear cells (PBMCs) of Peg-IFN-administered CLD patients produced significantly higher levels of some cytokines of innate immunity in comparison with the cytokines produced by PBMC of CLD patients before Peg-IFN intake. The pattern of cytokine responses and absence of infection of SARS-CoV-2 in 33 of 35 CLD patients represent some preliminary observations indicating a possible role of Peg-IFN in patients with CLD. The study may be extended to other chronic infections and cancers in which patients receive Peg-IFN. The role of Peg-IFN for pre- or postexposure prophylaxis in the acquisition of SARS-CoV-2 infection and influencing the natural course of COVID-19 remains to be clarified.

ARB-1740, a RNA Interference Therapeutic for Chronic Hepatitis B Infection

Current approved nucleoside analogue treatments for chronic hepatitis B virus (HBV) infection are effective at controlling viral titer but are not curative and have minimal impact on the production of viral proteins such as surface antigen (HBsAg), the HBV envelope protein believed to play a role in maintaining the immune tolerant state required for viral persistence. Novel agents are needed to effect HBV cure, and reduction of HBV antigenemia may potentiate activation of effective and long-lasting host immune control. ARB-1740 is a clinical stage RNA interference agent composed of three siRNAs delivered using lipid nanoparticle technology. In a number of cell and animal models of HBV, ARB-1740 caused HBV RNA reduction, leading to inhibition of multiple elements of the viral life cycle including HBsAg, HBeAg, and HBcAg viral proteins as well as replication marker HBV DNA. ARB-1740 demonstrated pan-genotypic activity in vitro and in vivo, targeting three distinct highly conserved regions of the HBV genome, and effectively inhibited replication of nucleoside analogue-resistant HBV variants. Combination of ARB-1740 with a capsid inhibitor and pegylated interferon-alpha led to greater liver HBsAg reduction which correlated with more robust induction of innate immune responses in a human chimeric mouse model of HBV. The preclinical profile of ARB-1740 demonstrates the promise of RNA interference and HBV antigen reduction in treatment strategies driving toward a cure for HBV.

Five-year Follow-up of Chronic Hepatitis B Patients Immunized by Nasal Route with the Therapeutic Vaccine HeberNasvac

A novel therapeutic vaccine for chronic hepatitis B (CHB) treatment comprising the recombinant hepatitis B surface (HBsAg) and nucleocapsid (HBcAg) antigens has been developed. Preclinical and clinical trials (CT) evidenced safety and immunogenicity in animal models as well as in phases I, II, and III clinical trials. A phase I CT has conducted in Cuba in 6 CHB patients refractory or incomplete responders to α-IFN. Patients were immunized ten times every two weeks via. nasal spray, with 100 ug HBsAg and 100 ug HBcAg. Clinical efficacy was monitored by assessing the levels of hepatitis B virus deoxyribonucleic acid (HBV DNA), alanine aminotransferase (ALT), HBeAg, and anti-HBeAg seroconversion as well as by qualitative/ quantitative HBsAg serology during this period. After a 5 year follow-up,HBeAg loss was verified in the three HBeAg (+) patients, in two cases with seroconversion to anti-HBeAg. A reduction to undetectable viral load was observed in 5 out of 6 patients, and in two cases HBsAg seroconversion was also detected. ALT increases above the 2X upper limit of normal (ULN) were only detected in HBeAg (+) patients and associated with HBe antigen loss. All patients had stiffness levels below 7.8 KPa by Fibroscan assessment at the end of this period. Although only a few patients were enrolled in this study, it seems that HeberNasvac may maintain some of the therapeutic effects for a prolonged period. How to cite this article: Fernandez G, Sanchez AL, Jerez E, Anillo LE, Freyre F, Aguiar JA, Leon Y, Cinza Z, Diaz PA, Figueroa N, Muzio V, Nieto GG, Lobaina Y, Aguilar A, Penton E, Aguilar JC. Five-year Follow-up of Chronic Hepatitis B Patients Immunized by Nasal Route with the Therapeutic Vaccine HeberNasvac. Euroasian J Hepatogastroenterol, 2018;8(2):133-139.