Adefovir dipivoxil added to ongoing lamivudine in chronic hepatitis B with YMDD mutant hepatitis B virus

Benefits and risks of nucleoside analog therapy for hepatitis B

Five oral agents have been approved for the treatment of chronic hepatitis B, ranging in virological potency, clinical efficacy, barrier to resistance, and side-effect profile. The degree of histological, biochemical, and serological improvement with therapy generally corresponds to the degree of suppression of serum hepatitis B virus (HBV) DNA achieved with therapy. Conversely, for agents with a low barrier to resistance, the profundity of HBV DNA suppression in individual patients correlates inversely with the likelihood of resistance. The durability of hepatitis B e antigen (HBeAg) responses after a consolidation period of an additional 6-12 months of therapy is approximately 80% in western populations, lower in Asian populations. Loss of hepatitis B surface antigen (HBsAg) during a year of oral-agent therapy is limited, except with the most potent agents, but extending therapy for a second year and beyond can yield frequencies of HBsAg responses close to those reported in trials of interferon-based therapy. The oral agents are approved for 1-2 years of therapy, but treatment is continued indefinitely in the majority of patients (except for the approximately 20% of patients who are HBeAg-reactive who achieve a durable HBeAg response). HBeAg responses and virological/biochemical benefit continue to be maintained and to increase with continued therapy beyond the first year. Data continue to accumulate supporting the link between long-term HBV DNA suppression and reduction in hepatic fibrosis, hepatic decompensation, and liver-related mortality. All the benefits of a single year of injectable peginterferon therapy can be achieved with the newer, low-resistance oral agents continued beyond the first year, without interferon side effects. Future studies are needed to develop drug regimens that are even more effective in achieving clinical endpoints, that are not hampered by resistance, and that are more confined in treatment duration but are more durable.

Adefovir dipivoxil resistance patterns in patients with lamivudine-resistant chronic hepatitis B

Background

Lamivudine (3TC)-resistant chronic hepatitis B patients demonstrated a higher rate of adefovir dipivoxil (ADV) resistance compared with nucleoside-naive patients. This study describes ADV mutation patterns in 3TC-resistant patients treated with ADV+3TC or ADV monotherapy, investigating whether mutations selected during 3TC therapy predispose to ADV resistance. Risk factors for ADV resistance were also evaluated.

Methods

A total of 60 3TC-experienced patients were treated with (or switched to) ADV monotherapy (30 patients) or ADV+3TC combination therapy (30 patients), and followed for at least 12 months. In all patients the hepatitis B virus reverse transcriptase (RT) region was amplified and directly sequenced before initiating ADV. The RT sequence was reevaluated for virological breakthrough patients and phenotypic analysis was performed for several patients.

Results

In total, 14 (23%) patients showed virological breakthrough (10/30 on ADV monotherapy and 4/30 on ADV+3TC). ADV resistance mutations (rtA181V/T and rtN236T) were detected alone or in combination for 11/14 patients, whereas novel substitutions were present in 3 patients. Before ADV treatment, apart from 3TC resistance signature mutations, additional changes were found, including the rtA181T mutation, which was already present in 2/14 ADV-resistant patients.

Conclusions

Although most patients showed virological breakthrough because of the well known rtA181V/T and rtN236T substitutions, more complex patterns were also found. ADV monotherapy, dose reduction and suboptimal virological response after 48 weeks of therapy were significantly associated with ADV resistance.

[The efficacy of adefovir dipivoxil monotherapy and the incidence of genotypic resistance to adefovir dipivoxil in patients with lamivudine-resistant chronic hepatitis B infection]

BACKGROUND/AIMS

Adefovir dipivoxil (ADV) is a nucleotide analogue that inhibits wild-type hepatitis B virus (HBV) and lamivudine (LMV)-resistant HBV mutants. The aim of this study was to elucidate the efficacy of ADV monotherapy and the incidence of genotypic resistance to ADV in patients with LMV-resistant chronic HBV infection.

METHODS

This study involved 124 patients with chronic HBV infection who had received ADV monotherapy due to the presence of LMV-resistant HBV mutants. The efficacy of ADV was evaluated by the normalization of serum alanine aminotransferase (ALT) level and by the reduction of serum HBV DNA level (with cutoff levels of 2x10(4) IU/mL and 2x10(2) IU/mL). The cumulative rate of HBeAg loss or seroconversion was assessed in HBeAg-positive patients. The development of mutations in the reverse trancriptase region of HBV DNA polymerase was evaluated by direct sequencing analysis during ADV monotherapy.

RESULTS

The mean serum HBV DNA level was 5.94 log10IU/mL. At 12 and 24 months after ADV monotherapy, the cumulative rates of serum ALT normalization were 69.4% and 75.5%, respectively, and those of serum HBV DNA reduction were 79.8% and 89.2% for a cutoff level of 2x10(4) IU/mL, and 44.2% and 59.0% for a cutoff of 2x10(2) IU/mL. The mean serum HBV DNA levels at 12 and 24 months were significantly lower than baseline, at 3.24 and 3.04 log10IU/mL, respectively (P<0.001). At 12 months after ADV treatment, the cumulative rates of HBeAg loss and seroconversion were 15.8% and 10.5%, respectively, and the rtN236T and rtA181T/V mutants in HBV DNA polymerase were identified in 25% and 64% of patients, respectively.

CONCLUSIONS

Although ADV monotherapy is effective, it leads to a high rate of mutations of HBV DNA reverse transcriptase gene in patients with chronic HBV infections who have LMV-resistant HBV mutants.

Chronic cirrhotic hepatitis B patients with a high incidence of hepatic decompensation after viral breakthrough with lamivudine-resistant mutants and during rescue treatment

OBJECTIVE

To compare the rate of biochemical and hepatic decompensation after viral breakthrough (V-BT) caused by lamivudine (LMV)-resistant HBV mutants and during rescue treatment for patients with liver cirrhosis (LC) and chronic hepatitis B (CHB).

MATERIAL AND METHODS

We reviewed the medical records of 205 CHB patients who developed V-BT with LMV-resistant HBV mutants (134 in the CHB group, 71 in the LC group).

RESULTS

Sixty-five of the 205 patients had an alanine aminotransferase (ALAT) flare-up (32%) and 21 (10%) had hepatic decompensation. The ALAT flare-up among the CHB and LC groups occurred in 43 (32%) and 22 patients (31%), respectively, and there was no significant difference between the two groups. Hepatic decompensation occurred in 5 (4%) and 16 (23%) patients with CHB and LC, respectively, and these differences were significant (p=0.001). A total of 187 patients were treated by rescue therapy (CHB 121, LC 66) and 13 cases with hepatic decompensation occurred only in LC patients during rescue therapy. Among them, 11 patients had serum ALAT levels two times higher than the upper normal limit (UNL) and the HBV-DNA was more than 10(7) copies/ml at the baseline of rescue therapy. In contrast, the cumulative ALAT normalization and viral response rates were reached significantly earlier in patients with a serum HBV-DNA of < or =10(7) copies/ml compared with those with an HBV-DNA >10(7) copies/ml (p=0.0221 and 0.0002, respectively).

CONCLUSION

Earlier rescue therapy for cirrhotic patients with genotypic resistance due to LMV-resistant mutants may improve patient outcome.

