Hepatitis B: progress in the last 15 years

Antiviral Therapy for AECHB and Severe Hepatitis B (Liver Failure)

This chapter describes the principles of antiviral therapy, treatment strategies, medications and recommendations for AECHB, HBV-ACLF, HBV-related liver cirrhosis, HBV-related HCC, and liver transplantation.

Severe exacerbation of chronic hepatitis B is closely related to continuous HBV replication. Therefore, inhibiting HBV replication to reduce viral load may block disease progression and improve the quality of life of these patients. ETV or TDF has been recommend first-line drug for the treatment of AECHB.

A hyperactive immune response due to continuous HBV replication is the main mechanism for development of severe hepatitis B. In addition to comprehensive treatment, early administration of potent nucleoside analogs can rapidly reduce HBV DNA concentration, relieve immune injury induced by HBV, and reduce liver inflammation and patient mortality. Antiviral agents have become important in the treatment of severe exacerbation of chronic hepatitis B.

Long-term antiviral treatment with nucleoside analogs can delay or reverse the progress of liver cirrhosis. Virologic response, viral resistance and adverse drug reactions should be closely monitored during treatment. The treatment should be optimized for maximum effect based on each patient’s responses.

Effective antiviral therapy can suppress HBV replication and reduce the incidence of HBV-related HCC. Patients with HBV-related HCC should receive individualized and optimal multidisciplinary comprehensive treatment. Anti-viral drugs with high efficacy, low resistance and low adverse drug reactions should be selected to improve the patient’s quality of life and prolong survival time.

Methods to prevent HBV reinfection after liver transplantation include passive immunization (HBIG), antiviral treatment (nucleoside analogs) and active immunization (hepatitis B vaccine).

Clinical trials involving sequential combination therapy with NUC and Peg-IFN have shown statistically significant decline in HBsAg levels on treatment and high rates of sustained post-treatment serologic response. Combination therapy with novel DAA and immunotherapeutic approach may hold promise to overcome both cccDNA persistence and immune escape, representing a critical step towards HBV cure.

Cost Analysis and Determinants of Living Donor Liver Transplantation in Taiwan

BACKGROUND

Liver transplantation (LT) has become established therapy for end-stage liver disease and small-cell hepatocellular carcinoma (HCC), relying mainly on living donor LT (LDLT) in Taiwan. The cost of LDLT varies in different countries depending on the insurance system, the costs of the facility, and staff. In this study we aimed to investigate cost outcomes and determinants of LDLT in Taiwan.

METHODS

From January 2014 to December 2015, 184 LDLT patients were enrolled in a study performed at the Kaohsiung Chang Gung Memorial Hospital. Patients' transplantation costs were defined as expense from immediately after surgery to discharge during hospitalization for LDLT. Antiviral therapy and hepatitis B immunoglobulin (HBIG) for prevention of hepatitis B virus (HBV) were included, but direct-acting antiviral (DAA) therapy for hepatitis C (HCV) was excluded.

RESULTS

The median total, intensive care unit (ICU), and ward costs of LT were US$64,250, $43,357, and $16,138 (currency ratio 1:30), respectively. HBV significantly increased the total cost of LT, followed by postoperative reintubation and bile duct complications.

CONCLUSION

The charges associated with anti-HBV viral therapy and HBIG increase the cost of LDLT. Disease severity of liver cirrhosis showed less importance in predicting cost. Postoperative complications such as reintubation or bile duct complications should be avoided to reduce the cost of LT.

Prevelance of common YMDD motif mutations in long term treated chronic HBV infections in a Turkish population

In the current study we aimed to show the common YMDD motif mutations in viral polymerase gene in chronic hepatitis B patients during lamivudine and adefovir therapy. Forty-one serum samples obtained from chronic hepatitis B patients (24 male, 17 female; age range: 34-68 years) were included in the study. HBV-DNA was extracted from the peripheral blood of the patients using an extraction kit (Invisorb, Instant Spin DNA/ RNA Virus Mini Kit, Germany). A line probe assay and direct sequencing analyses (INNO-LIPA HBV DR v2; INNOGENETICS N.V, Ghent, Belgium) were applied to determine target mutations of the viral polymerase gene in positive HBV-DNA samples. A total of 41 mutations located in 21 different codons were detected in the current results. In 17 (41.5%) patients various point mutations were detected leading to lamivudin, adefovir and/ or combined drug resistance. Wild polymerase gene profiles were detected in 24 (58.5%) HBV positive patients of the current cohort. Eight of the 17 samples (19.5%) having rtM204V/I/A missense transition and/or transversion point mutations and resistance to lamivudin. Six of the the mutated samples (14.6%) having rtL180M missense transversion mutation and resistance to combined adefovir and lamivudin. Three of the mutated samples (7.5%) having rtG215H by the double base substituation and resistance to adefovir. Three of the mutated samples (7.5%) having codon rtL181W due to the missense transversion point mutations and showed resistance to combined adefovir and lamivudin. Unreported novel point mutations were detected in the different codons of polymerase gene region in the current HBV positive cohort fromTurkish population. The current results provide evidence that rtL180M and rtM204V/I/A mutations of HBV-DNA may be associated with a poor antiviral response and HBV chronicity during conventional therapy in Turkish patients.

