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

Overview of the development of HBV small molecule inhibitors

Like tuberculosis and Acquired Immune Deficiency Syndrome (AIDS), hepatitis B is a globally recognized major public health threat. Although there are many small-molecule drugs for the treatment of hepatitis B, the approved drugs cannot eradicate the pathogenic culprit covalently closed circular DNA in patients, so the patients need long-term medication to control HBV amplification. Driven by a high unmet medical need, many pharmaceutical companies and research institutions have been engaged in the development of anti-HBV drugs to achieve a functional cure for chronic hepatitis B as soon as possible. This review summarizes the pathogenesis of hepatitis B virus and the research progress in the development of anti-HBV small molecule drugs, and introduces the cccDNA formation and transcription inhibitors and core inhibitors in detail, especially emphasizes the role of chinese herbal medicine in the treatment of chronic hepatitis B. Furthermore, this review proposes three potential strategies for cccDNA eradication in the future. We believe this review will provide meaningful guidance to achieve a functional cure for viral hepatitis B in the future.

Effects of nucleos(t)ide analogs on hepatitis B surface antigen reduction with interferon-lambda 3 induction in chronic hepatitis B patients

BACKGROUND & AIMS

Benefits of nucleos(t)ide analogs (NAs) on hepatitis B surface antigen (HBsAg) reduction and interferon-lambda3 (IFN-λ3) induction are still not known. This study aimed to investigate the effects of NAs on HBsAg reduction and association with serum IFN-λ3 levels in chronic hepatitis B (CHB) patients.

METHODS

A total of 91 patients [51 treated with nucleoside analog entecavir hydrate (ETV) and 40 treated with nucleotide analog adefovir dipivoxil (ADV) or tenofovir disoproxil fumarate (TDF)] with clinically evident CHB (chronic hepatitis, 57; liver cirrhosis, 34) were enrolled in this study. Serum IFN-λ3 levels among patients receiving ETV and ADV/TDF were measured before the initiation of therapy and 1, 3, and 5 years post-therapy.

RESULTS

The change (mean ± standard deviation) in serum HBsAg levels from baseline to year five was -0.38 ± 0.46 and -0.84 ± 0.64 log₁₀ IU/ml in ETV and ADV/TDF groups, respectively (p = 0.0004). Higher serum IFN-λ3 levels were observed in ADV/TDF group compared with ETV group during treatment (p < 0.001). Serum IFN-λ3 levels showed negative correlation with HBsAg reduction in ADV/TDF group (r = -0.386, p = 0.038) at week 48. Nucleotide analogs (ADV/TDF) treatment has associated factors with -0.3 log HBsAg decline at 1 year, -0.5 log HBsAg decline at 3 years, and -0.8 log HBsAg decline at 5 years after NAs treatment on multivariate analysis.

CONCLUSIONS

Nucleotide analog (ADV/TDF) treatment reduced HBsAg levels greater compared with nucleoside analog (ETV) in parallel with IFN-λ3 induction.

Adefovir for lamivudine-resistant hepatitis B

Adefovir, a nucleotide analog developed by John Martin, was a major breakthrough in the treatment of chronic Hepatitis B. Prior to adefovir, Hepatitis B treatment was limited to two therapeutic modalities, either interferon, which carried significant side effects and was efficacious in a minority of patients, or lamivudine which showed no durable effects with short-term use and a high rate of resistance with long-term use. Adefovir was found to be effective in suppressing viral replication and in resolving the hepatic inflammation associated with hepatitis B with only rare instances of resistance. In this article, we appreciate John Martin’s contribution to science and medicine as we review the landmark trials of adefovir that brought forth a new era of treatment of Hepatitis B.

Overview of Biologically Active Nucleoside Phosphonates

The use of the phosphonate motif featuring a carbon-phosphorous bond as bioisosteric replacement of the labile P–O bond is widely recognized as an attractive structural concept in different areas of medicinal chemistry, since it addresses the very fundamental principles of enzymatic stability and minimized metabolic activation. This review discusses the most influential successes in drug design with special emphasis on nucleoside phosphonates and their prodrugs as antiviral and cancer treatment agents. A description of structurally related analogs able to interfere with the transmission of other infectious diseases caused by pathogens like bacteria and parasites will then follow. Finally, molecules acting as agonists/antagonists of P2X and P2Y receptors along with nucleotidase inhibitors will also be covered. This review aims to guide readers through the fundamentals of nucleoside phosphonate therapeutics in order to inspire the future design of molecules to target infections that are refractory to currently available therapeutic options.

Entecavir+tenofovir vs. lamivudine/telbivudine+adefovir in chronic hepatitis B patients with prior suboptimal response

Background/Aims

Suboptimal responses to lamivudine or telbivudine plus adefovir (LAM/LdT+ADV) rescue therapy are common in patients with LAM-resistant hepatitis B virus (HBV) infections. We compared patients switched to entecavir plus tenofovir (ETV+TDF) to those maintained on LAM/LdT+ADV.

Methods

This prospective randomized controlled trial examined 91 patients whose serum HBV DNA levels were greater than 60 IU/mL after at least 24 weeks of treatment with LAM/LdT+ADV for LAM-resistant HBV. Patients were randomized to receive a new treatment (ETV+TDF, n=45) or maintained on the same treatment (LAM/LdT+ADV, n=46) for 48 weeks. Patients with baseline ADV resistance were excluded.

Results

Compared to LAM/LdT+ADV group, ETV+TDF group had more patients with a virologic response (42/45 [93.33%] vs. 3/46 [6.52%], P<0.001) and had a greater mean reduction in serum HBV DNA level from baseline (-4.16 vs. -0.37 log₁₀ IU/mL, P<0.001). Multivariate analysis indicated that high baseline HBV DNA level (P=0.005) and LAM/LdT+ADV maintenance therapy (P=0.001) were negatively associated with virologic response. At week 48, additional ADV- or ETV-associated mutations were cleared in ETV+TDF group, but such mutations were present in 4.3% of patients in LAM/LdT+ADV group (P=0.106). The two groups had similar rates of adverse events.

Conclusions

ETV+TDF combination treatment led to a significantly higher rate of virologic response compared to LAM/LdT+ADV combination treatment in patients with LAM-resistant HBV who had suboptimal responses to LAM/LdT+ADV regardless of HBV genotypic resistance profile (NCT01597934).

Nucleos(t)ide analogues for the treatment of chronic hepatitis B: a systematic review with network meta-analysis

OBJECTIVES

Chronic hepatitis B (CHB) is a major global health problem caused by hepatitis B virus (HBV) infection, and can put patients at high risk of death from cirrhosis and liver cancer. However, CHB can be treated with nucleos(t)ide analogues. We aimed to evaluate the effectiveness and safety of nucleos(t)ide analogues for the treatment of CHB patients.

METHODS

A systematic literature search was performed. Direct comparison meta-analyses and network meta-analysis (NMA) were carried out.

RESULTS

Thirty-six randomized controlled trials (RCTs) met inclusion criteria. Compared with placebo, the nucleos(t)ide analogues were all effective in HBeAg seroconversion, HBeAg loss, and achieving undetectable HBV DNA. Telbivudine was associated with higher HBeAg seroconversion compared with entecavir. For HBeAg loss rate and proportion of achieving undetectable HBV DNA, tenofovir ranked as the best. Entecavir might be the most potent in the normalization of alanine aminotransferase (ALT). The nucleos(t)ide analogues did not have higher serious adverse events rate as compared with placebo.