Intramuscular hepatitis B immunoglobulin combined with entecavir for long-term prophylaxis of hepatitis B re-infection after liver transplantation

AIM: To evaluate BIG on HBV recurrence after orthotopic liver transplantation (OLT), and to investigate prevention strategies for liver transplantation with YMDD.

METHODS: One hundred and twenty four cases who underwent orthotopic liver transplantation and fulfilled the enrollment criteria, were retrospectively analyzed. HBV reinfection was analyzed and compared between long-term intramuscular hepatitis B virus immunoglobulin & entecavir group and intramuscular hepatitis B virus & immunoglobulin and Lamivudine group. The effect of the prophylaxis for HBV reinfection in patients with YMDD mutants was investigated. HBV markers in serum, HBV DNA and the ratio of HBV reinfection were analyzed.

RESULTS: Entecavir group with a follow- up period of 19.5 ± 9.4 mo, showed no HBV reinfection. However, 10 patients had been traced for 18.1 ± 6.4 mo in lamivudine group. The rate of HBV reinfection in entecavir group was significantly lower than lamivudine group (0% vs 11.9%, P < 0.05). The patients with YMDD mutants before transplantation in Entecavir group had been traced no postoperative HBV reinfection.

CONCLUSION: Entecavir and intramuscular HBIG as the prophylaxis of HBV reinfection is more effective than the lamivudine and intramuscular HBIG, especially for patients with preoperative YMDD mutants.

Adefovir dipivoxil is effective for the treatment of cirrhotic patients with lamivudine failure

BACKGROUND/AIMS

Data on the efficacy of adefovir dipivoxil (ADV) in elderly and cirrhotic patients with lamivudine-resistant (LAM-R) chronic hepatitis B are scarce. This retrospective cohort study evaluated the safety and efficacy of ADV in this specific patient population.

METHODS

Sixty-eight cirrhotic LAM-R patients, of whom 19 (27.9%) were elderly (>or=65 years of age) and nine had severe disease (two post-orthotopic liver transplantation, four pre-orthotopic liver transplantation and three decompensated), with hepatitis B virus (HBV) infection received ADV. Virological and biochemical responses to the addition of ADV were analysed.

RESULTS

At inclusion, all patients were receiving LAM; ADV was added. 75.4% of patients received a combination of LAM and ADV throughout this study for a median treatment duration of 12.6 months; the remainder received ADV with an overlap with LAM treatment for a median duration of 7.9 months. At the end of follow-up, 41.2% of patients had undetectable HBV DNA (<or=2000 copies/ml) with a median reduction of 3.4 log(10) copies/ml. Time to reach undetectable HBV DNA was dependent on baseline alanine aminotransferase (ALT) levels and HBeAg status. Normalization of serum ALT levels was observed in 55.2% (32/58) of patients. In patients who were HBeAg positive at baseline, HBeAg loss and seroconversion occurred in 23% (9/39) and 10% (4/39) respectively. No resistance mutations and no significant side effects were observed during the study period.

CONCLUSION

Adefovir dipivoxil provides effective and safe treatment in cirrhotic and elderly patients who failed LAM therapy.

Efficacy of entecavir treatment for lamivudine-resistant hepatitis B over 3 years: histological improvement or entecavir resistance?

BACKGROUND AND AIMS

Long-term lamivudine therapy is required for patients with chronic hepatitis B, because hepatitis reappears frequently after it has withdrawn. However, hepatitis B virus (HBV) mutants resistant to lamivudine emerge frequently accompanied by breakthrough hepatitis.

METHODS

Effects of entecavir were evaluated in 19 patients who had developed breakthrough hepatitis during lamivudine therapy for longer than 5 years. This study is a subgroup analysis of a previously reported study. Entecavir, in either 0.5 or 1.0 mg/day doses, was given to 10 and nine patients for 52 weeks, respectively, and then all received 1.0 mg/day entecavir for an additional 68-92 weeks.

RESULTS

There were no differences in biochemical and virological responses in the two groups of patients with respect to the two different initial doses of entecavir. Serum levels of alanine aminotransferase were normalized in 17 (90%) patients, and hepatitis B e antigen (HBeAg) disappeared from the serum in two (14%) of the 14 patients who were HBeAg-positive before. Furthermore, a decrease in histological activity index score greater than 2 points was achieved in nine of the 11 (82%) patients in whom annual liver biopsies were performed during 3 years while they received entecavir. HBV mutants resistant to entecavir emerged in five of the 19 (26%) patients, and hepatitis flare occurred in two of them (40%).

CONCLUSION

Entecavir in the long term would be useful for histological improvement of breakthrough hepatitis induced by lamivudine-resistant HBV mutants in patients with chronic hepatitis B. However, the relatively high rate of entecavir resistance is a concern, and other strategies need to be considered when available.

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.

Role of combination therapy in chronic hepatitis B

Combination therapy includes the use of two or more antivirals for the treatment of chronic hepatitis B. No study has shown that combination therapy is superior to monotherapy in naive patients for achieving treatment end points, but combination appears to result in a lower incidence of resistance. Moreover, the higher-potency compounds have not yet been studied. Consideration should be given to treating lamivudine-resistant patients with combination therapy, preferably with a nucleotide analogue in conjunction with a nucleoside analogue. Combination therapy should be considered in patients with decompensated cirrhosis who are unable to achieve an undetectable viral level on monotherapy and in naive patients who still have a detectable viral level 6 to 12 months after starting therapy.

Clinical usefulness of sequential hepatitis B virus DNA measurement (the roadmap concept) during adefovir treatment in lamivudine-resistant patients

Background

Sequential on-treatment monitoring of hepatitis B virus (HBV) DNA levels, known as the roadmap concept, might predict the efficacy of oral therapy with nucleoside/nucleotide analogues among patients naive to this treatment. The goal of this study was to verify the usefulness of the roadmap concept to predict clinical outcomes of adefovir dipivoxil monotherapy in hepatitis B e antigen (HBeAg)-positive patients with lamivudine resistance.

Methods

In 231 patients, serum HBeAg, antibody against HBeAg and HBV DNA levels were measured at weeks 12, 24 and 48 of treatment and every 3 months thereafter.

Results

Complete (HBV DNA<60 IU/ml by PCR), partial (HBV DNA 60–<2,000 IU/ml) and inadequate (HBV DNA≥2,000 IU/ml) virological responses at week 24 were observed in 49 (21.2%), 66 (28.6%) and 116 (50.2%) lamivudine- resistant patients, respectively, who were treated with adefovir dipivoxil monotherapy. At final assessment, rates of complete virological response in these groups were 100%, 71.2%, and 22.4%. Of the total 42 virological breakthroughs, 33 (78.6%) and 8 (19.1%) developed in the inadequate and partial response groups, respectively. Among the 91 patients who had HBV DNA<200 IU/ml at week 48, complete virological response and HBeAg seroconversion were finally achieved in 87 (95.6%) and 39 (42.9%) patients, respectively. Of these 91 patients, virological breakthrough and genotype mutations developed in only 4 (4.4%) and 3 (3.3%) patients. The roadmap concept predicted virological response, HBeAg seroconversion and breakthrough (odds ratios 3.68, 9.67 and 0.15, respectively).

