Adefovir dipivoxil alone or in combination with lamivudine in patients with lamivudine-resistant chronic hepatitis B

Combination adefovir-lamivudine prevents emergence of adefovir resistance in lamivudine-resistant hepatitis B

BACKGROUND AND AIM

The outcomes of lamivudine-resistant chronic hepatitis B patients treated with long-term adefovir dipivoxil have not been well described. This study aims to characterize the virological and biochemical response and to determine factors that may influence the development of resistance to adefovir.

METHODS

A retrospective review was conducted on all patients with lamivudine-resistant chronic hepatitis B treated with adefovir for a minimum of 6 months at two tertiary referral centers.

RESULTS

Data on 161 patients were analyzed. Seventy-two percent achieved an initial virological response with eventual normalization of alanine aminotransferase in only 67% of patients. Seventeen patients developed adefovir resistance with cumulative resistance rates of 3.2%, 8.8%, and 18% at 12, 24, and 36 months, respectively. Twelve (71%) of these patients had a biochemical breakthrough, with one death from fulminant hepatic failure. The median duration of lamivudine crossover was 1 month in adefovir-resistant patients, compared with 12 months for the remainder of the cohort (P < 0.01). Longer crossover therapy reduced the adefovir resistance rate, but did not eliminate it. No adefovir resistance is reported in those who were continued on long-term combination lamivudine-adefovir without a period of adefovir monotherapy.

CONCLUSIONS

Combination lamivudine-adefovir therapy protected against the emergence of adefovir resistance.

Viral genotype and baseline load predict the response to adefovir treatment in lamivudine-resistant chronic hepatitis B patients

BACKGROUND/AIMS

To determine the factors associated with virological response (VR), HBeAg loss or the emergence of adefovir (ADV)-related mutations in ADV-treated chronic hepatitis B (CHB) patients with lamivudine (LAM) resistance.

METHODS

Fifty-four LAM-resistant CHB patients (46% HBeAg-positive) were treated with ADV monotherapy (n=28) or ADV plus LAM (n=26) for a mean of 30.4 months.

RESULTS

Thirty-eight patients (70.4%) achieved VR defined as HBV-DNA levels <10(4)copies/ml within the first 12 months of treatment. Six (24%) of 25 HBeAg-positive patients exhibited HBeAg loss and 20% seroconverted to anti-HBe. Eight patients (14.8%) developed ADV-related mutations. In the multivariate analysis, female gender (HR=0.20, 95% CI: 0.05-0.76, p=0.018), HBeAg-negative (HR=0.37, 95% CI: 0.14-0.96, p=0.040) and low baseline HBV-DNA levels (HR=0.65, 95% CI: 0.45-0.95, p=0.027) were independent predictors of VR, whereas low HBV-DNA levels (HR=0.36, 95% CI: 0.11-1.20, p=0.095) and HBV-genotype D (HR=0.06, 95% CI: 0.004-0.84, p=0.037) independently predicted HBeAg loss.

CONCLUSIONS

ADV therapy suppresses viral replication in more than 70% of LAM-R patients. Factors associated with virologic response are female gender, HBeAg-negative status and low baseline serum HBV-DNA levels. Genotype D HBV infection and low baseline HBV-DNA levels independently predict HBeAg loss.

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.

Antiviral efficacy of adefovir dipivoxil versus lamivudine in patients with chronic hepatitis B sequentially treated with lamivudine and adefovir due to lamivudine resistance

AIM: To compare the antiviral efficacy of adefovir (ADV) in lamivudine (LMV)-resistant patients with LMV treatment in nucleoside-naïve patients, using serum samples collected sequentially during the course of treatment progressing from LMV to ADV.

METHODS: Forty-four patients with chronic hepatitis B (CHB) were included. The patients were initially treated with LMV and then switched to ADV when LMV resistance developed. Antiviral efficacy was assessed by measuring the following: reduction in serum HBV DNA from baseline, HBV DNA negative conversion (defined as HBV DNA being undectable by the hybridization assay), and HBV DNA response (either HBV DNA level ≤ 10⁵ copies/mL or a ≥ 2 log₁₀ reduction from baseline HBV DNA level).

RESULTS: After two and six months of treatment, HBV DNA reduction was greater with LMV compared to ADV treatment (P = 0.021). HBV DNA negative conversion rates were 64% and 27% after one month of LMV and ADV treatment respectively (P = 0.001). Similarly, HBV DNA response rates were 74% and 51% after two months of LMV and ADV treatment respectively (P = 0.026).

The time taken to HBV DNA negative conversion and to HBV DNA response were both delayed in ADV treatment compared with LMV.

CONCLUSION: The antiviral efficacy of ADV in LMV-resistant patients is slower and less potent than that with LMV in nucleoside-naïve patients during the early course of treatment.

In vitro drug susceptibility analysis of hepatitis B virus clinical quasispecies populations

Analysis of the replication and drug resistance of patient serum hepatitis B virus (HBV) populations can contribute to the therapeutic management of chronic hepatitis B. We developed a procedure for cloning serum HBV quasispecies populations and for phenotypic analysis of the cloned populations for in vitro drug susceptibility. Equivalent sequences were compared to the respective serum HBV DNAs of the cloned quasispecies by population sequencing. Analysis of individual clones revealed that each population contained a diversity of HBV quasispecies. Furthermore, secreted HBV in the supernatant following transfection of the quasispecies populations remained mostly unchanged from the respective input populations. HBV obtained from patients who had developed resistance to adefovir or lamivudine, as demonstrated by development of the rtA181V or rtL180M/M204V mutations in HBV polymerase, respectively, were tested. Phenotypic analysis demonstrated that a population containing the HBV rtA181V mutation showed a 2.9-fold increase in the 50% effective concentration (EC(50)) for adefovir compared to the wild-type baseline isolate, while the lamivudine-resistant HBV quasispecies population showed a >1,000-fold increase in the lamivudine EC(50). In summary, a strategy of cloning full genome HBV quasispecies populations from patient sera was developed, which could provide a useful tool in clinical HBV drug resistance phenotyping and studies of the evolution of clinical viral species.

Cross-study analysis of the relative efficacies of oral antiviral therapies for chronic hepatitis B infection in nucleoside-naive patients

BACKGROUND AND OBJECTIVE

Lamivudine and adefovir were approved for treatment of chronic hepatitis B virus (HBV) infection based on placebo-controlled trials, and entecavir was recently approved on the basis of its superiority over lamivudine in phase II/III trials; however, to date, these three therapies have not been compared head to head.

METHODS

To evaluate the relative efficacy of these therapies, we applied a predefined protocol of established statistical techniques to compare data from phase III entecavir trials with published clinical trial results with lamivudine, adefovir and placebo in nucleoside-naive hepatitis B e antigen (HBeAg)-positive and -negative populations.