CONCLUSION

The nucleos(t)ide analogues are all effective for HBeAg seroconversion, HBeAg loss, undetectable HBV DNA, and most are effective for ALT normalization in adults with CHB. RCTs of multi-center, low risk of bias, and long-term follow-up are still needed.

Bayesian Network Meta-Analysis for Assessing Adverse Effects of Anti-hepatitis B Drugs

BACKGROUND AND OBJECTIVE

Oral nucleoside/nucleotide analogues (NAs) have been advocated for chronic hepatitis B (CHB) treatment with good efficacy. However, less attention has been put on their adverse events. Therefore, a Bayesian network meta-analysis (NMA) was performed to evaluate the relative safety of five NAs (lamivudine, adefovir dipivoxil, entecavir, telbivudine, and tenofovir disoproxil fumarate) in CHB treatment among adults.

METHODS

Eligible randomized clinical trials (RCTs) and prospective cohort studies were systematically and thoroughly searched until May 1, 2019. Poisson-prior-based Bayesian NMA was performed to synthesize both direct and indirect evidence with reporting hazard ratios (HRs) and 95% credible intervals (CrIs) for serious adverse events (SAEs) and hepatic/renal impairments.

RESULTS

Thirty-three RCTs and 11 prospective cohort studies were identified. As to SAEs, no statistically significant difference was found of any comparison among five NAs. In terms of hepatotoxicity, lamivudine was safer than telbivudine (HR 0.45; 95% CrI 0.21, 0.85), and entecavir increased the risk by 102% (entecavir vs lamivudine: HR 2.02; 95% CrI 1.19, 3.27).

CONCLUSIONS

The findings from this large NMA could influence clinical practice, and the methodological framework of this study could provide evidence-based support to analyze sparse safety data in the field.

Safety, efficacy, and pharmacokinetics of pradefovir for the treatment of chronic hepatitis B infection

BACKGROUND & AIMS

Pradefovir is a liver targeted novel prodrug of adefovir (PMEA) developed to provide higher antiviral activity with reduced systemic toxicities. This study evaluated the tolerability, pharmacokinetics, and antiviral activity of pradefovir in patients with chronic hepatitis B (CHB) virus infection.

METHODS

Non-cirrhotic, treatment-naïve subjects with CHB were divided into five groups (10 patients each) and randomized within each group in a ratio of 6:2:2 to receive an ascending dose of 30, 60, 75, 90, or 120 mg pradefovir, 10 mg adefovir dipivoxil (ADV), or 300 mg tenofovir disoproxil fumarate (TDF) once a day for 28 days.

RESULTS

A total of 51 subjects were randomized and 49 subjects completed the study. The groups were well matched and included 39 males, of whom 71% were hepatitis B e-antigen-negative with a mean hepatitis B virus (HBV) DNA level of 6.4-7.16 log10 IU/mL. No subject experienced a serious adverse event or nephrotoxicity. The most frequently reported adverse event was asymptomatic reduction in blood cholinesterase levels in the pradefovir group which recovered without any treatment about 13 ± 7 days after drug discontinuation. This adverse event was not observed in the ADV and TDF groups. The mean changes in serum HBV DNA were -2.78, -2.77, -3.08, -3.18, -3.44, -2.34, and -3.07 log10 IU/mL at 30, 60, 75, 90, and 120 mg pradefovir, 10 mg ADV and 300 mg TDF, respectively, with plateau levels reached with 60 mg pradefovir. Pradefovir and its metabolite PMEA showed linear pharmacokinetics proportional to the dose. The half-life of PMEA in the pradefovir group was 11.47-17.63 h.

CONCLUSIONS

Short-term use of pradefovir was well tolerated. A decline in HBV DNA levels was superior to TDF at higher doses of pradefovir. 30-60 mg pradefovir is recommended for CHB treatment.

CLINICAL TRIAL NUMBER

CTR20150224.

Management of Hepatitis B Virus Infection: 2018 Guidelines from the Canadian Association for the Study of Liver Disease and Association of Medical Microbiology and Infectious Disease Canada

Hepatitis B virus (HBV) infection is an important public health problem in Canada. In keeping with evolving evidence and understanding of HBV pathogenesis, the Canadian Association for the Study of Liver Disease periodically publishes HBV management guidelines. The goals of the 2018 guidelines are to (1) highlight the public health impact of HBV infection in Canada and the need to improve diagnosis and linkage to care, (2) recommend current best-practice guidelines for treatment of HBV, (3) summarize the key HBV laboratory diagnostic tests, and (4) review evidence on HBV management in special patient populations and include more detail on management of HBV in pediatric populations. An overview of novel HBV tests and therapies for HBV in development is provided to highlight the recent advances in HBV clinical research. The aim and scope of these guidelines are to serve as an up-to-date, comprehensive resource for Canadian health care providers in the management of HBV infection.

Tenofovir vs lamivudine plus adefovir in chronic hepatitis B: TENOSIMP-B study

AIM

To demonstrate the non-inferiority (15% non-inferiority limit) of monotherapy with tenofovir disoproxil fumarate (TDF) vs the combination of lamivudine (LAM) plus adefovir dipivoxil (ADV) in the maintenance of virologic response in patients with chronic hepatitis B (CHB) and prior failure with LAM.

METHODS

This study was a Phase IV prospective, randomized, open, controlled study with 2 parallel groups (TDF and LAM+ADV) of adult patients with hepatitis B e antigen (HBeAg)-negative CHB, prior failure with LAM, on treatment with LAM+ADV for at least 6 mo, without prior resistance to ADV and with an undetectable viral load at the start of the study, in 14 Spanish hospitals. The follow-up time for each patient was 48 wk after randomization, with quarterly visits in which the viral load, biochemical and serological parameters, adverse effects, adherence to treatment and consumption of hospital resources were analysed.

RESULTS

Forty-six patients were evaluated [median age: 55.4 years (30.2-75.2); 84.8% male], including 22 patients with TDF and 24 with LAM+ADV. During study development, hepatitis B virus DNA (HBV-DNA) remained undetectable, all patients remained HBeAg negative, and hepatitis B surface antigen (HBsAg) positive. Alanine aminotransferase (ALT) values at the end of the study were similar in the 2 groups (25.1 ± 7.65, TDF vs 24.22 ± 8.38, LAM+ADV, P = 0.646). No significant changes were observed in creatinine or serum phosphorus values in either group. No significant differences between the 2 groups were noted in the identification of adverse effects (AEs) (53.8%, TDF vs 37.5%, LAM+ADV, P = 0.170), and none of the AEs which occurred were serious. Treatment adherence was 95.5% and 83.3% in the TDF and the LAM+ADV groups, respectively (P = 0.488). The costs associated with hospital resource consumption were significantly lower with the TDF treatment than the LAM+ADV treatment (€4943 ± 1059 vs €5811 ± 1538, respectively, P < 0.001).

CONCLUSION

TDF monotherapy proved to be safe and not inferior to the LAM+ADV combination therapy in maintaining virologic response in patients with CHB and previous LAM failure. In addition, the use of TDF generated a significant savings in hospital costs.