Conclusions

The roadmap concept is useful for choosing between continuation of adefovir dipivoxil monotherapy or early switching to another therapy, or to suggest additional therapy in patients showing lamivudine resistance.

Entecavir therapy in a hepatitis B-related decompensated cirrhotic patient

A 58-year-old Arab-American male with HBeAg-negative chronic hepatitis B (HBV), presented with decompensated cirrhosis and a high HBV DNA level. He responded to entecavir with a significant reduction in serum HBV DNA level after 15 weeks of therapy with entecavir. However, he developed a progressive rise in prothrombin time/international normalized ratio (PT/INR) and bilirubin and underwent liver transplantation after receiving 22 weeks of entecavir therapy. Furthermore, with the continued use of combination entecavir and hepatitis B immunoglobulins (HBIG), he showed improvement in his clinical status with a nondetectable serum HBV DNA level 12 weeks after transplantation. He continued to maintain nondetectable serum HBV DNA 2 years following transplantation. To the best of our knowledge, this is the first reported case of a patient with decompensated chronic HBV who responded to entecavir both before and after transplantation without showing any evidence of recurrent HBV. Larger clinical trials are recommended to compare both short-term and long-term efficacy using entecavir among nucleoside-naïve decompensated chronic HBV patients before and after liver transplantation.

[Nucleoside and nucleotide analogs in the treatment of chronic hepatitis B]

At least 4 nucleos(t)ide analogs have been approved for the treatment of chronic hepatitis B: lamivudine, adefovir dipivoxil, entecavir, and telbivudine. The introduction of these drugs has radically changed the treatment of this disease. The advantages of these drugs are their oral administration, excellent tolerability and efficacy in all types of chronic hepatitis B (compensated and decompensated disease). The limitations are the need for prolonged treatments, which hampers adherence and can cause selection of HBV strains resistant to distinct drugs. The resistance rate differs for each of the drugs. Nucleotide analogs such as adefovir and tenofovir are useful in patients resistant to nucleoside analogs such as lamivudine, entecavir and telbivudine and vice versa. In cases of resistance to one of these drugs, combined treatment is advised.

A randomized study of adefovir dipivoxil in place of HBIG in combination with lamivudine as post-liver transplantation hepatitis B prophylaxis

Prior to effective prophylaxis, liver transplantation for hepatitis B virus (HBV)-related disease was frequently complicated by recurrence, which could be severe and rapidly progressive. Combination hepatitis B immunoglobulin (HBIG) and lamivudine prophylaxis reduces this rate of recurrence to <5% at 5 years; however, HBIG administration is costly and inconvenient. We conducted a multicenter randomized study of adefovir dipivoxil substitution for low-dose intramuscular (IM) HBIG in patients without HBV recurrence at least 12 months posttransplantation for HBV-related disease. Thirty-four patients were randomized, 16 to adefovir (1 patient withdrew consent at 3 months and is not considered in the results) and 18 to continue HBIG. All continued lamivudine. Groups were well matched by age, sex, and time since transplantation (median, 4.5 years), and background virological risk for HBV recurrence (30% of patients in the adefovir group, 24% in the HBIG group having detectable HBV DNA at transplantation). All patients were alive at study completion without recurrence. One patient in the adefovir group became hepatitis B surface antigen-positive at 5 months but was persistently HBV DNA undetectable via polymerase chain reaction (sensitivity 14 IU/mL) over the following 20 months. Median creatinine was not significantly changed over the course of the study in either group. One patient in the adefovir group with a background of diabetic and hypertensive nephropathy (baseline creatinine 150 micromol/L) developed increased creatinine leading to dose reduction and ultimately cessation of adefovir at 15 months. Yearly cost of combination adefovir/lamivudine prophylaxis was $8,290 versus $13,718 IM HBIG/lamivudine.

CONCLUSION

Compared with combination HBIG plus lamivudine prophylaxis, combination adefovir plus lamivudine provides equivalent protection against recurrent HBV infection but with better tolerability and less cost.

Predictive factors associated with the progression to hepatic failure caused by lamivudine-resistant HBV

The aims of this study were to select the patients with a potential for progression to hepatic failure due to lamivudine-resistant HBV and to standardize the treatment for patients with lamivudine-resistant HBV. Patients (n = 47) with reactivated hepatitis due to lamivudine-resistant HBV were classified into two groups, with and without potential for progression to hepatic failure, according to the criteria using the data of serum bilirubin level and prothrombin activity after the reactivated hepatitis. Multivariate analysis showed that prothrombin activity at the initiation of lamivudine therapy was related to the deterioration of the liver function after the emergence of lamivudine-resistant HBV (P = 0.0025, 95%CI 0.8269-0.9601). We assume that earlier additional or substitutive treatment with other antiviral agent, such as adefovir dipivoxil, should be recommended when the lamivudine-resistant HBV is detected in patients with the history of decompensated liver disease before the administration of lamivudine, even when hepatitis has not been reactivated yet.

Pharmacotherapy of chronic viral hepatitis and hepatocellular carcinoma

BACKGROUND

Hepatitis B virus (HBV) is a major etiologic agent of chronic liver disease (CLD) and hepatocellular carcinoma. Drugs have been developed and shown to be effective against HBV replication. These treatments are often associated with the resolution of CLD. However, they are too expensive, not well tolerated, and result in the development of resistance when given as mono or salvage therapies. In addition, most of these drugs target only the virus polymerase.

OBJECTIVE

To revitalize the field, drugs with other targets and combination therapies need to be developed.

METHODS

Major advances in HBV and liver cancer drug development over the past decade, focusing on Phase III trials and FDA-approved compounds, are presented.

RESULTS/DISCUSSION

A number of potent nucleoside/nucleotide analogs are now available for treatment, but for the long-term management of CLD, the development of combination therapies will probably be required. Development of compounds with new virus targets will enhance the utility of combination therapies. Development of compounds to host targets altered prior to or after the development of liver cancer, as demonstrated by sorafenib, need to be developed. The goal is to devise drug cocktails that will yield sustained virus responses and halt disease progression and tumor development.

Management of patients with decompensated hepatitis B virus associated [corrected] cirrhosis

1. Hepatitis B virus replication is associated with a severe outcome in patients with decompensated cirrhosis. 2. Viral suppression induced by antivirals results in a clinical improvement that allows liver transplantation to be delayed or avoided. 3. Early treatment intervention is mandatory in patients with decompensated cirrhosis because of the delay in the restoration of liver functions. 4. Lamivudine is no longer the drug of choice because the initial enthusiasm has been tempered by the high rate of resistance development. 5. Early add-on therapy with adefovir allows us to rescue lamivudine resistance, but its use may be limited by nephrotoxicity. 6. Studies are ongoing with the newer generation of antivirals (telbivudine, tenofovir, entecavir, and emtricitabine) in monotherapy or in combination to determine the best strategy for achieving rapid and prolonged suppression of viral replication. These improved strategies should enhance treatment success enough to obtain clinical stabilization, to delay or prevent the need for transplantation, and to reduce the risk of hepatitis B virus recurrence on the graft.AASLD.

