A preliminary benefit-risk assessment of lamivudine for the treatment of chronic hepatitis B virus infection

The strategy and efficacy of prophylaxis against hepatitis B virus recurrence after liver transplantation for HBV-related diseases in the era of potent nucleos(t)ide analogues: A meta-analysis

OBJECTIVES

This meta-analysis aimed to evaluate the clinical outcome of liver transplant (LT) recipients under potent nucleoside or nucleotide analogue (NA)-based regimens and investigate different prophylactic schemes.

METHODS

We followed PRISMA statement to conduct this study. Two reviewers independently searched relevant literature via PubMed, Embase, Ovid MEDLINE, Web of Science and Insightmeme. Studies were included if they evaluated hepatitis B virus (HBV) recurrence under potent NA-based regimens in patients who received HBV-related LT. Primary and secondary outcomes were HBV recurrence, hepatocellular carcinoma (HCC) recurrence, all-cause and HBV recurrence-related mortality. Incidences with 95% confidence intervals were calculated and assessed by fixed and random effects models. Subgroup analyses were used to examine the impact of different treatment strategies.

RESULTS

Altogether 25 studies (N = 2327) were included, with a pooled HBV recurrence rate of 1.01% (95% CI 0.53%-1.59%). HBV viremia or hepatitis D virus superinfection did not influence HBV recurrence significantly (P = 0.23 and 0.71, respectively). The recurrence rate under an indefinite combination of potent NA and hepatitis B immunoglobulin (HBIG) was lower than that under potent NA monotherapy (P = 0.000) and similar to that under NA plus a finite course of HBIG (P = 0.48). The pooled HCC recurrence rate was 5.34% (95% CI 0.78%-12.48%). HBV recurrence-related mortality and all-cause mortality were 0% and 6.95% (95% CI 4.30%-10.08%), respectively.

CONCLUSIONS

Potent NA-based regimens provide satisfactory HBV antiviral prophylaxis and improve long-term outcomes for LT recipients. A finite combination of potent NA and HBIG is an alternative to life-long dual therapy.

Antiviral therapy for chronic hepatitis B: Combination of nucleoside analogs and interferon

The ideal goal of chronic hepatitis B (CHB) treatment should be suppression of emergence of hepatocellular carcinoma through the disappearance of hepatitis B s antigen (HBsAg) rather than the control of serum hepatitis B virus-DNA level. For this purpose, various types of combination therapies using nucleoside analogs (NAs) and interferon (IFN) have been conducted. The therapeutic effects of combination of two different kinds of agents are better than those of the monotherapy using NAs or IFN alone, probably because different pharmaceutical properties might act in a coordinated manner. Recently, combination therapies with NAs and IFN and sequential therapies with NAs administration followed by IFN therapy have been routinely employed. We previously reported that combination therapy using entecavir (ETV) and pegylated (PEG)-IFN showed antiviral effects in 71% of CHB patients; the effect of this combination was better than that using lamivudine (LAM) and PEG-IFN. This is partially explained by the better antiviral effects of ETV than those of LAM. In our analysis, the cohort of CHB consisted of the patients who showed a flare-up of hepatitis before antiviral therapy, and their baseline HBsAg levels were relatively low. Therefore, in addition to the combination of the agents, the appropriate selection of patients is critical to achieve a good viral response.

Evaluation of hepatocyteprotective and anti-hepatitis B virus properties of Cichoric acid from Cichorium intybus leaves in cell culture

Hepatitis B is the most common serious liver infection in the world. To date, there is still no complete cure for chronic hepatitis B. Natural caffeic acid analogues possess prominent antiviral activity, especially anti-hepatitis B virus (HBV) and anti-human immunodeficiency virus effects. Cichoric acid is a caffeic acid derivative from Cichorium intybus. In the study, the anti-hepatitis B property of cichoric acid was evaluated by the D-galactosamine (D-GalN)-induced normal human HL-7702 hepatocyte injury model, the duck hepatitis B virus (DHBV)-infected duck fetal hepatocytes and the HBV-transfected cell line HepG2.2.15 cells, respectively. The results showed that cichoric acid attenuated significantly D-GalN-induced HL-7702 hepatocyte injury at 10-100 µg/mL and produced a maximum protection rate of 56.26%. Moreover, cichoric acid at 1-100 µg/mL inhibited markedly DHBV DNA replication in infected duck fetal hepatocytes. Also, cichoric acid at 10-100 µg/mL reduced significantly the hepatitis B surface and envelope antigen levels in HepG2.2.15 cells and produced the maximum inhibition rates of 79.94% and 76.41%, respectively. Meanwhile, test compound at 50-100 µg/mL inhibited markedly HBV DNA replication. In conclusion, this study verifies the anti-hepatitis B effect of cichoric acid from Cichorium intybus leaves. In addition, cichoric acid could be used to design the antiviral agents.

