Virologic monitoring of hepatitis B virus therapy in clinical trials and practice: recommendations for a standardized approach

Recent advances in micro/nanotechnologies for global control of hepatitis B infection

The control of hepatitis B virus (HBV) infection is a challenging task, specifically in developing countries there is limited access to diagnostics and antiviral treatment mainly due to high costs and insufficient healthcare infrastructure. Although the current diagnostic technologies can reliably detect HBV, they are relatively laborious, impractical and require expensive resources that are not suitable for resource-limited settings. Advances in micro/nanotechnology are pioneering the development of new generation methodologies in diagnosis and screening of HBV. Owing to combination of nanomaterials (metal/inorganic nanoparticles, carbon nanotubes, etc.) with microfabrication technologies, utilization of miniaturized sensors detecting HBV and other viruses from ultra-low volume of blood, serum and plasma is realized. The state-of-the-art microfluidic devices with integrated nanotechnologies potentially allow for inexpensive HBV screening at low cost. This review aims to highlight recent advances in nanotechnology and microfabrication processes that are employed for developing point-of-care (POC) HBV assays.

Evaluation of a Rapid One-step Real-time PCR Method as a High-throughput Screening for Quantification of Hepatitis B Virus DNA in a Resource-limited Setting

Virological monitoring is the best predictor for the management of chronic hepatitis B virus (HBV) infections. Consequently, it is important to use the most efficient, rapid and cost-effective testing systems for HBV DNA quantification. The present study compared the performance characteristics of a one-step HBV polymerase chain reaction (PCR) vs the two-step HBV PCR method for quantification of HBV DNA from clinical samples. A total of 100 samples consisting of 85 randomly selected samples from patients with chronic hepatitis B (CHB) and 15 samples from apparently healthy individuals were enrolled in this study. Of the 85 CHB clinical samples tested, HBV DNA was detected from 81% samples by one-step PCR method with median HBV DNA viral load (VL) of 7.50 × 103 lU/ml. In contrast, 72% samples were detected by the two-step PCR system with median HBV DNA of 3.71 × 103 lU/ml. The one-step method showed strong linear correlation with two-step PCR method (r = 0.89; p < 0.0001). Both methods showed good agreement at Bland-Altman plot, with a mean difference of 0.61 log10 IU/ml and limits of agreement of -1.82 to 3.03 log10 IU/ml. The intra-assay and interassay coefficients of variation (CV%) of plasma samples (4-7 log10 IU/ml) for the one-step PCR method ranged between 0.33 to 0.59 and 0.28 to 0.48 respectively, thus demonstrating a high level of concordance between the two methods. Moreover, elimination of the DNA extraction step in the one-step PCR kit allowed time-efficient and significant labor and cost savings for the quantification of HBV DNA in a resource limited setting.

HOW TO CITE THIS ARTICLE

Rashed-Ul Islam SM, Jahan M, Tabassum S. Evaluation of a Rapid One-step Real-time PCR Method as a High-throughput Screening for Quantification of Hepatitis B Virus DNA in a Resource-limited Setting. Euroasian J Hepato-Gastroenterol 2015;5(1):11-15.

A novel method for detection of HBVcccDNA in hepatocytes using rolling circle amplification combined with in situ PCR

BACKGROUND

Intrahepatic hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) is the original template for HBV replication. The persistence of cccDNA is responsible for the recurrence of HBV infection. The detection of cccDNA can help the development of new antiviral drugs against HBV replication links, and reduce the resistance and recurrence as well as to discover extrahepatic HBV infection. In situ polymerase chain reaction (IS-PCR) can be used to determine the distribution and localization of cccDNA in liver tissues, but it is hampered by its low sensitivity and specificity. We developed a novel method to detect HBV cccDNA using rolling circle amplification (RCA) combined with IS-PCR.

METHODS

Biopsy liver tissues were obtained from 26 patients with HBV infection, including 10 chronic hepatitis B (CHB), 6 liver cirrhosis (LC) and 10 hepatocellular carcinoma (HCC) patients. Four pairs of primers were designed to mediating RCA for the first round amplification of HBV cccDNA specifically. The liver tissue sections from patients were treated by plasmid-safe ATP-dependent DNase (PSAD) prior to RCA. After RCA, HBV cccDNA was further amplified by a pair of selective primers labeled digoxigenin that target the gap region between the two direct repeat regions (DR1 and DR2) of the virus via IS-PCR.

RESULTS

HBVcccDNA was expressed and located in hepatocyte nucleus in 19 patients (73.07%). Compared with the IS-PCR, the introduction of RCA increase the limit of detection. RCA combined with IS-PCR yielded strong positive signals in HCC liver tissue in spite of low copy number cccDNA (2 copies of target sequence per cell), meanwhile, no positive signal was detected via negative control.

CONCLUSIONS

RCA combined with IS-PCR is an effective and practicable method which could detect the presence of low copy number of cccDNA sensitively and specifically, and reflect the relationship between cccDNA expression level and liver tissue pathological characteristics.

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.

Re-appraisal of old and new diagnostic tools in the current management of chronic hepatitis B

Hepatitis B virus (HBV) is a very complex and intricate DNA structure associated with a particular genomic organization and replication cycle. However, many years of investigations allowed clarification of the real HBV natural history, through a deeper knowledge of the behavior of HBV antigens and viral structures. Several of the old diagnostic tools, such as HBV surface antigen (HBsAg) and HBV e antigen (HBeAg) determinations, gained prominence now, since the variation of both HBsAg and HBeAg plasma levels was shown to predict treatment response. In addition, the availability of more sensitive methods, such as HBV DNA detection by real-time PCR, has improved the current knowledge of the relationships between HBV replication levels and the natural history of the disease. It is now well established that some HBV genotypes are associated with a better response to treatment with pegylated interferon. Despite the widely accepted value of liver biopsy as a staging tool, transient elastography is being increasingly acknowledged as a non-invasive method to assess liver stiffness, chiefly for detection of advanced fibrosis. Current international guidelines for the management of chronic hepatitis B have provided several accurate biochemical and serological criteria for selecting patients for treatment, allowing a higher number of cases to be enrolled into antiviral therapy. This review describes the different serological markers used for the study of HBV and their clinical significance. It also deals with methods used for detection of genotypes and HBV DNA, emphasizing the effectiveness of such determinations for both patient selection and chronic hepatitis B therapy/monitoring.