[Treatment of chronic hepatitis B]

SUMMARY

In recent years, marked progress has been made in the treatment of chronic hepatitis B. Several agents have been approved: interferon alpha-(IFN), pegylated interferon alpha2a (PEG-IFN alpha2a), lamivudine, adefovir, entecavir, telbivudine and recently, tenofovir. Each drug has advantages and limitations. IFN and PEG-IFN alpha2a have the advantage of inducing a sustained virologic response after a defined, limited course of treatment. However, these drugs are only effective in a minority of patients and have frequent side effects. Analogues have the advantage of being administered orally, with good safety profiles and a potent antiviral effect. However, these drugs need to be administered indefinitely since withdrawal of therapy is generally associated with reactivation, and a sustained response is uncommon except in HBeAg positive patients who develop HBe seroconversion. In case of HBe seroconversion, therapy should usually be continued for at least another 24 weeks. The efficacy of lamivudine is limited by the emergence of lamivudine-resistant HBV. Adefovir is associated with a moderate incidence of resistance but its antiviral effect is not optimal. Entecavir has shown to be more effective with a favourable safety profile and a low incidence of resistance. Telbivudine is more potent and has a lower rate of resistance than lamivudine but the resistance rate is significantly higher than other approved drugs. Tenofovir has a potent antiviral effect with a good resistance profile. The future of chronic hepatitis B therapy appears to be different drug combinations. Normally the advantage of drug combinations versus monotherapy should be additive or synergistic antiviral effects and a decrease in viral resistance. Unfortunately, there are few data available and none of the evaluated analogue combinations have been shown to be better than monotherapy. The only combination which has shown a synergistic effect is of pegylated interferon alpha2a with lamivudine. Therefore, combinations of pegylated interferon with the most potent analogues need to be evaluated. The ultimate goal of therapy is HBsAg seroconversion which is more often observed with interferon. Indeed, quantification of serum HBsAg will be a useful tool to predict the treatment outcome. More potent drugs and new combinations as well as understanding the mechanisms of viral resistance should be evaluated to improve the efficacy of treatment.

Dynamics of lamivudine-resistant hepatitis B virus during adefovir monotherapy versus lamivudine plus adefovir combination therapy

Adefovir dipivoxil has been used alone or together with lamivudine to suppress lamivudine-resistant hepatitis B virus (HBV). However, the dynamics of HBV populations under different selection pressures and their impact on treatment outcome are poorly understood. Pyrosequencing was applied to quantify longitudinally the evolution of wild type and lamivudine/adefovir-resistant HBV. Eight patients, with lamivudine-resistant HBV, were randomized to receive adefovir monotherapy or adefovir/lamivudine combination therapy for a median of 79 and 71 weeks, respectively. Pyrosequencing proved highly sensitive with a lower limit of quantitation of minor HBV populations of 2% irrespective of viraemia levels. Adefovir/lamivudine treatment resulted in greater viraemia reduction than adefovir monotherapy. During combination therapy, lamivudine-resistant HBV populations (codons 180 and 204) remained dominant (>90%) and no adefovir-resistance developed. During adefovir monotherapy, reversion to wild-type HBV was detected in two patients with one patient accumulating rapidly adefovir-resistant HBV along with increased viraemia. In conclusion, the dynamics of drug-resistant HBV strains vary under different selection pressures which have a significant impact on the success of rescue therapy, as well as for the selection of new mutations. The use of techniques such as Pyrosequencing provides an evidence-based approach for successful management of drug-resistant HBV.

Pharmacology, clinical efficacy and safety of lamivudine in hepatitis B virus infection

Lamivudine was the first nucleoside analog for the treatment of chronic hepatitis B (CHB). It is well-tolerated and induces a decrease in serum HBV DNA levels associated with normalization of serum alanine aminotransferase levels. However, a sustained response with hepatitis B 'e' antigen to anti-hepatitis B e seroconversion is obtained in a smaller proportion of patients and hepatitis B surface antigen loss is exceptional. The response is maintained during therapy, and needs to be continued indefinitely in the majority of patients since withdrawal of treatment is generally followed by a rapid reappearance of the virus. However, mutations can be induced in long-term treatment.

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.

Hepatitis B: reflections on the current approach to antiviral therapy

This article summarizes the current state of antiviral therapy of hepatitis B with special attention given to areas that remain controversial or poorly defined. Strict adherence to liver association practice guidelines may result in missed opportunities to treat patients with significant underlying liver disease. In particular, recommended ALT thresholds may not appropriately reflect disease activity or degree of fibrosis. There is growing evidence that an alternative treatment paradigm for preventing late-stage disease complications may be indicated in highly viremic patients with early life exposure to hepatitis B. Pegylated interferon therapy is often a better choice for young to middle-aged patients with genotype A and B because of the higher rate of HBeAg seroconversion and a greater chance for HBsAg seroconversion in both HBeAg-positive and -negative patients as compared to nucleoside analogs. Nucleoside analog monotherapy is the current standard of care for many patients. However, long-term monotherapy results in resistance to a variable degree and sequential monotherapy may result in multi-drug resistant virus. Which patients would specifically benefit from early combination therapy also remains poorly defined. The rapidity and robustness of the suppression of HBV DNA while on a nucleoside analog should be monitored relatively early during treatment because it affects treatment outcome and the rate of resistance. While great progress has been made in treating hepatitis B, many important issues require further study.

Solid lipid nanoparticles loading adefovir dipivoxil for antiviral therapy

Herein, solid lipid nanoparticles (SLN) were proposed as a new drug delivery system for adefovir dipivoxil (ADV). The octadecylamine-fluorescein isothiocynate (ODA-FITC) was synthesized and used as a fluorescence maker to be incorporated into SLN to investigate the time-dependent cellular uptake of SLN by HepG2.2.15. The SLN of monostearin with ODA-FITC or ADV were prepared by solvent diffusion method in an aqueous system. About 15 wt% drug entrapment efficiency (EE) and 3 wt% drug loading (DL) could be reached in SLN loading ADV. Comparing with free ADV, the inhibitory effects of ADV loaded in SLN on hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg) and hepatitis B virus (HBV) DNA levels in vitro were significantly enhanced.

Low risk of adefovir resistance in lamivudine-resistant chronic hepatitis B patients treated with adefovir plus lamivudine combination therapy: two-year follow-up

BACKGROUND/AIMS

We studied the long-term efficacy (median follow-up of 28 months) of adefovir (ADV) in combination with lamivudine (LAM) in 132 LAM-resistant Japanese patients with chronic genotype C-dominant hepatitis B virus (HBV) infection.

METHODS

The viral response (undetectable HBV-DNA by PCR assay) and the predictor of viral response were evaluated. The emergence of ADV-resistant mutants was investigated during the combination therapy.

RESULTS

The cumulative probability of viral response was 69% at 12 months, and 81% at 24 months. Multivariate analysis identified baseline HBe antigen status (P=0.0001), aspartate aminotransferase level (AST) (P=0.001) and HBV-DNA level (P=0.002) as determinants of viral response to treatment. At the beginning of ADV therapy, substitutions at rtA181 (rtA181T and rtA181S) were identified in 3 patients (2.3%). In the remaining 129 patients, the rtM204 mutants were identified at baseline, and two (1.6%) of the 129 patients developed new ADV-resistant mutants; one was rtA181S and another was rtA181T plus rtN236T mutation.