Lamivudine Therapy Exacerbates Bilirubinemia in Patients Underlying Severely Advanced Hepatitis

Lamivudine belongs to the set of antiviral agents effective against hepatitis B virus infection. Given case reports on liver injuries after certain antiviral agent treatments, this study examined the effects of lamivudine on alanine aminotransferase (ALT) and total bilirubin (TB) using a medical system database. A total of 1,321 patients taking lamivudine alone or with others were evaluated using laboratory hits in an electronic medical system at Seoul National University Hospital from 2005 through 2011. The patients were grouped according to prior ALT results: G#1, ALT < 40 IU/L; G#2, 40 IU/L ≤ ALT < 120 IU/L; G#3, 120 IU/L ≤ ALT < 240 IU/L; and G#4, ALT ≥ 240 IU/L. In G#1 and G#2 patients, lamivudine or adefovir treatment decreased ALT and TB compared to prior values. In G#3 and G#4 patients with three times the upper limit of normal (ULN) ≤ ALT < 15 times the ULN, both ALT and TB were decreased after treatment with lamivudine alone, or adefovir following lamivudine therapy, indicating that lamivudine therapy ameliorated liver functions. However, in G#4 patients who experienced severely advanced hepatitis (ALT ≥ 15 times the ULN, or ≥ 600 IU/L), lamivudine augmented TBmax (6.3→13.3 mg/dL) despite a slight improvement in ALT (839→783 IU/L), indicative of exacerbation of bilirubinemia. Patients who used adefovir after lamivudine also showed a high incidence of hyperbilirubinemia when they experienced severely advanced hepatitis. Treatment with adefovir alone did not show the effect. In conclusion, lamivudine may increase the risk of hyperbilirubinemia in patients with severely advanced hepatitis, implying that caution should be exercised when using lamivudine therapy in certain patient populations.

Management of Clevudine-Resistant Chronic Hepatitis B: A Multicenter Cohort Study

Background/Aims

Data are lacking regarding the management of chronic hepatitis B (CHB) with resistance to clevudine (CLV). This study evaluated the efficacy of different rescue therapies for CLV-resistant CHB.

Methods

Patients with CLV-resistant CHB were enrolled in the cohort, and all patients developed virologic breakthrough during CLV therapy and had confirmed-genotypic resistance to CLV (rtM204I mutation) before enrollment.

Results

Of the 107 patients, 12 received adefovir (ADV), 21 received a CLV plus ADV combination (CLV+ADV), 34 received a lamivudine plus ADV combination (LAM+ADV), and 40 received entecavir (ETV) therapy for 48 weeks. The CLV+ADV group had the lowest hepatitis B virus (HBV) DNA level (p<0.0001) and showed the greatest reduction of HBV DNA levels from baseline compared to all other groups (p=0.004) at week 48. HBV DNA was undetectable (<70 IU/mL) in 0%, 57.1%, 21.2%, and 27.5% (p=0.003) of the patients in each group, respectively, at week 48. At the end of the study, the mean alanine transaminase (ALT) level, rate of ALT normalization, and rate of hepatitis B envelope antigen loss or seroconversion did not differ between groups.

Conclusions

CLV+ADV combination therapy in patients with CLV-resistant CHB more effectively suppresses HBV replication than ETV, ADV, or LAM+ADV therapy.

A Practical Model Evaluating Antiviral Cytokines by Natural Killer Cells in Treatment Naïve Patients with Chronic Hepatitis B Virus Infection

Natural killer (NK) cells play a major role in anti-viral immunity as first line defense during hepatitis B infection, particularly in untreated patients whose T cells functions are profoundly impaired. Cytokine interferon (IFN)-γ and tumor necrosis factor (TNF)-α produced by NK cells are important anti-viral factors. However, there is lack of a quantifiable model to evaluate cytokine responses by NK cells. In this study, almost half of the patients (47.9%) beyond treatment criteria had high cytokine activity, although it was lower than those recommended for antiviral therapy (78.2%). Moreover, we developed a model that low levels of HBsAg, HBcAb, and albumin and high fibrosis values predicted strong antiviral cytokine production by NK cells. Based on the cut-off score (0.361) obtained from the multivariable model, patients with 67%, 8%, 92%, and 74% in immune-active (IA), immune-tolerant (IT), immune-inactive (IC), and grey zone (GZ), respectively, showed active antiviral cytokines produced by NK cells. These results suggest that those who possess activated cytokine responses beyond the current treatment criteria may have potential implications for the timing of antiviral therapy to achieve better virus control.

Management of Antiviral Resistance in Chronic Hepatitis B

The primary goal of therapy for chronic hepatitis B (CHB) is to prevent liver disease progression. Hepatitis B surface antigen (HBsAg) seroclearance or seroconversion is regarded as an optimal endpoint to discontinue treatment. However, HBsAg seroclearance occurs very rarely with nucleos(t)ide analog (NUC) treatment, and long-term, almost indefinite, NUC treatment is required for the majority of patients. In patients with drug-resistant hepatitis B virus (HBV), a combination of tenofovir disoproxil fumarate (TDF) and entecavir (ETV), which is currently regarded as the strongest combination therapy against HBV, would be potentially safe to prevent the emergence of additional HBV resistance mutations. However, long-term tolerance data are lacking, and cost may be an issue for combination therapies. Several recent, well-designed, randomized controlled trials have shown that TDF monotherapy provides similar antiviral efficacy compared with the combination of TDF and ETV. Furthermore, no additional HBV resistance mutations emerged during TDF monotherapy for up to 96 weeks. Considering a comparable antiviral efficacy, extremely low risk of TDF-resistance, lower cost, and better safety potential, TDF monotherapy would be a reasonable choice for the treatment of drug-resistant patients with CHB.

Pediatric hepatitis B treatment

Although the introduction of hepatitis B vaccine has been contributing to the reduction in the prevalence of hepatitis B virus (HBV) carriers worldwide, the treatment of children with chronic HBV infection is a challenge to be addressed. HBeAg seroconversion, which induces low replication of HBV, is widely accepted as the first goal of antiviral treatment in children with chronic hepatitis B. However, spontaneous HBeAg seroconversion is highly expected in children with chronic HBV infection. Therefore, the identification of children who need antiviral treatment to induce HBeAg seroconversion is essential in the management of chronic HBV infection. Guidelines and experts' opinion show how to identify children who should be treated and how to treat them. If decompensated cirrhosis is absent, interferon-alpha is the first-line antiviral treatment. Nucleos(t)ide analogues (NAs), such as lamivudine, adefovir, entecavir and tenofovir, are also available for the treatment of children, although the approval age differs among them. If decompensated cirrhosis is present, NAs are the first-line antivirals. When the emergence of drug-resistant HBV variants is taken into consideration, entecavir (approved for age 2 years or older) and tenofovir (age 12 years or older), which have high genetic barriers, will play a central role in the treatment of HBV infection. However, the optimal duration of NA treatment and adverse events of long-term NA treatment remain unclear in children. In resource-constrained countries and regions, the financial burden of visiting hospitals, receiving routine blood examination and purchasing antiviral drugs is heavy. Moreover, there is no clear evidence that the induction of HBeAg seroconversion by antiviral treatment prevents the progression of liver disease to cirrhosis and hepatocellular carcinoma in children with chronic HBV infection. It is thus imperative to clarify the clinical impact of antiviral treatment in children with HBV infection.

Comparison of the Efficacies and Safety of Combined Therapy between Telbivudine Plus Adefovir and Lamivudine Plus Adefovir in Patients with Hepatitis B Virus Infection in Real-World Practice

Background and Aim

Chronic hepatitis B infection remains a significant health issue worldwide. This study evaluated the efficacy and safety of combined therapy using lamivudine plus adefovir (LAM+ADV) versus telbivudine plus adefovir (LdT+ADV) and the corresponding renal function change and safety.

