HBV genotype B/C and response to lamivudine therapy: a systematic review. Biomed Res Int. 2013;2013:672614. [PMID: 24364035 PMCID: PMC3863712 DOI: 10.1155/2013/672614]

Genotype E: The neglected genotype of hepatitis B virus

Hepatitis B virus (HBV) (sub)genotypes A1, D3 and E circulate in sub-Saharan Africa, the region with one of the highest incidences of HBV-associated hepatocellular carcinoma globally. Although genotype E was identified more than 20 years ago, and is the most widespread genotype in Africa, it has not been extensively studied. The current knowledge status and gaps in its origin and evolution, natural history of infection, disease progression, response to antiviral therapy and vaccination are discussed. Genotype E is an African genotype, with unique molecular characteristics that is found mainly in Western and Central Africa and rarely outside Africa except in individuals of African descent. The low prevalence of this genotype in the African descendant populations in the New World, phylogeographic analyses, the low genetic diversity and evidence of remnants of genotype E in ancient HBV samples suggests the relatively recent re-introduction into the population. There is scarcity of information on the clinical and virological characteristics of genotype E-infected patients, disease progression and outcomes and efficacy of anti-HBV drugs. Individuals infected with genotype E have been characterised with high hepatitis B e antigen-positivity and high viral load with a lower end of treatment response to interferon-alpha. A minority of genotype E-infected participants have been included in studies in which treatment response was monitored. Of concern is that current guidelines do not consider patients infected with genotype E. Thus, there is an urgent need for further large-scale investigations into genotype E, the neglected genotype of HBV.

How viral genetic variants and genotypes influence disease and treatment outcome of chronic hepatitis B. Time for an individualised approach?

Chronic hepatitis B virus (HBV) infection remains a global problem. Several HBV genotypes exist with different biology and geographical prevalence. Whilst the future aim of HBV treatment remains viral eradication, current treatment strategies aim to suppress the virus and prevent the progression of liver disease. Current strategies also involve identification of patients for treatment, namely those at risk of progressive liver disease. Identification of HBV genotype, HBV mutants and other predictive factors allow for tailoured treatments, and risk-surveillance pathways, such as hepatocellular cancer screening. In the future, these factors may enable stratification not only of treatment decisions, but also of patients at risk of higher relapse rates when current therapies are discontinued. Newer technologies, such as next-generation sequencing, to assess drug-resistant or immune escape variants and quasi-species heterogeneity in patients, may allow for more information-based treatment decisions between the clinician and the patient. This article serves to discuss how HBV genotypes and genetic variants impact not only upon the disease course and outcomes, but also current treatment strategies. Adopting a personalised genotypic approach may play a role in future strategies to combat the disease. Herein, we discuss new technologies that may allow more informed decision-making for response guided therapy in the battle against HBV.

Efficacy of different antiviral treatments for chronic hepatitis B patients carrying different genotypes of hepatitis B virus

AIM

To compare the efficacy of different antiviral treatments for chronic hepatitis B patients carrying different genotypes of hepatitis B virus (HBV).

METHODS

One hundred and twenty hepatitis B patients with liver cirrhosis and 120 patients with chronic hepatitis B were included in the study. Hepatitis B patients with cirrhosis underwent entecavir treatment. Clinical efficacy was compared between patients carrying different genotypes of HBV. Chronic hepatitis B patients were randomly and equally divided into four groups (A, B, C, and D) to receive lamivudine, entecavir, lamivudine combined with adefovir ester, and polyethylene glycol (peg) interferon alpha 2a treatment for 96 wk, respectively. Clinical efficacy was compared between different groups.

RESULTS

After treatment, HBV DNA showed an obvious downward trend in hepatitis B associated liver cirrhosis. After 96 wk of treatment, mean HBV DNA level declined to 5.13 copies/mL, and the rate of conversion of HBV DNA to negativity and the rate of recovery of ALT to normal level were 94.17% and 94.17%, respectively. In 84 hepatitis B e antigen (HBeAg) positive liver cirrhosis patients, the rate of conversion of HBeAg to negativity and serum HBeAg conversion rate were 27.38% and 27.38%, respectively. Between liver cirrhosis patients carrying genotypes C/B, the rate of conversion of HBV DNA to negativity, the rate of recovery of ALT to normal level, the rate of conversion of HBeAg to negativity, serum HBeAg conversion rate, and hepatitis B surface antigen quantity had no statistical differences (P > 0.05). The rate of conversion of HBV DNA to negativity, the rate of recovery of ALT to normal level, the rate of conversion of HBeAg to negativity, and serum HBeAg conversion rate differed significantly among groups A-D (P < 0.05). The rate of conversion of HBV DNA to negativity, the rate of recovery of ALT to normal level, the rate of conversion of HBeAg to negativity, and serum HBeAg conversion rate were significantly higher in group C than in the other three groups, but no significant differences were observed among groups A, B and D (P > 0.05).

CONCLUSION

Entecavir treatment is effective in patients with hepatitis B associated liver cirrhosis, and the efficacy is not influenced by genotype. Of antiviral treatments tested for chronic hepatitis B, lamivudine combined with adefovir acetate has the best efficacy.