CONCLUSIONS

Adefovir and lamivudine combination therapy effectively suppressed viral replication and maintained the efficacy well in LAM-resistant patients with chronic HBV infection. Genotypic analysis indicated that the emergence of ADV-resistant mutants is rare, at least over a period of 2 years, in patients with combination therapy.

Recent data on treatment of chronic hepatitis B with nucleos(t)ide analogues

Forty years ago in 1967, Professor Blumberg discovered the Australian Antigen, later known as the hepatitis B surface antigen, and was awarded the Nobel Prize. This discovery enables the diagnosis of hepatitis B virus (HBV) infection and defines its epidemiology. Viral hepatitis B infection affects global health situation, and chronic hepatitis B (CHB) is particularly serious in the Asia-Pacific region. HBV vaccines created the first breakthrough in HBV prevention. Through universal HBV vaccination program for the newborns, promoted since the mid-1980s, the main route that perpetuates chronic infection from mother to child is curbed. Most children and young adults now have immunity against HBV infection. The next breakthrough comes with therapy for CHB. This prevents progression to cirrhosis and hepatocellular carcinoma. Standard interferon therapy with modest efficacy has been largely replaced by therapy with nuclos(t)ide analogues or pegylated interferons alfa-2a and -2b. Lamivudine was approved by the FDA USA in 1998, followed by adefovir dipivoxil in 2002, entecavir in 2005, and telbivudine in 2006. Clevudine, tenofovir, and many promising candidates are in different stages of development and clinical trial. This paper critically reviews recent data published or presented since the APASL Consensus and Guideline Update of 2005. Clinical efficacy mostly in patients with raised serum alanine aminotransferase will be analyzed.

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.

Viral persistence after liver transplantation for hepatitis B virus: a cross-sectional study

BACKGROUND

Prophylaxis to prevent recurrent HBV infection in liver transplant (LT) recipients has evolved over time, and we manage patients who receive lamivudine monoprophylaxis, lamivudine with HBV immunoglobulin (HBIg), and lamivudine and adefovir with HBIg.

METHODS

Serum was examined with sensitive assays to detect the persistence of HBV, and to identify mutations that might confer resistance to the antiviral prophylaxis. Forty patients were studied, and sera were collected 20 days to 13.3 years after LT.

RESULTS

Overall, HBV DNA was detected in serum of 67.5% of patients (8 of 10 of lamivudine monoprophylaxis patients, 15 of 24 of those receiving lamivudine and HBIg, and 4 of 6 of those receiving lamivudine, adefovir and HBIg). Thus, HBV infection persists for most of the patients despite successful prophylaxis after LT. Of those patients with detectable serum HBV DNA, three of eight of the lamivudine monoprophylaxis group had sequences associated with resistance to lamivudine (YMDD mutants), compared with only 1 of 15 of the lamivudine and HBIg cohort. Three of the lamivudine and HBIg cohort had the I126A Hepatitis B surface antigen escape variant. In those serum HBV DNA-positive patients who were receiving lamivudine, adefovir, and HBIg, only one of four had YMDD mutant, and none had Hepatitis B surface antigen escape variants. None of the 40 patients suffered clinical HBV recurrence.

CONCLUSIONS

Our observations imply that the selection of resistant virus may be essential, but is not sufficient to cause overt failure of prophylaxis with development of clinical disease. It seems likely that the patients' immune response contributes, at least partially, to the long-term control of infection in these patients.

Adefovir combined with lamivudine in treatment of lamivudine-resistant patients with decompensated liver cirrhosis: an analysis of 14 cases

AIM: To observe the efficacy and safety of adefovir in combination with lamivudine in the treatment of lamivudine-resistant patients with decompensated liver cirrhosis.

METHODS: Fourteen decompensated liver cirrhosis patients with lamivudine-resistant hepatitis B virus (HBV) mutants, positive HBsAg, HBeAg, and HBcAb, and HBV DNA level >10⁸ copies/L were treated with lamivudine in combination with adefovir. The clinical efficacy after 6 mo and the adverse reaction during treatment were observed.

RESULTS: The levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), albumin (Alb), and prothrombin activity (PTA) were improved distinctly after 6-mo combined treatment. The levels of serum ALT, AST and TBIL became normal in 57.1%, 42.8%, and 50.0% of patients, respectively. The percentages of patients with undetectable HBV DNA levels (<10⁵ copies/L), seropositive HBeAg and seroconversion were 50.0%, 28.4% and 7.1%, respectively. Ascites was retrogressed in those accompanied with ascites. There were no obvious renal toxicity and adverse reation. No adefovir-related HBV mutations were identified.

CONCLUSION: Combined treatment with lamivudine and adefovir is stable and safe for lamivudine-resistant patients with decompensated liver cirrhosis.

A prospective and comparative cohort study on efficacy and drug resistance during long-term lamivudine treatment for various stages of chronic hepatitis B and cirrhosis

BACKGROUND AND AIMS

A prospective, non-randomized cohort study on long-term lamivudine treatment, comparing efficacy, drug resistance, and prognosis for various stages of chronic hepatitis B virus (HBV)-related liver disease was performed to elucidate the significance and indication of lamivudine for individual patients at each stage of disease.

METHODS

A total of 158 cases consisting of 87 chronic hepatitis, 28 compensated cirrhosis, and 43 decompensated cirrhosis, with serum HBV-DNA > 5 log(10) copies/mL and with elevated alanine aminotransferase (ALT) over twice the upper normal limit or complications of hepatic insufficiency, were administered 100 mg of lamivudine daily and monitored for HBV markers, biochemistry, and prognosis.

RESULTS

Lamivudine reduced HBV-DNA and ALT equally in all groups. Serum albumin, prothrombin time (%), and platelet count increased in all groups. The increased margin of albumin was the highest in the decompensated cirrhosis and higher in the compensated cirrhosis than the chronic hepatitis groups. Cumulative incidence of virologic breakthrough was 16%, 42%, 49%, and 53% at 12, 24, 36, and 48 months, respectively, and the strongest predictive factor for lamivudine resistance was persistent HBV-DNA at 3 months. Ascites, encephalopathy, and jaundice improved in the majority of patients with decompensated cirrhosis. On the other hand, hepatic failure developed or deteriorated in 10 patients after virologic breakthrough, and nine of them had decompensated cirrhosis.

CONCLUSIONS

Lamivudine was effective in reducing HBV-DNA and improving hepatic reserve at all stages and was most beneficial and significant for decompensated cirrhosis. Meanwhile, close monitoring of viral load and immediate rescue treatment for lamivudine resistance is necessary to prevent hepatic failure in decompensated cirrhosis.

Lamivudine compared with lamivudine and adefovir dipivoxil for the treatment of HBeAg-positive chronic hepatitis B

BACKGROUND/AIMS

We aimed to evaluate nucleoside/nucleotide combination therapy in treatment-naïve HBeAg-positive patients with chronic hepatitis B (CHB).

METHODS

One hundred and fifteen HBeAg-positive patients received lamivudine 100 mg daily plus placebo (monotherapy) or lamivudine 100 mg plus adefovir dipoxil 10 mg daily (combination therapy) for 104 weeks in a randomized double-blind study.