Cyclosporin A and its analogs inhibit hepatitis B virus entry into cultured hepatocytes through targeting a membrane transporter, sodium taurocholate cotransporting polypeptide (NTCP)

Chronic hepatitis B virus (HBV) infection is a major public health problem worldwide. Although nucleos(t)ide analogs inhibiting viral reverse transcriptase are clinically available as anti-HBV agents, emergence of drug-resistant viruses highlights the need for new anti-HBV agents interfering with other targets. Here we report that cyclosporin A (CsA) can inhibit HBV entry into cultured hepatocytes. The anti-HBV effect of CsA was independent of binding to cyclophilin and calcineurin. Rather, blockade of HBV infection correlated with the ability to inhibit the transporter activity of sodium taurocholate cotransporting polypeptide (NTCP). We also found that HBV infection-susceptible cells, differentiated HepaRG cells and primary human hepatocytes expressed NTCP, while nonsusceptible cell lines did not. A series of compounds targeting NTCP could inhibit HBV infection. CsA inhibited the binding between NTCP and large envelope protein in vitro. Evaluation of CsA analogs identified a compound with higher anti-HBV potency, having a median inhibitory concentration <0.2 μM.

CONCLUSION

This study provides a proof of concept for the novel strategy to identify anti-HBV agents by targeting the candidate HBV receptor, NTCP, using CsA as a structural platform.

Changes of HBsAg and HBV DNA levels in Chinese chronic hepatitis B patients after 5 years of entecavir treatment

BACKGROUND AND AIM

Hepatitis B surface antigen (HBsAg) kinetics during long-term entecavir therapy has not been well investigated.

METHODS

We described the cumulative serologic, virologic, and biochemical outcomes and the occurrence of signature entecavir mutations among 222 Chinese treatment-naïve chronic hepatitis B (CHB) patients receiving entecavir for up to 5 years.

RESULTS

The median rate of HBsAg reduction over 5 years was 0.125 log IU/mL/year. Patients with high baseline HBV DNA levels (≥ 8 log copies/mL or ≥ 7.3 log IU/mL), when compared with those with baseline hepatitis B virus (HBV) DNA < 7.3 log IU/mL, had a significantly greater median rate of HBsAg reduction (0.178 and 0.102 log IU/mL/year, respectively, P < 0.001). The difference in HBsAg decline was most prominent in the first year (0.324 and 0.062 log IU/mL/year, respectively, P < 0.001). Greater median rates of HBsAg reduction were also found in hepatitis B e antigen (HBeAg)-positive patients when compared with HBeAg-negative patients (0.144 and 0.098 log IU/mL/year, P = 0.015), and in patients with high baseline HBsAg levels (≥ 3 log IU/mL), when compared with patients with low baseline HBsAg < 3 log IU/mL (0.131 and 0.045 log IU/mL/year, respectively, P = 0.001). The 5-year cumulative rate of HBV DNA undetectability (< 20 IU/mL) was 97.1%. There were two cases of entecavir resistance, resulting in a 5-year cumulative resistance rate of 1.2%.

CONCLUSION

In contrast to the profound HBV DNA suppression, long-term entecavir treatment achieved only a slow decline in serum HBsAg. Although certain patient subgroups exhibit a more rapid HBsAg reduction, additional therapeutic agents are needed to increase the chance of HBsAg seroclearance in CHB.

Hepatitis B virus reverse transcriptase mutations in treatment Naïve chronic hepatitis B patients

Mutations in the reverse transcriptase (RT) region of the hepatitis B virus (HBV) genome lead to decreased susceptibility to nucleos(t)ide analogs approved for treatment of HBV infection. The aim of this study was to detect and analyze pre-existing HBV RT mutations in treatment naïve patients with chronic hepatitis B. Seventy one chronic HBV treatment naïve patients were enrolled from January 2009 to June 2011. HBV RT sequence analysis was done by using direct bidirectional sequencing of semi-nested PCR products. HBV genotypes were determined by multiplex PCR. Genotype D was found in 64 patients (90.1%) followed by genotype C and A which were present in 5 (7.0%) and 2 (2.8%) patients respectively. The results of the RT sequence analysis showed mutations in 34 (47.9%) patients. The rtH248N mutation was the most common mutation, accounting for 47.1% patients. Other common mutations included rtD263E/S, rtM129L, rtF122L/V/I, rtS135Y/H, rtQ149K, rtL91I, rtH126R, rtC256S/G, rtY257W, rtS259T and rtE271D, which were present in 26.5% (9/34), 29.4% (10/34), 20.6% (7/34), 20.6% (7/34), 20.6% (7/34), 17.6% (6/34), 14.7% (5/34), 14.7% (5/34), 11.8% (4/34), 11.8% (4/34) and 11.8% (4/34) patients respectively. The known primary drug resistance mutations were found in 3 (8.8%) patients. The present study shows the presence of RT amino acid substitutions in treatment-naïve patients with chronic hepatitis B, which may decrease susceptibility to available oral antiviral drugs. On the basis of the finding of this study, genotypic testing is recommended before the start of therapy in naïve patients, so that suitable antiviral drugs can be prescribed.

Virologic response and breakthrough in chronic hepatitis B Egyptian patients receiving lamivudine therapy

BACKGROUND

Lamivudine monotherapy is effective in suppressing hepatitis B virus (HBV) replication to undetectable levels by PCR, in ameliorating liver disease and to some extent in achieving HBsAg seroconversion. This study aimed at assessing the virological and biochemical responses as well as breakthrough in HBeAg-negative chronic HBV (CHB) Egyptian patients receiving lamivudine therapy.

METHODS

This retrospective study included 140 CHB patients with positive serum HBV-DNA by quantitative PCR assays and negative HBeAg who had never received prior anti-viral therapy for HBV. According to duration of lamivudine therapy (100 mg/day) patients were grouped into: group I (n=59) who received lamivudine for 1 year, group II (n=50) who received lamivudine for 2 years, and group III (n=31) who received lamivudine for 3 years.

RESULTS

In group I, 76.3% patients had virologic response but this was reduced in group II and group III to 72% and 67.7% respectively. None of the patients in group I developed virologic breakthrough, whereas 12% and 25.8% in groups II and III respectively developed breakthrough. In group I, 25% of patients having high pre-treatment viremia showed virologic response compared to 84.6% and 83.3% having mild and moderate viremia respectively (P<0.01). However, in groups II and III, there was no significant relationship between pre-treatment viremia and virologic response. No significant relationship was found between pre-treatment viral load and incidence of breakthrough within each group.

CONCLUSION

Lamivudine remains one of the antiviral therapies for HBeAg negative CHB patients. The rates of maintained virologic and biochemical responses to lamivudine decrease in time due to selection of drug-resistant mutants and, hence, breakthrough.