A YIDD Mutation in a Case of Recurrent Hepatitis B after Liver Transplantation Induced by an S-escape Mutant

A 47-year-old woman underwent orthotopic liver transplantation (OLT) for hepatitis B virus (HBV)-related end-stage liver cirrhosis. The patient received hepatitis B immunoglobulin prophylaxis after OLT. Despite the protective level of the serum anti-hepatitis-B surface antibody, HBV recurred at 22 months post-OLT and induced subacute hepatic failure. The pre-OLT HBV genome contained a complex mutation pattern in overlapping frame regions of the surface (S) and polymerase (P) genes, which is the same mutation pattern as seen in post-OLT HBV DNA. G145R and K141R mutations in the "a" determinant were detected only in the post-OLT sample. Clevudine (30 mg once daily) was administered for recurrent hepatitis B. Hepatitis B was reactivated with a flare-up, and a M204I mutation (YIDD mutant type) appeared with a higher viral load at 9 months after clevudine treatment. We report here a case of a YIDD mutation that developed in recurrent hepatitis B after OLT induced by an S-escape mutant.

Recipient cytotoxic T lymphocyte antigen-4 +49 G/G genotype is associated with reduced incidence of hepatitis B virus recurrence after liver transplantation among Chinese patients

BACKGROUND

Single-nucleotide polymorphisms (SNP) of two-gene locus cytotoxic T lymphocyte antigen-4 (CTLA-4) +49 and CD86 +1057 were previously reported to influence the outcome of liver transplantation (LT) with respect to allograft acceptance. SNP at CTLA-4 +49 was also suggested to be associated with the individual difference in the clearance of hepatitis B virus (HBV). However, their influence on the incidence of post-LT HBV reinfection was not clear. With the increasing knowledge of costimulatory mechanisms on LT and host immune response, we designed this study to investigate the relationship between different alleles as well as genotypes at these two locations and HBV reinfection after LT.

METHODS

Genomic DNA from 167 LT recipients with HBV-related diseases was genotyped for CTLA-4 +49 and CD86 +1057 genomic polymorphisms using a sequence-specific primer-polymerase chain reaction (PCR-SSP). HBV recurrence was diagnosed based on the serological and pathological finding of HBV DNA and HBsAg.

RESULTS

The present study indicated that the recipients with CTLA-4 +49 GG genotype had a reduced risk (6.67%) of HBV recurrence compared with non-CTLA-4 +49 GG-carrying individuals (20.7%) (relative risk 3.098) (P=0.032). The allelic frequency of CTLA-4 +49 G was also significantly lower in patients with HBV recurrence, compared with that in patients without HBV recurrence (P=0.013, odds ratio 2.176, 95% confidence interval 1.170-4.046). However, no significant association was found between CD86 +1057 and HBV recurrence.

CONCLUSION

Our result on CTLA-4 +49 A/G polymorphism indicated that the CTLA-4 +49 GG genotype was related to a reduced risk in the incidence of HBV recurrence.

Combination therapy in liver transplant recipients with hepatitis B virus without hepatitis B immune globulin

INTRODUCTION

Conventional therapy to prevent HBV recurrence in liver transplant (LTx) recipients consists of Hepatitis B Immune Globulin (HBIg). The aim of this review is to investigate the safety and efficacy of converting HBIg and LAM therapy to ADV and LAM therapy.

METHODS

A retrospective review involving all liver transplant patients with HBV maintained on HBIg and LAM therapy. Results collected included: gender, age, HBV serological and DNA status (COBAS AmpliScreen PCR-based testing). Serologic testing was done every three months. Patients were followed for drug reactions, therapy compliance, and immune suppression compliance. A cost benefit analysis was done for drug comparisons using United States currency values.