RESULTS

Time-weighted average change in serum HBV DNA from baseline up to week 16 was -4.20 log(10)copies/mL for both groups (p=0.936). At week 104, median serum HBV DNA change from baseline (log(10)copies/mL) for monotherapy and combination therapy was -3.41 versus -5.22, respectively. HBV DNA breakthrough was detected in 44% of monotherapy and 19% of combination therapy patients. The M204V/I mutation was detected in 43% (15/35) and 15% (6/41) of each group, respectively. ALT normalization at week 100 and 104 was 34% (19/56) in the monotherapy group and 45% (23/51) in the combination therapy group (p=0.018). By week 104, HBeAg seroconversion occurred in 20% of monotherapy and 13% of combination therapy patients. Both regimens were well tolerated.

CONCLUSIONS

Lower rates of resistance to lamivudine, lower serum HBV DNA levels and higher rates of ALT normalization were seen in the combination therapy group after two years. However, serological outcomes were similar.

Evaluation of initial virological response to adefovir and development of adefovir-resistant mutations in patients with chronic hepatitis B

The aims of the present study were to assess initial virological response (IVR) to adefovir (ADV) treatment for chronic hepatitis B, to identify patients with suboptimal response and to determine the incidence of ADV-resistant mutants. All patients treated with ADV for at least 12 months were evaluated for virological response and ADV resistance. IVR was defined as a reduction > or = 4 log10 IU/mL in hepatitis B virus (HBV)-DNA at month 6. Forty-two patients were analysed. Mean treatment duration was 23 +/- 7 months; 50% had prior lamivudine (LAM) therapy (LAM resistance 62%); 88% were hepatitis B e antigen (HBeAg)-negative; and 76% carried genotype D. IVR was seen in 40.5% of patients. Higher baseline ALT level was the only factor associated with IVR (P = 0.043). Patients with IVR achieved undetectable HBV-DNA at month 12 in 77% of cases compared with only 5% of those without IVR (P < 0.001). Five (12%) patients developed ADV-resistant mutations: rtN236T in four cases and one case with an rtV207L change, which has not been previously reported. This mutation was accompanied by viral rebound and alanine aminotransferase (ALT) flare. The cumulative probability of ADV-resistant mutations at 12 and 24 months was 5% and 17% respectively. IVR defined as a reduction > or = 4 log10 IU/mL in HBV-DNA at month 6 is a useful tool to predict virological response at month 12 and to identify patients with suboptimal response to ADV. Cumulative probability of ADV resistance is higher than previously reported for nucleos(t)ide-naïve patients.

Lamivudine-resistant chronic hepatitis B: an observational study on adefovir in monotherapy or in combination with lamivudine

BACKGROUND/AIMS

In lamivudine-resistant patients with chronic hepatitis B (CHB), we compared efficacy, predictive response factors and changes in viral mutants in two antiviral approaches with adefovir.

METHODS

A prospective cohort study on therapy with adefovir alone (29 patients) or combined with ongoing lamivudine (23 patients) was performed.

RESULTS

A virological response was achieved in 55% of patients treated with adefovir and in 83% of those treated with the combination (p>0.05). This response was directly related to the basal viral load (p<0.0001) and obtained in 10 patients with basal HBV-DNA<17,200 IU/ml using both strategies. In patients with a higher basal viral load, the virological response was more frequent when treated with the combination (p<0.05). Mutation at locus rt181 predicted HBV-DNA persistence during therapy. A virological rebound was observed in 18% of non-responders while on adefovir monotherapy.

CONCLUSIONS

To achieve a complete virological response and reduce the risk of adefovir-resistant mutants in lamivudine-resistant patients, rescue therapy is preferable at early evidence of genotypic resistance. However, in subjects with a significant viral load, combination therapy is more effective. The presence of the rt181 mutation is associated with incomplete response.

Short-term overlap lamivudine treatment with adefovir dipivoxil in patients with lamivudine-resistant chronic hepatitis B

AIM: To evaluate the efficacy of short-term overlap lamivudine therapy with adefovir in patients with lamivudine-resistant and naïve chronic hepatitis B, we compared patients receiving overlap therapy with those receiving adefovir alone.

METHODS: Eighty patients who had received lamivudine treatment for various periods and had a lamivudine-resistant liver function abnormality were enrolled. Forty of these patients received adefovir treatment combined with lamivudine treatment for ≥ 2 mo, while the other 40 received adefovir alone. We assessed the levels of hepatitis B virus (HBV) DNA at 0, 12 and 48 wk and serum alanine aminotransferase (ALT) levels after 0, 12, 24 and 48 wk of adefovir treatment in each group.

RESULTS: We found serum ALT became normalized in 72 (87.5%) of the 80 patients, and HBV DNA decreased by ≥ 2 log₁₀ copies/mL in 60 (75%) of the 80 patients at the end of a 48-wk treatment. HBV DNA levels were not significantly different between the groups. The improvements in serum ALT were also not significantly different between the two groups.

CONCLUSION: These findings suggest short-term overlap lamivudine treatment results in no better virological and biological outcomes than non-overlap adefovir monotherapy.

Chronic hepatitis B: preventing, detecting, and managing viral resistance

Licensed oral agents for antiviral therapy in patients with chronic hepatitis B virus (HBV) infection include lamivudine, adefovir, entecavir, and telbivudine. Emtricitabine, tenofovir, and the combination of tenofovir plus emtricitabine in 1 tablet, which are licensed for the treatment of human immunodeficiency virus infection, are additional off-label options for treating HBV infection. Preventing HBV antiviral drug resistance to nucleoside/nucleotide analogues and appropriate management when resistance occurs has become a major focus in the management of chronic hepatitis B. HBV antiviral drug resistance may be best prevented by using an agent or combination of agents with a high genetic barrier to resistance, and 2 potent nucleoside and nucleotide drugs with different resistance profiles may prove to be the optimal first-line treatment for chronic hepatitis B. Frequent assessment of quantitative serum HBV DNA remains the best approach to early detection of resistance, and antiviral therapy should be modified as soon as resistance is detected. Results from several clinical trials have shown that the addition or substitution of newer antiviral agents can restore suppression of viral replication, normalize alanine aminotransferase levels, and reverse histologic progression in patients with resistance to lamivudine, but little information exists regarding the long-term benefits of second-line treatment regimens. Despite the substantial advances in treatment made to date, new agents with novel viral targets will be needed for patients who ultimately may fail second- or third-line therapy.

Efficacies of β-L-D4A against hepatitis B virus in 2.2.15 cells

AIM: To investigate the antiviral effect of beta-L-enantiomer of 2’,3’-didehydro-2’,3’-dideoxyadenosine (β-L-D4A) on 2.2.15 cells transfected with the hepatitis B virus (HBV) genome.

METHODS: Lamivudine (3TC) as a positive control. Then, HBV DNA in treated 2.2.15 cells and the Hepatitis B surface antigen (HBsAg) in the culture supernatants were detected to determine the inhibitory effect of β-L-D4A. At the same time, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) was used to detect the survival ratio of 2.2.15 cells.

RESULTS: β-L-D4A has a dose-dependent inhibitory effect on HBV DNA replication; this effect was apparent when the concentration was above 1 mol/L. When β-L-D4A was at the highest concentration, 100 mol/L, the HBsAg inhibition ratio was above 50%. The Therapeutic index (TI) of β-L-D4A was above 2.1.