Evaluation and identification of hepatitis B virus entry inhibitors using HepG2 cells overexpressing a membrane transporter NTCP

Hepatitis B virus (HBV) entry has been analyzed using infection-susceptible cells, including primary human hepatocytes, primary tupaia hepatocytes, and HepaRG cells. Recently, the sodium taurocholate cotransporting polypeptide (NTCP) membrane transporter was reported as an HBV entry receptor. In this study, we established a strain of HepG2 cells engineered to overexpress the human NTCP gene (HepG2-hNTCP-C4 cells). HepG2-hNTCP-C4 cells were shown to be susceptible to infection by blood-borne and cell culture-derived HBV. HBV infection was facilitated by pretreating cells with 3% dimethyl sulfoxide permitting nearly 50% of the cells to be infected with HBV. Knockdown analysis suggested that HBV infection of HepG2-hNTCP-C4 cells was mediated by NTCP. HBV infection was blocked by an anti-HBV surface protein neutralizing antibody, by compounds known to inhibit NTCP transporter activity, and by cyclosporin A and its derivatives. The infection assay suggested that cyclosporin B was a more potent inhibitor of HBV entry than was cyclosporin A. Further chemical screening identified oxysterols, oxidized derivatives of cholesterol, as inhibitors of HBV infection. Thus, the HepG2-hNTCP-C4 cell line established in this study is a useful tool for the identification of inhibitors of HBV infection as well as for the analysis of the molecular mechanisms of HBV infection.

Two-year results of a randomized, phase III comparative trial of telbivudine versus lamivudine in Chinese patients

PURPOSE

The burden of chronic hepatitis B infection is high in China, where prevalence exceeds 7 %. This was a randomized, double-blinded, phase III study of the efficacy and safety of telbivudine and lamivudine treatment at 104 weeks in Chinese patients with chronic hepatitis B.

METHODS

Hepatitis B e antigen-positive (n = 290) and -negative (n = 42) adults with nucleoside analog-naïve compensated chronic hepatitis B were randomized to receive telbivudine 600 mg/day or lamivudine 100 mg/day for 104 weeks. The primary endpoint was reduction from baseline in serum hepatitis B virus (HBV) DNA at week 52. Week 104 analyses included HBV DNA reductions, undetectable HBV DNA (<300 copies/mL), ALT normalization, and e-antigen loss/seroconversion. Efficacy at week 104 was also assessed as a function of week 24 HBV DNA.

RESULTS

In the intention-to-treat population (n = 332) at week 104, telbivudine was superior to lamivudine for reduction of HBV DNA [-5.48 vs. -4.00 log10 copies/mL; difference -1.49 log10 (95 % confidence interval -2.2, -0.8); p < 0.0001], for the proportion with undetectable HBV DNA (61.9 vs. 38.5 %; p < 0.0001), for ALT normalization (75.8 vs. 61.3 %; p = 0.0049), and for e-antigen loss (39.9 vs. 28.2 %; p = 0.0373). The cumulative probability of genotypic drug resistance was 15.4 % on telbivudine versus 23.6 % on lamivudine through week 104. Early virologic response at week 24 was associated with improved outcomes at week 104. Adverse events were similar to those seen in the GLOBE study.

CONCLUSIONS

Telbivudine is superior to lamivudine over 2 years of chronic hepatitis B treatment in Chinese patients.

HBV genotype B/C and response to lamivudine therapy: a systematic review

A number of nucleoside analogues such as lamivudine (LAM), actually used for the treatment of chronic hepatitis B, can suppress HBV DNA replication, improve transaminase level and liver histology, and enhance the rate of hepatitis B e antigen (HBeAg) clearance. The responses to LAM therapy involve HBeAg clearance and HBV DNA conversion of negative. However, the associations between HBV genotype B/C and response to LAM therapy remain ambiguous. The aim of this meta-analysis is to determine more precise estimations of the relationship. All the publications on the associations between HBV genotype B/C and response to LAM (HBeAg clearance and HBV DNA conversion of negative) through June 2013 were collected. Relative risk (RR) with 95% confidence intervals (95% CI) was calculated in fixed or random model, I² was calculated to examine heterogeneity, and funnel plots were plotted to examine small study effects with Stata 11 software. Overall, for HBeAg clearance and genotype B/C, the RR (95% CI) was 1.27 (0.94-1.71), while for HBV DNA conversion of negative and genotype B/C, the RR (95% CI) was 1.07 (0.98-1.17). HBV genotype B/C shows no significance associations with response to lamivudine therapy (HBeAg clearance and HBV DNA conversion of negative).

Comparison of the efficacy of Lamivudine plus adefovir versus entecavir in the treatment of Lamivudine-resistant chronic hepatitis B: a systematic review and meta-analysis

BACKGROUND

Hepatitis B virus infection remains 1 of the major health threats worldwide. Currently, lamivudine plus adefovir combination therapy or entecavir monotherapy is usually used for the treatment of patients with lamivudine-resistant chronic hepatitis B (CHB). However, there are few systematic comparisons between the efficacy of lamivudine plus adefovir and the efficacy of entecavir in the treatment of these patients.

OBJECTIVE

The goal of this systematic study and meta-analysis was to assess the efficacy of lamivudine plus adefovir compared with entecavir for the treatment of patients with lamivudine-resistant CHB.

METHODS

A comprehensive literature search of PUBMED, Web of Science, WANFANG database, the Cochrane Central Register of Controlled Trials, and the Cochrane Database of Systematic Review, were screened to obtain citations from January 1990 to January 2012 in this study. Data analysis was done by using the Review Manager Software 5.1.

RESULTS

Eight studies were suitable for analysis. A total of 696 patients with lamivudine-resistant CHB were studied and grouped according to treatment: 341 patients in the entecavir group and 355 patients in the lamivudine plus adefovir group. The results found that the rates of undetectable hepatitis B virus DNA levels, alanine aminotransferase normalization, hepatitis B e antigen loss, and hepatitis B e antigen seroconversion were not significantly different between the lamivudine plus adefovir group and the entecavir group. Moreover, the rate of adverse reactions was also not significantly different between the 2 groups. However, virologic breakthrough for the patients with lamivudine resistance was higher in the entecavir group than in the lamivudine plus adefovir group.

CONCLUSIONS

For these CHB patients with lamivudine resistance, lamivudine plus adefovir was a better treatment option than entecavir alone.