RESULTS

A comprehensive literature search identified 612 publications/data sources, of which 28 satisfied predefined inclusion criteria. Independent reviewers extracted week 48-52 histological, virological, biochemical and serological endpoints from these sources, which were analysed with a fixed-effects model. For each of the three histological endpoints in HBeAg-positive patients (Histological Improvement, Ranked Assessment of Necroinflammation [RA-N] and Ranked Assessment of Fibrosis [RA-F]), entecavir was superior to adefovir. Entecavir was superior to lamivudine for Histological Improvement and comparable to lamivudine for RA-N and RA-F. With respect to reducing HBV DNA levels, entecavir (-6.98 log(10) copies/mL) was more effective than lamivudine (-5.46 log(10) copies/mL, p < 0.0001) and adefovir (-3.60 log(10) copies/mL, p < 0.0001), and lamivudine was more effective than adefovir (p < 0.0001). The parallel goals of HBV DNA reduction below the limit of quantitation (LOQ) [by polymerase chain reaction] and ALT normalisation were achieved more often with entecavir (69% and 67% of patients, respectively) than with lamivudine (38% and 59%, respectively; p < 0.0001 and p < 0.05, respectively) or adefovir (21% and 48%, respectively; both p < 0.0001), and more often with lamivudine than with adefovir (p < 0.0001 and p < 0.05, respectively). HBeAg seroconversion rates were higher with entecavir (21% of patients) and lamivudine (18%) than with adefovir (12%, p < 0.01 and p < 0.05, respectively). For each of the three histological endpoints in the HBeAg-negative population, entecavir was comparable to adefovir. Entecavir was superior to lamivudine for Histological Improvement, and comparable to lamivudine for RA-N and RA-F, and all three antivirals were superior to placebo. Entecavir proved superior to lamivudine and adefovir in lowering HBV DNA levels (-5.20 vs -4.66 vs -3.91 log(10) copies/mL, respectively; p < 0.0005 and p < 0.0001, respectively) and in suppressing HBV DNA below the LOQ (91% vs 73% vs 51% of patients, respectively; both p < 0.0001); in the latter respect, lamivudine was in turn superior to adefovir (p < 0.0001). Entecavir was also superior to lamivudine in normalising ALT (76% vs 69% patients, respectively; p < 0.05).

CONCLUSIONS

Over a 12-month treatment period, this analysis predicts that the antiviral efficacy of entecavir would be superior to that of lamivudine, which in turn would be superior to that of adefovir, in nucleoside-naive patients with chronic HBV infection.

Antiviral drug-resistant HBV: standardization of nomenclature and assays and recommendations for management

Substantial advances have been made in the treatment of chronic hepatitis B in the past decade. Approved treatments for chronic hepatitis B include 2 formulations of interferon and 4 nucleos(t)ide analogues (NAs). Sustained viral suppression is rarely achieved after withdrawal of a 48-week course of NA therapy, necessitating long, and in many cases, indefinite treatment with increasing risk of development of drug resistance. Antiviral resistance and poor adherence are the most important factors in treatment failure of hepatitis B. Thus, there is a need to standardize nomenclature relating to hepatitis B antiviral resistance, and to define genotypic, phenotypic, and clinical resistance to NA therapy.

Lamivudine treatment-related morphological changes of esophageal varices in patients with liver cirrhosis

AIM

Many studies have reported the therapeutic effects of lamivudine on cirrhotic patients with hepatitis B; however, no study has investigated the morphological changes of esophageal varices after lamivudine treatment.

METHOD

The morphological changes of esophageal varices in patients with cirrhosis were retrospectively compared between 12 patients treated with lamivudine and six historical untreated patients.

RESULTS

In the treated group, the HBV DNA and hyaluronic acid (HA) levels in the serum were significantly lower than those in the untreated group (P = 0.013 and P = 0.009, respectively) at the end of follow-up, with a significant improvement in the Child-Pugh-Turcotte score (P = 0.022). In the treated group, the disappearance or reduction of esophageal varices was observed in six (50%) of the 12 patients. In three (25%) of the 12 patients, esophageal varices worsened. In the remaining three patients (25%), there were no changes in esophageal varices. In the untreated group, all patients showed the worsening of esophageal varices during the follow-up period, with a significant difference between this group and the treated group (P = 0.009). The serum HA level decreased in the nine treated patients without worsening of esophageal varices. However, in the three patients with worsening, the HA level significantly increased.

CONCLUSION

Lamivudine treatment for patients with cirrhosis improves not only liver function but also esophageal varices.

Pre- and post-treatment predictors of the early achievement of HBeAg loss in lamivudine-resistant patients receiving adefovir therapy

BACKGROUND AND AIM

This study investigated the clinical variables that predict hepatitis B e antigen (HBeAg) loss in lamivudine-resistant patients receiving adefovir therapy.

METHODS

Fifty-six consecutive HBeAg-positive patients treated with adefovir for at least 12 months were enrolled in this study. All had serum alanine aminotransferase (ALT) levels over twice the upper limit of normal (ULN) as a result of lamivudine resistance. Predictors of HBeAg loss after switching from lamivudine to adefovir were examined.

RESULTS

During the follow-up period, 18 (32.1%) of 56 patients showed a loss of HBeAg. The estimated rates of HBeAg loss at 6, 12, and 18 months were 11.5%, 26.8%, and 42.9%, respectively. Univariate analysis revealed that pretreatment ALT levels >10 x ULN (P = 0.029), a viral load at 3 months of therapy (P = 0.017), and viral decline by >3 log(10) from baseline at 3 months (P < 0.001) were significantly associated with the loss of HBeAg within 12 months of therapy. With multivariate analysis using the stepwise logistic regression model, pretreatment ALT > 10 x ULN (odds ratio [OR], 4.22; 95% confidence interval [CI], 1.09-19.44; P = 0.044) and viral suppression >3 log(10) at 3 months (OR, 10.39; 95% CI, 1.86-58.07; P = 0.008) were identified as the two independent predictors of HBeAg loss.

CONCLUSIONS

Pretreatment ALT levels and the initial pattern of post-treatment viral decline are the strongest predictors of the early achievement of HBeAg loss following treatment with adefovir in lamivudine-resistant patients. These results may provide useful information for the optimal timing of adefovir rescue as well as for better monitoring after treatment.

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.