CONCLUSION: β-L-D4A has a dose-dependent inhibitory effect on the replication of HBV DNA and the secretion of HBsAg at low toxicity.

The progression of hepatitis B- and C-infections to chronic liver disease and hepatocellular carcinoma: presentation, diagnosis, screening, prevention, and treatment of hepatocellular carcinoma

Much information has been gained in the diagnosis and treatment of HCC during the last 15 years. Ever improving imaging technology has made nonhistologic diagnostic criteria possible, albeit controversial. Liver transplantation, resection, and RFA are considered curative options. Yet,HCC incidence is steadily rising because of limited progress on disease prevention. Accurate and cost-effective screening is necessary. Presently, only 10% to 15% of HCC patients present with a curative stage of disease. Because the field of HCC is rapidly changing, patients with HCC should be referred to liver centers with a full array of services, from surgical to oncologic. The prognosis for HCC patients will surely improve with a multidisciplinary approach to care and further clinical research. Better screening and prevention of recurrence should eventually improve survival. It is hoped that antiviral treatment studies will lower the risk of HCC, and that these changes will occur soon enough to help the many patients at risk for or diagnosed with HCC over the next several years.

[Advances in the treatment of hepatitis B]

Over the last years there has been considerable progress in the treatment of chronic hepatitis B. Five drugs are now approved for the treatment of this virosis: interferon alpha, lamivudine, adefovir, entecavir and telbivudine. Interferons (conventional or PEG) were the first medicine used in the treatment of hepatitis being able to lead the persistent response (loss of DNA-HBV and of AgHbe) to up to one third of treated cases. A large number of nucleoside/nucleotide analogues are, at present, available to treat hepatitis B. The efficacy of lamivudine, the first nucleoside analogue used, is limited by the high rate of resistance. Adefovir has efficacy comparable to that of lamivudine, but with low resistance rate. Entecavir and tenofovir have also been particularly active in the control of hepatitis B virus replication and are associated with minimal resistance development, even during long treatment regimens. Other drugs, such as telbivudine, emtricitabine and clevudine, will become new treatment options in the near future. Individuals co-infected with HIV/HBV are particularly difficult to manage and are nowadays able to benefit from combinations of drugs of the HAART therapy, which should be effective towards both viruses. The development of more potent antiviral drugs as well as new drug combinations, together with a better understanding of hepatitis B virus resistance mechanisms are important milestones to improve treatment efficacy and to diminish, in the future, the global burden of hepatitis B virus.

Long-term therapy with adefovir dipivoxil in hepatitis B e antigen-negative patients developing resistance to lamivudine

BACKGROUND

The efficacy of long-term adefovir dipivoxil monotherapy or combination of adefovir and lamivudine in hepatitis B e antigen (HBe-Ag)-negative lamivudine-resistant chronic hepatitis B (CHB) patients is still under investigation.

AIM

To assess the safety and efficacy of the long-term adefovir treatment alone or in combination with lamivudine in HBe-Ag-negative CHB patients who had developed breakthrough because of lamivudine-resistant mutants.

METHODS

Fifty-nine patients received combination therapy, while 23 switched to adefovir alone after a 3-month course of combination therapy.

RESULTS

The median follow-up after adefovir's onset was 31 (18-40) months. Baseline characteristics were similar between the two groups. At 12 and 24 months, 69% and 89% of patients receiving combination therapy and 73% and 82% of patients receiving adefovir monotherapy had serum HBV-DNA <10(4) copies/mL (P > 0.5). Normalization of alanine aminotransferase levels occurred in 81% and 79% of patients receiving combination vs. 61% and 53% receiving adefovir monotherapy at 12 and 24 months, respectively (P > 0.50). Virological breakthroughs because of adefovir-resistant mutants occurred in five patients under adefovir monotherapy and in none receiving combination therapy (P = 0.001). No one developed decompensated liver disease or hepatocellular carcinoma during follow-up. Re-introduction of lamivudine in adefovir-resistant patients achieved reduction in HBV-DNA and biochemical remission, but re-emergence of lamivudine mutants was observed in one patient after 7.5 months.

CONCLUSION

In HBe-Ag-negative CHB patients with lamivudine resistance, adding adefovir to continuing lamivudine therapy maximizes anti-viral efficacy because of absence of viral resistance.

Lamivudine prophylaxis is effective in reducing hepatitis B reactivation and reactivation-related mortality in chemotherapy patients: a meta-analysis

BACKGROUND

Hepatitis B viral (HBV) reactivation in patients undergoing chemotherapy is associated with significant morbidity and mortality. Lamivudine has been suggested to be useful as a prophylaxis for HBV reactivation; however, its impact on overall survival and HBV reactivation-related liver disease survival is unclear.

OBJECTIVE

To determine the effect of lamivudine prophylaxis on the rate of HBV reactivation, overall survival and HBV reactivation-related survival in patients with HBV undergoing chemotherapy.

METHODS

A comprehensive search of MEDLINE, Cochrane Collaboration Database, reference lists and abstracts from national meetings. Statistical analysis was performed using revman.

RESULTS

Eleven studies met the defined inclusion criteria and were included in the analysis. Two-hundred and twenty patients received lamivudine prophylaxis and 400 did not receive prophylaxis. Patients given lamivudine prophylaxis had an 87% decrease in HBV reactivation [risk ratio (RR) 0.13, 95% confidence interval (CI), 0.07-0.24] than patients not given prophylaxis [absolute risk reduction (ARR) -0.46, 95% CI, -0.61 to -0.31]. The number needed to treat to prevent one reactivation was 3. The Lamivudine prophylaxis group was also associated with a 70% reduction in reactivation-related mortality (RR 0.30, 95% CI, 0.1-0.94) compared with controls (ARR -0.03, 95% CI, 0.07-0.00). There was a reduction in treatment delays and premature termination of chemotherapy in the lamivudine prophylaxis arm (RR 0.41, 95% CI, 0.27-0.63; ARR -0.33, 95% CI, -0.33 to -0.15). There was no significant heterogeneity in the comparisons.

CONCLUSION

Lamivudine prophylaxis during chemotherapy is effective in reducing the rate of HBV reactivation, and reactivation-related liver mortality. Patients with lamivudine prophylaxis had less chemotherapy treatment delays and premature termination of their chemotherapy. Few patients need to be treated to prevent reactivation. Patients with HBV undergoing chemotherapy should be started on lamivudine prophylaxis.

A cost-effectiveness analysis of currently approved treatments for HBeAg-positive chronic hepatitis B

BACKGROUND

A variety of pharmaceuticals are currently approved for the treatment of hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB), but their relative economic value is unclear. The goal of this analysis was to compare the cost effectiveness of adefovir, entecavir, lamivudine, pegylated interferon and telbivudine.

METHODS

We conducted a cost-utility analysis from a US payer perspective over a lifetime time horizon using a Markov model, in a hypothetical population with HBeAg-positive CHB and a mean age of 35 years. Disease progression probabilities, costs and quality-of-life data were derived from the literature. We assumed a treatment duration of 4 years, with the use of combination therapy for drug resistance. Nonresponders to pegylated interferon were assumed to receive entecavir in years 3-4. Sensitivity analyses, including probabilistic sensitivity analysis, were conducted to evaluate uncertainty in the results. All costs were valued in $US, year 2008 values. Costs and outcomes were discounted at 3% per annum.

