Predictors of HBeAg loss after lamivudine treatment for chronic hepatitis B

Antiviral therapy: nucleotide and nucleoside analogs

For the management of HBV infection, an increasing number of nucleotide and nucleoside analogs are active against wild-type HBV and some against HBV with YMDD and other compensatory mutations. Table 2 depicts the IC50 and susceptibilities of HBV to various antiviral agents. The dichotomy between in vitro and in vivo susceptibilities to YMDD mutants is due to a change in IC50 between wild-type and mutant virus. Thus a drug may have less activity in vitro but at doses used in vivo show activity against YMDD and other compensatory mutations. Some HBV drugs share activity against HIV, which may be useful in the co-infected patient. Other nucleoside analogs are in various stages of development, including MCC-478 and DAPD. In the future, clinicians will have a plethora of reagents to chose from, and combination therapies may be invoked.

Predictors of virologic response to Lamivudine treatment in children with chronic hepatitis B infection

BACKGROUND

Some children with chronic hepatitis B develop advanced liver disease. Lamivudine, an oral nucleoside, is a therapeutic option. A recent large, multicenter study demonstrated that lamivudine was superior to placebo in eliciting loss of hepatitis B e antigen (HBeAg) and hepatitis B virus (HBV) DNA from serum in children (2 to 17 years) treated for 52 weeks.

OBJECTIVE

To identify pretreatment factors that predict the likelihood of response to lamivudine in children with chronic hepatitis B infection.

STUDY DESIGN

Data from the multicenter trial in 297 children (191 lamivudine, 96 placebo) were analyzed for the effects of baseline factors on the likelihood of responses. These responses included virologic response, defined as loss of HBeAg and HBV DNA, and HBeAg seroconversion, defined as loss of HBeAg and development of antibody to HBeAg. Univariate and multivariate analyses examined the effects of lamivudine treatment, age, gender, race, body weight, body mass index, previous interferon treatment and baseline alanine aminotransferase (ALT), histologic activity index (HAI) score and HBV DNA on the virologic responses.

RESULTS

In the univariate analysis higher baseline ALT, higher HAI score and lower HBV DNA level predicted a greater likelihood of virologic responses to lamivudine. In the multivariate model only baseline ALT and HAI score were predictive of responses. There was no effect of age or ethnicity on response.

CONCLUSIONS

Children with higher pretreatment ALT and HAI scores are most likely to respond to lamivudine. Age, ethnicity and other factors do not significantly influence the frequency of virologic responses in children with chronic hepatitis B infection.

Interferon–Lamivudine Combination is No Better than Lamivudine Alone in Anti-Hbe-Positive Chronic Hepatitis B

Background and aims

Results of studies using lamivudine and interferon combination in the treatment of chronic hepatitis B are not consistent or conclusive. This study aimed to evaluate the efficacy of interferon plus lamivudine use versus single lamivudine in anti-HBe-positive chronic hepatitis B.

Methods

Eighty patients were treated with either lamivudine or lamivudine plus simultaneously started interferon. Patients were assigned in groups according to random allocation rule. Lamivudine was given 150 mg/day for 96 weeks in each group; interferon was administered 10 MU three times a week for 24 weeks in the combination therapy group.

Results

Alanine aminotransferase (ALT) normalization was achieved earlier in patients treated with lamivudine alone. At the end of treatment, there was no difference between the groups with respect to HBV DNA negativity, ALT normalization and breakthrough rate. Histological improvement was remarkable in each group, but fibrosis score and necro-inflammatory activity were much lower in lamivudine-treated patients.

Conclusions

Addition of interferon to the lamivudine regimen does not increase the effectiveness of the treatment. Considering the side effects of interferon treatment, this combination seems not to be convenient for anti-HBe-positive chronic hepatitis B.

A treatment algorithm for the management of chronic hepatitis B virus infection in the United States

BACKGROUND AND AIMS

Chronic hepatitis B is an important public health problem worldwide and in the United States. A treatment algorithm for chronic hepatitis B virus (HBV) infection was developed by a panel of US hepatologists based on new developments in the understanding of the virology of HBV, availability of more sensitive molecular diagnostic testing, and advantages and disadvantages of currently approved therapies.

METHODS

This algorithm is based on available evidence, but where data are lacking, the panel relied on clinical experience and consensus expert opinion.