The efficacy and safety of antiviral therapy with lamivudine to stop the vertical transmission of hepatitis B virus

The purpose of this study was to investigate the efficacy and safety of lamivudine (LAM) in stopping the vertical transmission of hepatitis B virus (HBV). Pregnant women with normal alanine transaminase (ALT) (n = 100) and with abnormal ALT (n = 100) who were positive for hepatitis B e antigen (HBeAg), and with HBV DNA (deoxyribonucleic acid) levels ≥1.0 × 107 copies/ml were enrolled in this study. One hundred volunteers (50 with normal ALT, 50 with abnormal ALT) received 100 mg of LAM daily from the 24th to 32nd week of gestation and the untreated 100 volunteers served as controls. All infants received passive-active immunoprophylaxis. Compared to the control group, the study group got a marked reduction in serum levels (P < 0.001) and high negativity (P < 0.001) of HBV DNA before delivery. They also got normalization in ALT levels as much as controls received general medication (P > 0.05). The prenatal transmission rate in the study group was significantly lower than that of the control group (P < 0.05). There were no differences in incidences of congenital malformation between the two groups (P > 0.05). LAM treatment can effectively and safely stop vertical transmission of HBV and normalize the ALT levels of pregnant women.

Emerging drugs for hepatitis B

Chronic hepatitis B remains a treatment challenge despite the availability of new nucleoside analogs. This is due to the persistence of viral infection during therapy, which exposes the patient to the risk of developing antiviral drug resistance. Therefore, new polymerase inhibitors are needed to manage resistance to existing drugs and new trials of combination therapy are required to delay drug resistance. In the future, antiviral agents targeting other steps of the viral life cycle will be needed to achieve antiviral synergy and prevent antiviral drug resistance. Immune modulators are also expected to enhance antiviral response and to achieve sustained response. Discovery of new antiviral drugs and design of new treatment strategies are, therefore, needed to manage this disease, which is still the main cause of cirrhosis and hepatocellular carcinoma worldwide.

In vitro antiviral activities of Chinese medicinal herbs against duck hepatitis B virus

Fifty-six different Chinese medicinal herbs from 29 families were evaluated for their antiviral activities against duck hepatitis B virus (DHBV) in vitro. The DHBV DNA level in primary duck hepatocyte cultures was monitored by dot blot hybridization and the cytotoxicity was evaluated by MTT assay. Anti-DHBV activities were found more strongly in the aqueous extracts of Ardisia chinensis and Pithecellobium clypearia with selective indices of 2.6 and >2.7, respectively, which were comparable to that of 2',3'-dideoxycytidine. Further research on the isolation of the active antiviral phytochemicals from these herbs may provide alternative options for the treatment of chronic hepatitis B.

Evaluation of alpha-glutathione-S-transferase as a biomarker of lamivudine therapy for chronic hepatitis B

Hepatic damage associated with chronic hepatitis B (CHB) relies on measurement of serum transaminases and asssessment of hepatic histology. We determined if serum hepatic function tests, including alpha-glutathione-S-transferase ((GST), were of value in monitoring or predicting the effect of lamivudine therapy for CHB. Thirty-nine patients received orally 100 mg of lamivudine daily for 48 weeks. Blood samples were obtained at baseline and at 24 and 48 weeks. At the end of the treatment period the patients were then divided into four groups according to the pattern of HBs and HBe antigens. At baseline and at 24 weeks ALT, AST, and (GST had lower values in the complete response compared to the complete failure groups. Using ROC analysis, only ALT at 24 weeks (area under the curve = 0.803) had significant diagnostic ability in detecting responders. These results reaffirm the value of measuring serum ALT as an indicator of treatment response and provide information on the potential use of (GST as an additional prognostic biomarker in this patient group.

