Adefovir dipivoxil therapy for lamivudine-resistant hepatitis B in pre- and post-liver transplantation patients

Hepatitis B virus recurrence after liver transplantation: An old tale or a clear and present danger?

Hepatitis B virus (HBV) recurrence after liver transplantation (LT) has been described more than 50 years ago. Similarly, to other clinical conditions, in which impairment of host immune defense favors viral replication, early reports described in details recurrence and reactivation of HBV in liver transplant recipients. The evidence of a possible, severe, clinical evolution of HBV reappearance in a significant percentage of these patients, allowed to consider, for some years, HBV positivity a contraindication for LT. Moving from the old to the new millennium this picture has changed dramatically. Several studies contributed to establish efficient prophylactic protocols for HBV recurrence and with the advent of more potent anti-viral drugs an increased control of infection was achieved in transplanted patients as well as in the general immune-competent HBV population. Success obtained in the last decade led some authors to the conclusion that HBV is now to consider just as a “mere nuisance”. However, with regard to HBV and LT, outstanding issues are still on the table: (1) A standard HBV prophylaxis protocol after transplant has not yet been clearly defined; (2) The evidence of HBV resistant strains to the most potent antiviral agents is claiming for a new generation of drugs; and (3) The possibility of prophylaxis withdrawal in some patients has been demonstrated, but reliable methods for their selection are still lacking. The evolution of LT for HBV is examined in detail in this review together with the description of the strategies adopted to prevent HBV recurrence and their pros and cons.

Liver Fibrosis Reversion After Suppression of Hepatitis B Virus

Great strides have been made in hepatitis B virus (HBV)-related fibrosis and cirrhosis. Available evidence indicates that HBV viral suppression causes regression of advanced fibrosis and even cirrhosis, and therefore should be attempted in all patients with advanced fibrosis and cirrhosis. The preferred agents in patients with cirrhosis are entecavir and tenofovir, primarily because the risk of breakthrough is low. HBV viral suppression leads to improved clinical outcomes even in patients with cirrhosis and complications. The risk of hepatocellular carcinoma is reduced, but not eliminated. Thus, patients with HBV cirrhosis should continue to have routine screening for hepatocellular carcinoma, even after viral suppression.

Evidence-based clinical practice guidelines for liver cirrhosis 2015

The Japanese Society of Gastroenterology revised the evidence-based clinical practice guidelines for liver cirrhosis in 2015. Eighty-three clinical questions were selected, and a literature search was performed for the clinical questions with use of the MEDLINE, Cochrane, and Igaku Chuo Zasshi databases for the period between 1983 and June 2012. Manual searching of the latest important literature was added until August 2015. The guidelines were developed with use of the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. This digest version in English introduces selected clinical questions and statements related to the management of liver cirrhosis and its complications. Branched-chain amino acids relieve hypoalbuminemia and hepatic encephalopathy and improve quality of life. Nucleoside analogues and peginterferon plus ribavirin combination therapy improve the prognosis of patients with hepatitis B virus related liver cirrhosis and hepatitis C related compensated liver cirrhosis, respectively, although the latter therapy may be replaced by direct-acting antivirals. For liver cirrhosis caused by primary biliary cirrhosis and active autoimmune hepatitis, urosodeoxycholic acid and steroid are recommended, respectively. The most adequate modalities for the management of variceal bleeding are the endoscopic injection sclerotherapy for esophageal varices and the balloon-occluded retrograde transvenous obliteration following endoscopic obturation with cyanoacrylate for gastric varices. Beta-blockers are useful for primary prophylaxis of esophageal variceal bleeding. The V2 receptor antagonist tolvaptan is a useful add-on therapy in careful diuretic therapy for ascites. Albumin infusion is useful for the prevention of paracentesis-induced circulatory disturbance and renal failure. In addition to disaccharides, the nonabsorbable antibiotic rifaximin is useful for the management of encephalopathy. Anticoagulation therapy is proposed for patients with acute-onset or progressive portal vein thrombosis.

Disease Progression in Chronic Hepatitis B Patients under Long-Term Antiviral Therapy

BACKGROUND/AIMS

We investigated factors associated with the disease progression and development of hepatocellular carcinoma (HCC) in chronic hepatitis B (CHB) patients during long-term oral nucleos(t)ide analog (NA) therapy.

METHODS

This retrospective study included 524 naive CHB patients who received oral NA therapy for more than 48 weeks between January 2003 and December 2007. The primary outcome was 5-year cumulative probability of disease progression and HCC development. Disease progression was defined as cirrhosis development, cirrhotic complications, HCC or liver-related mortality.

RESULTS

For the 524 patients, the cumulative probabilities of disease progression and HCC development at 1, 2, 3, 4 and 5 years were 1.1%, 6.3%, 9.0%, 11.6%, and 16.2% and 0.2%, 1.8%, 3.6%, 5.8%, and 9.3%, respectively. In multivariate analysis, age >50 years (hazard ratio [HR], 1.05) and cirrhosis (HR, 2.95) were significant factors for disease progression. Similarly, age >50 years (HR, 1.05), family history of HCC (HR, 5.48), and cirrhosis (HR, 17.16) were significant factors for HCC development. Importantly, longer duration (>12 months) of maintained virological response (<20 IU/mL) reduced the risks of disease progression (HR, 0.19) and HCC development (HR, 0.09).

CONCLUSIONS

Longer duration of maintained virological response significantly reduces the risk of disease progression or HCC development in CHB patients undergoing long-term oral NA therapy.

Recent Advances in the Management of Chronic Hepatitis B Including Suppression of Hepatocellular Carcinoma by Entecavir and Interferon

At present, for adults with chronic hepatitis B virus (HBV) infection, two new analogues, entecavir (ETV) and tenofovir, are recommended as the first-line therapy by the EASL (European Association for the Study of the Liver), AASLD (American Association for the Study of Liver Diseases), and APASL (Asian Pacific Association for the Study of the Liver) guidelines. The use of pegylated interferon-α (PEG IFN-α) is recommended as the first-line therapy instead of standard IFN-α according to the above 3 guidelines. In this paper, the aim was to assess: (1) the long-term efficacy and safety as well as the resistance to ETV and tenofovir disoproxil fumarate (TDF); (2) the efficacy of PEG IFN-α; (3) the role of combination therapy with IFN plus two analogues, such as lamivudine and ETV; (4) the efficacy and safety of two analogues with cirrhosis, and (5) suppression of hepatocellular carcinoma (HCC) by ETV and IFN treatment. The results are as follows: (1) both ETV and TDF showed long-term efficacy and safety; (2) PEG IFN-α resulted in a greater decline in HBV DNA levels and a higher rate of HBeAg seroconversion; (3) combination therapy with IFN plus two analogues did not elevate the rate of sustained responses; (4) both ETV and TDF showed efficacy and safety with cirrhosis (ETV especially displayed efficacy and safety with decompensated cirrhosis), and (5) suppression of HCC was observed by ETV and IFN.

