Safety and efficacy of oral entecavir given for 28 days in patients with chronic hepatitis B virus infection

Real-world safety and effectiveness of tenofovir alafenamide for 144 weeks in Japanese patients with chronic hepatitis B

Tenofovir alafenamide (TAF), a prodrug of tenofovir, delivers high levels of active drug to hepatocytes and is given in a lower dose than tenofovir disoproxil fumarate (TDF). TAF reduces viral replication in patients with chronic hepatitis B (CHB) similar to TDF and has shown a lower risk of the renal and bone toxicities associated with TDF use. This post-marketing surveillance study examined the safety and effectiveness of TAF in treatment-naïve and -experienced CHB patients who received TAF for 144 weeks at real-world clinical sites in Japan. Safety assessments included the incidence of adverse drug reactions (ADRs), renal and bone events, and changes in selected laboratory parameters. Effectiveness was based on the proportion of patients with HBV DNA levels below the lower limit of quantitation or <29 IU/mL. This analysis included 580 patients; 18.4% of whom were treatment-naïve. The cumulative incidence of ADRs was 0.21 per 100 person-months, and the incidence of serious ADRs was 0.01 (95% CI, 0.00-0.04) per 100 person-months. There were no ADRs of declines in estimated glomerular filtration rates, renal failure or proximal tubulopathy. The most common ADR was hypophosphataemia in seven (1.2%) patients. Two (0.4%) patients each had decreased blood phosphorus, bone mineral density decreased, dizziness and alopecia. Overall, the proportion of virologically suppressed patients increased from 68.8% at baseline to 97.5% at Week 144. These results confirm the real-world safety and effectiveness of TAF in Japanese patients with CHB and are consistent with the findings of other evaluations of the safety and efficacy of TAF in CHB.

Entecavir versus tenofovir for prevention of hepatitis B virus-associated hepatocellular carcinoma after curative resection: study protocol for a randomized, open-label trial

BACKGROUND

Entecavir and tenofovir disoproxil fumarate (TDF) are standard first-line treatments to prevent viral reactivation and hepatocellular carcinoma (HCC) in individuals chronically infected with the hepatitis B virus (HBV), but the long-term efficacy of the two drugs remains controversial. Also unclear is whether the drugs are effective at preventing viral reactivation or HCC recurrence after hepatectomy to treat HBV-associated HCC. This trial will compare recurrence-free survival, overall survival, viral indicators and adverse events in the long term between patients with HBV-associated HCC who receive entecavir or TDF after curative resection.

METHODS

This study is a randomized, open-label trial. A total of 240 participants will be randomized 1:1 into groups receiving TDF or entecavir monotherapy. The two groups will be compared in terms of recurrence-free and overall survival at 1, 3, and 5 years after surgery; adverse events; virological response; rate of alanine transaminase normalization; and seroreactivity at 24 and 48 weeks after surgery.

DISCUSSION

This study will compare long-term survival between patients with HBV-associated HCC who receive TDF or entecavir monotherapy. Numerous outcomes related to prognosis will be analyzed and compared in this study.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02650271. Registered on January 7, 2016.

A Multi-Center, Double-Blind Randomized Controlled Phase III Clinical Trial to Evaluate the Antiviral Activity and Safety of DA-2802 (Tenofovir Disoproxil Orotate) and Viread (Tenofovir Disoproxil Fumarate) in Chronic Hepatitis B Patients

BACKGROUND

Tenofovir disoproxil fumarate (TDF, Viread^®) had been used as a standard treatment option of chronic hepatitis B (CHB). This clinical trial was conducted to evaluate the efficacy and safety of DA-2802 (tenofovir disoproxil orotate) compared to TDF.

METHODS

The present study was a double blind randomized controlled trial. Patients with CHB were recruited from 25 hospitals in Korea and given DA-2802 at a dose of 319 mg once daily or Viread^® at a dose of 300 mg once daily for 48 weeks from March 2017 to January 2019. Change in hepatitis B virus (HBV) DNA level at week 48 after dosing compared to baseline was the primary efficacy endpoint. Secondary efficacy endpoints were proportions of subjects with undetectable HBV DNA, those with normal alanine aminotransferase (ALT) levels, and those with loss of hepatitis B envelop antigen (HBeAg), those with loss of hepatitis B surface antigen (HBsAg). Adverse events (AEs) were also investigated.