Future prospectives for the management of chronic hepatitis B

Chronic hepatitis B virus infection affects about 400 million people around the globe and causes approximately one million deaths a year. Since the discovery of interferon-α as a therapeutic option the treatment of hepatitis B has evolved fast and management has become increasingly complicated. The amount of viral replication reflected in the viral load (HBV-DNA) plays an important role in the development of cirrhosis and hepatocellular carcinoma. The current treatment modalities for chronic hepatitis B are immunomodulatory (interferons) and antiviral suppressants (nucleoside and nucleotide analogues) all with their own advantages and limitations. An overview of the treatment efficacy for both immunomodulatory as antiviral compounds is provided in order to provide the clinician insight into the factors influencing treatment outcome. With nucleoside or nucleotide analogues suppression of viral replication by 5-7 log₁₀ is feasible, but not all patients respond to therapy. Known factors influencing treatment outcome are viral load, ALT levels and compliance. Many other factors which might influence treatment are scarcely investigated. Identifying the factors associated with response might result in stopping rules, so treatment could be adapted in an early stage to provide adequate treatment and avoid the development of resistance. The efficacy of compounds for the treatment of mutant virus and the cross-resistance is largely unknown. However, genotypic and phenotypic testing as well as small clinical trials provided some data on efficacy in this population. Discontinuation of nucleoside or nucleotide analogues frequently results in viral relapse; however, some patients have a sustained response. Data on the risk factors for relapse are necessary in order to determine when treatment can be discontinued safely. In conclusion: chronic hepatitis B has become a treatable disease; however, much research is needed to tailor therapy to an individual patient, to predict the sustainability of response and determine the best treatment for those failing treatment.

Factors associated with the virological response of lamivudine-resistant hepatitis B virus during combination therapy with adefovir dipivoxil plus lamivudine

BACKGROUND

The aim of this study was to investigate the factors associated with the response of lamivudine-resistant hepatitis B virus (HBV) during combination therapy with adefovir dipivoxil plus lamivudine.

METHODS

Sixty-three patients with breakthrough hepatitis received a 10-mg once-daily dose of oral adefovir dipivoxil.

RESULTS

The rates of undetectable serum HBV-DNA were 49.2% after 24 weeks, 61.9% after 48 weeks, and 67.2% after 72 weeks. The cumulative hepatitis B e antigen (HBeAg) loss rates in patients with alanine aminotransferase (ALT) levels of more than twice the upper limit of normal (ULN) were significantly higher than in patients with ALT less than twice the ULN (P = 0.0145). Multivariate analysis revealed that baseline ALT level (P = 0.003) and HBeAg status (P = 0.049) were associated with early virological response.

CONCLUSIONS

Baseline ALT level was associated with HBeAg loss and seroconversion, and baseline ALT level and HBeAg status were associated with the virological response of lamivudine-resistant HBV during combination therapy with adefovir dipivoxil plus lamivudine.

Efficacy and safety of adefovir dipivoxil 20 mg daily in HBeAg-positive patients with lamivudine-resistant hepatitis B virus and a suboptimal virological response to adefovir dipivoxil 10 mg daily

BACKGROUND/AIMS

Some patients receiving adefovir at the approved dose of 10 mg daily for chronic hepatitis B have a "suboptimal" virological response characterized by a slow and moderate decrease in viral replication.

METHODS

We assessed the efficacy and safety of adefovir 20 mg daily in patients with hepatitis B e antigen-positive chronic hepatitis B resistant to lamivudine and a suboptimal virological response to adefovir 10 mg daily add-on.

RESULTS

No amino acid substitutions known to confer adefovir resistance were found in these patients. In the five treated patients, the switch from 10 mg to 20 mg of adefovir daily significantly improved antiviral efficacy (-1.78+/-0.28 log international units/mL versus -3.73+/-0.51 log international units/mL, respectively, p=0.0039), and alanine aminotransferase levels normalized in all but one of the patients. No signs of renal dysfunction occurred.

CONCLUSIONS

These results suggest: (i) that suboptimal responses to adefovir 10 mg daily are due to underdosing; and (ii) that increasing the adefovir dose to 20 mg daily is beneficial and safe in patients with lamivudine-resistant HBV and a suboptimal response to adefovir 10 mg daily, especially when alanine aminotransferase levels are elevated and/or the liver disease is severe or rapidly progressive. Careful monitoring of renal function is necessary.

Prevention of hepatitis B virus recurrence after liver transplantation

Liver transplantation for hepatitis B virus (HBV)-related liver disease has changed from a contraindication to outcomes comparable with non-HBV-related liver transplantations during the last two decades. Mainly the implementation of immunoprophylaxis with hepatitis B immunoglobulin (HBIG) and the use of nucleoside analogs such as lamivudine and adefovir account for this dramatic change. The standard of care in most centers today consists of lamivudine treatment in replicating hepatitis B pre-orthotopic liver transplantation (OLT) and a combination regimen of lamivudine and HBIG post-OLT. With adefovir, a potent antiviral drug became available in recent years that allows for the treatment of patients with lamivudine-resistant tyrosine-methionine-aspartate-aspartate (YMDD)-mutant HBV. In the transplantation setting, first studies indicate that a triple prophylactic therapy consisting of lamivudine, adefovir, and HBIG will become the standard of care for YMDD-mutant-related hepatitis B. With new drugs emerging for the treatment of chronic HBV, there is optimism for new options also in the transplant setting.

[The prophylaxis against post-liver-transplant hepatitis B re-infection]

OBJECTIVE

To review the prophylaxis against post-liver transplantation hepatitis B reinfection with anti-hepatitis B immunoglobulin and nucleoside analogues.

METHOD

A bibliographic search was carried out using Pubmed, entering the following key words: hepatitis B and liver transplantation and (hepatitis B hyperimmune globulin and lamivudine and adefovir dipivoxil) up to June 2006. The initial search was filtered using the terms clinical trial, randomized clinical trial and review. The data contained in selected studies were reviewed.

RESULTS

A total of 53 works were found. Prophylaxis with anti-HB immunoglobulin and lamivudine is the best strategy for avoiding recurrence of the hepatitis B virus in patients undergoing hepatic transplants; achieving very low reinfection rates (0-10%) with follow up periods of between 1-5 years. There is a great degree of variability (dose, duration and method of HBIg administration) in the prophylactic protocols reviewed. The use of low doses of anti-HB immunoglobulin (administered intravenously followed by intramuscular administration, or administered intramuscularly from the anhepatic stage), and lamivudine in patients who receive transplants with a low risk of recurrence, shows prophylactic efficacy comparable to the use of high doses of anti-HB immunoglobulin. Furthermore, it implies a considerable reduction in costs.

CONCLUSIONS

The availability of suitably designed clinical trials is required to design a more cost-effective protocol and reduce variability.

Special Considerations and Treatment of Patients with HBV-HIV Coinfection

Coinfection with HIV and hepatitis B virus (HBV) substantially alters the natural course of HBV infection as well as its management. Therapy for HBV infection in HIV-coinfected patients requires several factors to be taken into consideration, such as whether the antiviral activity of a particular agent is specific for HBV (that is, adefovir, entecavir, telbivudine and pegylated interferon) or for both viruses (that is, lamivudine, emtricitabine and tenofovir), whether the chosen drug has the potential for inducing drug resistance and cross-resistance, and whether use of the agent is associated with hepatotoxicity. For coinfected patients who do not require therapy for their HIV infection, clinicians should avoid prescribing monotherapy with agents that have activity against HIV (that is, tenofovir, entecavir, emtricitabine or lamivudine) so as not to compromise future HIV care. This review discusses the current status of treatment of hepatitis B in the setting of HIV infection. It describes emerging therapeutic strategies and addresses challenges in the treatment of coinfection.