Association between adefovir dipivoxil treatment and the risk of renal insufficiency in patients with chronic hepatitis B: A meta-analysis

Adefovir dipivoxil (ADV) is an effective antiviral drug against hepatitis B virus. The renal tolerance of ADV at the currently approved dose of 10 mg daily for the treatment of chronic hepatitis B (CHB) remains controversial. The present meta-analysis was therefore performed to evaluate the renal safety of ADV treatment in patients with CHB. Two independent investigators searched MEDLINE, Embase and China National Knowledge Infrastructure databases for eligible studies published in English or Chinese until June 1, 2014. The Peto odds ratios (Peto ORs) or the rates of each study were analyzed. Seven randomized controlled trials (RCTs), four cohort studies and six single-arm studies were identified. ADV treatment was not associated with a higher incidence of nephrotoxicity in RCTs [Peto OR, 1.781; 95% confidence interval (CI), 0.637-4.979; P=0.271] but appeared to increase nephrotoxicity significantly in cohort studies (Peto OR, 2.682; 95% CI, 1.470-4.894; P=0.001); the significant increase was further observed in CHB patients receiving long-term ADV treatment in cohort studies (Peto OR, 2.275; 95% CI, 1.127-4.593; P=0.022). The analysis based on single-arm studies showed that the rate of renal dysfunction in the ADV-treated patients was 10.6% (95% CI, 0.059-0.185); the subgroup analysis with the standard of createnine levels showed a lower rate (6.9%, 95% CI, 0.013-0.298) than those in the overall studies. In conclusion, although current evidence indicated a positive link between treatment with ADV in CHB patients and an increased risk of renal dysfunction, optimally designed studies are required for definitive conclusions.

Prophylaxis against Recurrence in Liver Transplantation Patients with Hepatitis B Virus: What is New?

Hepatitis B virus (HBV) causes an endemic infection that affects nearly 2 billion patients worldwide. It is one of the leading causes of liver cirrhosis, hepatocellular carcinoma (HCC), and liver transplantation (LT). Recurrence of HBV infection after LT is due to specific HBV-host genome interactions. Although hepatitis B immunoglobulin treatment constituted the backbone of HBV recurrence, use of the nucleoside and nucleotide analogs (especially the ones with a higher genetic barrier to resistance), either alone or in combination, offer us new and powerful options in overcoming this serious issue.

Rescue therapy with adefovir in decompensated liver cirrhosis patients with lamivudine-resistant hepatitis B virus

Background/Aims

Adefovir dipivoxil (ADV) is a nucleotide analogue that is effective against lamivudine-resistant hepatitis B virus (HBV). The aim of this study was to determine the long-term clinical outcomes after ADV rescue therapy in decompensated patients infected with lamivudine-resistant HBV.

Methods

In total, 128 patients with a decompensated state and lamivudine-resistant HBV were treated with ADV at a dosage of 10 mg/day for a median of 33 months in this multicenter cohort study.

Results

Following ADV treatment, 86 (72.3%) of 119 patients experienced a decrease in Child-Pugh score of at least 2 points, and the overall end-stage liver disease score decreased from 16±5 to 14±10 (mean ± SD, P<0.001) during the follow-up period. With ADV treatment, 67 patients (56.3%) had undetectable serum HBV DNA (detection limit, 0.5 pg/mL). Virologic breakthrough occurred in 38 patients (36.1%) and 9 patients had a suboptimal ADV response. The overall survival rate was 89.9% (107/119), and a suboptimal response to ADV treatment was associated with both no improvement in Child-Pugh score (≥2 points; P=0.001) and high mortality following ADV rescue therapy (P=0.012).

Conclusions

Three years of ADV treatment was effective and safe in decompensated patients with lamivudine-resistant HBV.

Comparison of the antiviral effects of different nucleos(t)ide analogues in chinese patients with chronic hepatitis B: a head-to-head study

BACKGROUND/AIMS

To assess the antiviral efficacy of lamivudine (LAM), entecavir (ETV), telbivudine (LDT), and lamivudine and adefovir dipivoxil (CLA) combination in previously untreated hepatitis B patients at different time points during a 52-week treatment period.

PATIENTS AND METHODS

A total of 164 patients were included in this prospective, open-label, head-to-head study. Serum levels of alanine transaminase (ALT), hepatitis B virus (HBV) DNA, and hepatitis B e antigen (HBeAg) were measured at baseline, and at 12, 24, and 52 weeks of treatment.

RESULTS

Median reductions in serum HBV DNA levels at 52 weeks (log 10 copies/mL) were as follows: LAM, 3.98; ETV, 3.89; LDT, 4.11; and CLA, 3.36. The corresponding HBV DNA undetectability rates were 83%, 96%, 91%, and 89%, respectively. These two measures showed no significant intergroup differences. Clinical efficacy appeared related to HBV DNA level reduction after 24 weeks of therapy. Patients were divided into three groups based on HBV DNA levels at week 24: Undetectable (<10(3) copies/mL), detectable but <10(4) copies/mL, and >10(4) copies/mL. Patients with levels below quantitation limit (QL) were analyzed at 52 weeks for HBV DNA undetectability rate (94%), ALT normalization rate (83%), and viral breakthrough rate (0%). The corresponding values in the QL-10(4) copies/mL group were 50%, 75%, and 13%, whereas those in the above 10(4) copies/mL group were 53%, 65%, and 18%. There were significant differences at week 52 for HBV DNA levels and viral breakthrough rate between the three groups.

CONCLUSIONS

Different nucleos(t)ide (NUC) analogues tested exhibited no significant differences in effectiveness for Chinese NUC-naive HBV patients during 1-year treatment period.

De novo combined lamivudine and adefovir dipivoxil therapy vs entecavir monotherapy for hepatitis B virus-related decompensated cirrhosis

AIM: To compare efficacy of combined lamivudine (LAM) and adefovir dipivoxil (ADV) therapy with that of entecavir (ETV) monotherapy for hepatitis B virus (HBV)-related decompensated liver cirrhosis.

METHODS: A total of 120 naïve patients with HBV-related decompensated cirrhosis participated in this study. Sixty patients were treated with combined LAM and ADV therapy (LAM + ADV group), while the other 60 were treated with ETV monotherapy (ETV group) for two years. Tests for liver and kidney function, alpha-fetoprotein, HBV serum markers, HBV DNA load, prothrombin time (PT), and ultrasonography or computed tomography scan of the liver were performed every 1 to 3 mo. Repeated measure ANOVA and the χ² test were performed to compare the efficacy, side effects, and the cumulative survival rates at 48 and 96 wk.

