Extended lamivudine retreatment for chronic hepatitis B: maintenance of viral suppression after discontinuation of therapy

Efficacy of lamivudine re-treatment for relapsed patients after an initial lamivudine therapy in HBeAg-positive chronic hepatitis B

The efficacy of lamivudine re-treatment in chronic hepatitis B (CHB) patients who relapse after HBeAg seroconversion with lamivudine has not been investigated. The aim of this study was to evaluate the efficacy of lamivudine re-treatment in relapsed patients. Among 192 patients who had achieved HBeAg seroconversion with lamivudine at a dose of 100 mg/day, 121 patients discontinued lamivudine. Relapse occurred in 49 patients (40.5%). Thirty-three relapsed patients received lamivudine re-treatment for at least 6 months. The mean duration of lamivudine re-treatment was 16 months and the follow-up period was 8.9 months. HBeAg seroconversion was achieved in 23 patients (69.7%). The cumulative HBeAg seroconversion rates at 5, 9, and 12 months were 60, 64, and 67%, respectively. The mean time to HBeAg seroconversion in lamivudine re-treatment was shorter than that in the initial therapy (4.7 months vs. 9.7 months). Viral breakthrough occurred in six (18.2%) patients. All patients with viral breakthrough were accompanied by elevation of serum alanine aminotransferase (ALT) levels. Among 15 patients who discontinued lamivudine re-treatment after HBeAg seroconversion, relapse occurred in six patients (40%). All relapses occurred within 9 months after the discontinuation of lamivudine re-treatment. In conclusion, lamivudine re-treatment in relapsed patients after initial lamivudine therapy had a higher response rate and shorter duration to HBeAg seroconversion than during the initial therapy. However, HBeAg seroconversion induced by lamivudine re-treatment was not durable.

Precore stop codon mutation of hepatitis B virus is associated with low breakthrough rate following long-term lamivudine therapy

BACKGROUND

Frequent viral breakthroughs limit the usefulness of lamivudine in the treatment of chronic hepatitis B (CHB). The purpose of the present study was to evaluate the effects of precore stop codon mutation (G to A mutation at nucleotide 1896; A(1896)) of hepatitis B virus (HBV) on the occurrence of viral breakthrough following lamivudine therapy.

METHODS

Among 260 consecutive CHB patients treated with lamivudine for >12 months, 231 patients whose pretreatment sera were available were tested for A(1896) variant of HBV using direct sequencing.

RESULTS

Between patients with A(1896) variant (n = 74) and those without it (n = 157), there was no difference in age, gender, serum alanine aminotransferase (ALT) level, the duration of therapy and prevalence of core promoter mutants. Serum hepatitis B e antigen (HBeAg) positivity and HBV-DNA level were lower (P = 0.00 and P = 0.01) and liver cirrhosis was more commonly associated in patients with A(1896) variant mutant compared with those without it. In univariate analysis, viral breakthrough was more frequent in HBeAg-positive patients (P = 0.03) and in those with high serum HBV-DNA level (P = 0.01) as well as in those without A(1896) variant (P = 0.01). However, in multivariate analysis, the absence of A(1896) variant (P = 0.02) and high serum HBV-DNA level (P = 0.03) were independent factors for viral breakthrough following lamivudine therapy. The cumulative viral breakthrough rates at 1 and 2 years were much lower in patients with A(1896) variant compared with those without it (P = 0.01).

CONCLUSION

The stop codon mutation at the precore region of HBV in addition to low serum HBV-DNA level may be associated with low breakthrough rate following lamivudine therapy.

Changes in different regions of hepatitis B virus gene in hepatitis B 'e' antigen-negative patients with chronic hepatitis B: the effect of long-term lamivudine therapy

BACKGROUND

Lamivudine therapy for chronic hepatitis B has been associated with changes in different regions of the hepatitis B virus nucleotide sequence.

AIM

To study changes in the sequences of polymerase and precore/core promoter regions of hepatitis B virus, before and during 5 years of therapy with lamivudine.

METHODS

Eighty consecutive samples were taken from 10 chronic hepatitis B 'e' antigen-negative patients.

RESULTS

Nine patients carried hepatitis B virus precore mutations during the study. Before therapy, wild type was replaced by A1896 in two (20%) cases. During treatment, A1896 reverted transitory to wild type in five cases (50%) and in one case wild type was replaced by A1896. The continuous detection of precore mutations during therapy was associated with a lower response rate. YMDD mutations were observed in nine cases and both, L180M and M204V/I mutations were simultaneously detected in six cases. About 75% of the patients with M204V mutations were responders and none with M204I or mixed pattern sustained response.

CONCLUSION

Hepatitis B 'e' antigen-negative patients exhibit changes in the precore regions both spontaneously and under lamivudine therapy, the transitory reversion to wild type being most frequently witnessed. Patients carrying M204V mutations are more likely to respond to therapy. If, in further studies, these results are confirmed some patients with YMDD mutations could benefit from prolonging the duration of lamivudine therapy.

Predictive value of HBV cccDNA in PBMC of response to lamivudine therapy in patients with chronic hepatitis B

AIM: To assess the value of hepatitis B virus (HBV) covalently closed circle DNA (cccDNA) in peripheral blood mononuclear cells (PBMC) for the prediction of the sustained response to lamivudine therapy in patients with chronic hepatitis B.

METHODS: Seventeen chronic hepatitis B patients with complete or partial response (serum HBV DNA turned negative, and ALT was normalized with or without HBeAg/anti-HBe seroconversion) were selected. HBV cccDNA in PBMC was detected at the end of lamivudine treatment, and 1 year after treatment.

RESULTS: Nine out of 17 patients were positive for HBV cccDNA in their PBMC at the end of lamivudine treatment. Virological relapse were found during 1-year follow-up in all of these 9 patients; whereas only 1 relapse was observed among the 8 patients without HBV cccDNA.

CONCLUSION: HBV cccDNA in PBMC at the end of treatment is of good predictive value for the sustained response to lamivudine treatment in chronic hepatitis B patients.

Monitoring of HBeAg levels may help to predict the outcomes of lamivudine therapy for HBeAg positive chronic hepatitis B

The aim of this study was to determine whether the changing patterns of quantitative hepatitis B e antigen (HBeAg) levels by serial monitoring could predict HBeAg seroconversion and viral breakthrough during lamivudine therapy. We retrospectively analysed 340 HBeAg positive naive chronic hepatitis B patients treated with lamivudine. The mean duration of lamivudine therapy was 18.7 (range 6-56) months. The changing patterns and reduction rates of pretreatment HBeAg levels by serial monitoring were categorized into three groups: Decrescendo group (n = 195), Decrescendo-crescendo group (n = 65) and no changing or fluctuating group (n = 80). Of 109 patients who had achieved HBeAg seroconversion, 105 (96.3%) were included in the decrescendo group. The decrescendo group, pretreatment quantitative HBeAg levels, alanine aminotransferase levels, and the duration of lamivudine therapy were independent predictive factors for HBeAg seroconversion. Of 82 patients who had viral breakthrough, 53 (64.6%) were in the decrescendo-crescendo group and 21 (25.6%) were in the no changing or fluctuating group. The only predictive factor for viral breakthrough was the changing patterns of quantitative HBeAg levels, especially, the decrescendo-crescendo group and the no changing or fluctuating group. The mean time of turning points in the decrescendo-crescendo group was 7.1 months earlier than the mean time of viral breakthrough (9.0 months vs 16.5 months). Therefore, the changing patterns of quantitative HBeAg levels by serial monitoring during lamivudine therapy may allow not only the prediction of treatment responses, but also an early recognition of a viral breakthrough.