RESULTS

Serum HBV DNA can be detected at levels as low as 100-1000 copies/mL by using molecular assays and should be determined to establish a baseline level before treatment, monitor response to antiviral therapy, and survey for the development of drug resistance. The primary aim of antiviral therapy is durable suppression of serum HBV DNA to the lowest level possible. The threshold level of HBV DNA for determination of candidacy for therapy is >/=10(5) copies/mL for patients with hepatitis B e antigen (HBeAg)-positive chronic hepatitis B. A lower serum HBV DNA threshold is appropriate for patients with HBeAg-negative chronic hepatitis B and those with decompensated cirrhosis, and the panel recommends thresholds of 10(4) copies/mL and 10(3) copies/mL, respectively.

CONCLUSIONS

Interferon alfa-2b, lamivudine, and adefovir dipivoxil are all approved as initial therapy for chronic hepatitis B and have certain advantages and disadvantages. Issues for consideration include efficacy, safety, incidence of resistance, method of administration, and cost. Studies are under way to explore the safety and efficacy of combination therapy, which may prove to be more effective than monotherapy in suppressing viral replication and may decrease or delay the incidence of drug resistance.

Identification of HBV DNA sequences that are predictive of response to lamivudine therapy

Numerous studies have shown that resistance to long-term lamivudine therapy occurs in as many as (2/3) of hepatitis B virus (HBV) chronic carriers. Additional studies have shown that reversion of HBV mutations in the precore/core promoter region conferring an HBeAg-negative phenotype/genotype can occur in up to 30% of lamivudine-treated patients. In this study, sequences of the HBV polymerase and precore/core coding regions in 26 HBV-infected patients (24 with HBeAg-negative virus infection, 25 genotype D, 1 genotype A) treated for 27 to 53 months with lamivudine were analyzed to determine the relationship between pretreatment HBV DNA sequence patterns and long-term treatment response, and the effect of therapy on the status of HBV precore mutations. Reversions of precore mutations A1762T/G1764A and G1896A were observed in 29% and 25% of patients, respectively, but none became HBeAg-positive. These data are consistent with previously published reversion frequencies for 2 other groups of lamivudine-treated patients. Two naturally-occurring DNA polymorphisms at aa91 and aa256 of the HBV polymerase were observed in the pretreatment serum samples, which correlated with extended treatment failure. In conclusion, reversion of mutations conferring an HBeAg-negative phenotype occur relatively frequently under lamivudine therapy. Furthermore, at least in HBeAg-negative patients infected predominantly with HBV genotype D, specific viral DNA sequences which are present before therapy appear to be useful as predictors of long-term response to lamivudine treatment.

Core promoter/pre-core mutations are associated with lamivudine-induced HBeAg loss in chronic hepatitis B with genotype C

BACKGROUND/AIMS

To clarify the factors associated with the efficacy of lamivudine.

METHODS

Variables including basic core promoter (BCP) and pre-core (PreC) mutations were evaluated in 60 chronic hepatitis B e antigen (HBeAg)-positive patients with genotype C. Thirty patients were treated with lamivudine and the remaining 30 patients were age- and sex-matched controls.

RESULTS

Severe fibrosis was significantly more frequent in patients with the BCP-mutant/PreC-wild (MW) and BCP-mutant/PreC-mutant (MM) patterns compared to BCP-wild/PreC-wild (WW) pattern (P=0.02). The cumulative rates of HBeAg loss at 6, 12 and 18 months were significantly higher in the lamivudine group (14.2, 36.3, and 60.9%) compared with the control group (17.6, 17.6, and 24.5%, P=0.03), and was especially pronounced in patients with the MW pattern (P=0.04). The rate of lamivudine-related HBeAg loss was significantly lower in patients with the WW pattern (P=0.03). Factors correlating with HBeAg loss were histological fibrosis and activity, hepatitis B virus-DNA levels, BCP/PreC mutation and lamivudine therapy. Multivariate analysis revealed BCP/PreC mutations and fibrosis were independent factors for HBeAg loss.

CONCLUSIONS

With specific reference to the genotype C, we found earlier HBeAg loss was expected in patients carrying MM and MW patterns, while the efficacy of lamivudine was limited in patients with the WW pattern.