RESULTS: Forty-five patients in each group were observed for 96 wk. No significant differences in HBV DNA negative rates and alanine aminotransferase (ALT) normalization rates at weeks 48 (χ² = 2.12 and 2.88) and 96 (χ² = 3.21 and 3.24) between the two groups were observed. Hepatitis B e antigen seroconversion rate in the LAM + ADV group at week 96 was significantly higher in the ETV group (43.5% vs 36.4%, χ² = 4.09, P < 0.05). Viral breakthrough occurred in 2 cases (4.4%) by week 48 and in 3 cases (6.7%) by week 96 in the LAM + ADV group, and no viral mutation was detected. In the ETV group, viral breakthrough occurred in 1 case (2.2%) at the end of week 96. An increase in albumin (F = 18.9 and 17.3), decrease in total bilirubin and in ALT (F = 16.5, 17.1 and 23.7, 24.8), reduced PT (F = 22.7 and 24.5), and improved Child-Turcotte-Pugh and the model for end-stage liver disease scores (F = 18.5, 17.8, and 24.2, 23.8) were observed in both groups. The cumulative rates of mortality and liver transplantation were 16.7% (10/60) and 18.3% (11/60) in the LAM + ADV and ETV groups, respectively.

CONCLUSION: Both LAM + ADV combination therapy and ETV monotherapy can effectively inhibit HBV replication, improve liver function, and decrease mortality.

Outcome of various treatments for posttransplant hepatitis B virus recurrence

BACKGROUND

Currently, no treatment guidelines are available for posttransplant hepatitis B virus (HBV) recurrence. We retrospectively evaluated the rate of clearance of hepatitis B surface antigen (HBsAg) from serum according to various treatment regimens in two large Korean liver transplantation centers.

METHODS

Between 1996 and 2008, HBV recurred in 59 patients among 933 HBV liver recipients (6.3 %). Patients with HBV recurrence were divided into four groups according to their treatment: group L (lamivudine-based therapy n = 21) and group N [new nucleos(t)ide analogue (NA)-based therapy, n = 38]. Intravenous hepatitis B immunoglobulin (ivHBIG) had been simultaneously administered to 10 patients in group L and 26 patients in group N. The mean posttransplant follow-up duration and time to HBV recurrence were 69 (14-152) months and 37 (3-120) months.

RESULTS

Overall, 22 patients (37.3 %) showed seronegative conversion of HBsAg for a median 8 months after treatment (range 1-15 months). The seroclearance rate was significantly higher in group N (n = 20, 52.6 %) than in group L (n = 2, 9.5 %) (p < 0.000). The time to seroconversion did not differ between group L (7 months, range 5-16) and group N (7 months, range 1-15) (p = 0.428). Subgroup analysis showed that the HBsAg seroconversion rate was much higher for patients given combined ivHBIG and new NAs (15/26 patients, 58.0 %) than the others (p = 0.006).

CONCLUSIONS

Seroclearance of HBsAg could be achieved using new NAs in half of the patients after posttransplant HBV recurrence. Combined ivHBIG may add a synergistic effect to new NAs for clearing HBsAg.

Effects of nucleoside analogue on patients with chronic hepatitis B-associated liver failure: meta-analysis

Purpose

The effectiveness of nucleoside analogue on patients with chronic hepatitis B-associated liver failure is still controversial. To address this issue, we did a review of the literatures and analyzed the data with emphasis on the survival and reduction in serum HBV DNA level.

Methods

We searched 11 randomized controlled trials that included 654 patients with chronic hepatitis B-associated liver failure. 340 patients adopted nucleoside analogue, such as lamivudine (LAM), entecavir (ETV), telbivudine (LdT), or tenofovir disoproxil fumarate (TDF), and the remaining 314 patients adopted no nucleoside analogue or placebo. A meta-analysis was carried out to examine the survival, HBV e antigen serologic conversion, and reduction in serum HBV DNA level. The pooled odds ratio (OR) was used to reflect the treatment effects.

Results

The overall analysis revealed nucleoside analogue significantly improved 1-month(OR = 2.10; 95% CI, [1.29, 3.41]; p = 0.003), 3-month (OR = 2.15; 95% CI, [1.26, 3.65]; p = 0.005), 12-month survival (OR = 4.62; 95% CI, [1.96, 10.89]; p = 0.0005). Comparison of 3-month HBV DNA showed significant reduction for adoptive nucleoside analogue patients (OR = 54.47; 95% CI, [16.37, 201.74]; p<0.00001). Comparison of 3-month HBV e antigen serologic conversion showed a highly significant improvement of HBV e antigen lost for patients received adoptive antiviral therapy (OR = 6.57; 95% CI, [1.64, 26.31]; p = 0.008).

Conclusions

The benefits of nucleoside analogue on patients with chronic hepatitis B-associated liver failure is significant for improving patient survival, HBV e antigen serologic conversion, and rapid reduction of HBV DNA levels.

Direct acting antivirals for the treatment of chronic viral hepatitis

The development and evaluation of antiviral agents through carefully designed clinical trials over the last 25 years have heralded a new dawn in the treatment of patients chronically infected with the hepatitis B and C viruses, but not so for the D virus (HBV, HCV, and HDV). The introduction of direct acting antivirals (DDAs) for the treatment of HBV carriers has permitted the long-term use of these compounds for the continuous suppression of viral replication, whilst in the case of HCV in combination with the standard of care [SOC, pegylated interferon (PegIFN), and ribavirin] sustained virological responses (SVRs) have been achieved with increasing frequency. Progress in the case of HDV has been slow and lacking in significant breakthroughs.This paper aims to summarise the current state of play in treatment approaches for chonic viral hepatitis patients and future perspectives.

A case of adefovir-induced membranous nephropathy related to hepatitis B caused by lamivudine-resistant virus after liver transplant due to Byler's disease

We report on how adefovir-induced membranous nephropathy related to hepatitis B was caused by lamivudine-resistant virus after a liver transplant due to Byler's disease. In 1980, a 2-year-old girl was diagnosed with Byler's disease (familial progressive familial intrahepatic cholestasis). In 1994 (at the age of 14 years) she underwent a liver transplant with her father as the donor. In 2003, hematuria and proteinuria appeared and shortly afterwards her renal function rapidly decreased. A renal biopsy showed atypical membranous nephropathy, which suggested the possibility of a secondary renal disease. The patient had suffered from chronic hepatitis type B (HBV). In 2001 she was administered lamivudine which is an antiviral drug; it was around this time that hematuria and proteinuria appeared as well as an increase of the virus titer. We believed the HBV-related membranous nephropathy was the cause of the virus titer and the renal histology. We concluded that the patient's condition had become resistant to lamivudine medication. Therefore, in February 2004 we administered adefovir, a new drug at the time, to treat the HBV. In April 2004, the HB virus titer decreased and the hematuria and proteinuria decreased. The patient's renal function also showed improvement. HBV-associated nephropathy is caused by HBV antigen deposition in the glomeruli. Generally the first choice of treatment is antivirus therapy. There are many reports demonstrating that administration of interferon and lamivudine are effective; however, there are few reports that show adefovir as an effective treatment for HBV-associated nephropathy.