Emerging treatments in chronic hepatitis B

Although the management of chronic hepatitis B has improved over the last decade, none of the available therapeutic agents, IFN-alpha, lamivudine and adefovir dipivoxil, can achieve sustained off-therapy responses in most cases. Therefore, several newer, mainly antiviral and immunomodulatory agents, are being evaluated. Pegylated IFN-alpha(2a) has been shown to be more effective than lamivudine or standard IFN-alpha monotherapy in achieving post-therapy biochemical and virological responses, and is expected to be licensed soon for the treatment of chronic hepatitis B. Newer antiviral agents, such as entecavir and telbivudine, appear to be quite effective initially, but their sustained off-therapy response rates remain unknown. The preliminary data of monotherapies with immunomodulatory agents, or of combination therapies, have been rather disappointing. Long-term maintenance treatment with antiviral agent(s) with good safety and tolerability profiles and low resistance rates appears to be the most realistic future therapeutic option for most chronic hepatitis B patients.

Suppression of lamivudine-resistant B-domain mutants by adefovir dipivoxil in the woodchuck hepatitis virus model

Adult woodchucks (Marmota monax) chronically infected with woodchuck hepatitis virus (WHV) were treated orally with lamivudine (15 mg/kg per day) for 57 weeks. After 20 weeks of treatment a 2-3 log reduction in serum WHV DNA was detected. Serum titers of WHV then increased gradually, in the presence of lamivudine treatment, reaching pre-treatment values by week 40. Viral recrudescence was associated with development of mutations in the B domain of the WHV polymerase gene. Mutations observed in the highly conserved FLLA motif of the B domain were L564V, L565M, and A566T, with A566T being the most frequently observed. Beginning on week 57 of lamivudine treatment, one group (n = 3) was treated orally with adefovir dipivoxil at a dose of 15 mg/kg per day plus lamivudine, and a second group (n = 3) was treated with H2O placebo plus lamivudine. In woodchucks treated with adefovir dipivoxil, two had the A566T mutation, and one had both A566T and L565V. In the group maintained on lamivudine monotherapy, A566T alone was present in one animal, another carried both A566T and L565V, and in the third, no B-domain mutations were detected. There was a 4.5 log reduction in serum WHV DNA after 12 weeks of treatment with the adefovir/lamivudine combination, while in the lamivudine monotherapy controls, WHV DNA decreased by only 0.83 log (P > 0.001). A slight recurrence in serum titers of WHV DNA was observed one week after withdrawal of adefovir treatment but no further increase in viral load was observed during the remainder of the 12-week post-treatment follow-up period. The results demonstrate that supplemental adefovir dipivoxil treatment is effective in suppressing replication of lamivudine-resistant B-domain mutants in the woodchuck model of hepatitis B virus infection.

Clinical and virological characteristics of lamivudine resistance in chronic hepatitis B patients: A single center experience

We have investigated the characteristics of lamivudine-resistant strains in patients with chronic hepatitis B in Guangdong, China, where the predominant genotypes are B and C. Two hundred forty-seven patients treated with lamivudine in Nanfang Hospital were followed-up. Patients with hepatitis B e antigen (HBeAg) positive and hepatitis B virus (HBV)-DNA levels over 7.5 x 10(6) copies/ml at baseline had a shorter time to the selection of YMDD mutant (P = 0.02 and 0.00, respectively). The detection of YMDD mutant precedes HBV-DNA breakthrough and alanine transaminase (ALT) flare in about 2 and 3 months, respectively. The ALT flare after the appearance of YMDD mutants was more evident in HBeAg positive patients than HBeAg negative patients (P = 0.02). After emergence of YMDD mutant, the HBV-DNA level was significantly higher in genotype C patients compared with genotype B patients (P = 0.02). No significant difference of YMDD mutant pattern was found between patients with genotype B and C. Four kinds of new mutants were found in over two patients including rtL80I, rtG172E, rtG174C, and rtG172E/rtG174C. In vitro transfection and real-time analysis showed that rtG172E, rtG174C, and rtG172E/rtG174C mutants had a decreased replication competence compared with wild type (33%, 27%, and 15% of the wild type HBV, respectively). Our result suggest that genotypic monitoring of YMDD mutant is important for the management of patients treated with lamivudine.

End-of-treatment virologic response does not predict relapse after lamivudine treatment for chronic hepatitis B

AIM: Attaining hepatitis B e antigen (HBeAg) seroconversion during lamivudine treatment is associated with fewer relapses in HBeAg-positive patients. In HBeAg-negative patients, predictors for post-treatment relapse remain largely unknown. We therefore studied whether end-of-treatment virologic response correlated with relapse after lamivudine treatment.

METHODS: We prospectively analyzed 12 HBeAg-negative patients and 14 HBeAg-positive patients with chronic hepatitis B, who received at least 9 mo of lamivudine treatment and were followed up for 12 mo post-treatment. Relapse of hepatitis B activity was defined by an elevation of serum ALT level above twice the upper limit of normal as well as reappearance of serum HBV DNA by the branched DNA assay or HBeAg during the follow-up period. The serum viral loads during and at the end of treatment were further determined by a quantitative real-time polymerase chain reaction assay.

RESULTS: Relapse occurred in 6 (50.0%) HBeAg-negative patients within 12 mo post-treatment. Two relapsers had end-of-treatment serum viral load < 1000 copies/mL, the proportion was not significantly different from that in the 6 non-relapsers (33.3% vs 16.7%; P = 1.00). Hepatitis B virus (HBV) DNA levels did not correlate with post-treatment relapse in HBeAg-positive patients either. However, genotype C patients tended to have a lower relapse rate than genotype B patients (14.3% vs 57.9%, P = 0.08).

CONCLUSION: Our results suggest that end-of-treatment virologic response cannot predict post-treatment relapse in patients with HBeAg-negative or -positive chronic hepatitis B. The impact of HBV genotype on the response to lamivudine treatment awaits further studies.

Current therapies for chronic hepatitis B virus infection

Patients who are chronically infected with the hepatitis B virus are at an increased risk of developing cirrhosis, hepatic decompensation and hepatocellular carcinoma. Therapeutic intervention offers the only means of interrupting this progression. Currently there are three licensed agents for the treatment of chronic hepatitis B virus infection. These are interferon-alpha, an immunomodulator, and two synthetic nucleos(t)ide analogs, namely lamivudine (Epivir, GlaxoSmithKline) and adefovir dipivoxil (Hepsera, Gilead Sciences). This review aims to summarize current experience with these drugs in the treatment and management of patients with chronic hepatitis B virus infection, their efficacy, and current problems of drug resistance. An outline of future treatment perspectives is also included.

Safety and efficacy of alamifovir in patients with chronic hepatitis B virus infection

BACKGROUND/AIMS

Alamifovir is a purine nucleotide analogue prodrug that shows potent activity against wild type and lamivudine resistant hepatitis B virus in preclinical studies. The aim of this study was to assess the safety and potential antiviral effects of alamifovir in humans.

METHODS

A randomised, placebo controlled, dose escalation study of oral alamifovir was conducted in 66 chronic hepatitis B infected patients who were selected based on stable HBV DNA (>10(5)copies/ml), with no significant liver pathology. They received either placebo or alamifovir at a total daily dose ranging from 2.5 to 20mg in single or divided doses for 28 days and were followed up for approximately 12 weeks after cessation of treatment.