Management of hepatitis B: summary of a clinical research workshop

Chronic hepatitis B is caused by persistent infection with the hepatitis B virus (HBV), a unique DNA virus that replicates through an RNA intermediate produced from a stable covalently closed circular DNA molecule. Viral persistence appears to be due to inadequate innate and adaptive immune responses. Chronic infection has a variable course after several decades resulting in cirrhosis in up to one-third of patients and liver cancer in a proportion of those with cirrhosis. Sensitive assays for HBV DNA levels in serum have been developed that provide important insights into pathogenesis and natural history. Therapy of hepatitis B is evolving. Peginterferon induces long-term remissions in disease in one-third of patients with typical hepatitis B e antigen (HBeAg) positive chronic hepatitis B, but a lesser proportion of those without HBeAg. Several oral nucleoside analogues with activity against HBV have been shown to be effective in suppressing viral levels and improving biochemical and histological features of disease in a high proportion of patients with and without HBeAg, at least in the short term. What is uncertain is which agent or combination of agents is most effective, how long therapy should last, and which criteria should be used to start, continue, switch or stop therapy. Long-term therapy with nucleoside analogues may be the most appropriate approach to treatment, but the expense and lack of data on long-term safety and efficacy make recommendations difficult. Clearly, many basic and clinical research challenges remain in defining optimal means of management of chronic hepatitis B.

Treatment of Chronic Hepatitis B

Hepatitis B virus (HBV) infection is the leading cause of chronic liver disease and hepatocellular carcinoma worldwide. Approximately 350 million individuals are infected with HBV and >500,000 deaths per year can be attributed to HBV. Although universal vaccination has reduced HBV incidence in many countries, it still remains a major public health problem, especially in parts of Asia and Africa. Improved understanding of HBV virology and virus-host interactions has revolutionized chronic hepatitis B therapy in the past two decades. Development of oral nucleoside/nucleotide analogues heralds a new era of safe and effective treatment of this disease. On the basis of these advances, new guidelines for the treatment of chronic hepatitis B have been issued. Successful long-term treatment of chronic hepatitis B may rest on combination therapy that is based on molecular approaches targeting various stages of the HBV life-cycle. In this review, we summarize the current modalities and highlight important issues in the treatment of chronic hepatitis B monoinfection.

Targets of emerging therapies for viral hepatitis B and C

Viral hepatitis B and C, structurally two completely different viruses, commonly infect human hepatocytes and cause similar clinical manifestations. Since their discovery, IFN has been a pillar in the treatment. However, because of the different natures of the viruses, therapeutic approaches diverge and new treatment targets are tailored specifically for each virus. Herein, the authors analyse therapeutic approaches for hepatitis B virus (HBV) and hepatitis C virus (HCV) and focus on emerging concepts that are under clinical evaluation. In particular, promising viral inhibitors for HBV and HCV are reviewed and the current status of research for gene therapy for HCV is described. Immune therapy is a fast-moving field with fascinating results which include therapeutic vaccines and toll-like receptor agonists that could improve tomorrow's treatment approaches.

Treatment of hepatitis B with lamivudine and tenofovir in HIV/HBV-coinfected patients: factors associated with response

As therapy for human immunodeficiency virus (HIV) infection evolves, optimizing hepatitis B virus (HBV) treatment and identifying factors that impact its response in the HIV/HBV-coinfected population is critical. We identified retrospectively 45 HBV/HIV-coinfected patients with detectable HBV DNA by the Bayer VERSANT HBV 3.0 bDNA assay (limit of quantification 2000 copies/mL) at baseline and/or year 1 of therapy. Patients were divided into three groups based on the active HBV agent in their antiretroviral regimen: group 1 (n = 15) received lamivudine; group 2 (n = 10), lamivudine plus tenofovir and group 3 (n = 20), lamivudine followed by lamivudine plus tenofovir. HBV genotypes and resistance profiles were determined by the Bayer Trugene HBV 1.0 assay. More patients in group 2 achieved HBV DNA suppression below 2000 copies/mL (80%), loss of HBe antigen (HBeAg) (40%) and loss of HBeAg and gain of anti-HBe (20%) than did patients in group 1 or 3. More patients with HBV genotype A, achieved HBV DNA suppression <2000 copies/mL than did patients with non-A genotypes [74% (26/35) vs 20% (2/10)], respectively (P = 0.003). Risk for virological nonresponse was significant in those with non-A genotypes [odds ratio (OR) 11.1; 95% CI: 2.0-50], previous HIV therapy (OR 6.5; 95% CI: 1.2-35) and <90% compliance (OR 3.7; 95% CI: 0.99-14.3). Simultaneous therapy with lamivudine/tenofovir suppresses HBV DNA more effectively than lamivudine or tenofovir added to lamivudine. More patients infected with HBV genotype A responded than the non-A patients, regardless of therapeutic regimen, compliance or prior HIV therapy.

Why do we not yet have combination chemotherapy for chronic hepatitis B?

Despite the emergence of multidrug-resistant strains of hepatitis B virus (HBV) and previous success with combination therapy for other chronic viral infections, we are still using sequential monotherapy for chronic HBV infection. Antiviral-resistant HBV can result in major life-threatening complications. We now have complementary drugs, such as lamivudine and adefovir dipivoxil, with fundamentally different structures and associated with different signature resistance mutations, with adefovir dipivoxil showing antiviral activity against most lamivudine-resistant strains. Studies of combination therapy to date have used traditional endpoints--short-term reduction of HBV DNA levels and HBeAg seroconversion--rather than evolution of resistance. There is now an emerging body of data suggesting that combination therapy can decrease antiviral resistance in HBV infection, the endpoint likely to be of greatest long-term importance, and, rather than adding or replacing an antiviral agent after resistance develops, it is likely to be more effective in treatment-naive patients.

Treatment of lamivudine-resistant hepatitis B infection in post-renal transplant patients with adefovir dipivoxil: preliminary results

We report the treatment outcome in six post-renal transplant patients with lamivudine-resistant hepatitis B virus (LR-HBV) infection using adefovir dipivoxil and followed for 6 to 18 months. Posttransplant immunosuppressive therapy was not altered. Adefovir dipivoxil effectively suppressed hepatitis B virus DNA and improved alanine transferase, although DNA suppression seemed dependent on continued therapy. Nephrotoxicity led to withdrawal of the drug in three patients. This may limit therapeutic usefulness in a significant proportion of post-renal transplant patients with LR-HBV infection.