KASL Clinical Practice Guidelines: Management of chronic hepatitis B

The guideline on the management of chronic hepatitis B (CHB) was first developed in 2004 and revised in 2007 by the Korean Association for the Study of the Liver (KASL). Since then there have been many developments, including the introduction of new antiviral agents and the publications of many novel research results from both Korea and other countries. In particular, a large amount of knowledge on antiviral resistance--which is a serious issue in Korea--has accumulated, which has led to new strategies being suggested. This prompted the new guideline discussed herein to be developed based on recent evidence and expert opinion.

TARGET POPULATION

The main targets of this guideline comprise patients who are newly diagnosed with CHB and those who are followed or treated for known CHB. This guideline is also intended to provide guidance for the management of patients under the following special circumstances: malignancy, transplantation, dialysis, coinfection with other viruses, pregnancy, and children.

Asian-Pacific consensus statement on the management of chronic hepatitis B: a 2012 update

Large volume of new data on the natural history and treatment of chronic hepatitis B virus (HBV) infection have become available since 2008. These include further studies in asymptomatic subjects with chronic HBV infection and community-based cohorts, the role of HBV genotype/naturally occurring HBV mutations, the application of non-invasive assessment of hepatic fibrosis and quantitation of HBV surface antigen and new drug or new strategies towards more effective therapy. To update HBV management guidelines, relevant new data were reviewed and assessed by experts from the region, and the significance of the reported findings was discussed and debated. The earlier "Asian-Pacific consensus statement on the management of chronic hepatitis B" was revised accordingly. The key terms used in the statement were also defined. The new guidelines include general management, indications for fibrosis assessment, time to start or stop drug therapy, choice of drug to initiate therapy, when and how to monitor the patients during and after stopping drug therapy. Recommendations on the therapy of patients in special circumstances, including women in childbearing age, patients with antiviral drug resistance, concurrent viral infection, hepatic decompensation, patients receiving immune suppression or chemotherapy and patients in the setting of liver transplantation and hepatocellular carcinoma, are also included.

Telbivudine in combination with adefovir versus adefovir monotherapy in HBeAg-positive, lamivudine-resistant chronic hepatitis B

PURPOSE

Lamivudine (LAM) resistance is common on lamivudine monotherapy for chronic hepatitis B. This study examined the safety and efficacy of telbivudine (LDT) given with adefovir (ADV) versus ADV monotherapy in patients with chronic, lamivudine-resistant HBV infection.

METHODS

An open-label, 96 week study with planned recruitment of 150 HBeAg-positive, lamivudine-experienced Asian patients with a confirmed YMDD resistance mutation, randomized 1:1 to receive ADV alone or with LDT. The study was terminated early due to difficulty in enrolling monotherapy patients. At termination, 42 patients had received study medication for 8-61 weeks. Due to incomplete enrolment, summary statistics only were prepared, without significance testing.

RESULTS

A total of 42 patients underwent rescue therapy (switch to ADV or LDT + ADV; n = 21 per group). Median treatment duration was 48 weeks in both groups. HBV DNA changes from baseline were greater in the LDT + ADV arm at all time points (Week 48: -7.4 log10 vs. -4.9 log10 copies/ml), and serum DNA was undetectable (<300 copies/mL) at week 48 in 38.5% (5/13) on LDT + ADV versus 0% (0/9) on ADV monotherapy Two patients (9.6%) on ADV monotherapy experienced virologic breakthrough without evidence of ADV resistance, but none on LDT + ADV; and no confirmed ADV resistance was observed in any on-treatment sample. HBeAg loss occurred in three patients on LDT + ADV and one patient on ADV monotherapy through week 48. Safety profiles were similar between the arms.

CONCLUSION

LDT + ADV combination treatment showed better outcomes against lamivudine resistant HBV than ADV alone, with a similar safety profile.

Prevention of post liver transplant HBV recurrence

BACKGROUND

Twenty years ago, liver transplantation for hepatitis B had been a relative contraindication to universal HBV recurrence and poor outcomes. Over the ensuing two decades, there has been refinement of prevention strategies in order to minimize HBV recurrence in the allograft.

RESULTS

Currently, the most efficacious and cost-effective strategies include newer oral antiviral drugs in combination with low doses of hepatitis B immunoglobulin (HBIG). More recently, strategies have been successful in withdrawing HBIG and newer approaches of HBIG avoidance are currently under development.

CONCLUSION

Thus, 20 years afterward, HBV recurrence is <5% and outcomes following liver transplantation are excellent.

Recent advances in the management of chronic hepatitis B

There are seven approved treatments for adults with chronic hepatitis B virus infection in the United States and European countries: interferon-α, pegylated interferon-α, lamivudine, adefovir dipivoxil, entecavir, telbivudine, and tenofovir disoproxil fumarate. At present, two new analogues, entecavir and tenofovir are recommended as the first line therapy by the guidelines of European Association for the Study of the Liver and American Association Study for the Liver Diseases. On the other hand, regarding interferon therapy, use of pegylated interferon-α is recommended as the first line therapy instead of standard interferon-α by both guidelines. Therefore, the main scientific interests and unmet medical needs for treatment of chronic hepatitis B have been narrowed down to long-term efficacy and safety of the two said analogues-entecavir and tenofovir-and combination therapy of pegylated interferon-α with the two analogues. To put it concretely, further studies are needed to assess (1) the long-term efficacy and safety and resistance to entecavir and tenofovir; (2) the efficacy of different durations (24 weeks to 2 years) and lower doses of pegylated interferon-α; (3) the role of combination therapy with two analogues to reduce resistance; and (4) the efficacy and safety of the two analogues with decompensated cirrhosis. Herein, we review the recent available data and results.

A randomized, multi-central, controlled study of patients with hepatitis B e antigen-positive chronic hepatitis B treated by adefovir dipivoxil or adefovir dipivoxil plus bicyclol

Objective

To evaluate the efficacy and safety profiles of patients with hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) treated with adefovir dipivoxil (ADV) or ADV plus bicyclol, and to optimize the treatment strategy for CHB patients.