RESULTS

All doses showed significant antiviral activity, with mean plasma viral load reductions ranging from 1.5 to 2.6 log(10) after 28 days of dosing. Once and twice daily regimen for the same daily dose (5mg BID vs 10mg QD, 10mg BID vs 20mg QD) showed no apparent difference in the rate and extent of viral decline, or viral reduction at day 28. Post-treatment viral suppression was dose dependent. There were no serious adverse events attributable to study drug, nor were significant dose related events identified.

CONCLUSIONS

Alamifovir has shown potent in vivo anti-HBV activity, with a favourable safety profile.

Clinical outcome of HBeAg-negative chronic hepatitis B in relation to virological response to lamivudine

The effect of lamivudine treatment on the outcome of patients with hepatitis B e antigen (HBeAg)-negative chronic hepatitis is unclear. In a retrospective multicenter study, we have analyzed the virological events observed during lamivudine therapy in patients with HBeAg-negative chronic hepatitis and evaluated the correlation between virological response and clinical outcomes. Among 656 patients (mean age 49.1 years) included in the database, 54% had chronic hepatitis, 30% had Child-Turcotte-Pugh (CTP) A cirrhosis, and 16% had CTP B/C cirrhosis. On therapy (median 22 months, range 1-66), a virological response was obtained in 616 patients (93.9%). The rate of maintained virological response was 39% after 4 years. During follow-up, 47 (7.2%) patients underwent liver transplantation, liver disease worsened in 31 (4.7%), hepatocellular carcinoma (HCC) developed in 31 (4.7%), and 24 patients (3.6%) died of liver-related causes. Patients who had cirrhosis and who maintained virological response were less likely than those with viral breakthrough to develop HCC (P <.001) and disease worsening (P <.001). Survival was better in CTP A patients with cirrhosis and maintained virological response (P =.01 by rank test). Multivariate analysis revealed that presence of cirrhosis and viral breakthrough were independently related to mortality and development of HCC. In conclusion, lamivudine is highly effective in reducing viral load in HBeAg-negative patients. After 4 years of therapy, 39% of patients maintain a virological and biochemical response. Loss of virological response may lead to clinical deterioration in patients with cirrhosis.

Clinical outcome of HBeAg-negative chronic hepatitis B in relation to virological response to lamivudine

The effect of lamivudine treatment on the outcome of patients with hepatitis B e antigen (HBeAg)-negative chronic hepatitis is unclear. In a retrospective multicenter study, we have analyzed the virological events observed during lamivudine therapy in patients with HBeAg-negative chronic hepatitis and evaluated the correlation between virological response and clinical outcomes. Among 656 patients (mean age 49.1 years) included in the database, 54% had chronic hepatitis, 30% had Child-Turcotte-Pugh (CTP) A cirrhosis, and 16% had CTP B/C cirrhosis. On therapy (median 22 months, range 1-66), a virological response was obtained in 616 patients (93.9%). The rate of maintained virological response was 39% after 4 years. During follow-up, 47 (7.2%) patients underwent liver transplantation, liver disease worsened in 31 (4.7%), hepatocellular carcinoma (HCC) developed in 31 (4.7%), and 24 patients (3.6%) died of liver-related causes. Patients who had cirrhosis and who maintained virological response were less likely than those with viral breakthrough to develop HCC (P <.001) and disease worsening (P <.001). Survival was better in CTP A patients with cirrhosis and maintained virological response (P =.01 by rank test). Multivariate analysis revealed that presence of cirrhosis and viral breakthrough were independently related to mortality and development of HCC. In conclusion, lamivudine is highly effective in reducing viral load in HBeAg-negative patients. After 4 years of therapy, 39% of patients maintain a virological and biochemical response. Loss of virological response may lead to clinical deterioration in patients with cirrhosis.

Antiviral therapy in patients with chronic hepatitis B and cirrhosis

Chronic hepatitis B virus infection (HBV) may result in significant morbidity, including cirrhosis, end-stage liver disease, and hepatocellular carcinoma. The management of chronic HBV cirrhosis is advancing rapidly. Current treatment options for patients with HBV-related cirrhosis include interferon-alpha (IFN-alpha), lamivudine and adefovir dipivoxil. IFN-a is used less commonly today because of its toxicity, difficulty with administration, and the availability of safer drugs. Lamivudine, an oral nucleoside analog, has proven to be at least as effective, and is safer, than IFN-a in the treatment of HBV-related cirrhosis. It is plagued by the development of resistant viral mutants, however. The newest oral nucleotide analog, adefovir dipivoxil, has shown excellent efficacy in treatment-naïve and lamivudine-resistant HBV patients and has lower rates of resistance in the short-term.

Quantitation of covalently closed circular hepatitis B virus DNA in chronic hepatitis B patients

This study examined a signal amplification assay, the Invader assay, for the quantitation of hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) in liver biopsies and sera. DNA was extracted from liver biopsy and serum samples were collected from 16 hepatitis B e antigen (HBeAg)-positive and 36 antibody-to-HBeAg-positive (anti-HBe-positive) chronic hepatitis B patients. The amount of total HBV DNA and cccDNA was measured using the Invader assay. Anti-HBe-positive patients had lower median total intrahepatic HBV DNA (P < .001) and intrahepatic cccDNA levels (P = .001) than HBeAg-positive patients. Intrahepatic cccDNA correlated positively with the total intrahepatic HBV DNA (r = 0.950, P < .001). However, the proportion of intrahepatic HBV DNA in the form of cccDNA was inversely related to the amount of total intrahepatic HBV DNA (r = -0.822, P < .001). A small amount of cccDNA was detected in 39 of 52 (75%) serum samples. Anti-HBe-positive patients had lower median serum cccDNA levels than HBeAg-positive patients (P = .002). Serum HBV DNA correlated positively with intrahepatic total HBV DNA (r = 0.778, P < .001) and intrahepatic cccDNA (r = 0.481, P = .002). In conclusion, the Invader assay is a reliable assay for the quantitation of cccDNA. Serum and intrahepatic total HBV DNA and cccDNA levels become lower as the disease progresses from HBeAg-positive to anti-HBe-positive phase, with cccDNA becoming the predominant form of intrahepatic HBV DNA.

N/A

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Prospective study on lamivudine-resistant hepatitis B in renal allograft recipients

The natural history of lamivudine-resistant hepatitis B virus (HBV) infection in renal transplant recipients (RTx) is unclear, despite its increasing incidence. Twenty-nine HBsAg-positive RTx with rising HBV DNA received lamivudine therapy. The course of lamivudine-resistant HBV infection was studied prospectively. During 68.7 +/- 12.5 months of follow-up, 14 (48.3%) patients developed lamivudine resistance, at 10-35 months (mean 16.9 +/- 7.0). All showed mutant sequences at codons 552 and 528 of the YMDD motif, while 13 patients demonstrated wild-type sequence at codon 555. Lamivudine resistance was unrelated to patient demographics, HBeAg status/sero-conversion, or genotype. Following resistance, HBV DNA and alanine aminotransferase showed an initial increase followed by spontaneous gradual reduction. The subsequent peak HBV DNA was lower (1.26 +/- 1.09 x 10(9) vs. 6.26 +/- 12.23 x 10(9) copies/mL, p = 0.011), while that of alanine aminotransferase was higher (196 +/- 117 vs. 77 +/- 47 imicro/l, p = 0.005), compared with pretreatment levels. Post-resistance hepatitic flare occurred in 11 (78.6%) patients. This was transient in four (36.4%), but became chronic in six (54.5%) patients. Decompensation was noted in one patient during this flare, but all survived. We conclude that drug resistance is prevalent in lamivudine-treated RTx. Despite a lower ensuing peak viremia compared with baseline, hepatitic flare is common. While most patients have spontaneous resolution, a minority may develop potentially fatal decompensation during the preceding exacerbation.