RESULTS

Patient demographics included: Male (n=6), Female (n=4), mean age 44 years (range 33 to 65). The mean length of follow up since therapy conversion (from HBIg and LMV to ADV and LMV) was 21 months (range 16 to 25 months). Serological status at time of conversion revealed that DNA status remained negative in all patients, HBsAg negative in 10/10, HB eAg (+) (5/10) and HBeAb (+)(5/10). None of the patients experienced an increase in transaminases while on dual ADV and LAM therapy. All patients were maintained on immune suppression monotherapy (tacrolimus) at 7-9 ng/mL. All patients reported compliance with the dual therapy and that they experienced no drug related side effects. Mean yearly costs for ADV and LAM was 7,235.00 United States dollars (range 6,550.00 to 8,225.00); while mean monthly costs for HBIg and LAM; 9225.00 (range 7205.00 to 12005.00).

CONCLUSION

The above results demonstrate beneficial effects of ADV and LAM in place of the current standard of HBIg and LAM therapy. Safety and short term results show nucleoside therapy is adequate at preventing HBV viral recurrence. Lastly, the economic benefit for ADV and LAM vastly outweighed the HBIg and LAM group.

Emergence of hepatitis B virus quasispecies with lower susceptibility to nucleos(t)ide analogues during lamivudine treatment

OBJECTIVES

We studied the impact of hepatitis B virus (HBV) polymerase/reverse transcriptase (Pol/Rt) heterogeneity on adefovir rescue therapy in 34 consecutive chronic hepatitis B patients with viral breakthrough during lamivudine monotherapy.

METHODS

The Pol/Rt A-F domains were directly sequenced in all patients at baseline, and 12 and 24 months. Response to therapy was evaluated at 3, 6, 12 and 24 months by quantitative HBV-DNA.

RESULTS

Primary treatment failures did not occur. At 6 months 24/34 (70.6%) patients had viraemia<10(4) copies/mL [initial viral response (IVR)]; at 12 and 24 months 23 (71.9%) and 26 (81.3%) of 32 had HBV-DNA<200 copies/mL [complete viral response (CVR)]. IVR or CVR patients did not show viral breakthroughs, which occurred in one of the six remaining patients. All but three patients had baseline rtM204I/V substitutions associated with rtL180M in 23, rtL80I/V in 14, rtV173L in 4, rtT184S in 3, rtQ215S in 2 and rtA181S in 2 cases. rtA181S without rtM204I/V was found in one patient. Four of the six patients (67%) without 24 month CVR showed rtA181S or rtT184S substitutions either alone or with typical lamivudine resistance profiles. Baseline HBV-DNA levels were negatively associated with IVR (univariate analysis, P=0.023). At least one of rtA181S and rtT184S substitutions correlated negatively with IVR and CVR (univariate analysis, P=0.001) and was independently associated with absence of CVR (P = 0.016).

CONCLUSIONS

Lamivudine monotherapy favours the emergence of viral quasispecies that influence the response rate to adefovir rescue therapy independently from baseline viraemia and lower the susceptibility to other nucleos(t)ide analogues.

Hepatitis B in liver transplant recipients

1. The use of low-dose immunosuppressive therapy along with pre- and posttransplantation nucleos(t)ide therapy and posttransplantation hepatitis B immunoglobulin (HBIG) has yielded marked improvements in survival. 2. Lamivudine (Epivir-HBV), adefovir (Hepsera), entecavir (Baraclude), tenofovir (Viread), emtricitabine (Emtriva), and the combination drugs tenofovir + emtricitabine (Truvada) and abacavir + lamivudine (Epzicom) are effective nucleos(t)ide antiviral agents that, in some cases, may help reverse liver disease sufficiently to avoid transplant. 3. In posttransplantation patients, virus suppression with some combination of HBIG and the nucleos(t)ide agents may prevent graft loss and death or the need for a second transplant. 4. In both the pre- and posttransplantation setting, the goal of hepatitis B virus management is complete virus suppression. 5. The use of low-dose intramuscular HBIG is evolving, with studies showing that dosing and cost can be reduced by 50-300% with a customized approach. 6. Elimination of HBIG from the treatment paradigm is currently under evaluation and may be possible with the use of newer medications that have no or low resistance rates. 7. Although there is growing evidence that some types of combination therapy may decrease the chance that drug resistance will develop and increase the likelihood of long-term success in preventing graft loss and death, additional research will be required to determine which combinations will work well in the long term, and which will not.

Protocol liver biopsies in long-term management of patients transplanted for hepatitis B-related liver disease

AIM: To evaluate the long-term histological outcome of patients transplanted for HBV-related liver disease and given HBIg prophylaxis indefinitely after LT.