Entecavir: a new treatment for chronic hepatitis B infection

Hepatitis B virus can cause both acute and chronic liver disease in humans. Entecavir, a new, potent, orally administered guanosine analog for the treatment of chronic hepatitis B, has recently approved in the USA and Europe. Monotherapy with entecavir in nucleoside-naive patients has been associated with statistically superior histological improvement, greater reduction in hepatitis B virus-DNA levels, and improved normalization of alanine aminotransferase levels when compared with lamivudine. After 2 years of treatment, viral resistance to entecavir has not developed in the antiviral-naive patient population. Similar findings in terms of efficacy have also been observed in patients with lamivudine-resistant hepatitis B virus. The use of entecavir in the lamivudine-resistant patient population could lead to the development of entecavir-resistant mutants at the rate of 9% by 2 years. Entecavir is well tolerated with a good safety profile and should be considered as primary therapy for chronic hepatitis B. Entecavir may also be considered for use in the lamivudine-resistant patient at twice the dose recommended for nucleoside-naive patients, with the recognition that virologic breakthrough could develop.

Antiviral therapy of chronic hepatitis B

Treatment of chronic hepatitis B remains a clinical challenge. Long-term viral suppression is a major goal of antiviral therapy to improve the clinical outcome of the patients. Antiviral treatment of chronic hepatitis B relies currently on immune modulators such as interferon alpha and its pegylated form, and viral polymerase inhibitors. Because of the slow kinetics of viral clearance and the spontaneous viral genome variability, viral mutants resistant to nucleoside analogs may be selected. However, the development of new antiviral agents is rapidly improving the offing of therapy of chronic hepatitis B. These new therapeutic advances are reviewed in this manuscript.

Prevention and treatment of recurrent Hepatitis B after liver transplantation: the current role of nucleoside and nucleotide analogues

The Hepatitis B virus (HBV) is a DNA virus that can cause both acute and chronic liver disease in humans. Approximately 350–400 million people are affected worldwide and up to one million deaths occur annually from cirrhosis and hepatocellular carcinoma. When cirrhosis and liver failure develop, the definitive treatment of choice remains orthotopic liver transplantation (OLT). In the past, an unacceptable HBV recurrence rate with a high rate of graft loss was noted. The use of Hepatitis B immunoglobulin (HBIG) has resulted in improved patient and graft survival rates. The addition of the nucleoside analog Lamivudine (LAM) to HBIG has improved these survival curves to an even greater degree. Prolonged use of LAM will almost invariably lead to the development of viral mutations resistant to the drug. There are now several other nucleoside and nucleotide analogs (Adefovir, Entecavir, Tenofovir, and Truvada) available for the clinician to utilize against these resistant strains. It should be possible to prevent recurrence in most, if not all, post-transplant patients and also to significantly reduce viral loads with normalization of transaminases in those who have developed recurrent infection. The antiviral regimen should be robust and minimize the risk of breakthrough mutations. A prudent approach may be the implication of combination antiviral therapy. This review summarizes the efficacy of previous regimens utilized to prevent and treat recurrent HBV following OLT. Particular attention will be paid to the newer nucleoside and nucleotide analogs and the direction for future strategies to treat HBV in the post transplant setting.

Changes in serological biomarkers of liver function and connective tissue turnover in chronic hepatitis B during lamivudine therapy

Assessment of hepatic damage associated with chronic hepatitis B (CHB) currently relies on measurement of serum transaminases and assessment of hepatic histology. It was determined serum hepatic function tests and the liver fibrosis biomarkers type IV collagen (CIV), amino-terminal propeptide of type I procollagen (PINP), amino-terminal propeptide of type III procollagen (PIIINP) and carboxy-terminal telopeptide of type I collagen (ICTP) were of value in monitoring the effect of lamivudine therapy for CHB. Thirty-nine patients received orally 100 mg lamivudine daily for 48 weeks. Blood samples were obtained at baseline, 24 and 48 weeks. At the end of the treatment period, the patients were then divided into four groups according to the pattern of HBs and HBe antigens. At baseline, alanine aminotransferase, aspartate aminotransferase, PIIINP and the PINP/ICTP ratio and at 24 weeks alanine aminotransferase, aspartate aminotransferase and the PINP/ICTP ratio had lower values in the complete response compared with complete failure groups. Using receiver-operated curve analysis, only the PINP/ICTP ratio at baseline (area under the curve 0.806) and ALT and the PINP/ICTP ratio at 24 weeks (areas under the curve 0.803 and 0.776, respectively) had significant diagnostic ability in detecting responders. In conclusion, the PINP/ITCP ratio is sensitive and specific in detecting responders to treatment.