Severe acute exacerbation of liver disease may reduce or delay emergence of YMDD motif mutants in long-term lamivudine therapy for hepatitis B e antigen-positive chronic hepatitis B

The pretherapy factors that could influence the emergence of resistant hepatitis B virus (HBV) tyrosine-methionine-aspartate-aspartate (YMDD) motif mutants against lamivudine are not fully known in prolonged lamivudine therapy for hepatitis B e antigen (HBeAg)-positive chronic hepatitis B. We analyzed prospectively 116 consecutive lamivudine-naïve patients who received long-term lamivudine therapy (>1 year) by using multivariate regression analyses. The cumulative HBeAg loss rates were 29, 44, and 47% at 1, 2, and 3 years of treatment, respectively. Stepwise Cox's regression analyses indicated that pretherapy viral load was a significant factor associated with HBeAg loss (P = 0.0068). The cumulative emergence rates of YMDD mutants were 23% at 1 year, 45% at 2 year, and 47% at 3 year of treatment. Stepwise Cox's regression analyses indicated that patient age and presence or absence of severe acute exacerbation of liver disease were independent significant factors associated with emergence of YMDD mutants (P = 0.018 and 0.048, respectively). For the development of virological breakthrough, patient age, the presence or absence of severe acute exacerbation, and pretherapy viral load were independent significant factors (P = 0.028, 0.043, and 0.044, respectively). Severe acute exacerbation tended to reduce or delay development of biochemical breakthrough. The present study provides important information for the development of more effective and rational long-term lamivudine therapy for HBeAg-positive chronic hepatitis B patients infected exclusively with genotype

Cadaveric renal transplantation in hepatitis B antigen–positive recipients using hepatitis B antigen–positive donor organs with lamivudine treatment

Although renal transplantation has been regarded as the best renal replacement therapy in end-stage renal disease patients, there have never been enough organ donors. Therefore, hepatitis B surface antigen (HBsAg)-negative patients are often given priority over HBsAg-positive patients. We performed cadaveric renal transplantation in six HBsAg-positive recipients given HBsAg-positive donor organs who were on lamivudine treatment. Donors were found to have normal renal function by serum and urine laboratory tests. All recipients underwent liver biopsies before transplantation; those with liver cirrhosis were excluded. All recipients were treated with 100 mg lamivudine once daily because of positive titers of hepatitis B viral (HBV) DNA (three patients), and increased levels of alanine aminotransferase (ALT) (three patients). During the follow-up period, one patient died from hepatic failure at 50 months after transplantation without deterioration of graft function. The remaining five patients showed sustained normal ALT levels. Decreases in HBV DNA titer were observed among patients who were positive before transplantation, but did not reverse to negative. Acute rejection developed in two patients: one was treated successfully with steroid pulse therapy, and the other had two bouts of acute rejection within a 33-month interval. The first was successfully treated with steroid pulse therapy, but the second failed. The four remaining patients have maintained normal renal function for a considerable time. HBsAg-positive donor organs must be used carefully in renal transplantation of HBsAg-positive recipients.

Hepatitis B virus epidemiology, disease burden, treatment, and current and emerging prevention and control measures

Hepatitis B virus (HBV) infection is a serious global health problem, with 2 billion people infected worldwide, and 350 million suffering from chronic HBV infection. The 10th leading cause of death worldwide, HBV infections result in 500 000 to 1.2 million deaths per year caused by chronic hepatitis, cirrhosis, and hepatocellular carcinoma; the last accounts for 320 000 deaths per year. In Western countries, the disease is relatively rare and acquired primarily in adulthood, whereas in Asia and most of Africa, chronic HBV infection is common and usually acquired perinatally or in childhood. More efficacious treatments, mass immunization programs, and safe injection techniques are essential for eliminating HBV infection and reducing global HBV-related morbidity and mortality. Safe and effective vaccines against HBV infection have been available since 1982. The implementation of mass immunization programs, which have been recommended by the World Health Organization since 1991, have dramatically decreased the incidence of HBV infection among infants, children, and adolescents in many countries. However, not all countries have adopted these recommendations and there remains a large number of persons that were infected with HBV prior to the implementation of immunization programs. Antiviral treatment is the only way to reduce morbidity and mortality from chronic HBV infection. Conventional interferon alfa and lamivudine have been the primary treatments to date. Conventional interferon alfa produces a durable response in a moderate proportion of patients but has undesirable side-effects and must be administered subcutaneously three times per week. Lamivudine also produces a response in a modest proportion of patients and causes few side-effects. However, prolonged treatment is often necessary to prevent relapse on cessation of therapy, and continuous treatment can lead to the development of lamivudine resistance. Promising emerging new treatments include adefovir, entecavir and peginterferon alfa-2a (40 kDa).

Predicting relapse after cessation of Lamivudine monotherapy for chronic hepatitis B virus infection

There have been reports of relapse after cessation of lamivudine monotherapy for hepatitis B virus (HBV) infection. The aim of this study was to examine factors that predict posttreatment relapse. Comparison 22 patients who experienced relapse with 11 who did not after cessation of therapy showed that predictive factors for nonrelapse were hepatitis B e antigen seroconversion and duration of undetectable HBV DNA load (<0.7 log IU/mL), as determined by HBV real-time detection direct testing. However, 7 of 12 patients with seroconversion experienced relapse after cessation of therapy. Multivariate analysis revealed that the duration of an undetectable HBV DNA load was the only independent predictive factor for nonrelapse (odds ratio, 0.50; 95% confidence interval, 0.27-0.9). More-prolonged lamivudine therapy is required after seroconversion, and persistent duration of an HBV DNA level of <0.7 log IU/mL for >6 months can more accurately aid in the decision of when to stop lamivudine therapy.

Review article: current management of chronic hepatitis B

Chronic hepatitis B can be diagnosed in patients with increased aminotransferases, hepatitis B virus viraemia and necroinflammation with fibrosis on liver biopsy. Although, ideally, all patients with chronic hepatitis B should be treated, therapeutic intervention is currently recommended for cases with a relatively satisfactory likelihood of response and/or advanced disease. A realistic therapeutic approach aims to sustain hepatitis B e antigen (HBeAg) loss and hepatitis B e antibody (anti-HBe) seroconversion in HBeAg-positive chronic hepatitis B and to sustain biochemical and virological remission in HBeAg-negative chronic hepatitis B. Currently, three drugs are licensed for chronic hepatitis B: interferon-alpha, lamivudine and adefovir dipivoxil. In patients with HBeAg-positive chronic hepatitis B, all of these drugs achieve HBeAg loss (24-33%) and anti-HBe seroconversion (12-30%) rates significantly superior to those observed in untreated placebo controls. In patients with HBeAg-negative chronic hepatitis B, the sustained off-therapy response rate is 20-25% after a > or =12-month course of interferon-alpha and minimal (<10%), if any, after a 12-month course of lamivudine or adefovir. Long-term lamivudine induces an initial response in 70-90% of patients, but only 30-40% of patients remain in remission after the third year due to progressively increasing viral resistance. Long-term adefovir achieves a response in approximately 70% of patients at 12 months, which is maintained at 24 months with rare (<2%) drug resistance. Adefovir is also effective against lamivudine-resistant strains. Many other anti-viral agents, immunomodulatory approaches and combination therapies are currently being evaluated in chronic hepatitis B.