METHODS: Forty-two consecutive patients transplanted for hepatitis B were prospectively studied. HBsAg, HBV-DNA and liver function tests were evaluated in the serum 3, 6 and 12 mo after LT and then yearly. LB was obtained 6 and 12 mo after LT and yearly thereafter. Chronic hepatitis (CH) B after LT was classified as minimal, mild, moderate or severe.

RESULTS: HBV recurred in 7/42 (16.6 %) patients after 6-96 mo of follow-up. A hundred and eighty-seven LB were evaluated. Four of 7 patients with graft reinfection, all with unknown HBV DNA status before LT, developed cirrhosis at 12-36 mo of follow-up. Of the 122 LB obtained from 28 HBsAg+/HCV- recipients with no HBV recurrence after LT, all biopsies were completely normal in only 2 patients (7.1 %), minimal/non-specific changes were observed in 18 (64.2 %), and at least 1 biopsy showed CH in the remaining 8 (28.5 %). Twenty-nine LB obtained from 7 patients transplanted for HBV-HCV cirrhosis and remaining HBsAg- after LT revealed recurrent CH-C. Actuarial survival was similar in patients with HBsAg+ or HBsAg- liver diseases.

CONCLUSION: Though protocol biopsies may enable the detection of graft dysfunction at an early stage, the risk of progression and the clinical significance of these findings remains to be determined.

YMDD variants of HBV DNA polymerase gene: Rapid detection and clinicopathological analysis with long-term lamivudine therapy after liver transplantation

AIM: To look for a rapid low-cost technique for the detection of HBV variants.

METHODS: Two patients who underwent orthotopic liver transplantation (OLT) for HBV infection were treated with lamivudine (100 mg daily) and HBV infection recurred in the grafted livers. The patients were monitored intensively for liver enzymes, hepatitis B surface antigen (HBsAg) and HBV DNA in serum. Liver biopsy was performed regularly. HBV DNA in a conserved polymerase domain (the YMDD locus) was amplified from serum of each patient by PCR and sequenced. HBV genotypes were analyzed by restriction fragment length polymorphism (RFLP) of the PCR products generated from a fragment of the polymerase gene.

RESULTS: YMDD wild-type HBV was detected in one patient by PCR-RFLP and DNA sequencing 19 mo after OLT, and YIDD mutant-type HBV in the other patient, 16 mo after OLT.

CONCLUSION: PCR-RFLP assay is an accurate and simple method for genotyping lamivudine-resistant HBV variants.

Differential effects of donor age in liver transplant recipients infected with hepatitis B, hepatitis C and without viral hepatitis

The variable impact of specific risk factors on survival outcomes based on pre-transplantation diagnosis was analyzed in adult liver transplant recipients reported to the Scientific Registry of Transplant Recipients: 778 with hepatitis B (HBV), 3463 with hepatitis C (HCV) and 7429 without viral hepatitis. Graft and patient survival for the HBV and no viral hepatitis groups did not differ significantly. The HCV group had significantly lower graft (p = 0.0019) and patient survival (p < 0.0001) than the no viral hepatitis group. Patient survival was significantly lower (p = 0.0011) for HCV compared to HBV patients; differences in graft survival approached significance (p = 0.0561). Donor age, which was not a risk factor in patients with HBV, was the strongest predictor of graft loss and death in patients with HCV, starting with donors >40 years. Donor age >60 years was the strongest predictor of graft loss and death in patients without viral hepatitis. The risks of graft loss and death were reduced for patients on tacrolimus-based immunosuppression with mycophenolate mofetil, regardless of disease etiology. There are clear differences in risk factors for poor outcomes based on underlying liver disease, particularly with regard to the impact of donor age.

Outcomes in liver transplant recipients with hepatitis B virus: resistance and recurrence patterns from a large transplant center over the last decade

Hepatitis B virus (HBV) recurrence following liver transplantation (LTx) has been controllable primarily with the use of hepatitis B immune globulin (HBIg) and lamivudine (LAM). However, HBV resistance to LAM and/or HBIg has become an increasing problem prompting the use of newer antiviral agents. The purpose of our study was to investigate the association between therapy, HBV breakthrough, and allograft / patient survival in HBV-positive liver transplant recipients. We performed a retrospective review of the medical records of patients that were transplanted for HBV from June 1994 to May 2003. A total of 92 patients, positive for either hepatitis B surface antigen (HBsAg) or HBV deoxyribonucleic acid (DNA) pretransplant, received LAM monotherapy or HBIg (6 months) plus LAM therapy post-liver transplant. HBV breakthrough post-LTx was noted in 14 patients. All patients had detectable HBV DNA prior to liver transplantation; none of the patients that were HBV DNA negative prior to transplant had detectable HBV DNA posttransplant. Of these 14, 9 patients (64%) were switched from LAM to adefovir dipivoxil (ADF) and 5 patients (36%) to tenofovir disoproxil fumarate (TNV). In conclusion, pre-LTx HBV viremia should be considered in planning post-LTx prophylaxis. Trials to evaluate oral antiviral agents in combination with or without HBIg therapy are needed.