Better plans and more powerful evidence are needed in the research and treatment of chronic hepatitis B in China

China has the first largest global pool of chronic hepatitis B (CHB) infection. With the implementation of comprehensive intervention of neonatal vaccination based on national strategy, some achievements have been made in control of hepatitis B in China. However, some problems remain unresolved in the research field as well as management of CHB. Currently, empirical therapy, poor study design, inefficient management, low compliance rate of patients, lack of public awareness and economic factor hampers the research and treatment of CHB in China. We propose that China should take more effective measures to improve the study quality, social management, the relief of economic burden for the needed patients, public awareness, evidence-based policies and medicine, supervision for clinical practice, diagnostics ability and laboratory quality, the compliance of patients, and the quality of Traditional Chinese Medicine (TCM) in the management of CHB infection in the future.

Hepatitis B virus genotypes and variants

At least 10 hepatitis B virus (HBV) genotypes (A to J) with distinct geographic distributions and several HBV mutants, including precore/core promoter mutations and pre-S/S deletion mutations, have been recognized to be not only predictive of liver disease progression but also associated with response to antiviral therapy. HBV genotype-specific pathogenesis may contribute to heterogeneous clinical outcomes in chronic hepatitis B patients across the world. For example, patients with HBV genotypes C and D infection have a lower rate of spontaneous HBeAg seroconversion. In addition, HBV genotypes C and D have a higher frequency of core promoter and pre-S mutations than genotypes A and B. Genotypes C and D also carry a higher lifetime risk of cirrhosis and HCC development than genotypes A and B. Core promoter and pre-S mutations also correlate with an increased risk of hepatocellular carcinoma (HCC). Therapeutically, genotypes A and B patients have a better response to interferon-based therapy than genotypes C and D patients, but the response to nucleos(t)ide analogs is comparable across different HBV genotypes. In conclusion, HBV genotypes and variants may serve as viral genetic markers to predict disease progression as well as help practicing physicians optimize individualized antiviral therapy in clinical practice.

Variations and mutations in the hepatitis B virus genome and their associations with clinical characteristics

Hepatitis B virus (HBV) infection is major global issue, because chronic HBV infection is strongly associated with liver cancer. HBV spread worldwide with various mutations and variations. This variability, called quasispecies, is derived from no proof-reading capacity of viral reverse transcriptase. So far, thousands of studies reported that the variety of genome is closely related to the geographic distribution and clinical characteristics. Recent technological advances including capillary sequencer and next generation sequencer have made in easier to analyze mutations. The variety of HBV genome is related to not only antigenicity of HBs-antigen but also resistance to antiviral therapies. Understanding of these variations is important for the development of diagnostic tools and the appropriate therapy for chronic hepatitis B. In this review, recent publications in relation to HBV mutations and variations are updated and summarized.

Tenofovir disoproxil fumarate is superior to lamivudine plus adefovir in lamivudine-resistant chronic hepatitis B patients

AIM: To assess the efficacy of tenofovir disoproxil fumarate (TDF) in lamivudine (LAM)-resistant patients with a suboptimal response to LAM plus adefovir (ADV).

METHODS: We retrospectively analyzed the efficacy of switching to tenofovir disoproxil fumarate in suboptimal responders to lamivudine plus adefovir. Charts were reviewed for LAM-resistant chronic hepatitis B (CHB) patients who visited the Zhejiang Province People’s Hospital and The First Affiliated Hospital, College of Medicine, Zhejiang University, from June 2009 to May 2013. Patients whose serum hepatitis B virus (HBV) DNA remained detectable despite at least 6 mo of LAM plus ADV combination therapy were included. Patients with a suboptimal response to LAM plus ADV were randomized to switch to TDF monotherapy (300 mg/d orally; TDF group) or to continuation with LAM (100 mg/d orally) plus ADV (10 mg/d orally; LAM plus ADV group) and were followed for 48 wk. Serum HBV DNA was determined at baseline and weeks 4, 12, 24, 36, and 48. HBV serological markers and biochemistry were assessed at baseline and weeks 12, 24, and 48. Resistance surveillance and side effects were monitored during therapy.

RESULTS: Fifty-nine patient were randomized to switch to TDF (n = 28) or continuation with LAM plus ADV (n = 31). No significant differences were found between the groups at baseline. Prior to TDF therapy, all patients had been exposed to LAM plus ADV for a median of 11 mo (range: 6-24 mo). No difference was seen in baseline serum HBV DNA between the two groups [5.13 ± 1.08 log₁₀ copies/mL (TDF) vs 5.04 ± 31.16 log₁₀ copies/mL (LAM + ADV), P = 0.639]. There was no significant difference in the rates of achieving complete virological response (CVR) at week 4 between the TDF and LAM + ADV groups (17.86% vs 6.45%, P = 0.24). The rate of achieving CVR in the TDF and LAM plus ADV groups was 75% vs 16.13% at week 12, 82.14% vs 22.58% at week 24, 89.29% vs 25.81% at week 36, and 96.43% vs 29.03% at week 48, respectively (P < 0.001). The rate of alanine aminotransferase normalization was significantly higher in the TDF than in the LAM plus ADV group at week 12 (75% vs 17.86%, P < 0.001), but not at week 24 (78.57% vs 54.84%, P = 0.097) or 48 (89.26% vs 67.74%, P = 0.062). Patients were hepatitis B e antigen (HBeAg) positive at baseline. There was no significant difference in HBeAg negativity between the TDF and LAM plus ADV groups at week 48 (4% vs 0%, P = 0.481). There were no drug-related adverse effects at week 48 in either group.

CONCLUSION: Switching to TDF monotherapy was superior to continuous add-on therapy in patients with LAM-resistant CHB with a suboptimal response to LAM plus ADV.