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

BACKGROUND AND AIMS

Adefovir dipivoxil possesses potent in vitro and in vivo antiviral activity in wild-type hepatitis B. This study assessed the safety and efficacy of adefovir dipivoxil alone and in combination with lamivudine compared with ongoing lamivudine therapy in patients with chronic hepatitis B with compensated liver disease and lamivudine-resistant hepatitis B virus (HBV).

METHODS

Fifty-nine hepatitis B e antigen (HBeAg)-positive patients with genotypic evidence of lamivudine-resistant HBV, serum alanine aminotransferase (ALT) level > or =1.2 times the upper limit of normal, and serum HBV DNA level > or =6 log(10) copies/mL despite ongoing treatment with lamivudine were randomized to adefovir dipivoxil 10 mg, lamivudine 100 mg, or addition of adefovir dipivoxil to ongoing lamivudine daily. The primary end point was the time-weighted average change from baseline in serum HBV DNA level (DAVG) up to week 16.

RESULTS

Rapid reductions in serum HBV DNA level were seen by 4 weeks in all recipients of adefovir dipivoxil; DAVG(16) was -0.07 in the lamivudine group compared with -2.45 and -2.46 log(10) copies/mL in the adefovir dipivoxil/lamivudine and adefovir dipivoxil monotherapy groups, respectively (P < 0.001). Median change from baseline in serum HBV DNA level at week 48 was 0.0, -3.59, and -4.04 log(10) copies/mL in the lamivudine, adefovir dipivoxil/lamivudine, and adefovir dipivoxil groups, respectively. ALT level normalized in 10 of 19 (53%) and 9 of 18 (47%) recipients of adefovir dipivoxil/lamivudine and adefovir dipivoxil, respectively, compared with 1 of 19 (5%) recipients of lamivudine. Three patients receiving adefovir dipivoxil or adefovir dipivoxil/lamivudine and none receiving lamivudine monotherapy were HBeAg negative at week 48 and one became hepatitis B surface antigen negative.

CONCLUSIONS

These data, limited to patients with compensated liver disease, indicate that adefovir dipivoxil alone or in combination with ongoing lamivudine therapy provides effective antiviral therapy in patients with lamivudine-resistant HBV.

[Nucleoside analogues resistance in the treatment of chronic hepatitis B virus infection]

SUBJECT

Chronic hepatitis B virus (HBV) infection is usually treated by interferon alpha. However, a sustained response after stopping treatment is only obtained in 30% of patients.

ACTUALITY

New therapeutic nucleoside analogs have been developed, i.e. lamivudine, famciclovir, adefovir, entecavir, clevudine. However, as in HIV infection, clearance of the original hepatitis B virus with emergence of distinct resistant mutants have been observed during or after treatment with most nucleoside analogs. In this review, the underlying mechanisms of resistance and the characterisation of HBV mutants are described to optimize the best therapeutic regimen.

PERSPECTIVES

Treatment of chronic HBV infection, as most of other chronic viral infection, should be based on combination therapy with a special search for the appearance of HBV mutant resistant.

Histological improvements after a three-year lamivudine therapy in patients with chronic hepatitis B in whom YMDD mutants did not or did develop

OBJECTIVE

The long-term effects of lamivudine and the influence of YMDD mutants on the histology of chronic hepatitis B are not known.

METHODS

3-year lamivudine therapy was given to 16 patients with chronic hepatitis B. YMDD mutants did not develop in 9 patients (group A), while they appeared in the remaining 7 patients (group B).

RESULTS

Biochemical and virological responses were invariably achieved in the 9 patients without YMDD mutants, while virological breakthroughs with or without biochemical relapses occurred in all 7 patients with such mutants. All 16 patients accomplished histological improvement, with the total histology activity index (HAI) score decreasing from 11.3 +/- 3.0 to 4.1 +/- 1.7 (p < 0.001). The total HAI score decreased from 11.6 +/- 3.8 to 3.4 +/- 1.3 in the 9 patients in group A (p < 0.001). Although to a significantly lesser extent (p < 0.02), the total HAI score also decreased in the 7 patients in group B from 10.9 +/- 1.0 to 5.0 +/- 1.7 (p < 0.001).

CONCLUSION

The results obtained indicate that 3-year lamivudine therapy can induce histological improvements, regardless of the appearance of YMDD mutants accompanied by virological breakthroughs and biochemical relapses.

Long-term additional lamivudine therapy enhances durability of lamivudine-induced HBeAg loss: a prospective study

BACKGROUNDS/AIMS

In the treatment of chronic hepatitis B (CHB) with lamivudine, adequate duration of the therapy remains to be determined. In this prospective study, the authors intended to investigate whether long-term additional administration of lamivudine might enhance the durability of lamivudine-induced HBeAg seroconversion.

METHODS

Eighty-five CHB patients who achieved HBeAg seroconversion by lamivudine received additional lamivudine therapy for at least 24 months at a dose of 100 mg per day. Among them, 61 patients whose serum HBeAg and HBV-DNA (solution hybridization assay) had been negative persistently for >24 months discontinued lamivudine therapy and followed-up for >12 months. We calculated the cumulative reappearance rate of serum HBV-DNA and HBeAg and also evaluated the predictive factors for post-treatment virologic relapse.

RESULTS

The cumulative reappearance rates of serum HBV-DNA following cessation of lamivudine therapy at 6 months, 1 year and 2 years were 15%, 21%, and 31%, respectively. The cumulative reappearance rates of serum HBeAg at 6 months, 1 year and 2 years were 11%, 13% and 16%, respectively. Old age and presence of precore mutant were two independent predictive factors for viral relapse.

CONCLUSION

These results suggested that long-term additional administration of lamivudine might enhance the durability of lamivudine-induced HBeAg seroconversion.

Long-term alpha interferon and lamivudine combination therapy in non-responder patients with anti-HBe-positive chronic hepatitis B: results of an open, controlled trial

AIM

To investigate the safety and efficacy of long-term combination therapy with alpha interferon and lamivudine in non-responsive patients with anti-HBe-positive chronic hepatitis B.

METHODS

34 patients received combination treatment (1 month lamivudine, 12 month lamivudine+interferon, 6 month lamivudine), 24 received lamivudine (12 months), 24 received interferon (12 months). Interferon was administered at 6 MU tiw and lamivudine at 100 mg orally once daily. Patients were followed up for 6 months after treatment.

RESULTS

At the end of treatment, HBV DNA negativity rates were 88 % with lamivudine+interferon, 99 % with lamivudine and 55 % with interferon, (P=0.004, combination therapy vs. interferon, and P=0.001 lamivudine vs. interferon), and serum transaminase normalization rates were 84 %, 91 % and 53 % (P=0.01 combination therapy vs. interferon, and P=0.012 lamivudine vs. interferon). Six months later, HBV DNA negativity rates were 44 % with lamivudine+interferon, 33 % with lamivudine and 25 % with interferon, and serum transaminase normalization rates were 61 %, 42 % and 45 %, respectively, without statistical significance. No YMDD variants were observed with lamivudine+interferon (vs. 12 % with lamivudine). The combination therapy appeared to be safe.

CONCLUSION

Although viral clearance and transaminase normalization are slower with long-term lamivudine+interferon than that with lamivudine alone, the combination regimen seems to provide more lasting benefits and to protect against the appearance of YMDD variants. Studies with other regimens regarding sequence and duration are needed.