Patients and methods

A total of 250 patients with HBeAg-positive CHB were randomized to ADV plus bicyclol combination group and ADV monotherapy group. The patients in the ADV plus bicyclol combination therapy group (n = 125) received ADV 10 mg orally q.d. and bicyclol 25 mg orally t.i.d. for 48 weeks, and those in the ADV monotherapy group (n = 125) were administered ADV 10 mg orally q.d. alone for 48 weeks. The serum aminotransferases (ALT/AST), HBV DNA, HBeAg/HBeAb, and liver biopsy were conducted before and after therapy.

Results

The serum aminotransferase levels were decreased significantly in both groups. The serum aminotransferase level in ADV plus bicyclol combination therapy group decreased greater than that in ADV monotherapy group (P < 0.01). The virological response rate in ADV plus bicyclol combination therapy group was not significantly different from that in ADV monotherapy group (P > 0.05). After treatment for 48 weeks, the Knodell necroinflammatory score of the two groups were all alleviated significantly, and the Knodell score in the combination group was significantly lower than that in the ADV monotherapy group (P < 0.05). There were no remarkable adverse events probably related to the drug in this study.

Conclusion

Adefovir dipivoxil plus bicyclol combination therapy is a safe and superior treatment regimen for patients with HBeAg-positive CHB when compared with ADV monotherapy.

Treatment of hepatitis B in decompensated liver cirrhosis

Chronic hepatitis B infection progresses from an asymptomatic persistently infected state to chronic hepatitis, cirrhosis, decompensated liver disease, and/or hepatocellular carcinoma. About 3% of patients with chronic hepatitis develop cirrhosis yearly, and about 5% of individuals with hepatitis B cirrhosis become decompensated annually. The outcome for patients with decompensated cirrhosis is bleak. Lamivudine, the first oral antiviral agent available for hepatitis B treatment is safe and effective and can improve or stabilize liver disease in patients with advanced cirrhosis and viraemia. Viral resistance restricts its prolonged use. Entecavir and tenofovir are newer agents with excellent resistance profile to date. These and some other antiviral agents are being investigated for optimal use in this rather challenging patient group.

Trends in all cause and viral liver disease-related hospitalizations in people with hepatitis B or C: a population-based linkage study

Background

Previous studies have reported an excess burden of cancer and mortality in populations with chronic hepatitis B (HBV) or C (HCV), but there are limited data comparing hospitalization rates. In this study, we compared hospitalization rates for all causes and viral liver disease in people notified with HBV or HCV in New South Wales (NSW), Australia.

Methods

HBV and HCV notifications were linked to their hospital (July 2000-June 2006), HIV and death records. Standardized hospitalization ratios (SHRs) were calculated using rates for the NSW population. Random effects Poisson regression was used to examine temporal trends.

Results

The SHR for all causes and non alcoholic liver disease was two-fold higher in the HCV cohort compared with the HBV cohort (SHRs 1.4 (95%CI: 1.4-1.4) v 0.6 (95%CI: 0.6-0.6) and 14.0 (95%CI: 12.7-15.4) v 5.4 (95%CI: 4.5-6.4), respectively), whilst the opposite was seen for primary liver cancer (SHRs 16.2 (95%CI: 13.8-19.1) v 29.1 (95%CI: 24.7-34.2)). HIV co-infection doubled the SHR except for primary liver cancer in the HCV/HIV cohort. In HBV and HCV mono-infected cohorts, all cause hospitalization rates declined and primary liver cancer rates increased, whilst rates for non alcoholic liver disease increased by 9% in the HCV cohort but decreased by 14% in the HBV cohort (P < 0.001).

Conclusion

Hospital-related morbidity overall and for non alcoholic liver disease was considerably higher for HCV than HBV. Improved treatment of advanced HBV-related liver disease may explain why HBV liver-related morbidity declined. In contrast, HCV liver-related morbidity increased and improved treatments, especially for advanced liver disease, and higher levels of treatment uptake are required to reverse this trend.

Extended treatment with lamivudine and adefovir dipivoxil in chronic hepatitis B patients with lamivudine resistance

PURPOSE

We and others have reported that adding adefovir dipivoxil (adefovir) to lamivudine results in virological and biochemical improvement in cases of lamivudine resistance. The current study assessed the efficacy and safety of combined therapy after 104 weeks of combined treatment and analyzed the frequency of persistent lamivudine resistant HBV.

METHODS

A total of 78 patients with compensated CHB (Group A) were maintained on either adefovir 10 mg daily (n = 38) or placebo (n = 40) while continuing lamivudine. An additional 38 patients with decompensated cirrhosis or post liver transplantation (Group B) received lamivudine plus adefovir. The primary endpoint was HBV DNA response at year 2.

RESULTS

At week 104 of therapy, a significantly greater proportion of patients in Group A on combination therapy (76%) had a decline in serum HBV DNA to ≤10(5) copies or >2 log(10) reduction from baseline compared to those receiving lamivudine alone (13%; p < 0.001). Fifty-two percent of Group A patients on combination treatment continued to have the M204V/I HBV mutation compared to 92% receiving lamivudine alone (p = 0.0013). Virologic response occurred less frequently in patients expressing persistent lamivudine resistant HBV. In Group B, 87% of patients had HBV DNA response at week 104 (median change from baseline of -5.84 log(10) copies/mL).

CONCLUSIONS

The combination of lamivudine and adefovir for 2 years generally proved effective in lamivudine-resistant cases, but there was a persistently high rate of detection of lamivudine resistant mutants and impaired virologic response in compensated patients.

Development of osteomalacia in a post-liver transplant patient receiving adefovir dipivoxil

We report the case of a patient treated with living donor-related liver transplantation who suffered from osteomalacia during adefovir dipivoxil (ADV)-containing antiviral therapy for lamivudine-resistant hepatitis B virus infection. The patient had generalized bone pain, with severe hypophosphatemia after 20 mo of ADV therapy. Radiographic studies demonstrated the presence of osteomalacia. The peak plasma ADV level was 38 ng/mL after administration of ADV at 10 mg/d. It was also found that ADV affected the metabolism of tacrolimus, a calcineurin-inhibitor, and caused an increase in the plasma levels of tacrolimus. The disability was reversed with the withdrawal of ADV and with mineral supplementation. ADV can cause an elevation of plasma tacrolimus levels, which may be associated with renal dysfunction. High levels of ADV and tacrolimus can cause nephrotoxicity and osteomalacia. This case highlights the importance of considering a diagnosis of osteomalacia in liver transplantation recipients treated with both ADV and tacrolimus.