Interleukin-1 and tumor necrosis factor-α trigger restriction of hepatitis B virus infection via a cytidine deaminase activation-induced cytidine deaminase (AID)

Virus infection is restricted by intracellular immune responses in host cells, and this is typically modulated by stimulation of cytokines. The cytokines and host factors that determine the host cell restriction against hepatitis B virus (HBV) infection are not well understood. We screened 36 cytokines and chemokines to determine which were able to reduce the susceptibility of HepaRG cells to HBV infection. Here, we found that pretreatment with IL-1β and TNFα remarkably reduced the host cell susceptibility to HBV infection. This effect was mediated by activation of the NF-κB signaling pathway. A cytidine deaminase, activation-induced cytidine deaminase (AID), was up-regulated by both IL-1β and TNFα in a variety of hepatocyte cell lines and primary human hepatocytes. Another deaminase APOBEC3G was not induced by these proinflammatory cytokines. Knockdown of AID expression impaired the anti-HBV effect of IL-1β, and overexpression of AID antagonized HBV infection, suggesting that AID was one of the responsible factors for the anti-HBV activity of IL-1/TNFα. Although AID induced hypermutation of HBV DNA, this activity was dispensable for the anti-HBV activity. The antiviral effect of IL-1/TNFα was also observed on different HBV genotypes but not on hepatitis C virus. These results demonstrate that proinflammatory cytokines IL-1/TNFα trigger a novel antiviral mechanism involving AID to regulate host cell permissiveness to HBV infection.

Interleukin-1 and tumor necrosis factor-α trigger restriction of hepatitis B virus infection via a cytidine deaminase activation-induced cytidine deaminase (AID)

Virus infection is restricted by intracellular immune responses in host cells, and this is typically modulated by stimulation of cytokines. The cytokines and host factors that determine the host cell restriction against hepatitis B virus (HBV) infection are not well understood. We screened 36 cytokines and chemokines to determine which were able to reduce the susceptibility of HepaRG cells to HBV infection. Here, we found that pretreatment with IL-1β and TNFα remarkably reduced the host cell susceptibility to HBV infection. This effect was mediated by activation of the NF-κB signaling pathway. A cytidine deaminase, activation-induced cytidine deaminase (AID), was up-regulated by both IL-1β and TNFα in a variety of hepatocyte cell lines and primary human hepatocytes. Another deaminase APOBEC3G was not induced by these proinflammatory cytokines. Knockdown of AID expression impaired the anti-HBV effect of IL-1β, and overexpression of AID antagonized HBV infection, suggesting that AID was one of the responsible factors for the anti-HBV activity of IL-1/TNFα. Although AID induced hypermutation of HBV DNA, this activity was dispensable for the anti-HBV activity. The antiviral effect of IL-1/TNFα was also observed on different HBV genotypes but not on hepatitis C virus. These results demonstrate that proinflammatory cytokines IL-1/TNFα trigger a novel antiviral mechanism involving AID to regulate host cell permissiveness to HBV infection.

Association of preexisting drug-resistance mutations and treatment failure in hepatitis B patients

The role of preexisting minority drug-resistance mutations in treatment failure has not been fully understood in chronic hepatitis B patients. To understand mechanisms of drug resistance, we analyzed drug-resistance mutations in 46 treatment-failure patients and in 29 treatment-naïve patients and determined linkage patterns of the drug-resistance mutations in individual viral genomes using a highly sensitive parallel allele-specific sequencing (PASS) method. Lamivudine resistance (LAMr) mutations were predominant in treatment-failure patients, irrespective of the inclusion of LAM in the regimen. The primary LAMr mutations M204V and M204I were detected in 100% and 30% of the treatment-failure patients, respectively. Two secondary LAMr mutations (L180M and V173L) were also found in most treatment-failure patients (87% and 78%, respectively). The linkages containing these three mutations dominated the resistant viruses. Importantly, minority LAMr mutations present in <2% of the viral population were detected in 83% of the treatment-naïve patients. Moreover, the low-frequency same linked LAMr mutations (<0.15%) were detected in 24% of the treatment-naïve patients. Our results demonstrate that the selection of preexisting minority linked LAMr mutations may be an important mechanism for the rapid development of LAM resistance, caution the continuous use of LAM to treat drug-experienced and -naïve hepatitis B patients, and underline the importance of the detection of minority single and linked drug-resistance mutations before initiating antiviral therapy.

Comparison of INNO-LIPA and TRUGENE assays for genotyping and drug-resistance mutations in chronic hepatitis B virus infection

OBJECTIVE

Hepatitis B virus (HBV) genotyping and detection of resistance to drugs have become essential in epidemiological and clinical diagnosis. Our main objective was to determine the prevalence of HBV genotypes and drug-resistance mutations in chronic asymptomatic carriers and chronic HBV sufferers comparing 2 detection assays.

METHODS

Serum samples from 28 chronic HBV patients and 22 chronic asymptomatic carriers were analyzed. For HBV genotyping, the INNO-LIPA and TRUGENE™ HBV genotyping kits were evaluated. For drug-resistance mutations, INNO-LIPA DR v2 and INNO-LIPA DR v3 prototype and the TRUGENE™ HBV genotyping kit were evaluated.

RESULTS

In HBV genotyping, concordant results were 98% and both assays were able to detect more than one genotype. Different genotypes were detected, the most prevalent being D (46%) and A (26%). In relation to drug-resistance mutations, the sensitivity of the line probe assay was lower than TRUGENE because INNO-LIPA could not detect two mutations (S202G and V214A).

CONCLUSIONS

Both assays are easy and suitable for detecting HBV genotype and drug-resistance mutations and for routine laboratory use. However, TRUGENE presented better sensitivity in both analyses and it is possible to conduct both on the same sample. This assay is also able to detect primary and secondary mutations.

Differences in metabolites of different tongue coatings in patients with chronic hepatitis B

Tongue coating is one of the important foundations of tongue diagnosis in traditional Chinese medicine (TCM) and plays an important role in reflecting the occurrence, development, and prognosis of the disease. However, its material basis is still poorly understood. In this study, a urinary metabonomic method based on gas chromatography coupled to mass spectrometry (GC/MS) was developed. The distinct clustering in metabolic profile was observed from Group A (thick yellow coating in patients with chronic hepatitis B), Group B (thick white coating in patients with chronic hepatitis B), and Group C (thin white coating with healthy humans) using orthogonal projections to latent structures (OPLS). Based on the variable of importance in the project (VIP) values, some significantly changed metabolites have been identified. These changes were related to the disturbance in energy metabolism, amino acid metabolism, nucleotide metabolism, and gut microflora, which were helpful to understand the material basis leading to the formation of tongue coating. This study demonstrated that tongue coating may have an objective material basis.