RESULTS

A total of 122 patients (DA-2802 group: n = 61, Viread^® group: n = 61) were used as full analysis set for efficacy analysis. Mean age, proportion of males, laboratory results and virologic characteristics were not different between the two groups. The change in HBV DNA level at week 48 from baseline was -5.13 ± 1.40 in the DA-2802 group and -4.97 ± 1.40 log₁₀ copies/mL in the Viread^® group. The analysis of primary endpoint using the nonparametric analysis of covariance showed statistically significant results (P < 0.001), which confirmed non-inferiority of DA-2802 to Viread^® by a prespecified noninferiority margin of 1. The proportion of undetectable HBV DNA was 78.7% in the DA-2802 group and 75.4% in the Viread^® group (P = 0.698). The proportion of subjects who had normal ALT levels was 75.4% in the DA-2802 group and 73.3% in the Viread^® group (P = 0.795). The proportion of those with HBeAg loss was 8.1% in the DA-2802 group and 10.8% in the Viread^® group (P = 1.000). No subject showed HBsAg loss. The frequency of AEs during treatment was similar between the two groups. Most AEs were mild to moderate in severity.

CONCLUSION

DA-2802 is considered an effective and safe treatment for patients with CHB.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02967939.

Safety, pharmacokinetics, and antiviral activity of RO7049389, a core protein allosteric modulator, in patients with chronic hepatitis B virus infection: a multicentre, randomised, placebo-controlled, phase 1 trial

BACKGROUND

RO7049389, a hepatitis B virus (HBV) core protein allosteric modulator being developed for the treatment of chronic HBV infection, was found to be safe and well tolerated in healthy participants (part 1 of this study). The objective of this proof-of-mechanism study (part 2) was to evaluate the safety, pharmacokinetics, and antiviral activity of RO7049389 in patients with chronic HBV infection.

METHODS

This was a multicentre, randomised, placebo-controlled, phase 1 study. Patients with chronic HBV infection who were not currently on anti-HBV therapy were enrolled at 11 liver disease centres in Hong Kong, New Zealand, Singapore, Taiwan, and Thailand. Seven patients per dose cohort were randomly assigned (6:1) to receive oral administration of RO7049389 at 200 mg or 400 mg twice a day, or 200 mg, 600 mg, or 1000 mg once a day, for 4 weeks, or matching placebo. Randomisation was via interactive voice web response system-generated numbers, with study participants, investigators, and site personnel masked to treatment allocation. The primary endpoint of the study was safety of RO7049389 and its antiviral effect on HBV DNA concentration at the end of treatment, assessed in all patients who received at least one dose of study drug. This study is registered with ClinicalTrials.gov, number NCT02952924.

FINDINGS

Between May 21, 2017, and April 3, 2019, 62 patients were screened for eligibility, and 37 eligible patients were enrolled in five dose cohorts sequentially. All adverse events were of mild or moderate intensity. Among the 31 patients who received RO7049389, the most common adverse events were headache (in five [16%] of 31 patients), increased alanine aminotransferase (ALT; five [16%]), increased aspartate aminotransferase (AST; four [13%]), upper respiratory tract infection (four [13%]), and diarrhoea (three [10%]). The most common moderate adverse events were ALT increase (three [10%]) and AST increase (two [6%]), and there were no serious adverse events. At the end of 4 weeks treatment, mean HBV DNA declines from baseline in RO7049389-treated patients were 2·44 log₁₀ IU/mL (SD 0·98) in the 200 mg twice a day group, 3·33 log₁₀ IU/mL (1·14) in the 400 mg twice a day group, 3·00 log₁₀ IU/mL (0·54) in the 200 mg once a day group, 2·86 log₁₀ IU/mL (0·79) in the 600 mg once a day group, and 3·19 log₁₀ IU/mL (0·33) in the 1000 mg once a day group versus 0·34 log₁₀ IU/mL (0·54) in the pooled placebo patients.

INTERPRETATION

RO7049389 was safe and well tolerated and demonstrated antiviral activity over 4 weeks of treatment in patients with chronic HBV infection. These findings support further clinical development of RO7049389 as a component of novel combination treatment regimens for patients with chronic HBV infection.

FUNDING

F Hoffmann-La Roche.

JNJ-56136379, an HBV Capsid Assembly Modulator, Is Well-Tolerated and Has Antiviral Activity in a Phase 1 Study of Patients With Chronic Infection

BACKGROUND & AIMS

JNJ-56136379 (JNJ-6379), a capsid assembly modulator that blocks hepatitis B virus (HBV) replication, was well tolerated and demonstrated dose-proportional pharmacokinetics in healthy participants in part 1 of its first clinical trial. In part 2, we have evaluated the safety, pharmacokinetics, and antiviral activity of multiple doses of JNJ-6379 in patients with chronic HBV infection.