Hepatitis B virus infection and renal transplantation

Although the prevalence of chronic hepatitis B virus (HBV) infection has declined in renal transplant recipients (RTRs), it remains a relevant clinical problem with high morbidity and mortality in long-term follow up. A thorough evaluation, including liver biopsy as well as assessment of HBV replication in serum (i.e. hepatitis B e antigen and/or HBV DNA) is required before transplantation. Interferon should not be used in this setting because of low efficacy and precipitation on acute allograft rejection. The advent of effective antiviral therapies offers the opportunity to prevent the progression of liver disease after renal transplantation. However, as far as we are aware, no studies have compared prophylactic and preemptive strategies. To date, the majority of RTRs with HBV-related liver disease have had a high virological and biochemical response to lamivudine use. However, lamivudine resistance is frequent with a prolonged course of therapy. Considering long-term treatment, antiviral agents with a high genetic barrier to resistance and lack of nephrotoxicity are suggested. The optimal strategy in RTRs with HBV infection remains to be established in the near future.

Antiviral drug resistance: mechanisms and clinical implications

Antiviral drug resistance is an increasing concern in immunocompromised patient populations, where ongoing viral replication and prolonged drug exposure lead to the selection of resistant strains. Rapid diagnosis of resistance can be made by associating characteristic viral mutations with resistance to various drugs as determined by phenotypic assays. Management of drug resistance includes optimization of host factors and drug delivery, selection of alternative therapies based on knowledge of mechanisms of resistance, and the development of new antivirals. This article discusses drug resistance in herpesviruses and hepatitis B.

Virologic response at 12 months of treatment predicts sustained antiviral efficacy in patients with adefovir-treated Lamivudine-resistant chronic hepatitis B

BACKGROUND/AIMS

The aim of our study was to define the potential role of virologic response at 12 months of treatment (VR12) in predicting subsequent virologic and clinical outcomes in adefovir (ADV)-treated lamivudine-resistant chronic hepatitis B.

METHODS

Two hundred and four patients with lamivudine-resistant chronic hepatitis B virus (HBV) treated with ADV monotherapy were included. Serum HBV DNA was quantified by real-time polymerase chain reactions. VR12 was defined as a HBV DNA level of less than 4 log(10) copies/mL after 12 months of ADV treatment.

RESULTS

VR12 was observed in 110 of the 204 patients (54%). The mean HBV DNA reductions from baseline after 12 months of ADV treatment were 3.8 and 1.9 log(10) copies/mL in patients with and without VR12, respectively (p<0.001). The hepatitis B "e" antigen (HBeAg) seroconversion rates in patients with and without VR12 were 32% and 14% at 12 months treatment, respectively (p=0.018), and 40% and 27% at 24 months of treatment (p=0.032). The genotypic mutation rates to ADV in patients with and without VR12 were 0% and 6% at 12 months of treatment, respectively (p=0.033), and 21% and 42% at 24 months (p=0.012). The rates of viral breakthrough in patients with and without VR12 were 0% and 7% at 12 months of treatment, respectively (p=0.072), and 9% and 25% at 24 months (p=0.006).

CONCLUSIONS

Patients without VR12 may need to switch to or add on other potent antiviral drugs in their medical regimens.

Current therapeutic strategies for recurrent hepatitis B virus infection after liver transplantation

Hepatitis B virus (HBV)-related liver disease is the leading indication for liver transplantation (LT) in Asia, especially in China. With the introduction of hepatitis B immunoglobulin (HBIG) and oral antiviral drugs, the recurrent HBV infection rate after LT has been evidently reduced. However, complete eradication of recurrent HBV infection after LT is almost impossible. Recurrent graft infection may lead to rapid disease progression and is a frequent cause of death within the first year after LT. At present, the availability of new oral medications, especially nucleoside or nucleotide analogues such as adefovir dipivoxil, entecavir and tenofovir disoproxil fumarate, further strengthens our ability to treat recurrent HBV infection after LT. Moreover, since combined treatment with HBIG and antiviral agents after liver re-transplantation may play an important role in improving the prognosis of recurrent HBV infection, irreversible graft dysfunction secondary to recurrent HBV infection in spite of oral medications should no longer be considered an absolute contraindication for liver re-transplantation. Published reviews focusing on the therapeutic strategies for recurrent HBV infection after LT are very limited. In this article, the current therapeutic strategies for recurrent HBV infection after LT and evolving new trends are reviewed to guide clinical doctors to choose an optimal treatment plan in different clinical settings.

Trends in waiting list registration for liver transplantation for viral hepatitis in the United States

BACKGROUND & AIMS

In the last decade, significant progress has been made in the treatment of liver disease associated with chronic hepatitis, especially in patients infected with the hepatitis B virus (HBV). To investigate whether the population-wide application of antiviral therapies has impacted liver transplant waiting list registration, we analyzed longitudinal trends in waiting list registration for patients with hepatitis B and C and those with nonviral liver disease.

METHODS

This study represented a retrospective analysis of registry data containing all US liver transplant centers. All adult, primary liver transplantation candidates registered to the Organ Procurement and Transplantation Network between 1985 and 2006 were included in the analysis. Standardized incidence rates were calculated for waiting list registration for liver transplantation by underlying disease (HBV and HCV infection and other) and by indication for transplantation (fulminant liver disease, hepatocellular carcinoma [HCC], and end-stage liver disease [ESLD]).

RESULTS

Of 113,927 unique waiting list registrants, 4793 (4.2%) had HBV, and 40,923 (35.9%) had HCV infections; the remaining 68,211 (59.9%) had neither. The incidence of waiting list registration for ESLD and fulminant liver disease decreased, whereas that for HCC increased. The decrease in ESLD registration was most pronounced, and the increase in HCC was least dramatic among registrants with hepatitis B. The decrease in registration for ESLD secondary to HCV infection was also significantly larger than that for ESLD patients with nonviral etiologies.

CONCLUSIONS

The pattern of liver transplantation waiting list registration among patients with hepatitis B suggests that the widespread application of oral antiviral therapy for HBV contributed to the decreased incidence of decompensated liver disease.

Current prophylactic strategies against hepatitis B virus recurrence after liver transplantation

Prophylactic strategies against hepatitis B virus (HBV) recurrence after liver transplantation (LT) are essential for patients with HBV-related disease. Before LT, lamivudine (LAM) was proposed to be down-graded from first- to second-line therapy. In contrast, adefovir dipivoxil (ADV) has been approved not only as first-line therapy but also as rescue therapy for patients with LAM resistance. Furthermore, combination of ADV and LAM may result in lower risk of ADV resistance than ADV monotherapy. Other new drugs such as entecavir, telbivudine and tenofovir, are probably candidates for the treatment of hepatitis-B-surface-antigen-positive patients awaiting LT. After LT, low-dose intramuscular hepatitis B immunoglobulin (HBIG), in combination with LAM, has been regarded as the most cost-effective regimen for the prevention of post-transplant HBV recurrence in recipients without pretransplant LAM resistance and rapidly accepted in many transplant centers. With the introduction of new antiviral drugs, new hepatitis B vaccine and its new adjuvants, post-transplant HBIG-free therapeutic regimens with new oral antiviral drug combinations or active HBV vaccination combined with adjuvants will be promising, particularly in those patients with low risk of HBV recurrence.