Methods

This study enrolled a total of 171 patients (110 patients received LAM+ADV and 60 patients received LdT+ADV). We analyzed the changes in renal function using the estimated glomerular filtration rate (eGFR). The DNA undetectable rate, hepatitis B e antigen (HBeAg) seroconversion rate, and alanine aminotransferase (ALT) normalization rate were analyzed. We checked the serum uric acid, phosphate and creatine kinase, and lactic acid levels to analyze safety. We observed these patients for 48 to 240 weeks and checked their serum profile every 6 months.

Results

There was no statistically significant difference between the two groups in anti-hepatitis B virus (HBV) efficacy in terms of DNA undetectable rate, ALT normalization rate, and HBeAg seroconversion rate. Both the LAM+ADV and LdT+ADV groups had stable or improved renal function. However, a higher eGFR was found in the LdT+ADV group with continuous serum fluctuation during 3 years of combined therapy as well as a higher serum creatine kinase level.

Conclusions

Long-term LdT+ADV combined therapy and LAM+ADV combined therapy were both associated with stable or improved renal function. The clinical efficacy was similar between the two groups, but the LdT group had a higher serum creatine kinase level. We need to monitor the data regularly in clinical practice.

Profile of HBV polymerase gene mutations during entecavir treatment in patients with chronic hepatitis B

BACKGROUND/AIMS

We investigated the efficacy of entecavir (ETV) monotherapy in 54 naïve patients and 27 lamivudine (LMV) and/or adefovir (ADV) experienced patients.

METHODS

Eighty-one chronic hepatitis B patients with a viral load above 4 log 10 copies/ml and high levels of serum alanine aminotransferase were treated with ETV 0.5mg daily. The viruses of patients were sequenced before ETV therapy and after every three months of ETV therapy.

RESULTS

Eight LAM-experienced and ADV-experienced patients emerged mutations in the ETV treatment. In one of these experienced patients, the ETV-resistant mutations were detected during ETV treatment, with the virological and the biochemical breakthrough. Two LAM-experienced and ADV-naïve patients were detected mutation during 1-2 years ETV therapy. All three LAM-naïve and ADV-experienced patients were detected mutations in the ETV treatment. Five in fifty for LAM-naïve and ADV-naïve patients showed mutations in the ETV monotherapy.

CONCLUSIONS

ETV has a high genetic barrier to resistance and the efficacy in LAM-experienced and/or ADV-experienced patients were much lower than in naïve patients.

Detection of Anti-Hepatitis B Virus Drug Resistance Mutations Based on Multicolor Melting Curve Analysis

Detection of anti-hepatitis B virus (HBV) drug resistance mutations is critical for therapeutic decisions for chronic hepatitis B virus infection. We describe a real-time PCR-based assay using multicolor melting curve analysis (MMCA) that could accurately detect 24 HBV nucleotide mutations at 10 amino acid positions in the reverse transcriptase region of the HBV polymerase gene. The two-reaction assay had a limit of detection of 5 copies per reaction and could detect a minor mutant population (5% of the total population) with the reverse transcriptase M204V amino acid mutation in the presence of the major wild-type population when the overall concentration was 10⁴ copies/μl. The assay could be finished within 3 h, and the cost of materials for each sample was less than $10. Clinical validation studies using three groups of samples from both nucleos(t)ide analog-treated and -untreated patients showed that the results for 99.3% (840/846) of the samples and 99.9% (8,454/8,460) of the amino acids were concordant with those of Sanger sequencing of the PCR amplicon from the HBV reverse transcriptase region (PCR Sanger sequencing). HBV DNA in six samples with mixed infections consisting of minor mutant subpopulations was undetected by the PCR Sanger sequencing method but was detected by MMCA, and the results were confirmed by coamplification at a lower denaturation temperature-PCR Sanger sequencing. Among the treated patients, 48.6% (103/212) harbored viruses that displayed lamivudine monoresistance, adefovir monoresistance, entecavir resistance, or lamivudine and adefovir resistance. Among the untreated patients, the Chinese group had more mutation-containing samples than did the Pakistani group (3.3% versus 0.56%). Because of its accuracy, rapidness, wide-range coverage, and cost-effectiveness, the real-time PCR assay could be a robust tool for the detection if anti-HBV drug resistance mutations in resource-limited countries.

Entecavir plus tenofovir combination therapy in patients with multidrug-resistant chronic hepatitis B: results of a multicentre, prospective study

BACKGROUND & AIMS

Sequential therapy posed a high risk of emergence of multidrug resistance and presented a management issue in chronic hepatitis B (CHB) treatment. We evaluated the antiviral efficacy and safety of entecavir (ETV) plus tenofovir (TDF) combination therapy in multidrug-resistant (MDR) CHB patients.

METHODS

In this prospective, multicentre study, MDR CHB patients, defined as measurable serum HBV DNA (≥60 IU/ml) while on any rescue treatment regimen for at least 24 weeks and the presence of documented prior genotypic resistance to both nucleoside analogue(s) and nucleotide analogue, were treated with ETV 1.0 mg and TDF 300 mg combination therapy for 48 weeks.

RESULTS

A total of 64 eligible patients who had previously failed to a median three lines of antiviral therapy (range, 2-6) were included. At baseline, median age was 47.0 years, 89.1% were HBeAg(+), and median HBV DNA was 4.24 (range, 2.11-6.73) log10 IU/ml. By week 4, 12, 24 and 48, 15/64 (23.4%), 36/64 (56.3%), 43/64 (67.2%) and 55/64 (85.9%) patients achieved a HBV DNA <60 IU/ml respectively. The mean reduction of HBV DNA from baseline to 4 and 48 weeks was 1.23 log10 IU/ml and 2.38 log10 IU/ml respectively. Although five patients experienced virological breakthrough, all were transient and no resistant mutation to TDF or novel mutation was detected in any patients.

CONCLUSIONS

In difficult-to-treat MDR CHB patients with a high exposure to multiple antiviral drugs, ETV plus TDF combination therapy can provide a very high rate of viral suppression through 48 weeks of treatment.

Durability of the virological response after lamivudine discontinuation in lamivudine-resistant patients with a complete virological response after lamivudine and adefovir combination therapy

We investigated the durability of virological response after lamivudine (LAM) discontinuation in LAM-resistant chronic hepatitis B (CHB) patients with complete virological response after LAM-adefovir (ADV) combination therapy. We enrolled 58 patients switched to ADV monotherapy with undetectable viral loads (<12 IU/ml) and normal alanine aminotransferase levels after ADV add-on combination treatment for at least 6 months in LAM-resistant CHB patients. Virologic relapse was defined as HBV DNA detection at more than 20 IU/ml by quantitative polymerase chain reaction determined on two consecutive measurements. During median 40.9 months of follow-up (range 11.5-79.0 months), seven (12.1%) patients experienced virological relapse. The cumulative rate of virological relapse at 3 and 5 years was 5.5% and 22.4%, respectively. Two patients had elevated alanine aminotransferase during virological relapse. These seven patients with virological relapse had undetectable HBV DNA after switching to tenofovir therapy. In our study, switching to ADV monotherapy resulted in sustained HBV DNA suppression in 87.9% of the patients during median 40.9 months follow-up. This adapting step-down strategy, switching from combination therapy to monotherapy in virologically suppressed CHB patients with stable liver disease, may reduce the cost burden and the risk of potentially harmful effects of combination therapy. J. Med. Virol. 89:85-90, 2017. © 2016 Wiley Periodicals, Inc.