Treatment of chronic hepatitis B: current challenges and future directions

The clinical management of chronic hepatitis B infection has entered a new era with the introduction and widespread use of oral nucleoside analogues such as lamivudine and nucleotides such as adefovir dipivoxil. From this, new challenges have now emerged in terms of preventing antiviral drug resistance, promoting viral clearance and improving long-term survival. For example, the natural history of nucleoside or nucleotide analogue-associated hepatitis B virus resistant mutants has yet to be determined. Furthermore, the increasing prevalence of HBeAg negative disease with its reduced response to current therapies represents an ongoing challenge to attempts to improve standard of care. There is increasing recognition of the pivotal role that viral load and genotype, and their complex interactions with the host immune response, play in determining the outcome of these treatment interventions. The purpose of this paper is to highlight several key factors that should be considered in the context of future clinical research and management of chronic hepatitis B.

Lamivudine and 24 weeks of lamivudine/interferon combination therapy for hepatitis B e antigen-positive chronic hepatitis B in interferon nonresponders

BACKGROUND/AIMS

Lamivudine is effective in treatment-naive patients with chronic hepatitis B, but its role in interferon nonresponders has not been described. We assessed lamivudine treatment, with or without added interferon, in patients with hepatitis B e antigen (HBeAg)-positive chronic hepatitis B who had failed interferon therapy previously.

METHODS

Patients were randomized to lamivudine (100 mg) or placebo for 52 weeks or to a 24-week regimen of lamivudine plus interferon. Primary treatment comparisons were at week 52, with a 16-week posttreatment follow-up period. Measurements included histology (primary endpoint), HBeAg response, normalization of alanine aminotransferase, reduction of hepatitis B virus (HBV) DNA, and safety.

RESULTS

Among 238 patients, histologic response was significantly more common in patients treated with lamivudine (52 versus placebo 25%, P=0.002) or the combination regimen (32%, P=0.01). HBeAg loss was also more common with lamivudine (33 versus 13 versus 21%), as were virologic and alanine aminotransferase responses. Among 28 subjects with HBeAg loss/seroconversion, 71% had durable responses 16 weeks posttreatment.

CONCLUSIONS

Lamivudine for 52 weeks is as effective in interferon nonresponders as in previously reported treatment-naive patients; however, a combination of lamivudine for 24 weeks and interferon for 16 weeks was not effective in this population.

Durability of serologic response after lamivudine treatment of chronic hepatitis B

Forty subjects with chronic hepatitis B and hepatitis B e antigen (HBeAg) seroconversion following lamivudine therapy in previous trials were monitored after treatment to assess the durability of serologic responses. Patient follow-up began a median of 4.3 months after completion of therapy in previous trials. At months 2, 4, 6, 9, and 12 of year 1, and every 6 months thereafter, we tested for HBeAg and hepatitis B surface antigen (HBsAg), hepatitis B virus (HBV) DNA, and alanine aminotransferase (ALT). After a median (range) of 36.6 (4.8-45.6) months of follow-up monitoring, HBeAg seroconversion was demonstrated at the last visit by 77% (30 of 39) of patients. In a post hoc analysis of a slightly different population of all 65 patients with HBeAg seroconversion in previous trials, the 3-year durability of HBeAg seroconversion measured from the time immediately after discontinuing lamivudine therapy was 64%. Nine (9 of 40, 23%) patients were HBsAg negative at the last assessment. Seventy-four percent (17 of 23) of patients with baseline undetectable HBV DNA and normal ALT maintained these responses at the last visit. Eight patients (8 of 40, 20%) initiated retreatment for reappearance of HBV markers, and 7 showed biochemical and/or virologic improvement (including regained HBeAg seroconversion in 2). No safety issues of concern emerged. In conclusion, most HBeAg responses achieved during lamivudine therapy were durable, and most responders experienced prolonged clinical benefit after HBeAg seroconversion and subsequent discontinuation of lamivudine. Lamivudine retreatment for reappearance of hepatitis B markers can achieve resumption of viral suppression.

Prevalence and clinical correlates of YMDD variants during lamivudine therapy for patients with chronic hepatitis B

YMDD variants of hepatitis B virus (HBV) emerge in some patients with chronic hepatitis B who receive lamivudine. YMDD variants were examined in 794 patients in 4 controlled studies of 1 year's duration. The long-term effects of YMDD variants were examined in a subset of patients treated up to 4 years. YMDD variants were detected by polymerase chain reaction (PCR) and restriction fragment-length polymorphism assays. After 1 year, YMDD variants were detected in 81 (24%) of 335 patients. In these patients, the median serum HBV DNA concentration at 1 year was <20% of the baseline level, and serum alanine transaminase (ALT) levels and liver histologic findings had significantly improved. In patients with YMDD variants who were treated for up to 4 years, median HBV DNA and ALT levels showed improvements. Sex, baseline body mass index, and HBV DNA level were associated with emergence of YMDD variants. Patients with YMDD variants losing clinical response with a significant increase in the HBV DNA and ALT levels may require additional therapy.

Lamivudine and famciclovir combination therapy with or without addition of interferon-alpha-2b for HBeAg-positive chronic hepatitis B: a pilot study

Lamivudine and famciclovir combination therapy has been used in patients with chronic HBeAg-positive hepatitis B to enhance the antiviral effect and reduce the risk of development of resistance. Interferon-alpha (IFN-alpha) can theoretically be added to the regimen to further improve the antiviral effect. Twenty patients with HBeAg-positive chronic hepatitis B were given lamivudine and famciclovir combination therapy for 24 weeks. After 12 weeks of treatment, patients were randomized on a 1:1 basis to either the addition of IFN-alpha 2b or no addition for the last 3 months of therapy. The decline in HBV DNA levels, the loss of HBeAg and the HBeAg seroconversion rate were assessed. Patients with loss of HBeAg and/or development of anti-HBe were followed up for at least 1 y after stopping treatment. Four of 19 patients (21%) had lost HBeAg and/or developed anti-HBe 24 weeks after stopping treatment, 1 of whom had received additional IFN-alpha. During long-term follow-up post-treatment, 2/19 patients (10.5%) had a durable HBeAg seroconversion. The mean HBV DNA level declined by 5 logs during the first 12 weeks of treatment. Addition of IFN-alpha during the last 3 months of treatment did not result in any further decline in HBV DNA levels compared with the non-IFN-alpha-treated group, nor in any increase in the HBeAg seroconversion rate. In conclusion, lamivudine and famciclovir combination treatment induced seroconversion from HBeAg to anti-HBe in 4/19 patients, 2 of whom became long-term responders. Addition of IFN-alpha did not improve the seroconversion rate.

Lamivudine Therapy for Japanese Patients with Cirrhosis B

OBJECTIVE

The aim of this study was to investigate the emergence of YMDD mutants in patients with chronic hepatitis B during lamivudine therapy and to compare the emergence patterns of YMDD mutants in cirrhotic and noncirrhotic patients.

METHODS

Eighteen cirrhotic and 37 noncirrhotic patients with chronic hepatitis B were studied. The emergence of YMDD mutants was determined before, as well as at 1, 3, 6, 9 and 12 months after treatment using a highly sensitive method based on polymerase chain reaction.

RESULTS

Although YMDD mutants were elicited early, the emergence of YMDD mutants was not always associated with breakthrough hepatitis. YMDD mutants appeared in cirrhotic and noncirrhotic patients: in 22 and 8% at 1 month, 13 and 21% at 3 months, 46 and 19% at 6 months, 30 and 19% at 9 months, and 83 and 27% at 12 months, respectively.