RESULTS

The 10-year cumulative incidence of cirrhosis for no treatment was 26.1%, and ranged from 19.7% to 23.8% with treatment; undiscounted life-years were 36.2 for no treatment, or ranged from 36.82 to 37.54 with treatment. Initiation with entecavir (18.70 QALYs) and pegylated interferon (18.64 QALYs) provided the largest treatment benefits overall, followed by telbivudine (18.55 QALYs). The probabilities of the interventions being cost effective at a threshold of USD 50,000 per QALY were 57%, 37% and 2% for initiation with entecavir, pegylated interferon and telbivudine, respectively. The results were dependent on baseline seroconversion rate and the effect of viral suppression on cirrhosis risk.

CONCLUSIONS

Initiation of treatments for HBeAg-positive CHB with a favourable combination of seroconversion, viral suppression and resistance profile appear to offer the greatest clinical and economic value.

Personalized therapy in chronic viral hepatitis

Chronic carriers of major hepatitis viruses (i.e., hepatitis B and C viruses, HBV and HCV) account for at least 600 millions people worldwide. About 50% of them are at risk for chronic hepatitis and 20-30% of patients with chronic hepatitis develop progressive liver disease and symptomatic life-threatening liver lesions. Therefore, the identification of the carrier at risk is mandatory to prevent progressive liver disease, avoiding non-appropriate treatments. The decision making has three major steps. The 1st is the identification of the patient who needs to be treated; the 2nd is the choice of the best therapeutic strategy and the most appropriate drugs and timing during the phase of infection and disease; the 3rd is the treatment optimization to reduce non effective therapy and avoid drug resistance virus mutants. This careful evaluation takes into account the individual variability, the host/virus interplays and the drug impact on viral replication with the risk of selection of resistant mutants. The complexity of the virus/host interactions, however, cannot be managed by simple mean of probabilistic statistics and/or step-wise algorithms based on population statistics. A better answer for personalized antiviral therapy may come from the combined use of molecular biology and bio-mathematical modeling that can help the medical doctor to follow the dynamic of viral infection during therapy, like the flight simulator helps the pilot. We provide a concise review of the potentials of this approach in clinical practice.

Adefovir dipivoxil alone or in combination with lamivudine for three months in patients with lamivudine resistant compensated chronic hepatitis B

We studied clinical and laboratory effects of 3 months of lamivudine with adefovir combination and adefovir dipivoxil (AD) alone in the treatment of patients with lamivudine-resistant hepatitis B virus (HBV) infection. Eligible patients were hepatitis B surface antigen-positive men and women with compensated liver disease who were given lamivudine at least more than 6 months and had HBV polymerase gene mutation. Patients were assigned to receive adefovir 10 mg/day (Group 1) or adefovir 10 mg once daily and lamivudine 100 mg once daily combination during first 3 months, and then stopped lamivudine and continued adefovir (Group 2). Median age was 48 years (34 males and 20 females, and 35 were HBeAg-negative). Baseline median ALT, AST, and HBV DNA levels were 66 IU/l, 49 IU/l, and 6.7 log(10) copy/ml, respectively. Median adefovir therapy time and ALT normalization time were 9 and 3.5 months, respectively. There was no significant difference between groups according to the baseline HBV DNA, ALT, HBe Ag status, age, gender, and lamivudine resistance time. Virological and biochemical responses were similar in both groups during therapy. Two patients (8%) had ALT flare more than five times upper limit of normal without any clinical decompensation in Group 1. Mild ALT elevation according to baseline levels were found in 8 (27.6%) and 4 (17.4%) patients, respectively, in Group 2 and Group 1, and no statistically significance between two groups. In conclusion, this study showed that it is not necessary to continue lamivudine therapy while switching to AD therapy. Adefovir alone is effective in the treatment of patients with lamivudine resistant HBV infection and compensated liver disease, without significant clinical and laboratory flares. However, it is not easy to say that switching to AD with cessation of lamivudine is safe, because the study population is not enough for precise conclusion and resistance may be a considerable problem against AD in patients using long-term treatment.

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.

Adefovir dipivoxil therapy in liver transplant recipients for recurrence of hepatitis B virus infection despite lamivudine plus hepatitis B immunoglobulin prophylaxis

BACKGROUND

Treatment of post-transplantation recurrence of hepatitis B virus (HBV) infection despite prophylaxis with hepatitis B immunoglobulin (HBIG) and lamivudine combination therapy is not easy. Because HBV reinfection has a severe course and could result in graft failure in liver transplant recipients, prompt medication is essential. Herein is reported the authors' experience with adefovir dipivoxil (AD) therapy in 11 liver transplant recipients who had HBV reinfection despite the administration of lamivudine and HBIG.

METHOD

Two-hundred and nine patients underwent liver transplantation (100 deceased donor liver transplantations [DDLT], 109 living donor liver transplantation [LDLT]) due to chronic hepatitis B infection between April 1997 and May 2005 in Ege University Medical School, Liver Transplantation Unit. Patients had prophylaxis with lamivudine and low-dose HBIG combination after liver transplantation. Treatment of recurrence consisted of AD 10 mg once a day and lamivudine 300 mg/daily and HBIG was discontinued in those patients.

RESULTS

In total there were 11 HBV recurrences: five occurred in DDLT recipients and six in LDLT recipients, at a median follow up of 18 months (range, 6-48 months). In one of 11 patients, pretransplant HBV-DNA and HBeAg were positive. Three patients had a severe course and one patient had fibrosing cholestatic hepatitis. After AD treatment, HBV-DNA level decreased in all patients and became negative in seven patients. Two patients died due to hepatocellular carcinoma recurrence after 12 and 14 months of follow up. Serum creatinine level increased mildly in one patient and no other side-effect was observed, and all patients continued therapy.

CONCLUSION

Adefovir dipivoxil is a safe, effective treatment option for post-transplant HBV recurrence even among patients with fibrosing cholestatic hepatitis caused by lamivudine-resistant HBV.

Review article: Success and failure of nucleoside and nucleotide analogues in chronic hepatitis B

BACKGROUND

Strong suppression of viral replication and normalization of alanine aminotransferase is feasible with nucleos(t)ide analogues. It is estimated viral replication and liver inflammation can be controlled in 90% of patients with chronic hepatitis B with the current available treatments.

AIM

To review the studies currently available on the management of chronic hepatitis B with nucleos(t)ide analogues.

RESULTS

Although very potent, nucleos(t)ide analogues are not effective in every patient. Some factors are known to influence treatment outcome, but many host and viral factors are still unknown. Stopping rules have to be defined to assess treatment efficacy in an early stage and change the regimen. Discontinuation of nucleos(t)ide analogues is often followed by reactivation of HBV. Data on the risk factors for relapse are necessary in order to decide if treatment can be safely discontinued. Another major drawback of nucleos(t)ide analogues is the emergence of resistance. The efficacy of compounds for the treatment of mutant virus and the impact of cross-resistance is largely unknown. The use of combination therapy to prevent resistance looks promising, but has to be proven.

CONCLUSIONS

HBV has become a treatable disease, however much research is needed to optimize treatment for individual patients and treatment failures.