Tenofovir monotherapy versus tenofovir and entecavir combination therapy in patients with entecavir-resistant chronic hepatitis B with multiple drug failure: results of a randomised trial

OBJECTIVE

Little clinical data are available regarding the optimal treatment of patients who harbour entecavir (ETV)-resistant HBV.

DESIGN

In this multicentre randomised trial, patients who had HBV with ETV resistance-associated mutations and serum HBV DNA concentrations >60 IU/mL were randomised to receive tenofovir disoproxil fumarate (TDF, 300 mg/day) monotherapy (n=45) or TDF and ETV (1 mg/day) combination therapy (n=45) for 48 weeks.

RESULTS

Baseline characteristics were comparable between groups, including HBV DNA levels (median, 4.02 log10 IU/mL) and hepatitis B e antigen-positivity (89%). All patients had at least one ETV-resistance mutation: rtT184A/C/F/G/I/L/S (n=49), rtS202G (n=43) and rtM250L/V (n=7), in addition to rtM204V/I (n=90). All except one patient in the TDF group completed 48 weeks of treatment. At week 48, the proportion of patients with HBV DNA <15 IU/mL, the primary efficacy endpoint, was not significantly different between the TDF and TDF+ETV groups (71% vs. 73%; p>0.99). The mean change in HBV DNA levels from baseline was not significantly different between groups (-3.66 vs. -3.74 log10 IU/mL; p=0.81). Virological breakthrough occurred in one patient on TDF, which was attributed to poor drug adherence. At week 48, six and three patients in the TDF and TDF+ETV groups, respectively, retained their baseline resistance mutations (p>0.99). None developed additional resistance mutations. Safety profiles were comparable in the two groups.

CONCLUSIONS

TDF monotherapy for 48 weeks provided a virological response comparable to that of TDF and ETV combination therapy in patients infected with ETV-resistant HBV.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov ID NCT01639092.

Outcome of adefovir add-on lamivudine rescue therapy of up to 5 years in patients with lamivudine-resistant chronic hepatitis B

BACKGROUND AND AIM

We investigated the long-term efficacy of adefovir add-on lamivudine rescue therapy in lamivudine-resistant chronic hepatitis B and the optimal cutoff hepatitis B virus (HBV) DNA level that predicts complete virological response (CVR) among patients without CVR after 1 year of treatment.

METHODS

We reviewed 167 lamivudine-resistant chronic hepatitis B patients who received adefovir add-on rescue therapy for up to 5 years. Multivariate analysis, area under the receiver operating characteristic curves, and Youden index were used.

RESULTS

Median age was 47.0 years; 112 patients were male. Median baseline HBV DNA level was 6.6 log10 IU/mL; hepatitis B e antigen was positive in 130 (77.4%) patients. Five-year CVR, alanine aminotransferase normalization, hepatitis B e antigen seroconversion, and adefovir resistance rates were 86.9%, 92.5%, 16.7%, and 6.0%, respectively. One-year HBV DNA level independently associated with CVR. Optimal cutoff HBV DNA level to predict CVR among patients who failed to achieve CVR at 1 year was 800 IU/mL (area under receiver operating characteristic curve 0.752; sensitivity 49.3%, specificity 93.5%). During the 5-year treatment, 92.1% of patients with favorable response (HBV DNA < 800 IU/mL at 1 year) achieved CVR; 45.6% achieved CVR among suboptimal responders (HBV DNA ≥ 800 IU/mL at 1 year) (P < 0.001).

CONCLUSION

Complete virological response or HBV DNA level < 800 IU/mL after 1 year adefovir add-on lamivudine rescue therapy can favorably predict CVR.

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

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

Application of nucleoside analogues to liver transplant recipients with hepatitis B

Hepatitis B is a common yet serious infectious disease of the liver, affecting millions of people worldwide. Liver transplantation is the only possible treatment for those who advance to end-stage liver disease. Donors positive for hepatitis B virus (HBV) core antibody (HBcAb) have previously been considered unsuitable for transplants. However, those who test negative for the more serious hepatitis B surface antigen can now be used as liver donors, thereby reducing organ shortages. Remarkable improvements have been made in the treatment against HBV, most notably with the development of nucleoside analogues (NAs), which markedly lessen cirrhosis and reduce post-transplantation HBV recurrence. However, HBV recurrence still occurs in many patients following liver transplantation due to the development of drug resistance and poor compliance with therapy. Optimized prophylactic treatment with appropriate NA usage is crucial prior to liver transplantation, and undetectable HBV DNA at the time of transplantation should be achieved. NA-based and hepatitis B immune globulin-based treatment regimens can differ between patients depending on the patients' condition, virus status, and presence of drug resistance. This review focuses on the current progress in applying NAs during the perioperative period of liver transplantation and the prophylactic strategies using NAs to prevent de novo HBV infection in recipients of HBcAb-positive liver grafts.

Tenofovir-based rescue therapy for chronic hepatitis B patients who had failed treatment with lamivudine, adefovir, and entecavir

BACKGROUND AND AIM

In the past decade, many chronic hepatitis B (CHB) patients have undergone sequential treatment with lamivudine (LAM), adefovir (ADV), and entecavir (ETV) to manage antiviral resistance or insufficient suppression of HBV-DNA. Very limited data are available on the efficacy of tenofovir (TDF) rescue regimens in patients with multidrug resistance (MDR).

METHODS

We investigated the antiviral efficacy of TDF/LAM combination therapy versus TDF/ETV combination therapy in 52 patients who failed three previous antiviral therapies.

RESULTS

The study subjects were treated with TDF/LAM combination therapy (n = 25) or TDF/ETV combination therapy (n = 27) for more than six months. Virologic response (VR) occurred in 39 (75%) patients (19 patients belonged to the TDF/LAM group and 20 patients belonged to the TDF/ETV group). The VR rates were not different between the TDF/LAM and TDF/ETV groups (56.0% vs 51.9% at month 12, and 72.0% vs 78.8% at month 18; log rank P = 0.515). In addition, treatment efficacy of TDF/LAM combination or TDF/ETV combination was not statistically different according to types of MDR. In multivariate analysis, absolute HBV-DNA level at the start of TDF rescue treatment (P < 0.001; OR, 0.452; 95% CI, 0.306-0.666) was only significantly associated with VR.

CONCLUSIONS

TDF/ETV combination therapy was not associated with higher rate of VR compared with TDF/LAM combination therapy in MDR CHB patients. These results raise the suspicion about the superiority of the combination therapy over TDF monotherapy. The lower HBV-DNA levels at the start of TDF-based rescue therapy were associated with higher VR.

Tenofovir disoproxil fumarate has a substantial efficacy against multidrug-resistant strains of hepatitis B virus

BACKGROUND & AIMS

To evaluate the efficacy of tenofovir in chronic hepatitis B (CHB) patients with adefovir resistance (ADF-R) and suboptimal response to adefovir (ADF-S).

METHODS

Nucleos(t)ide analogue (NA)-naïve patients and patients with previous adefovir failure receiving tenofovir therapy for at least 6 months were included in the study. Biochemical and virological tests were obtained at baseline and 3-month intervals in the first year and every 6 months thereafter. The primary outcome measure was complete virological response (CVR) (HBVDNA < 20 IU/ml). CVR rates were calculated by Kaplan-Meier analysis, and a multivariate Cox proportional hazard model was generated to find out factors independently associated with CVR.