Polymorphism rtQ215H in primary resistance to adefovir dipivoxil in hepatitis B virus infection: a case report

The benefit of lamivudine (LAM) in hepatitis B virus (HBV) infection is compromised by the progressively increasing emergence of drug-resistant mutant strains. Although the addition of adefovir dipivoxil (ADV) usually induces complete suppression of viral replication, primary non-response to ADV in LAM resistant patients has been reported in a variable percentage of cases. Here we report a case of a patient with HBV infection and hepatocellular carcinoma who started LAM therapy and subsequently developed virological breakthrough. The patient was given ADV, but HBV-DNA negativisation was not reached. However, HBV clearance was obtained when the patient was switched from ADV to tenofovir. Virological evaluations showed two well-known LAM-related mutations (rtL180M and rtM204I) in addition to reverse-transcriptase rtQ215H. This is the first case suggesting that this mutation may have an impact on viral replication. Finally, we also report that rtQ215H is responsive to tenofovir.

Rapid re-emergence of YMDD mutation of hepatitis B virus with hepatic decompensation after lamivudine retreatment

Lamivudine has a high rate of antiviral resistance. Sequential treatment of anti-hepatitis B virus (HBV) is commonly used for lamivudine resistance. We report 4 cases of patients with rapid redetection of HBV mutants during the lamivudine retreatment. The four patients received lamivudine as an initial treatment of HBV and adefovir and lamivudine as a rescue therapy consecutively. HBV-DNA level, YMDD mutations and adefovir -resistant mutations (RFMP) were tested every 3 mo during the sequential treatment. All the patients showed YMDD mutations during the initial lamivudine therapy. After adefovir therapy for lamivudine resistance, they showed viral breakthrough. Adefovir was switched to lamivudine, however, it did not induce viral suppression at all, rather increased HBV-DNA with rapid reemergence of the YMDD mutations. All the patients had ALT flares, and hepatic decompensation occurred in two patients. After switching to adefovir combined with entecavir or lamivudine for a rescue therapy, the patients had reduction in HBV-DNA and ALT improvement. These cases demonstrated that lamivudine retreatment of patients with preexposed lamivudine resistance leads to rapid reemergence of YMDD mutation with significant viral rebounds and subsequent hepatic decompensation. Sequential administration of lamivudine in patients with a prior history of YMDD mutation should be abandoned.

Tenofovir (TDF) has stronger antiviral effect than adefovir (ADV) against lamivudine (LAM)-resistant hepatitis B virus (HBV)

OBJECTIVES

We retrospectively compared the antiviral effect of tenofovir disoproxil fumarate (TDF) with that of adefovir dipivoxil (ADV) for patients with chronic hepatitis B (CHB) who developed resistance to lamivudine (LAM).

MATERIALS AND METHODS

One hundred nine patients (86 males), all Asian-American except 1 Caucasian male, with LAM resistance received TDF or ADV. HBV DNA levels were measured every 3 months. The HBeAg loss and ALT normalization were assessed at 12 months on therapy.

RESULTS

Forty-four patients (37 males) received TDF (12 with LAM) and 65 (49 males) received ADV (18 with LAM). Median ages (years) for TDF and ADV were 49 (32-68) and 45 (22-68), respectively. Median duration of therapy was 13 months (6-38) and 17 months (6-34) for the TDF and ADV groups. Baseline HBV DNA levels (log(10) copies/ml) were 6.2 +/- 1.7 for the TDF and 6.5 +/- 1.6 for ADV groups. Baseline ALT (IU/l) levels were 77.0 +/- 86.0 and 100 +/- 195 for the TDF and ADV (P = 0.46) groups, respectively. At 12 months, mean levels of log(10) HBV DNA were 1.5 +/- 1.0 and 4.3 +/- 2.2 for TDF and ADV (P = 0.01). HBeAg loss and ALT normalization at 12 months showed no differences. Using a single factor, ANOVA (2-tailed P value), 4 groups, TDF (n = 32), TDF + LAM (12), ADV (47), and ADV + LAM (18), were compared. HBV DNA reduction at 12 months was the greatest for TDF + LAM (P < 0.001).

CONCLUSIONS

Our results suggest that for LAM-resistant HBV, TDF, alone or combined with LAM exerts greater viral reduction than ADV. However, no difference in HBeAg loss was observed. It appears that stronger HBV DNA reduction may not necessarily accelerate HBeAg loss.

Asian-Pacific consensus statement on the management of chronic hepatitis B: a 2008 update

Large amounts of new data on the natural history and treatment of chronic hepatitis B virus (HBV) infection have become available since 2005. These include long-term follow-up studies in large community-based cohorts or asymptomatic subjects with chronic HBV infection, further studies on the role of HBV genotype/naturally occurring HBV mutations, treatment of drug resistance and new therapies. In addition, Pegylated interferon alpha2a, entecavir and telbivudine have been approved globally. To update HBV management guidelines, relevant new data were reviewed and assessed by experts from the region, and the significance of the reported findings were discussed and debated. The earlier "Asian-Pacific consensus statement on the management of chronic hepatitis B" was revised accordingly. The key terms used in the statement were also defined. The new guidelines include general management, special indications for liver biopsy in patients with persistently normal alanine aminotransferase, time to start or stop drug therapy, choice of drug to initiate therapy, when and how to monitor the patients during and after stopping drug therapy. Recommendations on the therapy of patients in special circumstances, including women in childbearing age, patients with antiviral drug resistance, concurrent viral infection, hepatic decompensation, patients receiving immune-suppressive medications or chemotherapy and patients in the setting of liver transplantation, are also included.

Asian-Pacific consensus statement on the management of chronic hepatitis B: a 2008 update

Large amounts of new data on the natural history and treatment of chronic hepatitis B virus (HBV) infection have become available since 2005. These include long-term follow-up studies in large community-based cohorts or asymptomatic subjects with chronic HBV infection, further studies on the role of HBV genotype/naturally occurring HBV mutations, treatment of drug resistance and new therapies. In addition, Pegylated interferon alpha2a, entecavir and telbivudine have been approved globally. To update HBV management guidelines, relevant new data were reviewed and assessed by experts from the region, and the significance of the reported findings were discussed and debated. The earlier "Asian-Pacific consensus statement on the management of chronic hepatitis B" was revised accordingly. The key terms used in the statement were also defined. The new guidelines include general management, special indications for liver biopsy in patients with persistently normal alanine aminotransferase, time to start or stop drug therapy, choice of drug to initiate therapy, when and how to monitor the patients during and after stopping drug therapy. Recommendations on the therapy of patients in special circumstances, including women in childbearing age, patients with antiviral drug resistance, concurrent viral infection, hepatic decompensation, patients receiving immune-suppressive medications or chemotherapy and patients in the setting of liver transplantation, are also included.