Efficacy and safety of continuous 4-year telbivudine treatment in patients with chronic hepatitis B

In the phase-III GLOBE/015 studies, telbivudine demonstrated superior efficacy vs lamivudine during 2-year treatment in HBeAg-positive and HBeAg-negative chronic hepatitis B (CHB). After completion, 847 patients had an option to continue telbivudine treatment for further 2 years. A total of 596 (70%) of telbivudine-treated patients, who were serum HBV DNA positive or negative and without genotypic resistance to telbivudine at the end of the GLOBE/015 trials, were enrolled into a further 2-year extension study. A group of 502 patients completed 4 years of continuous telbivudine treatment and were included in the telbivudine per-protocol population. Amongst 293 HBeAg-positive patients, 76.2% had undetectable serum HBV DNA and 86.0% had normal serum ALT at the end of 4 years. Notably, the cumulative rate of HBeAg seroconversion was 53.2%. Amongst 209 HBeAg-negative patients, 86.4% had undetectable HBV DNA and 89.6% had normal serum ALT. In patients who had discontinued telbivudine treatment due to HBeAg seroconversion, the HBeAg response was durable in 82% of patients (median 111 weeks of off-treatment follow-up). The cumulative 4-year resistance rate was 10.6% for HBeAg-positive and 10.0% for HBeAg-negative patients. Most adverse events were mild or moderate in severity and transient. Renal function measured by estimated glomerular filtration rate (eGFR) increased by 14.9 mL/min/1.73 m(2) (16.6%) from baseline to 4 years (P < 0.0001). In conclusion, in HBeAg-positive and HBeAg-negative CHB patients without resistance after 2 years, two additional years of telbivudine treatment continued to provide effective viral suppression with a favourable safety profile. Moreover, telbivudine achieved 53% of HBeAg seroconversion in HBeAg-positive patients.

Chronic HBV carrier's acceptance of regular surveilling program in China

Long-term compliance with regular surveillance is important for the prevention and timely management of chronic hepatitis B (CHB). However, there are no researches focusing on the compliance of hepatitis B virus infected patients in regular surveillance so far. The purpose of our study was to investigate the outpatient compliance with long-term regular surveillance in China. Data of 3257 CHB outpatients was pooled and analyzed to assess the outpatient's compliance with the long-term regular surveillance plan. In all outpatients, the non-follow-up and the follow-up group accounted for 73.2% and 26.8%, respectively. Among the follow-up outpatient's, only 48.9% received ongoing-follow-up and 51.1% were finally lost to follow-up; the median length of visiting duration was 25 months; and the predictive 1-, 2-, 3-, 4- and 5-year ongoing follow-up rate was 72.7%, 52.5%, 42.4%, 33.8%, and 26.3%, respectively. In conclusion, our survey proved that the regular long-term surveillance on Chinese chronic HBV carrier is difficult to be fully implemented. A large proportion of outpatients do not receive routine follow-up and are at risk of treatment delay due to various social reasons.

A cutting-edge view on the current state of antiviral drug development

Prominent in the current stage of antiviral drug development are: (i) for human immunodeficiency virus (HIV), the use of fixed-dose combinations (FDCs), the most recent example being Stribild(TM); (ii) for hepatitis C virus (HCV), the pleiade of direct-acting antivirals (DAAs) that should be formulated in the most appropriate combinations so as to obtain a cure of the infection; (iii)-(v) new strategies (i.e., AIC316, AIC246, and FV-100) for the treatment of herpesvirus infections: herpes simplex virus (HSV), cytomegalovirus (CMV), and varicella-zoster virus (VZV), respectively; (vi) the role of a new tenofovir prodrug, tenofovir alafenamide (TAF) (GS-7340) for the treatment of HIV infections; (vii) the potential use of poxvirus inhibitors (CMX001 and ST-246); (viii) the usefulness of new influenza virus inhibitors (peramivir and laninamivir octanoate); (ix) the position of the hepatitis B virus (HBV) inhibitors [lamivudine, adefovir dipivoxil, entecavir, telbivudine, and tenofovir disoproxil fumarate (TDF)]; and (x) the potential of new compounds such as FGI-103, FGI-104, FGI-106, dUY11, and LJ-001 for the treatment of filoviruses (i.e., Ebola). Whereas for HIV and HCV therapy is aimed at multiple-drug combinations, for all other viruses, HSV, CMV, VZV, pox, influenza, HBV, and filoviruses, current strategies are based on the use of single compounds.

Australian tertiary care outcomes of entecavir monotherapy in treatment naive patients with chronic hepatitis B

AIM

To evaluate the long-term treatment outcomes of entecavir monotherapy in treatment naive patients in an Australian tertiary care setting.

METHODS

A retrospective analysis of treatment naive patients receiving entecavir monotherapy through Westmead Hospital was performed. Patients were excluded if they had received previous treatment with another nucleoside or nucleotide analogue, were pregnant or less than 18 years old.

RESULTS

Out of 336 patients, 163 patients fulfilled the selection criteria. Range of follow up was 3-46 mo (mean 26 mo). 134 patients (82.2%) had pre-treatment biopsies, with 26 patients (16.0 %) demonstrating F3-4 fibrosis. In total, 153 patients (93.9%) achieved at least Partial Virological Suppression (PVS), with 134 patients (82.2%) achieving complete virological suppression. The cumulative CVS and PVS rates at 36 mo were 82.1% and 96.4%, respectively. 3 patients (1.8%) failed to achieve PVS, while 5 patients (3.0%) developed virological rebound. 128 patients (78.5%) maintained CVS throughout follow up. Predictors of CVS included lower baseline DNA level (P = 0.001), hepatitis B virus e antigen negative status (P = 0.001) and increasing age at treatment (log rank 0.001). No significant adverse effects were reported necessitating cessation of entecavir.

CONCLUSION

Entecavir monotherapy is efficacious and safe in an Australian tertiary care setting. Resistance and rebound rates are very low. This is similar to data from controlled and uncontrolled trials around the world.

Adding adefovir vs. switching to entecavir for lamivudine-resistant chronic hepatitis B (ACE study): a 2-year follow-up randomized controlled trial

BACKGROUND

Management of lamivudine-resistant chronic hepatitis B (CHB) remains challenging, as inappropriate choice of treatment may cause multidrug resistance. Until now, randomized trials directly comparing adding adefovir and switching to entecavir monotherapy have not been reported.

AIMS

This multicentre prospective randomized study was designed to compare the efficacy of these two strategies.

METHODS

Two hundred and nineteen lamivudine-resistant CHB patients were randomized to either adefovir-lamivudine combination group or entecavir monotherapy group (n = 110 vs. 109), and followed up for 24 months.