RESULTS

A total of 165 patients (118 men, mean age 42 ± 12, 64 HBeAg(+) ) were included in the study. There were 105 patients in NA-naïve, 32 patients in ADF-S and 28 patients in ADF-R groups. All patients in the ADF-R group had multidrug resistance patterns. Mean duration of tenofovir treatment was 29 ± 14 months. CVR rates in NA-naïve, ADF-S and ADF-R groups were 65% vs. 75% vs. 58% at 12th month, 77% vs. 87% vs. 79% at 24th month and 83% vs. 94% vs. 79% at 36th month respectively. According to multivariate Cox regression model, HBeAg positivity (HR = 0.56, 95%CI 0.36-0.86, P = 0.008), high baseline HBVDNA level (HR = 0.64, 95%CI 0.55-0.74, P < 0.001) and ADF-R (HR = 0.47, 95%CI 0.28-0.81, P = 0.006) were independent predictors for CVR. Seven patients encountered mild renal dysfunction and were managed by dose adjustments.

CONCLUSION

CVR rates during the follow-up show that tenofovir has a decreased, yet still potent in vivo efficacy against multidrug-resistant strains of HBV.

Entecavir plus tenofovir versus entecavir plus adefovir in chronic hepatitis B patients with a suboptimal response to lamivudine and adefovir combination therapy

Background/Aims

We compared the efficacies of entecavir (ETV) plus tenofovir (TDF) and ETV plus adefovir (ADV) in chronic hepatitis B (CHB) patients with genotypic resistance to lamivudine (LAM) who showed a suboptimal response to LAM and ADV combination therapy.

Methods

We reviewed 63 CHB patients with genotypic resistance to LAM who showed a suboptimal response to LAM and ADV combination therapy. Among these patients, 30 were treated with ETV + ADV and 33 were treated with ETV + TDF for 12 months.

Results

The only baseline characteristic that differed significantly between the two groups was the ETV resistance profile. The rate of a virologic response [serum hepatitis B virus (HBV) DNA level of <20 IU/mL] was significant higher for ETV+TDF than for ETV+ADV over 12 months (57.6% vs. 23.3%, P=0.006, at 6 months; 84.8% vs. 26.7%, P<0.001, at 12 months). The probability of a virologic response was significantly increased in ETV+TDF (P<0.001, OR=54.78, 95% CI=7.15-419.54) and decreased in patients with higher baseline viral loads (P=0.001, OR=0.18, 95% CI=0.07-0.50) in multivariate analysis. No serious adverse event occurred during the study period.

Conclusions

In patients with CHB who showed a suboptimal response to LAM and ADV combination therapy, ETV+TDF was superior to ETV+ADV in achieving a virologic response regardless of the HBV resistance profile. Further large-scale and long-term follow-up prospective studies are needed to explain these results.

Hepatitis B virus reactivation with a rituximab-containing regimen

Rituximab is currently used not only in the treatment of B-cell lymphoma but also for various other diseases, including autoimmune diseases, post-transplant graft vs host disease, and rejection following kidney transplants. Due to rituximab’s widespread use, great progress has been made regarding research into complications that arise from its use, one of the most serious being the reactivation of hepatitis B virus (HBV), and efforts continue to establish guidelines for preventive treatment against this occurrence. This report discusses preventive measures against rituximab-induced HBV reactivation and future objectives.

Long-term outcomes and dynamics of mutants associated with lamivudine-adefovir rescue therapy in patients with lamivudine-resistant chronic hepatitis B

Background/Aims

To investigate the association between the baseline profiles and dynamics of hepatitis B virus (HBV) DNA polymerase gene mutations and the long-term virological response of lamivudine (LAM)-adefovir (ADV) combination therapy in patients with LAM-resistant chronic hepatitis B.

Methods

Seventy-five patients who received LAM-ADV combination therapy for more than 12 months were analyzed. Restriction fragment mass polymorphism assays were used to detect and monitor the dynamics of LAM- and ADV-resistant mutations.

Results

The median duration of LAM-ADV combination therapy was 26 months (range, 12 to 58 months). The baseline mutation profiles, rtM204I (p=0.992), rtM204I/V (p=0.177), and rtL180M (p=0.051), were not correlated with the cumulative virological response, and the baseline HBV DNA level (p=0.032) was the only independent predictive factor for cumulative virological response. Tests for LAM- and ADV-resistant mutations were performed in 12 suboptimal responders in weeks 48 and 96. The population of rtM204 mutants persisted or increased in 8 of 12 patients, and rtA181T mutants newly emerged as a minor population in four patients until 96 weeks. Nevertheless, the viral loads progressively decreased during rescue therapy, and these dynamics did not correlate with virological response.

Conclusions

The baseline profile and dynamics of LAM-resistant mutations during LAM-ADV combination therapy are not associated with a virological response.

Comparative Meta-Analysis of Tenofovir Disoproxil Fumarate versus Emtricitabine and Tenofovir Disoproxil Fumarate as Treatments for Patients with Chronic Hepatitis B

Tenofovir disoproxil fumarate (TDF) monotherapy has proven superior antiviral efficacy in chronic hepatitis B (CHB) patients; however, whether the combination of TDF and emtricitabine (FTC) exerts a significant advantage remains controversial. A meta-analysis was performed to comprehensively compare the therapeutic effects of FTC/TDF combination with TDF alone in CHB patients. Five studies involving 614 patients were identified, and subgroup analysis was performed based on the nucleos(t)ide treatment history. Our results revealed that in patients with nucleos(t)ide-naïve treatment, there were no significant differences between the treatment groups with TDF alone and FTC/TDF combination after 12 and 24 weeks; however, the FTC/TDF combination showed better viral suppression efficacy versus TDF alone after 48 (OR = 2.16, 95% CI = 1.06–4.41, P = 0.03), 96 (OR = 2.76, 95% CI = 1.29–5.92, P = 0.009) and 192 weeks (OR = 2.60, 95% CI = 1.21–5.56, P = 0.01). In patients with nucleos(t)ide treatment history, no differences were noted between the two treatment groups after 12, 24, 48 and 96 weeks. Our results indicated that FTC/TDF combination showed better viral suppression efficacy versus TDF alone in CHB patients with nucleos(t)ide-naïve treatment, while both treatments provided similar viral suppression efficacy in CHB patients with nucleos(t)ide treatment history.

Chronic hepatitis B: A wave of new therapies on the horizon

This year marks the 50th anniversary of the discovery of the Australia antigen (Blumberg et al., 1965), which in 1967 was identified to be the hepatitis B virus (HBV) surface antigen. Even though several antiviral medications have been in use for the management of chronic HBV infection for more than 20years, sustained clearance of HBsAg, similar to the sustained viral response (SVR) or cure in chronic hepatitis C, occurs in only a minority of treated patients. Moreover, even after 10years of effective suppression of HBV viremia with current therapy, there is only a 40-70% reduction in deaths from liver cancer. Recent success in developing antivirals for hepatitis C that are effective across all genotypes has renewed interest in a similar cure for chronic HBV infection. In this article, we review a wave of newly identified drug targets, investigational compounds and experimental strategies that are now under clinical evaluation or in preclinical development. The paper forms part of a symposium in Antiviral Research on "An unfinished story: From the discovery of the Australia antigen to the development of new curative therapies for hepatitis B."

Efficacy of Tenofovir-based Rescue Therapy in Lamivudine-resistant Chronic Hepatitis B Patients With Failure of Lamivudine and Adefovir Combination

PURPOSE

In chronic hepatitis B patients, lamivudine (LAM) and adefovir (ADV) combination therapy is commonly used as a rescue therapy for LAM resistance, but it often results in incomplete viral suppression. We investigated the antiviral efficacy of tenofovir (TDF)/LAM combination therapy versus TDF monotherapy in LAM-resistant chronic hepatitis B (CHB) patients who failed to respond to LAM plus ADV rescue therapy.