Liver cirrhosis

Cirrhosis is defined as the histological development of regenerative nodules surrounded by fibrous bands in response to chronic liver injury, which leads to portal hypertension and end-stage liver disease. Recent advances in the understanding of the natural history and pathophysiology of cirrhosis, and in treatment of its complications, have resulted in improved management, quality of life, and life expectancy of patients. Liver transplantation remains the only curative option for a selected group of patients, but pharmacological treatments that can halt progression to decompensated cirrhosis or even reverse cirrhosis are currently being developed. This Seminar focuses on the diagnosis, complications, and management of cirrhosis, and new clinical and scientific developments.

Liver cirrhosis

Cirrhosis is defined as the histological development of regenerative nodules surrounded by fibrous bands in response to chronic liver injury, which leads to portal hypertension and end-stage liver disease. Recent advances in the understanding of the natural history and pathophysiology of cirrhosis, and in treatment of its complications, have resulted in improved management, quality of life, and life expectancy of patients. Liver transplantation remains the only curative option for a selected group of patients, but pharmacological treatments that can halt progression to decompensated cirrhosis or even reverse cirrhosis are currently being developed. This Seminar focuses on the diagnosis, complications, and management of cirrhosis, and new clinical and scientific developments.

Outcomes of patients with hepatitis B who developed antiviral resistance while on the liver transplant waiting list

BACKGROUND & AIMS

Lamivudine has been shown to improve liver disease and survival of hepatitis B virus patients on the orthotopic liver transplantation (OLT) waiting list, but liver failure might worsen in patients with drug resistance. Use of antiviral salvage therapy might decrease this risk.

METHODS

We analyzed data from patients enrolled in the NIH HBV OLT cohort to study the effects of pretransplant antiviral therapy on transplant-free survival and survival without transplant. We also compared the clinical outcomes of those who did or did not develop antiviral failure (virologic breakthrough or genotypic resistance) while awaiting transplant.

RESULTS

One hundred twenty-two eligible patients received antiviral therapy before OLT and were followed for a median of 40.5 months (range, 0.4-123.0 months) after initiation of antiviral therapy. Forty-four (36.1%) patients developed antiviral failure; all had lamivudine monotherapy as initial treatment. Forty-two patients started salvage therapy a median of 5 months after lamivudine failure; the median Model for End-Stage Liver Disease (MELD) score was 12. Twenty-one (50%) patients had a full response to salvage therapy. Eleven (26.2%) patients had a suboptimal virologic response but remained clinically compensated. Antiviral failure was not a significant predictor of transplant or death (P = .09) or death without transplant (P = .39). Multivariate predictors of transplant or death were high MELD score, hepatocellular carcinoma, and low albumin. High MELD score and low albumin were predictors of death without transplant.

CONCLUSIONS

Antiviral failure in patients with HBV on the OLT waiting list did not impair clinical outcome if recognized early and if salvage therapy is promptly initiated.

Viral blips during long-term treatment with standard or double dose lamivudine in HBe antigen negative chronic hepatitis B

AIM: To evaluate safety and effect on hepatitis B virus (HBV) suppression of a long-term treatment with lamivudine (LAM) at standard (100 mg/d) or double (200 mg/d) dose in chronic hepatitis B.

METHODS: This was a case study with matched controls (1:3) in patients with chronic hepatitis B with anti-HBe antibodies.

RESULTS: Twelve patients received LAM 200 mg/d and 35 LAM 100 mg/d, for a median of 28 mo. A primary response (PR; i.e., negative HBV-DNA with Amplicor assay) was achieved in 100% of LAM-200 patients and 83% of LAM-100 patients. A virological breakthrough occurred in 16.7 and 24.7%, respectively, of the PR-patients, with the appearance of typical LAM resistance mutations in all but one patient. Viremia blips (i.e., transient HBV-DNA below 80 IU/mL in patients who tested negative at Amplicor assay) were detected using a real time polymerase chain reaction (PCR) and occurred in seven out of nine patients with subsequent BT and in four out of 32 patients with end-of-study response (77.7% vs 12.5%; P = 0.001) at chi-square test). At the end of the study, 51.4% of LAM-100 patients and 83.3% of LAM-200 patients had remained stably HBV-DNA negative. Double-dose LAM was well tolerated.

CONCLUSION: Long-term treatment of anti-HBe positive chronic hepatitis B with double dose lamivudine causes a more profound and stable viral suppression as compared to conventional treatment.

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.

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.

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.

The L80I substitution in the reverse transcriptase domain of the hepatitis B virus polymerase is associated with lamivudine resistance and enhanced viral replication in vitro

Long-term lamivudine (LMV) treatment of chronic hepatitis B almost inevitably engenders viral resistance. Mutations that result in the replacement of the methionine at position 204 of the deoxynucleoside triphosphate-binding site of the hepatitis B virus (HBV) reverse transcriptase (rt) by isoleucine, valine, or (rarely) serine (rtM204I/V/S) confer high-level resistance to LMV but reduce replication efficiency. The subsequent selection or coselection of secondary mutations that partially restore replication efficiency is common and may influence drug resistance. Genotyping has shown that LMV treatment can select for HBV rtL80V/I mutants, but their prevalence and phenotype have not been documented. Analysis of a large sequence database revealed that rtL80V/I occurred almost exclusively in association with LMV resistance, and 85% of these isolates encoded rtL80I. Coselection of rtL80V/I occurred in 46% of isolates in which LMV resistance was attributable to rtM204I but only 9% of those in which resistance was attributable to rtM204V. Moreover, rtL80V/I did not occur in HBV genotype A isolates but occurred at similar frequencies in genotype B, C, and D isolates. In vitro phenotyping showed that although the rtL80I mutant by itself replicated less efficiently and was hypersensitive to LMV compared to the replication efficiency and sensitivity of its wild-type parent, the presence of rtL80I enhanced the replication efficiency of rt204I/V mutants without significantly affecting LMV resistance. Molecular modeling revealed that rt80 does not interact directly with the enzyme's substrates. Collectively, these results suggest that coselection of rtL80V/I and rtM204I/V occurs because the former compensates for the loss of replication efficiency associated with the acquisition of LMV resistance, particularly in the case of rtM204I.

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.