A systematic review and economic evaluation of adefovir dipivoxil and pegylated interferon-alpha-2a for the treatment of chronic hepatitis B

Standard treatments for chronic hepatitis B (CHB) include interferon-alpha (IFN-alpha) and lamivudine (LAM), but these are associated with adverse effects and viral resistance, respectively. The aim of this systematic review and economic evaluation was to assess the clinical effectiveness and cost-effectiveness of two alternative drugs for the treatment of adults with CHB: adefovir dipivoxil (ADV) and pegylated IFN-alpha-2a. We searched electronic databases, including Cochrane Systematic Reviews and Medline, for literature that met criteria defined in a research protocol. Retrieved articles were independently assessed for inclusion by two reviewers. We developed a Markov state transition model to estimate the cost-effectiveness (cost-utility) of pegylated IFN-alpha-2a and of ADV compared with nonpegylated IFN-alpha-2a, LAM and best supportive care. Seven randomized controlled trials and two systematic reviews met the inclusion criteria for our review of clinical effectiveness. ADV was significantly more effective than placebo or ongoing LAM in reducing levels of hepatitis B virus (HBV) DNA. Rates of hepatitis B e antigen (HBeAg) seroconversion were higher among patients receiving ADV than either placebo or ongoing LAM. Patients treated with pegylated IFN-alpha-2a, either as monotherapy or in combination with LAM, showed significantly reduced HBV DNA levels compared with patients treated with LAM monotherapy. HBeAg seroconversion rates at follow-up were significantly higher for pegylated IFN-alpha-2a patients than for those receiving LAM monotherapy. Results of our cost-effectiveness analysis demonstrate that incremental costs per quality adjusted life year (QALY) for a range of comparisons were between 5,994 and 16,569 British Pound, and within the range considered by NHS decision-makers to represent good value for money.

Adding-on versus switching-to adefovir therapy in lamivudine-resistant HBeAg-negative chronic hepatitis B

We studied the long-term efficacy of adefovir dipivoxil (ADV) treatment in 42 HBeAg-negative patients with chronic hepatitis B (CHB) who had developed genotypical lamivudine (LAM) resistance with virological and clinical breakthroughs under long-term LAM treatment. Patients were allocated in 2 treatment groups. In the first (n = 14), LAM was switched to ADV monotherapy whereas in the second (n = 28) ADV was added to LAM. The two groups did not differ in patients' characteristics, all of them having HBV genotype D infection with the precore stop codon mutation. Within 12 months from start of ADV treatment, serum HBV DNA became nondetectable and ALT normalized in 71% and 90% of patients, respectively, with no difference between the 2 arms. Patients with baseline HBV DNA levels less than 10(7) copies/ml experienced a significantly earlier and more frequent decline in serum HBV DNA to nondetectable levels as compared with patients with greater than 10(7) HBV DNA copies/ml at baseline (P = 0.0013) This response has hitherto been maintained (median treatment duration 40 months) in all patients with ADV added to LAM, whereas virological and biochemical breakthroughs due to development of ADV signature resistance mutations occurred in 3 of 14 patients (21%) on ADV monotherapy 15 to 18 months from start of treatment (P = 0.0174).

CONCLUSION

Adding ADV to LAM in HBeAg-negative CHB patients with LAM resistance effectively suppresses HBV replication inmost of them and induces biochemical remission that can be maintained in all of them at least for 3 years without any evidence of development of resistance to ADV.

Natural course, therapeutic options and economic evaluation of therapies for chronic hepatitis B

Chronic hepatitis B virus infection afflicts 400 million people worldwide and untreated will progress to cirrhosis in 15-40% of individuals, with an associated increased risk for the development of hepatocellular carcinoma. The 'inactive carrier state' carries a benign prognosis with a very low risk of cirrhosis or hepatocellular carcinoma. However, the hepatitis B e antigen (HBeAg)-positive chronic hepatitis state is an active disease state with increased risk for progressing to cirrhosis and hepatocellular carcinoma. The HBeAg-negative mutant variety of chronic hepatitis B has been associated with a higher incidence of cirrhosis at initial presentation and more frequent progression to hepatocellular carcinoma compared with the wild-type hepatitis B. Five medications are currently approved by the US FDA for the treatment of chronic hepatitis B: interferon-alpha, lamivudine, adefovir dipivoxil, entecavir and peginterferon-alpha-2a. Interferon-alpha therapy has been shown to increase the rate of HBeAg and hepatitis B DNA loss with a small chance of hepatitis B surface antigen loss, but has significant adverse effects and is ineffective against the HBeAg-negative mutant. Lamivudine is a safely used, orally administered drug with good efficacy, but is associated with the development of a lamivudine-resistant (Lam-R) mutant in a large proportion of patients after long-term therapy. High relapse rates after lamivudine therapy make this medication less effective in the HBeAg-negative mutant also. Adefovir dipivoxil is a safely used, orally administered drug, which is effective against the Lam-R mutant. Adefovir dipivoxil is effective against the wild-type and HBeAg-negative hepatitis B and has a very low incidence of resistance development. Entecavir is a highly potent and selective new oral drug against hepatitis B. It has demonstrated no resistance development in treatment-naive patients, but a low incidence of resistance in patients infected with prior Lam-R mutants. Peginterferon-alpha-2a is administered once weekly and has improved efficacy compared with standard interferon-alpha and lamivudine. However, it has a similar adverse-effect profile to standard interferon-alpha. Pharmacoeconomic studies have demonstrated a cost benefit in treating chronic hepatitis B patients compared with no therapy. However, results have been conflicting, with earlier studies showing a cost advantage of lamivudine over interferon-alpha and a more recent, comprehensive study favouring interferon-alpha monotherapy in HBeAg-negative patients and adefovir dipivoxil 'salvage' after lamivudine resistance development in HBeAg-positive patients.

Entecavir: a new nucleoside analog for the treatment of chronic hepatitis B infection

BACKGROUND

Chronic hepatitis B infection carries considerable risk for the development of cirrhosis and hepatocellular carcinoma. Treatment options are increasing but are limited to interferon alfa-2b, pegylated interferon alfa-2a, lamivudine, adefovir dipivoxil, and entecavir. Entecavir, a nucleoside analog, is the newest oral antiviral approved in the United States for treatment of chronic hepatitis B.

OBJECTIVE

To review the available data for entecavir regarding its pharmacology, pharmacokinetics, safety, efficacy, and clinical use.

METHODS

A MEDLINE, EMBASE, and Cochrane search of the English-language literature from January 1997-May 2006 was performed. Preapproval studies provided by the manufacturer and abstracts from recent scientific meetings on infectious disease and hepatology were also reviewed.

RESULTS

Three phase III clinical trials representing more than 1600 subjects established the superior efficacy and equivalent safety of entecavir compared with lamivudine for treating patients who are hepatitis B early antigen (HBeAg) positive, HBeAg negative, or refractory to lamivudine. Entecavir resistance has not occurred in nucleoside-naïve patients but may develop in those who already possess lamivudine resistance mutations.