METHODS

Among 108 patients with LAM-resistant CHB who had a partial virologic response (VR) to LAM and ADV combination therapy, Eighty one patients were finally included in this study.

FINDINGS

Resistance to ADV (ADV-R) was present in 32 patients (39.5%), and the remaining 49 patients (60.5%) had a partial virologic response to LAM/ADV combination (ADV-P). The study subjects were treated with TDF alone (n=15) or TDF/LAM combination (n=66). VR was achieved in 61 patients (75.3%). The rates of VR at 6 and 12 months were not significantly different between TDF monotherapy and TDF/LAM combination therapy groups (46.7 vs. 68.2% at 6 months, and 66.7 vs. 75.9% at 12 months, log-rank P=0.357). Treatment efficacy of TDF alone or TDF/LAM combination was not statistically different according to pre-existing ADV or LAM resistant strains. In multivariate analysis, absolute HBV DNA levels at the start of TDF rescue treatment (P<0.001; OR, 0.556; 95% CI, 0.422-0.731) were the only significantly associated with VR.

IMPLICATIONS

TDF monotherapy was as effective as TDF/LAM combination therapy in maintaining viral suppression in patients with LAM-resistant patients who failed to respond to LAM/ADV combination therapy.

Safety and immunogenicity of therapeutic DNA vaccine with antiviral drug in chronic HBV patients and its immunogenicity in mice

BACKGROUND & AIMS

Here, we evaluated the safety and immunogenicity of hepatitis B virus (HBV) DNA vaccine, HB-110, in mice and Korean patients with chronic hepatitis B (CHB) undergoing adefovir dipivoxil (ADV) treatment.

METHODS

For animal study, mice (BALB/c or HBV transgenic) were immunized with mHB-110, and T-cell and antibody responses were evaluated. For clinical study, 27 patients randomly received either ADV alone or ADV in combination with HB-110. Liver function tests, serum HBV DNA levels and the presence of HBeAg/anti-HBe were analysed. T-cell responses were estimated by ELISPOT and FACS analysis.

RESULTS

mHB-110 induced higher T-cell and antibody responses than mHB-100 in mice. No adverse effects were observed by HB-110 cotreated with ADV. HBV-specific T-cell responses were induced in a portion of patients in medium to high dose of HB-110. Interestingly, HB-110 exhibited positive effects on ALT normalization and maintenance of HBeAg seroconversion. One patient, who received high dose of HB-110 exhibited HBeAg seroconversion during vaccination, which correlated with vaccine-induced T-cell responses without ALT elevation.

CONCLUSIONS

HB-110 was safe and tolerable in CHB patients. In contrast to results in animal models, HB-110 in Korean patients exhibited weaker capability of inducing HBV-specific T-cell responses and HBeAg seroconversion than HB-100 in Caucasian patients. As Asian patients, who are generally infected via vertical transmission, appeared to have higher level of immune tolerance than Caucasian, novel approaches for breaking immune tolerance rather than enhancing immunogenicity may be more urgently demanded to develop effective therapeutic HBV DNA vaccines.

Comparison of the efficacies of entecavir 0.5 and 1.0 mg combined with adefovir in patients with chronic hepatitis B who had failed on prior nucleos(t)ide analogue treatments

Entecavir (ETV) plus adefovir (ADV) combination therapy is one of the useful treatment option for the patients with chronic hepatitis B (CHB) who had failed on prior nucleos(t) ide analogue (NA) treatments. This study compared the efficacies of the combinations of ETV 0.5 mg plus ADV and ETV 1.0 mg plus ADV in patients who had failed on prior multiple NA treatments. This retrospective analysis included 148 consecutive patients with CHB infection in Korea (n = 37 with ETV 0.5 mg plus ADV and n = 111 with ETV 1.0 mg plus ADV). The virological and biochemical responses were compared between the two groups. The cumulative probability of viral suppression of ETV 0.5 mg plus ADV was not inferior to that of ETV 1.0 mg plus ADV (hazard ratio [HR], 0.64; 95% confidence interval [CI], 0.38-1.08; P = 0.094). The changes in serum HBV DNA level in the ETV 0.5 mg plus ADV group were not different between the two groups over 12 months. Moreover, no significant difference was observed in acquiring ETV-resistant variants between the two groups during the treatment (HR, 0.95; P = 0.953). This study suggests the proof-of-concept that the lower dose of NA in combination with other NA might be the theoretical option for rescue combination therapy in patients with CHB who had failed on prior multiple NA treatments in order to reduce systemic exposure and possible side effects of NA.

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

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

Maintaining remission in lamivudine-resistant patients with a virological response to adefovir add-on lamivudine after stopping lamivudine therapy

BACKGROUND & AIMS

We examined the durability of the virological response after discontinuing lamivudine (LVD) in chronic hepatitis B (CHB) patients with LVD-resistant hepatitis B virus (HBV), who responded to LVD plus adefovir (ADV) combination therapy, and the outcome of switching to ADV monotherapy compared to maintaining combination therapy.

METHODS

This study enrolled 72 patients with undetectable viral loads (≤12 IU/ml) and normal alanine aminotransferase levels after ADV add-on therapy for at least 6 months in LVD-resistant CHB patients. The enrolled patients were randomly assigned to continue with LVD-ADV combination therapy or switch to ADV monotherapy (n = 36 per group). Virological rebound was defined as HBV DNA detection at more than 12 IU/ml by quantitative polymerase chain reaction determined on two consecutive measurements.

RESULTS

During 96 weeks of follow-up, 100% (36/36) of the patients in the LVD-ADV combination maintained group had persistently undetectable HBV DNA, compared with 94.4% (34/36) patients in the ADV monotherapy switched group. These two patients had undetectable HBV DNA after switching back to LVD-ADV combination therapy. There were no significant differences in the HBsAg levels between the two treatment groups during the 96-week follow-up period.

CONCLUSIONS

In our study, switching to ADV monotherapy resulted in sustained HBV DNA suppression in 94.4% of the patients for 96 weeks. Prior complete viral suppression with LVD-ADV combination therapy conferred a significant advantage in patients who switched to ADV monotherapy. LVD may be discontinued in patients who show a complete virological response to LVD-ADV combination therapy for at least 6 months.

High dose of Lamivudine and resistance in patients with chronic hepatitis B

Background. Lamivudine is the most affordable drug used for chronic hepatitis B and has a high safety profile. With the daily dose of 100 mg there is progressive appearance of resistance to lamivudine therapy. In our study we used 150 mg of lamivudine daily as a standard dose which warrants further exploration for the efficacy of the drug. Aims of the Study. To assess the efficacy of lamivudine 150 mg daily on resistance in patients with chronic hepatitis B. Methods. This retrospective study consists of 53 patients with chronic hepatitis B treated with 150 mg of lamivudine daily. The biochemical and virological response to the treatment were recorded at a 1-year and 2-, 3-, 4-, and 5-year period and time of emergence of resistance to the treatment was noted. Results. The mean age of the patients was 54 years with 80% being males. The resistance to lamivudine 150 mg daily at 1 year and 2, 3, and 5 years was 12.5%, 22.5%, 37.5%, and 60%, respectively, which is much less compared to the standard dose of 100 mg of lamivudine. Conclusions. Lamivudine is safe and a higher dose of 150 mg daily delays the resistance in patients with chronic hepatitis B.