RESULTS

One hundred and eighty patients completed this study. At month 24, virological response rate [hepatitis B virus (HBV) DNA <60 IU/ml] was higher in the adefovir-lamivudine combination group compared with entecavir group (56.7% vs. 40%, P = 0.025), although biochemical and serological response rates were not significantly different. Genotypic resistance (9.2% vs. 24.6%, P = 0.005) and combined viral breakthrough (2.0% vs. 17.6%, P < 0.001) were more frequent in the entecavir group. However, by subgroup analysis, virological response rates were not significantly different between the two therapies in HBeAg-positive patients (44.9% vs. 35.7%, P = 0.268) or in patients with high baseline HBV DNA (≥7 log IU/ml) (40.7% vs. 31.3%, P = 0.320) at month 24.

CONCLUSION

This study showed that adefovir-lamivudine combination provides significantly higher antiviral efficacy and the lower resistance rate compared with the entecavir monotherapy in the management of lamivudine-resistant CHB. However, it had limited efficacy in HBeAg-positive patients or in patients with high baseline HBV DNA.

Optimal management of chronic hepatitis B patients with treatment failure and antiviral drug resistance

The management of treatment failure in patients with chronic hepatitis B, remains a clinical concern. Incomplete viral suppression and the emergence of drug resistance are key determinants of treatment failure. The correct choice of a potent first-line therapy to achieve sustained long-term suppression of viral replication provides the best chance of preventing treatment failure and drug resistance. Clinical studies have demonstrated that drugs with a high barrier to resistance have significantly lower rates of resistance compared with those with a low barrier to resistance. Management of treatment failure requires precise clinical and virological monitoring as well as early treatment intervention with appropriate noncross-resistant antivirals. Long-term surveillance of treatment efficacy and possible emergence of drug resistance is necessary in patients who have been sequentially treated with multiple antivirals. The identification of novel treatment targets remains a major research goal to improve the efficacy of current antiviral therapy through combination therapy regimens.

Early viral suppression predicts good postoperative survivals in patients with hepatocellular carcinoma with a high baseline HBV-DNA load

PURPOSE

To correlate early HBV-DNA suppression by antiviral treatment with posthepatectomy long-term survivals in patients with HBV-related hepatocellular carcinoma (HCC).

METHODS

A retrospective study was conducted on patients with a baseline HBV-DNA load of >2,000 IU/ml. The cumulative rates of HBV-DNA undetectability at weeks 24 and 48, as well as long-term tumor recurrence and overall survivals were determined.

RESULTS

Of 1,040 patients with a high baseline HBV-DNA load, 865 patients received antiviral treatment. At a median follow-up of 42 months, 616 patients (59.2 %) had developed HCC recurrence and 482 patients (46.3 %) had died. The median time to recurrence was 25 months. In patients who received antiviral treatment, the cumulative rates of HBV-DNA undetectability (<200 IU/ml) were 54.3 and 88.1 % at weeks 24 and 48, respectively. There was no significant difference between the two groups of patients who received antiviral treatment or not for disease-free survival. On multivariate analyses, tumor size >5 cm, blood transfusion, surgical margin <1 cm, presence of satellite nodules, presence of portal vein tumor thrombus and high Ishak inflammation score were significant risk factors of HCC recurrence. Also, tumor size >5 cm, surgical margin <1 cm, presence of satellite nodules, presence of portal vein tumor thrombus and high Ishak fibrosis score were significant factors associated with poor postoperative overall survival. On the other hand, an undetectable HBV-DNA level before week 24 was a significant protective factor of disease-free survival and overall survival.

CONCLUSIONS

Early HBV-DNA suppression with antiviral treatment improved prognosis of patients with HBV-related HCC.

Introduction of an automated system for the diagnosis and quantification of hepatitis B and hepatitis C viruses

Hepatitis B virus (HBV) and Hepatitis C virus (HCV) infections pose major public health problems because of their prevalence worldwide. Consequently, screening for these infections is an important part of routine laboratory activity. Serological and molecular markers are key elements in diagnosis, prognosis and treatment monitoring for HBV and HCV infections. Today, automated chemiluminescence immunoassay (CLIA) analyzers are widely used for virological diagnosis, particularly in high-volume clinical laboratories. Molecular biology techniques are routinely used to detect and quantify viral genomes as well as to analyze their sequence; in order to determine their genotype and detect resistance to antiviral drugs. Real-time PCR, which provides high sensitivity and a broad dynamic range, has gradually replaced other signal and target amplification technologies for the quantification and detection of nucleic acid. The next-generation DNA sequencing techniques are still restricted to research laboratories.The serological and molecular marker methods available for HBV and HCV are discussed in this article, along with their utility and limitations for use in Chronic Hepatitis B (CHB) diagnosis and monitoring.

Comparative efficacy of pegylated interferons α-2a and 2b in the treatment of HBeAg-negative chronic hepatitis B infection

INTRODUCTION

Interferons, pegylated interferons (PegIFN), and oral antivirals are used in the treatment of chronic hepatitis B (CHB) virus infection. The number of studies comparing the efficacy of PegIFNs in the treatment of HBe antigen-negative CHB is rather limited. In this trial, the efficacy of two PegIFN products used in the treatment of CHB is compared.

METHODS

Study data were obtained from 16 tertiary healthcare service centers located in various areas of Turkey. Data of patients who were consecutively treated with PegIFN α-2a or α-2b for CHB were recorded retrospectively. Hepatitis B virus DNA and liver enzymes were analyzed at the beginning of the treatment and during weeks 12, 24, 48, and 72. A P-value less than 0.05 was considered to be significant.

RESULTS

A total of 155 patients were enrolled in this trial. Two cases were excluded because of insufficient data. Among the remaining 153 patients, 81 (53%) patients were in the PegIFN α-2a group and 72 (47%) patients were in the α-2b group. Treatment success was found to be 17.2% for the PegIFN α-2a group and 18.0% for the PegIFN α-2b group (P>0.05). In terms of efficacy (weeks 24, 48, and 72), there were no significant differences between the groups (P>0.05).

CONCLUSION

According to our results, for HBe antigen-negative CHB cases, the response rate during the sixth month after the treatment with PegIFN was determined to be ∼17%. No difference was found between the efficacy rates of the two PegIFN products used in the treatment of HBe antigen-negative CHB.

Outcome of Lamivudine-Resistant Chronic Hepatitis B after up to 5 Years of Combination Therapy with Adefovir

Background

There is a paucity of data on the long-term efficacy of combination lamivudine and adefovir therapy in patients with lamivudine-resistant chronic hepatitis B.

Methods

We determined the cumulative virological, serological and biochemical outcomes of 165 lamivudine-resistant chronic hepatitis B patients on lamivudine and adefovir for up to 5 years. Resistance profiles using a line probe assay were determined among patients with detectable viraemia. The significance of different baseline and on-treatment virological parameters was analysed.