Determinants for sustained HBeAg response to lamivudine therapy

There are inconsistent data on the durability of hepatitis B e antigen (HBeAg) seroconversion after lamivudine is discontinued. The aim of this study was to examine the determinants for sustained HBeAg response to lamivudine therapy. Both host and viral factors as well as the drug factor were compared between 43 patients with sustained HBeAg response and 39 patients whose response was not sustained. All of them received a mean period of 16 months (range, 3-55 months) lamivudine therapy and had achieved complete response (HBeAg seroconversion plus HBV DNA seroclearance by hybrid capture assay and normal alanine aminotransferase [ALT]) and were followed-up for a mean period of 44 months (range, 12-88 months). Stepwise logistic regression model was used to estimate the sustained response on the presence of the following variables: age; gender; pretherapy ALT; total bilirubin and HBV DNA levels; time to HBeAg seroconversion; additional lamivudine treatment after HBeAg seroconversion; total duration of treatment; hepatitis activity index scores; periportal, intralobular, and portal inflammation and fibrosis scores; scores excluding fibrosis; status of precore mutation; basal core promoter mutation; and genotype. The results showed that genotype (OR, 5.922; 95% CI, 1.611-21.768; P =.007), age (OR, 0.943; 95% CI, 0.891-0.997; P =.040), and additional treatment (OR, 1.097; 95% CI, 1.028-1.171; P =.005) were independent factors to sustained HBeAg response. Further categorical analysis disclosed that patients with genotype B, age < or =36 years, and additional lamivudine treatment over 8 months have higher sustained response. In conclusion, HBV genotype, age, and additional treatment are the major determinants for the sustained HBeAg response to lamivudine therapy.

Efficacy of lamivudine therapy and factors associated with emergence of resistance in chronic hepatitis B virus infection in Japan

OBJECTIVE

Several reports have examined the efficacy of long-term lamivudine therapy and the risk factors involved in emergence of viral resistance in Japanese patients with hepatitis B virus (HBV) infection. However, the patient cohorts in such studies are relatively small.

METHODS

We analyzed 234 chronically HBV-infected Japanese patients who were treated with lamivudine for more than 12 months. They comprised patients with HBV genotype A (n = 8), genotype B (n = 21), genotype C (n = 203) and other HBV genotypes (n = 2).

RESULTS

In most patients, lamivudine resulted in normalization of alanine transaminase (ALT) levels at 6 and 12 months, and suppression of serum HBV DNA to undetectable levels by the branched chain DNA probe assay (bDNA). Rates of ALT normalization and non-detection of HBV DNA were higher among patients with genotype B than genotype C disease. The proportions of patients who achieved HBeAg loss were 27, 42 and 45% after 6 months, 1 year and 2 years, respectively. The emergence of mutations was not different among genotypes A, B and C by the Kaplan-Meier method. Multivariate analyses identified high HBV DNA level (bDNA >or=100 MEq/ml) as an independent factor associated with emergence of the YMDD motif mutation in all patients. Among patients with genotype C disease, which is the predominant HBV genotype in Japan, multivariate analysis also identified high HBV DNA level and HBeAg positivity as factors associated with emergence of resistance.

CONCLUSION

Patients exhibiting these factors at the commencement of lamivudine treatment must be monitored carefully at regular intervals for emergence of viral resistance.

HBe antigen loss during lamivudine therapy is not caused by mutations in precore and core promoter genes in patients with chronic hepatitis B

HBe antigen (HBeAg) loss or seroconversion can occur during lamivudine therapy. The purpose of this study was to analyze nucleotide sequences in precore and core promoter regions, and examine the influence of mutations in these regions on the disappearance of HBeAg during lamivudine therapy. Serial serum samples were obtained from 51 patients (HBeAg loss in 26 patients) at commencement of therapy (baseline) and after 1 year of lamivudine therapy. Serum samples were amplified with PCR and nucleotide sequences of HBV were analyzed. At baseline, a precore stop codon mutation (A1896) was identified in 8 of 26 HBeAg loss patients and in 8 of 25 HBeAg non-loss patients. At 1 year, precore mutation was observed in 4 of 14 patients analyzed who showed HBeAg loss. At 1 year, however, a precore mutation was observed also in 3 of 9 analyzed patients who showed no HBeAg loss. Core promoter mutations were noted in 21 of 26 HBeAg loss patients and in 20 of 25 HBeAg non-loss patients. At 1 year, core promoter mutations were noted in 11 of 14 HBeAg loss patients and in 8 of 9 HBeAg non-loss patients. Our data suggested that during lamivudine therapy, core promoter and precore mutations do not influence HBeAg loss or seroconversion but may reduce the viral level upon HBeAg loss or seroconversion.