METHODS

We performed a double-blind study of 57 treatment-naïve patients with HB e antigen-positive or -negative (74%) chronic HBV infection without cirrhosis. Patients were randomly assigned to groups given JNJ-6379 at 25 mg (100 mg loading dose), 75 mg, 150 mg, or 250 mg or placebo daily for 4 weeks with an 8-week follow-up period.

RESULTS

Twenty-three (56%) of 41 patients given JNJ-6379 had at least 1 adverse event (AE) during treatment, compared with 10 (63%) of 16 patients given placebo. No serious AEs were reported during the treatment period. Three patients (7%) given JNJ-6379 vs none given placebo had grade 3 AEs; of these, 1 patient (150 mg) also had an isolated grade 4 increase in the level of alanine aminotransferase that led to treatment discontinuation. JNJ-6379 exposure increased with dose, with time-linear pharmacokinetics. HBV-DNA and HBV-RNA decreased from baseline in patients receiving all doses of JNJ-6379, independently of viral genotype and HB e antigen status. On day 29, 13 (32%) of 41 patients had levels of HBV DNA below the lower limit of quantification. No clinically significant changes in levels of HB surface antigen were observed.

CONCLUSIONS

In a phase 1 study of treatment-naïve patients with chronic HBV infection, all doses tested of JNJ-6379 were well tolerated, showed dose-dependent pharmacokinetics, and had potent antiviral activity in patients with CHB. The findings support a phase 2a study to evaluate JNJ-6379 ± nucleos(t)ide analogs in patients with chronic HBV infection, which is under way. ClinicalTrials.gov identifier: NCT02662712.

Revisiting HBV resistance to entecavir with a phenotypic approach

Treatment adaptation after hepatitis B virus (HBV) treatment failure relies on genotypic resistance testing. However, the results of such tests are not always consistent with treatment response. These discrepancies may be due to differences in resistance levels between isolates with the same genotypic resistance testing profiles. We explored this hypothesis by investigating six cases of entecavir treatment failure with an integrative strategy combining genotypic and phenotypic resistance testing, medical record review and therapeutic drug monitoring. Among isolates with genotypic reduced susceptibility to entecavir, one displayed a higher level of resistance to entecavir (mean fold change in entecavir IC₅₀ of 1 508 ± 531 vs. 318 ± 53, p = 0.008). This isolate harbored a substitution (rt250L) at a position reported to be associated with resistance (rt250V). Reversion to wild-type amino acid at this position partially restored susceptibility to entecavir, confirming that the rt250L mutation was responsible for the high level of resistance to entecavir. This is the first description of entecavir treatment failure associated with selection of the rt250L mutation without other entecavir resistance mutations. One isolate with genotypic resistance to entecavir, harboring the rt173L mutation, displayed a lower level of resistance than the other, harboring the rt202G mutation (mean fold change of 323 ± 124 vs. 6 036 ± 2 100, p = 0.20). These results suggest that isolates harboring the rt250L mutations should be considered resistant to entecavir, whereas isolates harboring the rt173L mutations should be considered to display reduced susceptibility to entecavir. An integrative approach to antiviral drug resistance in HBV would provide a more accurate assessment of entecavir treatment failures and help to improve the accuracy of genotypic testing algorithms.

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.

Adverse events of nucleos(t)ide analogues for chronic hepatitis B: a systematic review

Nucleos(t)ide analogues (NAs) are the main drug category used in chronic hepatitis B (CHB) treatment. Despite the fact that NAs have a favourable safety profile, undesired adverse events (AEs) may occur during the treatment of CHB. Given the eminent number of patients currently receiving NAs, even a small risk of any of these toxicities can represent a major medical issue. The main objective of this review was to analyse information available on AEs associated with the use of NAs in published studies. We choose the following MesH terms for this systematic review: chronic hepatitis B, side effects and treatment. All articles published from 1 January 1990 up to 19 February 2018 in MEDLINE of PubMed, EMBASE, the Cochrane Library and LILACS databases were searched. A total of 120 articles were selected for analysis, comprising 6419 patients treated with lamivudine (LAM), 5947 with entecavir (ETV), 3566 with tenofovir disoproxil fumarate (TDF), 3096 with telbivudine (LdT), 1178 with adefovir dipivoxil (ADV) and 876 with tenofovir alafenamide (TAF). The most common AEs in all NAs assessed were abdominal pain/discomfort, nasopharyngitis/upper respiratory tract infections, fatigue, and headache. TAF displays the highest density of AEs per patient treated among NAs (1.14 AE/treated patient). In conclusion, treatment of CHB with NAs is safe, with a low incidence of AEs. Despite the general understanding TAF being safer than TDF, the number of patients treated with TAF still is too small in comparison to other NAs to consolidate an accurate safety profile. PROSPERO Registration No. CRD42018086471.