Different mechanism of selection of adefovir-resistant mutant viruses during adefovir monotherapy in patients with lamivudine-resistant chronic hepatitis B

BACKGROUND

Adefovir (ADV) resistance is more frequent in lamivudine (LMV)-resistant chronic hepatitis B (CHB) patients than in nucleos(t)ide analogue-naïve patients. The majority of LMV-resistant mutants harbor the rtM204V/I mutation, while a minor fraction harbor the rtA181V/T mutation. We aimed to elucidate the mechanism of the high rate of ADV resistance in LMV-resistant patients during ADV therapy.

METHODS

We performed a clonal analysis of HBV reverse transcriptase in treatment-naïve (n = 3) and LMV-resistant patients before ADV therapy (n = 14). Dynamic changes in the viral population (n = 9) during ADV therapy were also analyzed.

RESULTS

Before ADV therapy, rtA181V/T was observed in 30 of 680 clones (4.4%) from 7 patients with LMV resistance under dominant rt204V/I mutation and in one of 150 clones in treatment-naïve patients. The rtA181V/T mutation was more frequently found in clones from LMV-resistant patients than in treatment-naïve patients (p = 0.029). The rtN236T mutation was not observed in any clone. During ADV therapy, most rtM204V/I mutants were replaced by wild type in all 3 patients without the rtA181V/T mutation and in one patient with the rtA181V/T mutation. Subsequently, wild type was replaced by the rtN236T and/or rtA181V/T mutant. In patients with the rtA181V/T mutation (n = 6), the rtA181V/T mutant overtook the rtM204V/I mutant in 3 of 4 patients with ADV resistance. In 2 patients without ADV resistance, most of the viral population was replaced by wild type by the last follow-up.

CONCLUSION

The high rate of ADV resistance in patients with LMV-resistance might be attributable to preexisting rtA181V/T mutant virus.

Long-term outcomes of two rescue therapies in lamivudine-refractory patients with chronic hepatitis B: combined lamivudine and adefovir, and 1-mg entecavir

BACKGROUND/AIMS

Adefovir (ADV) and lamivudine (LAM) combination therapy (ADV+LAM) has been a useful option for patients with LAM-resistant (LAM-r) chronic hepatitis B (CHB). However, the long-term outcomes of LAM+ADV and 1-mg entecavir (ETV) rescue therapies have still been limited. The aim of this study was to determine the long-term outcomes of these two rescue therapies.

METHODS

Sixty patients with LAM-r CHB underwent rescue therapy with LAM+ADV (n=36) or 1-mg ETV (n=24). We determined the duration of rescue therapy, timing and type of mutation, undetectable serum hepatitis B virus (HBV) DNA by PCR (lower limitation of detection, < 140 copies/mL), biochemical response (alanine aminotransferase < 40 IU/mL), and the incidence of hepatitis B virus e antigen (HBeAg) seroconversion and virologic breakthrough.

RESULTS

Baseline characteristics did not differ between the two therapy groups. The duration of rescue therapy was 56 months (range, 14-100 months) in the ADV+LAM group and 42 months (range, 12-73 months) in the ETV group (P=0.036). The cumulative rates of HBV DNA undetectability and HBeAg seroconversion up to 6 years were 88.6% and 43.0%, respectively, in the ADV+LAM group, and 45.8% and 31.8% in the ETV group. The rate of virologic breakthrough and resistance was 14.4% in the ADV+LAM group and 71.9% in the ETV group (P=0.001).

CONCLUSIONS

Combination of LAM and ADV therapy for up to 6 years achieved modest rates of virological suppression and resistance. ETV is not an optimal therapy because the risk of viral breakthrough to ETV increases over time.

The feasibility of discontinuing lamivudine in lamivudine-resistant chronic hepatitis B patients on lamivudine and adefovir combination therapy

OBJECTIVES

This study investigated the antiviral efficacy of adefovir (ADV) rescue therapy and the feasibility of lamivudine (LAM) discontinuation in LAM-resistant chronic hepatitis B (CH-B) patients who had attained a virological response (VR) with LAM + ADV combination therapy.

METHODS

The VR and virological breakthrough (VBT) were analyzed in 106 consecutively enrolled LAM-resistant CH-B patients who received ADV rescue therapy during a mean follow-up period of 55.2 months. Seventy-four patients achieved VR, and were divided into the LAM-discontinuation group (n = 39) and the LAM-continuation group (n = 35). The VR and VBT between the 2 groups were compared.

RESULTS

For all 106 LAM-resistant CH-B patients, the overall cumulative probabilities of VR at 1, 2, 3 and 5 years of ADV rescue therapy were 40.6, 55.7, 64.6 and 81.3%, respectively. The cumulative probabilities of VBT at 1, 2, 3 and 5 years were 0, 2.9, 8.8 and 13.9%, respectively. Whether they discontinued or continued LAM after achieving VR on LAM + ADV therapy, VR and VBT were not significantly different during a mean follow-up period of 40.4 months.

CONCLUSIONS

There was a good long-term VR with ADV rescue therapy for LAM-resistant CH-B patients. Moreover, discontinuing LAM was found to be feasible for patients who attained VR during ADV + LAM therapy.

Management of antiviral drug resistance in chronic hepatitis B

Rescue antiviral treatment for patients with resistance to preexisting nucleos(t)ide analogues remains a clinical challenge. The correct choice of a first-line treatment of high potency and with a high genetic barrier to achieve sustained long-term suppression of viral replication provides the best chance of preventing treatment failure and the emergence of drug resistance. The management of treatment failure and drug resistance requires a precise and accurate clinical and virologic monitoring. Combination treatment with antiviral drugs that belong to different groups is associated with a lower chance of developing resistance to rescue drugs. To guarantee better control of viral replication in patients with drug resistance, the addition of another drug without a cross resistance profile should be given as early as possible, preferably at the time when genotypic resistance emerges. Long-term surveillance for treatment efficacy and possible emergence of drug resistance should be continued to prevent the emergence of multidrug-resistant strains.

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

Background/Aims

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

Methods

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

Results

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

Conclusions

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

Entecavir plus adefovir combination therapy versus lamivudine add-on adefovir for lamivudine-resistant chronic hepatitis B: A meta-analysis

To determine whether adefovir (ADV) in combination with entecavir (ETV) is more effective than with lamivudine (LAM) in patients with lamivudine-resistant chronic HBV infection, electronic databases were searched through May 10th, 2013 to obtain relevant trials which met the inclusion criteria. Meta-analysis was performed on randomized controlled trials (RCTs) and non-randomized studies. Four trials containing a total of 323 patients were included. Serum HBV DNA reductions after 3 and 6 months of treatment in the ETV + ADV group were greater than that of LAM + ADV group (mean difference (MD) = 0.90, 95% confidence interval (CI): 0.74-1.07, P < 0.00001; MD = 0.81, 95% CI: 0.57-1.06, P < 0.00001). The rate of 6 months HBV DNA undetectability with ETV and ADV was higher than that of LAM and ADV (relative risk (RR) = 1.63, 95% CI: 1.14-2.34, P < 0.007). There were higher rates of serum ALT normalization than those in LAM + ADV group after 6 months of treatment (RR = 1.40, 95% CI: 1.11-1.77, P < 0.005). The ETV + ADV group had lower viral breakthrough and genotypic mutation rates than LAM + ADV group after 12 months of treatment (RR = 0.24, 95% CI: 0.10-0.58, P = 0.002). The combination of ETV plus ADV is a more effective rescue therapy than LAM add-on ADV in patients with LAM-resistant HBV.