Hepatitis flares and hepatitis B e antigen seroconversion: implication in anti-hepatitis B virus therapy

Hepatitis flares or acute exacerbations, defined as an abrupt elevation of serum alanine aminotransferase (ALT) over fivefold the upper limit of normal (ULN), of chronic hepatitis B virus (HBV) infection are the results of HLA-I restricted, cytotoxic T lymphocyte (CTL)-mediated immune response against HBV and its downstream mechanisms. Higher ALT levels reflect a more vigorous immune response and a more extensive hepatolysis that, in the extreme situation, may lead to decompensation and failure. In contrast, higher ALT also reflects a more robust immune clearance of HBV and, therefore, a higher chance of HBV-DNA loss and hepatitis B e antigen (HBeAg) seroconversion, both in the setting of natural course and drug therapy. Alanine aminotransferase of fivefold the ULN appears to be a significant cut-off level to categorize the patients in terms of endogenous immune response against HBV. Patients with ALT levels less than fivefold the ULN or those with a less vigorous immune response require immunomodulation to induce robust immune response to enhance HBV clearance. In contrast, those with a more vigorous immune response or those with ALT flare over fivefold the ULN should be monitored closely for spontaneous HBV clearance/HBeAg seroconversion or to start direct antiviral therapy in time to prevent the occurrence or deterioration of hepatic decompensation. In conclusion, a better understanding of the pathogenetic mechanisms and natural course of hepatitis flares, wiser selection of patients and the timing of drug therapy are crucial to achieve better treatment results.

HBV genotype B is associated with better response to interferon therapy in HBeAg(+) chronic hepatitis than genotype C

Hepatitis B virus (HBV) genotype and precore/core promoter mutations have been implicated in spontaneous and interferon alfa (IFN-alpha)-related hepatitis B e antigen (HBeAg) seroconversion. We performed a retrospective analysis of a previously reported randomized controlled trial to determine the effects of HBV genotype and precore/core promoter mutations on IFN-alpha response in patients with HBeAg-positive chronic hepatitis. Clinical data and stored sera from 109 (95%) patients in the original trial were analyzed. Seventy-three patients received IFN-alpha and 34 received no treatment (controls). Almost all patients had HBV genotypes B (38%) and C (60%). Antiviral response was achieved in 39% and 17% of IFN-alpha-treated patients (P =.03) and in 10% and 8% of untreated controls (P =.88) with HBV genotype B and C, respectively. Multivariate analysis identified HBV genotype B, elevated pretreatment alanine aminotransferase (ALT) levels, and low pretreatment HBV-DNA levels but not IFN-alpha treatment as independent factors associated with antiviral response. Among the 66 patients with elevated pretreatment ALT level, antiviral response was achieved in 57% and 21% of IFN-alpha-treated patients (P =.019), and in 25% and 8% of untreated controls (P =.45) with HBV genotype B and C, respectively. Multivariate analysis showed that genotype B and low pretreatment HBV-DNA levels were independent predictors of antiviral response. In conclusion, our data showed that HBV genotype B was associated with a higher rate of IFN-induced HBeAg clearance compared with genotype C. Stratification for HBV genotypes should be considered in future clinical trials of antiviral therapy of chronic hepatitis B.

Therapy of chronic hepatitis B: current challenges and opportunities

Better understanding of hepatitis B virus (HBV) replication, natural history and the immunopathogenesis of chronic hepatitis B, together with the introduction of effective agents with different mechanisms of action are the basis for better therapeutic strategies against chronic hepatitis B. Among currently available drugs, interferon-alpha and thymosin-alpha1 have only modest efficacy (approximately 40% vs 9-20% in controls). In the past decade, lamivudine has dominated in the treatment of chronic HBV infection because it is easy to use, safe, and is effective in terms of hepatitis B e antigen and/or HBV-DNA loss, ALT normalization, and improvement in histology. The response rate increases with increasing pretherapy alanine aminotransferase (ALT) levels, suggesting that patients with stronger endogenous immune response against HBV have a better response to direct antiviral agents. Lamivudine is also beneficial in decompensated cirrhotics with HBV replication. Hepatitic flares may occur after stopping lamivudine therapy in nonresponders and also in responders. Therefore, prolonged therapy is usually required. However, tyrosine-methionine-aspartate-aspartate (YMDD) mutations conferring resistance to lamivudine start to emerge after 6-9 months of therapy, and hepatitis flare, even decompensation, may develop after viral breakthrough. Thus the benefits of long-term lamivudine therapy must be balanced against the concern about YMDD mutations and the durability of treatment response. Adefovir dipivoxil, entecavir, emtricitabine, clevudine and other nucleoside/ nucleotide analogues have shown encouraging results and some agents appear effective in patients with YMDD mutants. Further development of new drugs and new strategies may help to improve treatment in the new century.