CONCLUSION

YMDD mutants emerge more frequently in cirrhotic than noncirrhotic patients during the early period on lamivudine treatment. The highly sensitive method may be useful for monitoring the development of YMDD mutants in patients with chronic hepatitis B during lamivudine therapy.

Durability of lamivudine-induced HBeAg seroconversion for chronic hepatitis B patients with acute exacerbation

BACKGROUND/AIMS

Lamivudine-induced hepatitis B e antigen (HBeAg) seroconversion in patients with chronic hepatitis B was reported to be durable by several studies but controversy still exists. The aim of this study was to evaluate the durability of the responses of lamivudine treatment.

METHODS

Among 53 chronic hepatitis B patients who had acute exacerbation and had finished lamivudine therapy after at least 6 months of treatment, 31 patients achieved full HBeAg seroconversion twice at least 1 month apart, and subsequently stopped lamivudine therapy. Post-treatment monitoring was continued for up to 87 weeks. Alanine transaminase (ALT), HBeAg and hepatitis B virus (HBV) DNA were used as indicators for relapse.

RESULTS

The cumulative relapse rates at 48 and 72 weeks post-treatment were 45.4% and 56.3%, respectively. During follow up, normal ALT levels precluded relapse while ALT levels over two times the upper limit of normal indicated relapse, which correlated well with HBeAg or HBV DNA reappearance. Patients older than 25 years were more likely to experience post-treatment relapse.

CONCLUSIONS

Lamivudine-induced full HBeAg seroconversion was not durable in the Taiwanese population. ALT levels were useful for relapse detection. Age was the only independent predictive factor for relapse.

Drug treatment of pediatric chronic hepatitis B

Children with chronic hepatitis B are at risk of developing long-term complications such as cirrhosis and hepatocarcinoma. It is estimated that half to two-thirds of affected children will clear the hepatitis B e antigen (HBeAg) naturally before reaching adulthood. As in adults, treatments in children accelerate the virological response (DNA negativity and HBeAg loss, with anti-HBe seroconversion), which is associated with normalization of transaminase levels. Treatments also favor subsequent loss of hepatitis B surface antigen (HbsAg), the ultimate goal for minimizing long-term consequences. Interferon-alpha was the first approved treatment for pediatric chronic hepatitis B, and was shown to promote DNA negativity and HBeAg loss in 26% of treated patients (6 MU/m(2) body surface area for 6 months) at 1 year and 33% at 18 months (versus 11% in controls). 10% of treated patients also lost HBsAg. Adverse effects mainly included fever, flu-like symptoms and growth impairment during the treatment phase. Nucleotide analogs have now emerged as promising alternatives for the treatment of chronic hepatitis B. Lamivudine dose-ranging studies showed a higher clearance in children, and the optimal dosage was established to be 3 mg/kg once daily in children up to 12 years of age. Efficacy trials showed complete virological response (HBeAg loss and DNA negativity) in 23% of all treated patients after 1 year, and in 34% of patients with initial transaminase levels >2 x the upper limit of normal. Lamivudine resistance due to mutant/variant viruses is observed in 19% of children after 1 year, a figure that may increase by an average of 20% per year. Other nucleotide analogs, such as adefovir, will soon be tested in children, and have shown promising results in adults without so far demonstrating viral resistance. Finally, therapeutic vaccines aiming to induce a cellular immune response towards hepatitis B antigens are being tested in adults, but no clinical benefit has so far been established.

Monitoring drug resistance in chronic hepatitis B virus (HBV)-infected patients during lamivudine therapy: evaluation of performance of INNO-LiPA HBV DR assay

Sensitive and early detection of emerging hepatitis B virus (HBV) drug resistance may not only help monitor the viral dynamics associated with lamivudine treatment but could also improve therapeutic decision making. This is especially important when new antivirals effective against lamivudine-resistant HBV become available. A total of 159 serum samples from 33 chronic HBV patients receiving lamivudine treatment were analyzed at four centers for the presence of lamivudine-resistant mutations at codons 528 [180] (proposed revised nomenclature according to Stuyver et al. [Hepatology 33:751-757, 2001] shown in brackets), 552 [204], and 555 [207] of the HBV polymerase. Sequencing data were compared with results generated by the INNO-LiPA HBV DR line probe assay (LiPA), an assay based on reverse hybridization of amplified HBV DNA fragments with specific nucleotide probes immobilized on nitrocellulose strips. LiPA provided at least the same information as sequencing for 97.5% of all codons analyzed for codon 528 [180], 95% for codon 552 [204], and 100% for codon 555 [207]. The most common reason for discrepant or indeterminate results (0.4% and 1.5%, respectively) in a small percentage of the population tested could be attributed to polymorphisms not yet covered by LiPA probes. In at least five patients, a mutant could be detected earlier by LiPA than by sequencing. In 15 patients, LiPA detected mixed wild-type and mutant virus populations before viral breakthrough. These results demonstrate that INNO-LiPA HBV DR is a highly sensitive and easily applicable assay for the detection and monitoring of lamivudine-resistant mutations in chronic hepatitis B patients and that the assay is more sensitive than sequencing in detecting mixed mutant and wild-type sequences.

Fatal hepatitis B reactivation following discontinuation of nucleoside analogues for chronic hepatitis B

BACKGROUND

Nucleoside analogues such as lamivudine for chronic hepatitis B have an excellent safety profile while patients are on therapy but reactivation flares occur in 19-50% of patients after stopping therapy, some of whom develop liver decompensation.

AIMS

To describe and report three cases who developed fatal hepatitis B reactivation after stopping nucleoside analogue therapy.

SUBJECTS AND RESULTS

Three patients are described who developed hepatitis B reactivation and liver decompensation after stopping therapy. One of the three patients was participating in a famciclovir trial and the other two were receiving lamivudine therapy for active hepatitis B infection. All three patients had documented hepatitis B flares, and all had hepatitis B virus DNA detected at that time. All patients developed decompensated liver disease despite one patient having had a prior liver biopsy showing absence of cirrhosis. Reintroduction of lamivudine therapy failed to halt progression of liver decompensation even after hepatitis B virus DNA had been demonstrated to be absent. Sequencing for lamivudine resistant mutants in two cases where serum was available failed to show evidence of mutations associated with lamivudine resistance.

CONCLUSION

Hepatitis B virus reactivation, leading to decompensation and death, are possible complications of treatment withdrawal and patients should be monitored closely if therapy is ceased.

Antiviral agents: Nonantiviral drugs

The current arsenal of antiviral agents available to the practitioner is expanding rapidly, such that by the time this article goes to press, new drugs may have already been added. Although the majority of approved drugs have been developed for use in only a few viral infections (eg, HIV, herpesviruses, and papillomavirus), discoveries made in the development of these drugs may lead to antiviral agents effective against other viruses. In addition, new uses for the currently available drugs are under evaluation. This review of antiviral agents discusses the treatments available for viral infections such as herpes simplex virus, varicella zoster virus, cytomegalovirus, human papillomavirus, chronic viral hepatitis, and others.

Detection of YMDD mutant using a novel sensitive method in chronic liver disease type B patients before and during lamivudine treatment

BACKGROUND/AIMS

The emergence of lamivudine-resistant hepatitis B virus (HBV) was reported in patients with prolonged lamivudine administration. There was no report of the existence of tyrosine-methionine-aspartate-aspartate (YMDD) mutant in non-lamivudine treated chronic hepatitis B patients. In the present study, we developed a sensitive assay and applied it to the detection of YMDD mutant.