A new strategy for studying in vitro the drug susceptibility of clinical isolates of human hepatitis B virus

Resistance of hepatitis B virus (HBV) to antivirals has become a major clinical problem. Our objective was to develop a new method for the cloning of naturally occurring HBV genomes and a phenotypic assay capable of assessing HBV drug susceptibility and DNA synthesis capacity in vitro. Viral DNA was extracted from sera and was amplified by polymerase chain reaction, and amplicons were cloned into vectors that enable, after cell transfection, the initiation of the intracellular HBV replication cycle. Single or multiple clones were used to transfect Huh7 cells. The viral DNA synthesis capacity and drug susceptibility were determined by measuring the level of intracellular DNA intermediate, synthesized in absence or presence of antiviral, using Southern blot analysis. We have developed, calibrated, then used this phenotypic assay to determine the drug susceptibility of HBV quasispecies isolated throughout the course of therapy from patients selected according to their mutation profile. A multiclonal and longitudinal analysis enabled us to measure the variation of drug susceptibility of different viral quasispecies by comparison of IC(50)/IC(90)s with standards. The presence of famciclovir- or lamivudine-induced mutations in the viral population caused a change in viral DNA synthesis capacity and drug susceptibility in vitro, demonstrating the clinical relevance of the assay. In conclusion, our phenotypic assay enables the in vitro characterization of DNA synthesis capacity and drug susceptibility of HBV quasispecies isolated from patients. This assay should allow a better monitoring of patients undergoing antiviral therapy, as well as the screening of novel drugs on emerging resistant strains.

Selection of a hepatitis B virus strain resistant to adefovir in a liver transplantation patient

BACKGROUND/AIMS

In contrast to lamivudine, adefovir dipivoxil (ADV) therapy is associated with delayed and infrequent selection of drug resistant hepatitis B virus (HBV).

METHODS

A 52 year-old man was treated with lamivudine for an HBV recurrence on his liver graft. A viral breakthrough was observed and the patient received ADV. Serum HBV DNA decreased rapidly and lamivudine was discontinued while ADV monotherapy was maintained. Serum HBV DNA levels remained suppressed until a second breakthrough was observed. Lamivudine was then reintroduced together with ADV, and serum HBV DNA became undetectable by polymerase chain reaction.

RESULTS

Sequence analyses of the HBV polymerase gene revealed a sequential selection of lamivudine resistance mutations L180M+M204V, followed by a reversion to wild-type, and subsequently the selection of a novel adefovir resistance mutation N236T. Phenotypic analyses in cell culture assays demonstrated that the HBV isolates at the time of ADV breakthrough had reduced susceptibility to ADV. This mutant remained sensitive to lamivudine, entecavir and emtricitabine in vitro.

CONCLUSIONS

We describe the first case of sequential selection of lamivudine and adefovir resistant strains of HBV in a liver transplantation patient. The selection of the N236T polymerase mutant was associated with resistance to ADV but remained sensitive to lamivudine in vitro and in vivo.

Rapid and high throughput detection of HBV YMDD mutants with fluorescence polarization

AIM: To develop a simple and rapid detection of HBV gene variants and prediction of lamivudine-resistance in patients.

METHODS: Initially, plasmids harboring the wild-type or mutant HBV DNA fragments were used in a model system. The technique was then applied to clinical samples for an analysis of YMDD mutations. The sera were extracted from chronic hepatitis patients who had received lamivudine treatment for more than one year. P region gene of HBV was amplified by polymerase chain reaction. The excess primers and dNTPs in PCR products were removed by cleaning-up reagents. Template-directed dye-terminator incorporation reaction was performed and R110 or TAMRA labeled acyclo-terminator was added on the 3’ end of TDI-primer specifically. Fluorescence polarization value was measured with Victor 2 multilabel counter and the genotypes of HBV were analyzed.

RESULTS: The YMDD genotypes in recombined positive plasmid and 56 serum samples of HBV infected patients were analyzed by using our TDI-FP method and the specificity and sensitivity were confirmed by DNA sequencing. Five of 56 serum samples showed YVDD phenotype (9%), including 1 YMDD and YVDD mixed infection. Four of 56 showed YIDD phenotype (7.1%).

CONCLUSION: This is a simple, rapid, low cost and high throughput assay to detect HBV polymerase gene variants and suitable for large-scale screening and prediction of the lamivudine-resistance in clinical samples.

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