CONCLUSION

Trial results, along with previously published response rates for adefovir dipivoxil and interferon monotherapy, make entecavir the preferred first-line treatment option for patients with chronic hepatitis B who are nucleoside naïve, HBeAg positive or negative, and have compensated liver disease. Both entecavir and adefovir dipivoxil maintain activity against hepatitis B virus in patients with chronic hepatitis B who are refractory to lamivudine, and both agents are reasonable first-line treatment options. Longer trials involving nucleoside-naïve, lamivudine-refractory patients are needed to determine entecavir's optimal treatment duration, long-term safety, and durability of response, including rate of resistance.

Antiviral therapy and resistance with hepatitis B virus infection

Hepatitis B virus (HBV) infection is still the most common cause of hepatocellular carcinoma and liver cirrhosis world wide. Recently, however, there has been quite dramatic improvement in the understanding of HBV associated liver disease and its treatment. It has become clear that high viral replication is a major risk factor for the development of both cirrhosis and hepatocellular carcinoma. Early studies have shown lamivudine lowers the risk of HBV associated complications. There are currently three nucleos(t)ides licensed, in addition to interferon, and there are more drugs coming to the market soon. Interferon or its pegylated counterpart are still the only options for treatment with defined end points, while nucleos(t)ides therapy is used mostly for long term treatment. Combination therapies have not been shown to be superior to monotherapy in naïve patients, however, the outcome depends on how the end point is defined. Interferon plus lamivudine achieves a higher viral suppression than either treatment alone, even though Hbe-seroconversion was not different after a one year treatment. HBV-genotypes emerge as relevant factors, with genotypes "A" and "B" responding relatively well to interferon, achieving up to 20% HBsAg clearance in the case of genotype "A". In addition to having a defined treatment duration, interferon has the advantage of lacking resistance selection, which is a major drawback for lamivudine and the other nucleos(t)ides. The emergence of resistance against adefovir and entecavir is somewhat slower in naïve compared to lamivudine resistant patients. Adefovir has a low resistance profile with 3%, 9%, 18%, and 28% after 2, 3, 4, and 5 years, respectively, while entecavir has rarely produced resistance in naïve patients for up to 3 years.

Adefovir Dipivoxil Monotherapy and Combination Therapy with Lamivudine for the Treatment of Chronic Hepatitis B in an Asian Population

Aim

To determine differences in Chinese patients treated with adefovir (ADV) monotherapy or ADV in combination with lamivudine (3TC) after development of resistance to 3TC, with respect to biochemical improvement, HBV DNA suppression and development of subsequent ADV resistance.

Methods

All hepatitis B patients with 3TC resistance treated with ADV for 3 months or more at our centre were included, and monitored 3–6 monthly for biochemical and virological response, and development of ADV resistance.

Results

A total of 56 patients were included, 50% switched to ADV monotherapy and 50% received combination 3TC/ADV therapy. Median follow-up was 15.5 months. Normalization of alanine aminotransferase (ALT) occurred in 25 (89%) patients in the ADV group compared with 24 (86%) in the 3TC/ADV group (P=0.686). Virological response (VR) was achieved in seven (35%) patients in the ADV group at 12 months compared with five (28%) in the 3TC/ADV group (P=0.637). By 24 months, seven (64%) patients in the ADV group achieved VR compared with two (40%) in the 3TC/ADV group (P=0.377). Cumulative probability of developing genotypic ADV resistance in the ADV group at 24 months was 18% compared with 7% in the 3TC/ADV group (P=0.94).

Conclusions

There was no obvious improvement in ALT normalization and virological suppression or reduction in the development of ADV-resistant mutations with 3TC/ADV therapy compared with ADV monotherapy. Further studies with longer follow-ups are required to determine whether combination 3TC/ADV therapy will reduce the emergence of ADV resistance compared with ADV monotherapy.

Cost effectiveness of entecavir versus lamivudine with adefovir salvage in HBeAg-positive chronic hepatitis B

OBJECTIVE

To evaluate the cost effectiveness of treatment of hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) with entecavir compared with lamivudine with adefovir salvage, based primarily on the results of a recent 2-year, randomised, multicentre, clinical trial (n = 709). Previous economic analyses have been limited by the lack of comparative clinical data for entecavir and lamivudine beyond 1-year duration and for salvage therapy.

METHODS

We conducted a cost-utility analysis using a Markov model from a US-payer perspective over a lifetime time horizon. The hypothetical cohort was 35-year-old patients with HBeAg-positive CHB. We evaluated 2 years of treatment with entecavir 0.5mg/day versus lamivudine 100mg/day, plus addition of adefovir 10mg/day for patients who developed virologic breakthrough due to resistance to either drug. In a scenario analysis, we considered adefovir plus lamivudine combination therapy for treatment-naive patients. Clinical and economic inputs ($US, year 2006 values) were derived from publicly available data, and probabilistic sensitivity analyses were conducted to evaluate uncertainty in the results.

RESULTS

The estimated 10-year cumulative incidence of cirrhosis for patients initiated on entecavir was 2.3% lower than for those on lamivudine (20.5% vs 22.8%). The discounted incremental cost per QALY gained was $US7600 in the base-case analysis, and the 95% central range from probabilistic sensitivity analysis was $US2500-$US19 100. Combination therapy for treatment-naive patients led to an increase in costs without improvement in patient outcomes compared with entecavir monotherapy.

CONCLUSIONS

Our analysis suggests entecavir improves health outcomes in a cost-effective manner compared with lamivudine with adefovir salvage or combination therapy, and highlights the importance of using evidence-based effectiveness estimates in economic studies of CHB therapies.

Effect of switching to tenofovir with emtricitabine in patients with chronic hepatitis B failing to respond to an adefovir-containing regimen

BACKGROUND

In patients with chronic hepatitis B, long-term use of lamivudine is limited by resistance mutations. Adefovir dipivoxil has a very low rate of resistance, but there have been recent reports describing resistance mutations. Tenofovir disoproxil fumarate and emtricitabine show potent activity against wild-type and lamivudine-resistant hepatitis B virus.

METHODS

We describe a series of seven HIV-seronegative patients who failed to achieve undetectable hepatitis B viral DNA on adefovir. No lamivudine resistance testing was performed. The antiviral regimen was changed to tenofovir (300 mg daily) and emtricitabine (200 mg daily). Variables collected included levels of hepatitis B viral DNA by polymerase chain reaction, alanine and aspartate aminotransferase, hepatitis B e antigen and hepatitis B e antibody.