METHODS

We developed peptide nucleic acid (PNA) mediated polymerase chain reaction clamping for detecting mutations in a YMDD motif of the hepatitis B virus DNA polymerase gene. We studied YMDD mutants in a patient with HBV DNA breakthrough longitudinally and in non-lamivudine treated patients (36 patients).

RESULTS

We could detect as little as 0.01-0.001% of mutant viruses coexisting in 10(5)-10(9) copies of wild-type viruses using this assay. YMDD mutant was detected 7 months before clinical breakthrough, which was 6 months earlier than using the conventional restriction fragment length polymorphism assay. YMDD mutants were also detected in four of 18 anti-HBe antibody positive untreated chronic hepatitis type B: YMDD+tyrosine-valine-aspartate-aspartate (YVDD) in two patients and YMDD+tyrosine-isoleucine-aspartate-aspartate (YIDD) in two patients, however, none in HBe antigen positive patients.

CONCLUSIONS

We developed a highly sensitive assay for detecting YMDD mutants. This is an effective procedure for monitoring patients during or before lamivudine treatment and can provide more insights into the therapeutic strategies for chronic hepatitis B patients.

Restoration of replication phenotype of lamivudine-resistant hepatitis B virus mutants by compensatory changes in the "fingers" subdomain of the viral polymerase selected as a consequence of mutations in the overlapping S gene

The introduction of lamivudine (LMV) for the treatment of chronic hepatitis B infection has been an important advance in the management of this disease. However, the long-term efficacy of LMV may become limited by the emergence of antiviral-resistant hepatitis B virus (HBV) mutants. The two most common LMV-resistant mutants produce changes in the viral polymerase protein (rt) of rtM204I and rtL180M/M204V (previously rtM550I and rtL526M/M550V). A number of studies have demonstrated that these HBV mutants appear to be replication impaired, both in vitro and in vivo. The detection and selection of compensatory mutations in the polymerase protein that restore the replication phenotype of these HBV mutants have been poorly described to date. The effects of mutations in the fingers subdomain of the viral polymerase protein arising as a consequence of vaccine and hepatitis B immune globulin (HBIg) selected changes in the overlapping envelope gene (S), and a determinant of the hepatitis Bs antigen (HBsAg) were analyzed in vitro. The LMV-resistant HBV mutants rtM204I and rtL180M/M204V produced substantially weaker HBV DNA replicative intermediate signals by Southern blot analysis and less total intracellular HBV DNA by real-time PCR compared to wild-type virus. The viral polymerase protein of these mutants produced little detectable radiolabeled HBV DNA in an endogenous polymerase assay. In contrast, the HBV a determinant HBIg/vaccine escape mutants sP120T, sT123N, sG145R, and sD144E/G145R (that produce rtT128N, Q130P, rtW153Q, and rtG153E respectively) yielded as much virus as wild-type HBV while the sM133L (rtY141S) mutant was replication impaired. Two of these mutants, rtT128N and rtW153Q, when introduced into a replication-competent HBV vector containing the rtL180M/M204V polymerase mutation restored the replication phenotype of this LMV-resistant mutant. These viruses produced levels of intracellular HBV DNA as determined by Southern blot and real-time PCR that were comparable to those of wild-type HBV, indicating that the changes in the fingers subdomain were able to compensate for the reduced replication of the LMV-resistant mutations. Since these viruses carry mutations in the a determinant of HBsAg that may potentially decrease the ability of anti-HBs antibody to neutralize these viruses, these HBV mutants also have the potential to behave as vaccine escape mutants.

Nucleoside analogues for chronic hepatitis B: antiviral efficacy and viral resistance

Nucleoside analogues have been recently introduced in the management of chronic hepatitis B virus (HBV) infection. They mainly act by inhibition of HBV polymerase activity resulting in decrease of viral replication. They are administered orally, and most of them have an excellent tolerance and safety profile. Lamivudine is the only nucleoside analogue licensed for chronic hepatitis B. It has potent activity against HBV, and a 12-month course achieves clearance of hepatitis B e antigen (HBeAg) in 20-30% of HBeAg-positive patients and both biochemical and virological remission in more than 65-70% of HBeAg-negative chronic hepatitis B patients. Famciclovir and ganciclovir are less effective, whereas other nucleoside or nucleotide analogues, such as adefovir, entecavir, and emtricitabine, are currently under evaluation. Prolonged effective antiviral therapy is required for eradication of chronic HBV infection, but long-term treatment with nucleoside analogues has been found to be associated with progressively increasing rates of viral resistance because of emergence of resistant HBV mutant strains. Virological breakthroughs usually develop after the first 6 months of lamivudine monotherapy, and their rate ranges between 15% and 30% at 12 months and exceeds 50% after 3 yr of therapy. Resistant HBV mutant strains harbor point mutations in the HBV polymerase gene and predominantly in the well-conserved YMDD motif. Although resistant HBV strains may have impaired replication capacity compared with the wild HBV, their clinical significance has not been completely clarified yet. No significant biochemical or clinical event may develop in some cases, whereas severe biochemical breakthroughs with or without deterioration of liver function may develop in others. To date, there is no proven effective therapy for the resistant HBV mutant strains, although adefovir and entecavir seem to be interesting candidates.

Chronic hepatitis B: current and future treatment options

Hepatitis B, a major viral infection that can lead to cirrhosis and hepatocellular carcinoma, is the ninth most common cause of death worldwide. Prevention of hepatitis B virus transmission is key to reducing the spread of this serious condition. Management of chronic hepatitis B requires significant knowledge of approved pharmacotherapeutic agents and their limitations. Today, agents approved by the Food and Drug Administration for this infection are interferon-alpha-2b and lamivudine. Newer agents are being developed and hold promise: adefovir, famciclovir, ganciclovir, lobucavir, entecavir, emtricitabine, L-deoxythymidine, clevudine, a therapeutic vaccine, and thymosin alpha-1. Therapeutic options for managing hepatitis infection after liver transplantation are also evolving. These include hepatitis B immunoglobulin and nucleoside analogues.

Dose range study of pharmacokinetics, safety, and preliminary antiviral activity of emtricitabine in adults with hepatitis B virus infection

A multicenter, open-label study was performed to evaluate the safety, anti-hepatitis B virus (anti-HBV) activity, and pharmacokinetics of emtricitabine therapy administered once daily for 8 weeks to patients infected with HBV. Clinical and virologic evaluations were completed at the baseline; at 7, 14, 28, 42, and 56 days during treatment; and at 24, 48, and 28 days posttreatment. Forty-nine patients were enrolled in five dose cohorts (doses of 25, 50, 100, 200, and 300 mg, all of which were administered once daily [q.d.]). Peak plasma emtricitabine concentrations occurred within 1.5 h following dosing. Plasma emtricitabine concentrations (maximum concentrations of drug in plasma and areas under the concentration-time curves) increased nearly dose proportionally over the 25- to 300-mg dose range, with relatively small intersubject variabilities. The plasma half-life of emtricitabine ranged from 6 to 9 h. HBV DNA levels were measured by the Digene HBV Hybrid Capture II assay. Viral suppression (reduction in log(10) serum HBV DNA levels) occurred in all dose cohorts. All doses demonstrated potent and rapid antiviral activities, with a trend toward a greater suppression with daily doses of 100 mg or greater. At 2 months, the median change in the serum HBV DNA level from the baseline level ranged from -1.7 log(10) for the 25-mg dose administered q.d. to -3.3 log(10) for the 300 mg dose administered q.d. Emtricitabine was well tolerated over the 2-month dosing period. These results support further clinical development of emtricitabine for the treatment of chronic hepatitis B infection.