Critical overview and outlook: pathogenesis, prevention, and treatment of hepatitis and hepatocarcinoma caused by hepatitis B virus

Viral hepatitis B is an enigmatic disease in which the host's own immune response to persistent viral infection may bring about host destruction through antiviral inflammatory responses which might otherwise present as a benign or inapparent disease. The simple solution to the hepatitis B problem is by immunoprophylaxis using the vaccine licensed in 1981, which prevents both infection and the late sequelae of liver cirrhosis and hepatocarcinoma. Immunotherapeutic vaccines against persistent hepatitis B infection have not been successful and new explorations are being directed to therapies which include antisense, ribozymes, gene silencing by RNA interference (RNAi) and aptamer approaches. Limited benefits from nucleoside therapy and limitations in opportunity for liver transplantation have left a large void of curative treatments. Findings with respect to e antigen tolerance provide a basis for exploration to determine whether passively administered e antigen might suppress cell-mediated immunity, creating a commensal state in which virus persists but without pathologic damage to the host. Therapy of hepatocarcinoma by conventional chemotherapy, radiation, or surgical resection and ablation gives little hope for restoration of health unless the tumor is detected very early. The large engagement of the world medical science community to develop therapeutic vaccines against cancer is now in major clinical trials to determine the hope and credibility for the immunization approach. Vaccines based on tumor peptides which are linked to heat shock proteins and directed to host dendritic cells give reason for excitement and may be the "best show in town". A new era of tumor therapy will need to be based on new discoveries in immune function which are required to pursue immunotherapy on a more rational basis. The many facets of current hepatitis B virology, pathogenesis, immunoprophylaxis, immunotherapeusis, chemotherapy, and tumor pathogenesis and therapy are discussed here, in depth, but in keeping with needed brevity.

A quantitative method to detect HBV cccDNA by chimeric primer and real-time polymerase chain reaction

Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA), is a continuous double chain ring, while other DNA forms contain a gap on each chain at the position of direct repeat 1 sequence (DR1) and direct repeat 2 sequence (DR2), respectively. At present it is still difficult to detect with high sensitivity and specificity and quantify the HBV cccDNA pool in the nucleus of the hepatocyte. A chimeric primer was designated in which segment A near 3' end is complementary to HBV plus strand just before the DR2 region gap, and segment B near 5' end is consensus to part of the human immunodefficient virus genomic sequence, without homogenetic relationship to HBV genome. Promoted by taq DNA polymerase, a single nucleotide strand is elongated from chimeric primer generated by HBV cccDNA. In contrast, other HBV DNA forms do not produce a single nucleotide strand due to the cessation of elongation reaction at the DR2 gap. The newly formed single nucleotide strand is subsequently amplified by a new polymerase chain reaction system (PCR), in which a primer, identical to chimeric primer segments B, is used to ensure specific amplification, avoiding other HBV DNA format inference. In addition, a taqman probe was used in the PCR system to report the detection signal, and for constructing a standard curve between cycle threshold (Ct) value and the template quantity. This technique proved to be effective for rapid and sensitive detection and quantitation of HBV cccDNA with high specificity and efficacy.

Expression of RNase H of human hepatitis B virus polymerase in Escherichia coli

AIM: To amplify HBV-RNase H gene fragment and expression of RNase H for further use in the studies of HBV associated liver diseases.

METHODS: The encoding gene of HBV-RNase H was separately amplified for the first half and second half (H1 and H2) by PCR from full length HBV gene and cloned into pT7Blue-T vector. Clones were first screened by digestion with Xba I and Hind III enzyme for the correct size, and analyzed further by DNA sequencing. The RNase H1 and H2 fragments isolated from XbaI and Hind III digestion products of pT7 Blue-RNase H plasmid were ligated to the GSTag expressing vectors separately, and expressed in E.coli BL21. The expressed proteins were checked by PAGE gel and Western blot.

RESULTS: Both H1 and H2 nucleotide seqences consisting of known genes and proteins, in correct size, were further confirmed by Western blot to be the GST and RNase H1 or H2 fusion proteins.

CONCLUSION: The successful cloning and expression of HBV-RNase H will contribute to further research and application in HBV-associated diseases.