RESULTS

The median hepatitis B viral DNA level while on adefovir was 430,000 copies/ml with a median fall in hepatitis B viral DNA levels of 2.0 log10 copies/ml. Patients were on adefovir for a median period of 10 months before a change in regimen to tenofovir and emtricitabine. This regimen change resulted in a median fall in hepatitis B viral DNA levels of 3.0 log10 copies/ml (range, 2-4) after a median treatment duration of 23 months (range, 14-28). All patients (100%) had achieved undetectable hepatitis B viral DNA levels following combination therapy. Anti-hepatitis B e seroconversion occurred in one patient. No change in serum creatinine was observed during therapy, and no significant adverse events were reported.

CONCLUSIONS

In patients failing to respond to adefovir monotherapy or an adefovir-containing regimen for chronic hepatitis B virus, a combination of tenofovir and emtricitabine resulted in undetectable hepatitis B viral DNA levels without any renal toxicity. Tenofovir, in combination with emtricitabine, may be an alternative treatment for those with detectable hepatitis B viral DNA on adefovir.

Hepatitis B treatment: Lessons for the nephrologist

Hepatitis B affects approximately 350 million people worldwide, and an estimated 1.25 million people in the United States. Although most people infected with the virus do not develop significant hepatic disease from hepatitis B, 15-40% will develop serious complications. These complications include cirrhosis, the development of hepatocellular carcinoma , and hepatic decompensation. Patients with renal failure have increased risk of acquiring the virus through blood transfusions and contact with bodily fluids at hemodialysis centers, and of developing complications from hepatitis B virus infection. Renal transplant patients are at increased risk for exacerbations of hepatitis B with immunosuppression. Thus, it is crucial for the nephrologist to have a clear understanding of the natural history and treatment of hepatitis B, both pre- and post-renal transplant.

Treatment of chronic hepatitis B

Treatment of chronic hepatitis B has improved substantially over the past five years. Pegylated interferon alpha2a and entecavir have been approved by the FDA and joined the armamentarium of therapies that includes inteferon alpha (IFN-alpha), lamivudine, and adefovir dipivoxil. Several key questions come to mind regarding treatment. Who should receive treatment? Which agent should they be given? How long should treatment last? Treatment is indicated for patients with a high pretreatment alanine aminotransferase level, detectable HBV DNA, and active inflammation on liver biopsy. When selecting an agent, the likelihood of achieving a sustained response should be weighed against long-term risks. IFN-alpha, lamivudine, and adefovir dipivoxil are equally efficacious; however, even though IFN-alpha and pegylated IFN-alpha have a durable response, both are associated with unpleasant side effects. Long-term lamivudine therapy has a high rate of drug resistance compared with adefovir dipivoxil, which has a low rate of drug resistance and a small risk of reversible nephrotoxicity. Entecavir reduces HBV load more effectively than the other therapies, but it is associated with increased drug resistance in patients with lamivudine-resistant HBV. The key to therapy seems to be some combination of therapies--both existing and those in development--that has yet to be determined.

Treatment of chronic hepatitis B: efficacy of current drugs and prospects for the future

Chronic hepatitis B is an important clinical problem often leading to severe complications. In this review, the results obtained in the last few years with the use of current drugs, such as interferon and nucleo(t)side analogues, are summarized and the problems of obtaining a sustained remission, which is only achieved in a small number of patients, are discussed. The new approaches, such as the use of combinations of drugs, to optimize long-term tolerable treatment are also considered.

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.

Randomized controlled study of tenofovir and adefovir in chronic hepatitis B virus and HIV infection: ACTG A5127

Chronic hepatitis B virus (HBV) infection is an important cause of morbidity and mortality in subjects coinfected with HIV. Tenofovir disoproxil fumarate (TDF) and adefovir dipivoxil (ADV) are licensed for the treatment of HIV-1 and HBV infection, respectively, but both have in vivo and in vitro activity against HBV. This study evaluated the anti-HBV activity of TDF compared to ADV in HIV/HBV-coinfected subjects. ACTG A5127 was a prospective randomized, double-blind, placebo-controlled trial of daily 10 mg of ADV versus 300 mg of TDF in subjects with HBV and HIV coinfection on stable ART, with serum HBV DNA >/= 100,000 copies/mL, and plasma HIV-1 RNA </= 10,000 copies/mL. This study closed early based on results of a prespecified interim review, as the primary noninferiority end point had been met without safety issues. Fifty-two subjects were randomized. At baseline, 73% of subjects had a plasma HIV-1 RNA < 50 copies/mL, 86% were HBeAg positive, 94% were 3TC resistant, median serum ALT was 52 IU/L, and 98% had compensated liver disease. The mean time-weighted average change in serum HBV DNA from baseline to week 48 (DAVG(48)) was -4.44 log(10) copies/mL for TDF and -3.21 log(10) copies/mL for ADV. There was no difference in toxicity between the 2 treatment arms, with 11 subjects (5 ADV and 6 TDF) experiencing elevations of serum ALT on treatment. In conclusion, over 48 weeks, treatment with either ADV or TDF resulted in clinically important suppression of serum HBV DNA. Both drugs are safe and efficacious for patients coinfected with HBV and HIV.

Unusual Selection of Rta181V Hbv Mutants Cross-Resistant to Adefovir following Prolonged Lamivudine Monotherapy: Report of Two Cases

Development of hepatitis B virus (HBV)-resistant strains following nucleos(t)ide analogue treatment is a major concern. The A181V mutation within the reverse transcriptase (RT) of HBV has been shown to be associated with HBV resistance to adefovir dipivoxil (ADV), and its level of sensitivity to other nucleos(t)ide analogues is an important issue. This article reports two cases of chronically HBV infected patients who developed rtA181V HBV mutants following lamivudine (LAM) monotherapy. This was subsequently associated with virological breakthrough under LAM monotherapy or LAM/ADV bi-therapy, which were rescued by tenofovir disoproxil fumarate treatment. These observations suggest that rtA181V mutation may unusually emerge under LAM monotherapy, and may be associated with cross resistance to LAM and ADV, but remains sensitive to tenofovir disoproxil fumarate. Moreover, they highlight that HBV sequence analysis is an essential tool to optimize therapeutic management of HBV chronic infection in clinical practice in order to choose the appropriate nucleos(t)ide analogues.

Chinese medicine Jiangganlong combined with anti-virus medicine in long-term treatment of active liver cirrhosis and its effect on prognosis of patients

AIM: To study the efficacy of Chinese medicine Jiangganlong combined with anti-virus medicine in the treatment of active liver cirrhosis (ALC).

METHODS: A total of 114 ALC patients were divided into treatment group and control group, named A and B, respectively. The patients in group A were treated with Jiangganlong and lamivudine (LAM). Jiangganlong decoction or pills were given a dose every three days, or 4.0 g (tid). LAM was administered 0.1 g per day. After the emergence of YMDD variations, adefovir (ADV) was added. LAM was stopped when HBV DNA YMDD variation became negative. The patients in group B received general and symptomatic treatment. The mean treatment therapeutic time was 36 months.