Results

The median age and duration of follow-up were 45.1 years and 37.1 months, respectively. The cumulative rates of HBV DNA undetectability (<20 IU/ml), alanine aminotransferase normalization and hepatitis B e antigen seroconversion up to 5 years were 74.0%, 95.1% and 44.4%, respectively. One patient achieved hepatitis B surface antigen seroclearance. The 5-year cumulative resistance rate to adefovir was 10.2%. Among different baseline and on-treatment virological parameters, week 24 HBV DNA<200 IU/ml was associated with an increased chance of long-term virological suppression ( P<0.001, OR 13.89, 95% CI 3.90, 49.46). Primary non-response and high baseline viral titres were not useful in predicting long-term virological outcomes. The 5-year cumulative rate of serum creatinine elevation >0.5 mg/dl was 4.1%.

Conclusions

Combination lamivudine and adefovir therapy for up to 5 years achieved modest rates of virological suppression, but resistance developed in only 10.2% of patients. Week 24 HBV DNA<200 IU/ml was predictive of favourable long-term virological outcomes and could be used to assist treatment decisions on continuing lamivudine and adefovir or switching to more potent therapy.

Efficacy of entecavir with or without tenofovir disoproxil fumarate for nucleos(t)ide-naïve patients with chronic hepatitis B

BACKGROUND & AIMS

Entecavir (ETV) and tenofovir disoproxil fumarate (TDF) are potent antiviral agents that might have additive or synergistic antiviral activity in treatment of patients with chronic hepatitis B (CHB). We compared the efficacy and safety of ETV monotherapy with those of a combination of ETV and TDF.

METHODS

We performed a randomized, open-label, multicenter, superiority study of 379 nucleos(t)ide-naïve patients with hepatitis B e antigen (HBeAg)-positive (n = 264) or HBeAg-negative (n = 115) CHB. Subjects were given ETV 0.5 mg (n = 182) or a combination of ETV 0.5 mg and TDF 300 mg (n = 197) for 100 weeks.

RESULTS

At week 96, comparable proportions of patients in each study arm achieved the primary end point of a level of hepatitis B virus (HBV) DNA <50 IU/mL (83.2% vs 76.4%; P = .088). Among HBeAg-positive patients, a greater proportion given combination therapy achieved levels of HBV DNA <50 IU/mL than those given ETV alone (80.4% vs 69.8%; P = .046). However, this difference was observed only in patients with baseline levels of HBV DNA ≥ 10(8) IU/mL (79% vs 62%) and not in those with baseline levels of HBV DNA <10(8) IU/mL (83% in both arms). Rates of HBeAg loss and HBeAg seroconversion were comparable between groups, whereas the rate of alanine aminotransferase normalization was greater in the ETV monotherapy group. No HBV variants associated with ETV or TDF resistance were detected. Safety profiles were consistent with previous reports of ETV or TDF monotherapy.

CONCLUSIONS

The antiviral efficacy of ETV monotherapy is comparable to that of ETV plus TDF in a mixed population of nucleos(t)ide-naïve patients with CHB (70% HBeAg positive). The combination therapy could provide an incremental benefit to HBeAg-positive patients with baseline levels of HBV DNA ≥ 10(8) IU/mL.

Skewed T-cell receptor beta chain variable gene (TCRBV) usage among different clinical types of patients with chronic HBV infection

This study aimed to determine the degree of clonal expansion of T cells in peripheral blood mononuclear cells (PBMCs) isolated from patients suffering from different clinical types of hepatitis B (HB) infection and to analyse the clinical relevance of the skewed T-cell receptor beta variable (TCRBV). Sera and PBMCs were collected from 90 HB patients. Gene melting spectral pattern (GMSP) analysis was used to determine the distribution and expansion of populations expressing specific TCRBV complementary determined region 3 (CDR3) genes. TCRBV genes associated with monoclonal expansion were sequenced. TCRBV families from the majority of patients (80/90) displayed skewed T-cell expansion. Furthermore, TCRBV11, BV12 and BV13.1 were more frequent than other TCRBV genes; the sequence of TCRBV11 CDR3 was expressed as 'VYNEQ' in all patients and was accompanied by the BJ2.1 fragment. In patients with chronic HB, the frequency of skewed TCRBV was inversely correlated with hepatitis B virus (HBV) DNA levels. The persistently skewed TCRBV gene families in HB patients may be associated with the development and maintenance of hepatitis. GMSP analysis of TCRBV gene families may be helpful in estimating disease status, and BV11 may be associated with HBV replication in patients with chronic HBV infection.

Management of treatment failure in chronic hepatitis B

Antiviral therapy of chronic hepatitis B remains a clinical challenge. The primary goal of therapy is to prevent liver disease progression. Because of the mechanism of viral persistence in infected hepatocytes, long-term antiviral therapy is needed in the majority of patients. Incomplete viral suppression and emergence of drug resistance is a major concern. The correct choice of a first-line potent therapy to achieve sustained long-term suppression of viral replication provides the best chance of preventing treatment failure and drug resistance. Clinical studies have demonstrated that drugs with a high barrier to resistance, such as entecavir and tenofovir, have significantly lower rates of resistance when compared with those with a low barrier to resistance such as lamivudine, adefovir, or telbivudine. Management of treatment failure requires a precise clinical and accurate virologic monitoring as well as an early treatment intervention with appropriate complementary drugs with respect to their cross-resistance profile. Long-term surveillance for treatment efficacy and possible emergence of drug resistance is necessary for those patients who have been sequentially treated with multiple antivirals. Finally, the identification of novel treatment targets remains a major research challenge to improve the efficacy of current antiviral therapy.

Identification of disubstituted sulfonamide compounds as specific inhibitors of hepatitis B virus covalently closed circular DNA formation

Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) plays a central role in viral infection and persistence and is the basis for viral rebound after the cessation of therapy, as well as the elusiveness of a cure even after extended treatment. Therefore, there is an urgent need for the development of novel therapeutic agents that directly target cccDNA formation and maintenance. By employing an innovative cell-based cccDNA assay in which secreted HBV e antigen is a cccDNA-dependent surrogate, we screened an in-house small-molecule library consisting of 85,000 drug-like compounds. Two structurally related disubstituted sulfonamides (DSS), termed CCC-0975 and CCC-0346, emerged and were confirmed as inhibitors of cccDNA production, with low micromolar 50% effective concentrations (EC(50)s) in cell culture. Further mechanistic studies demonstrated that DSS compound treatment neither directly inhibited HBV DNA replication in cell culture nor reduced viral polymerase activity in the in vitro endogenous polymerase assay but synchronously reduced the levels of HBV cccDNA and its putative precursor, deproteinized relaxed circular DNA (DP-rcDNA). However, DSS compounds did not promote the intracellular decay of HBV DP-rcDNA and cccDNA, suggesting that the compounds interfere primarily with rcDNA conversion into cccDNA. In addition, we demonstrated that CCC-0975 was able to reduce cccDNA biosynthesis in duck HBV-infected primary duck hepatocytes. This is the first attempt, to our knowledge, to identify small molecules that target cccDNA formation, and DSS compounds thus potentially serve as proof-of-concept drug candidates for development into therapeutics to eliminate cccDNA from chronic HBV infection.

New virologic tools for management of chronic hepatitis B and C

Molecular biology techniques are routinely used to diagnose and monitor treatment of patients with chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) infections. These tools can detect and quantify viral genomes and analyze their sequence to determine their genotype or subtype and to identify nucleotide or amino acid substitutions associated with resistance to antiviral drugs. They include real-time target amplification methods, which have been standardized and are widely used in clinical practice to diagnose and monitor HBV and HCV infections, and next-generation sequencing techniques, which are still restricted to research laboratories. In addition, new enzyme immunoassays can quantify hepatitis B surface and hepatitis C core antigens, and point-of-care tests and alternatives to biologic tests that require whole-blood samples obtained by venipuncture have been developed. We review these new virologic methods and their clinical and research applications to HBV and HCV infections.

Antiviral therapies: focus on hepatitis B reverse transcriptase

Hepatitis B virus (HBV) is the etiologic agent of mankind's most serious liver disease. While the availability of a vaccine has reduced the number of new HBV infections, the vaccine does not benefit the approximately 350 million people already chronically infected by the virus. Most of the drugs approved by the FDA for the treatment of hepatitis B target the reverse transcriptase (RT or P gene product) and are nucleoside RT inhibitors (NRTIs) that suppress viral replication. However, prolonged monotherapies directed against a single target result in the emergence of viral resistance. HBV genotypic differences affect NRTI resistance, and because the reading frames of the S (surface antigen) and P genes partially overlap, genomic differences that affect the surface of the virus may also alter the viral polymerase sequence, function and drug susceptibility. The scope of this review is to assess the effects of HBV genotypic variation on the development of drug resistance to NRTIs. Some RT residues that vary among different genotypes are in the vicinity of residues that mutate and give rise to NRTI resistance. Interactions between these amino acids can help explain the effect of HBV genotype on the development of NRTI resistance during antiviral therapies, and might help in the design of improved therapeutic strategies.

Therapeutic implications of hepatitis C virus resistance to antiviral drugs

Treatment of chronic hepatitis C is currently based on a combination of pegylated interferon-o! and ribavirin. Neither drug exerts direct selective pressure on viral functions, meaning that interferon-a/ribavirin treatment failure is not due to selection of interferon-a- or ribavirin-resistant viral variants. Several novel antiviral approaches are currently in preclinical or clinical development, and most target viral enzymes and functions, such as hepatitis C virus protease and polymerase. These new drugs all potentially select resistant viral variants both in vitro and in vivo, and resistance is therefore likely to become an important issue in clinical practice.

Significance of HBV DNA levels at 12 weeks of telbivudine treatment and the 3 years treatment outcome

BACKGROUND & AIMS

The significance of early HBV DNA suppression during telbivudine treatment in predicting long-term outcomes needs further investigation.

METHODS

We determined the cumulative rates of HBeAg seroconversion, ALT normalization, HBV DNA suppression (<12IU/ml) and telbivudine resistant mutations (using the highly sensitive line probe assay) for 117 treatment-native chronic hepatitis B (CHB) patients (61.5% HBeAg-positive) on telbivudine for 3years. The significance of serum HBV DNA at week 12 and 24 was compared.

RESULTS

The median age and duration of follow-up were 39years and 24.2months, respectively. 117, 105, 69, and 43 patients had been followed up for at least 6months and 1, 2, and 3years, respectively. The cumulative rates of HBeAg seroconversion, ALT normalization, HBV DNA undetectability were 46.8%, 80.5%, and 51.2%, respectively, at 3years. There was an incremental increase in virologic breakthroughs to 39.5% by year 3. The cumulative rate of telbivudine resistant mutations was 4.8%, 17.6%, and 34.0% for year 1, 2, and 3, respectively. Week 12 HBV DNA of <200IU/ml was predictive of a higher chance of HBV DNA undetectability (p=0.022) and lower chance of resistance (p=0.001) by year 3. Undetectable HBV DNA at week 24 was predictive of viral suppression at year 2 (p<0.001) but not at year 3 (p=0.241).

CONCLUSIONS

Continuous telbivudine resulted in improved biochemical and virologic outcomes, although there was an incremental increase in cumulative rate of resistance up to year 3. Week 12 HBV DNA of <200IU/ml was predictive of favorable long-term outcomes.

Lamivudine plus adefovir combination therapy versus entecavir monotherapy for lamivudine-resistant chronic hepatitis B: a systematic review and meta-analysis

Background

Chronic hepatitis B virus (HBV) infection represents a serious global health problem and resistance to lamivudine (LAM) has become a serious clinical challenge. Previous rescue therapy for the treatment of chronic LAM-resistant hepatitis B infected patients included switching to entecavir (ETV) and adding adefovir (ADV) or tenofovir (TFV). At present, switching to ETV is not recommended for rescue therapy for LAM-resistant chronic hepatitis B (CHB). The aim of this report was to determine whether add-on ADV was a superior rescue strategy in the treatment of CHB patients with LAM resistance.

Methods

We searched Medline/PubMed, EMBASE, Web of Knowledge, and the Cochrane Library. Relative risks (RRs) of virologic response, virologic breakthrough, normalization of serum alanine aminotransferase (ALT) levels and HBeAg seroconversion rates were studied. Factors predicting virologic response, standardized mean differences (SMD) in HBV DNA levels and safety were reviewed.

Results

Six eligible trials (451 patients in total) were included in the analysis. The rate of virologic breakthrough in the ETV group was higher than that in the LAM plus ADV group. There were no statistical differences in virologic response, ALT normalization and HBeAg seroconversion in either group 48 weeks post treatment. LAM plus ADV combination therapy produced faster and greater HBV DNA reduction rates 24 weeks post therapy compared to ETV monotherapy. HBV DNA baseline levels and the initial virologic response (IVR) were predictive of the virologic response. Additionally, combination therapy or monotherapy were both well tolerated.

Conclusions

LAM plus ADV combination therapy was more effective and produced longer-lasting effects than switching to ETV monotherapy in treating CHB patients with LAM resistance. However, considering the practical benefits and limitations of ADV, individualized therapy will be needed in patients with prior history of LAM resistant infections.