RESULTS: The rates of negative conversion for the serum HBV DNA were 75.4% (43/57) and 3.5% (2/57) in group A and B, respectively, and there was significant difference between them (P < 0.01). The cumulative rate of YMDD variations among patients of group A was 40.4% (23/57). After the emergence of YMDD variations, 20 patients received ADV treatment, 90% (18/20) of which were found YMDD variation-negative; there were 3 patients who did not receive ADV treatment, and they died of liver failure. The negative conversion rates of HBeAg were 44.4% (16/36), 16.7% (5/30) in group A, B, respectively, and there was marked difference between them (P < 0.05). The total bilirubin (TBIL) and alanine aminotransferase (ALT) returned to the normal level, and the albumin level, Child-Pugh score, and decompensation status were improved in group A. The rate of complications was dramatically lower in group A than that in group B [14.0% (8/57) vs 50.8% (29/57), P < 0.01]. The mortality rate was also decreased in group A as compared with that in group B [7.0% (4/57) vs 29.8% (17/57), P < 0.01], while the survival time was notably prolonged (3.3 ± 2.1 year vs 1.1 ± 1.0 year, P < 0.01).

CONCLUSION: Chinese medicine Jiangganlong combined with anti-virus medicine can inhibit the replication of HBV DNA, ameliorate liver function, decrease the rate of complications, reduce the mortality rate, and prolong the survival time as well as improve the prognosis of ALC patients.

Favorable effect of adefovir on the number and functionality of myeloid dendritic cells of patients with chronic HBV

In patients with chronic hepatitis B virus (HBV), 2 predominant precursor dendritic cell (DC) subtypes, the myeloid dendritic cell (mDC) and the plasmacytoid dendritic cell (pDC), were recently found to be functionally impaired. HBV DNA was found to be present in the DC subtypes, but no viral replication could be detected. The question remains whether simply the presence of the virus and viral proteins causes this dysfunction of DCs. To address this issue, the effect of viral load reduction resulting from treatment with the nucleotide analogue adefovir dipivoxil on the number and functionality of circulating DCs was studied during 6 months of treatment. Treatment resulted in a mean 5 log(10) decrease in the viral load and normalization of alanine aminotransferase within 3 months. The number of mDCs, but not of pDCs, increased significantly over 6 months of treatment to a level comparable to that of uninfected healthy controls. The allostimulatory capacity of isolated and in vitro matured mDCs increased significantly after 3 months of treatment. Accordingly, mDCs exhibited an increased capacity to produce tumor necrosis factor alpha and interleukin-12 after 3-6 months of treatment. There was no change in interferon alpha production by pDCs during treatment. In conclusion, adefovir treatment results in an improvement in the number and functionality of mDCs, but not of pDCs. Our findings provide clues for the reasons why current antiviral therapy does not lead to consistently sustained viral eradication.

New developments in the treatment of chronic hepatitis B

Significant progress has been made during the last 2 years in the treatment of chronic hepatitis B (CHB). Treatment decisions differ significantly depending on whether patients are HBeAg+ or HBeAg-, treatment-naive or nucleoside/nucleotide-resistant, and in early or advanced stages of liver disease. Courses of finite duration, aiming to achieve sustained off-therapy responses, are practically restricted to HBeAg+ patients with compensated chronic liver disease, whereas long-term therapy aiming to achieve maintained on-therapy remission is mostly applicable to HBeAg- individuals either with early or advanced liver disease. A course of finite duration with pegylated (PEG)-IFN-alpha-2a offers the highest probability of sustained off-therapy response in HBeAg+ individuals, as well as in some HBeAg- individuals. Long-term therapy with nucleoside/nucleotide analogues, both in HBeAg+ and HBeAg- CHB, has most favourable effects on patient outcome, provided that virological and biochemical remission is maintained without development of viral resistance. The best results are achievable with potent analogues suppressing serum hepatitis B virus (HBV) DNA to non-detectability by most sensitive techniques. The best 2-year resistance profile has hitherto been reported with entecavir monotherapy, and the best long-term resistance profile was seen with adefovir of 5-year duration. Adefovir is effective in most lamivudine (LAM)-resistant patients, but should be administered as an add-on rather than as a substitute for LAM. Combination therapies have entered the treatment arena of CHB by the side doors of LAM-resistance and of end-stage liver disease, and the most recent results suggest that treatment with combinations of two strong nucleosides/nucleotides with different resistance profiles may turn out to be the optimal first-line/first choice option in CHB.

Where does adefovir stand amongst newly developed antivirals: from pharmacology to virology

Adefovir, an acyclic nucleotide analog of adenosine monophosphate, has demonstrated potent activities against several viruses in vitro. Since 2002, the diester prodrug of this molecule, adefovir dipivoxil, has been approved as a well-tolerated and efficacious treatment for chronic hepatitis B. It is the first nucleotide analog to be approved for this indication and it is now challenged by several other molecules that also inhibit hepatitis B virus replication. In this article, we analyze the strengths and limitations of adefovir in the context of hepatitis B treatment and consider the other alternatives in the treatment of this difficult-to-treat chronic disease. Adefovir dipivoxil has offered a real opportunity for patients who developed lamivudine resistance and were facing a therapeutic deadlock; the next challenge for clinicians will be to offer the best therapeutic strategy to limit the inexorable selection of resistant strains.

Successful Treatment of Hepatitis B Virus Infection With Lamivudine After Heart Transplantation

Patients with hepatitis B virus (HBV) infection have a higher morbidity and mortality after heart transplantation (HT). HBV infection is endemic in Taiwan. We studied the effect of lamivudine treatment of HBV infection after HT. From July 1987 to July 2005, 252 patients underwent HT. All recipients and donors underwent routine screening of hepatitis B surface antigen (HBsAg), hepatitis B e antigen, antibody to hepatitis B surface antigen, antibody to hepatitis B core antigen, antibody to hepatitis B e antigen, and an alanine aminotransferase (ALT) level before HT. When ALT was two times greater than the upper limit of normal or serum bilirubin was higher than 3 mg/dL in HBsAg-positive patients, HBV-DNA were checked by a branched DNA assay or polymerase chain reaction. When HVB-DNA was greater than 100,000 copies/mL, lamivudine (100 mg per day) was prescribed indefinitely. There were 14 patients under lamivudine treatment after HT, among whom, none suffered severe adverse reactions from lamivudine. Four patients died: one due to end-stage cirrhosis while awaiting liver transplantation at 14 months after HT. Two died of sudden death at 54 months and 138 months after HT. Another died of diffuse B cell lymphoma at 62 months after HT. All the survivors have normal ALT and undetectable HBV-DNA after lamivudine treatment. But the YMDD mutant was detected in two patients. With successful treatment of HBV infection in HT, it is not necessary to exclude HBV infection patients from HT.