Safety, pharmacokinetics, and antiviral effects of ABI-H0731, a hepatitis B virus core inhibitor: a randomised, placebo-controlled phase 1 trial

BACKGROUND

Therapies with novel mechanisms of action against hepatitis B virus (HBV) infection are being explored with the goal of achieving a functional cure (sustained off-treatment response) without requiring lifelong therapy. We aimed to evaluate the pharmacokinetics, safety, and antiviral activity of ABI-H0731, an investigational inhibitor of the HBV core protein.

METHODS

This phase 1, randomised, placebo-controlled study was done in two parts. In part 1, healthy adults without hepatitis B aged 18-65 years at one clinical research centre in New Zealand (eight participants per dose cohort) were randomly assigned (3:1) to receive single oral doses of ABI-H0731 (100, 300, 600, or 1000 mg) or matching placebo, or once-daily or twice-daily doses of ABI-H0731 800 mg or matching placebo for 7 days. In part 2, adults aged 18-65 years at clinical research centres in New Zealand, Australia, the UK, Hong Kong, Taiwan, and South Korea with chronic HBV (12 participants per dose cohort) were randomly assigned (5:1) to receive ABI-H0731 (100, 200, 300, or 400 mg) or matching placebo once daily for 28 days. In part 2, participants were required to have HBeAg-positive or HBeAg-negative chronic HBV infection, with serum HBV DNA concentrations of at least 2 × 10⁴ IU/mL (HBeAg-positive) or 2 × 10³ IU/mL (HBeAg-negative) and serum alanine aminotransferase concentrations less than seven times the upper limit of normal. Both parts used simple randomisation, with study participants, site personnel, and study monitors masked to treatment assignments. The primary study objective was dose-related safety and tolerability of ABI-H0731 in healthy volunteers and in participants with chronic HBV infection, assessed in all treated participants. Key secondary assessments included pharmacokinetic analyses and virological responses. This study is registered with ClinicalTrials.gov, identifier NCT02908191 and is completed.

FINDINGS

48 [61%] of 79 healthy volunteers were enrolled in the single-ascending or multiple-ascending dose phase of part 1 between Nov 16, 2016, and Jan, 27, 2017. 38 [55%] of 69 HBV-infected participants were enrolled in part 2 between June 15, 2017, and March 15, 2018. All adverse events were non-specific and of mild or moderate intensity apart from a single HBV-infected participant given the 400 mg dose who developed a severe (grade 3) maculopapular rash and terminated treatment. Overall, the most frequent adverse events of any grade among the 74 participants who received ABI-H0731 were headache (11 [15%]), influenza-like illness (seven [9%]), and dizziness (six [8%]); the most frequent adverse events considered treatment-related were rash (four [5%]) and dizziness (three [4%]). In part 1, ABI-H0731 reached maximum plasma concentrations (T_max) in 2·50-4·17 h; the mean plasma half-life (t_1/2) was 23·5-28·4 h. In part 2, mean maximum HBV DNA declines from baseline were 1·7 log₁₀ IU/mL in the 100 mg dose cohort, 2·1 log₁₀ IU/mL in the 200 mg dose cohort, and 2·8 log₁₀ IU/mL in the 300 mg dose cohort. Across dose cohorts, serum HBV RNA declines correlated with HBV DNA declines.

INTERPRETATION

No pattern of treatment-emergent adverse events was observed at ABI-H0731 doses up to 300 mg in individuals with chronic hepatitis B. ABI-H0731 was rapidly absorbed and exhibited a plasma half-life supportive of once-daily dosing. Dose-dependent decreases in serum HBV DNA and RNA concentrations are consistent with the proposed mechanism of action.

FUNDING

Assembly Biosciences.

Antiviral Activity, Safety, and Pharmacokinetics of Capsid Assembly Modulator NVR 3-778 in Patients with Chronic HBV Infection

BACKGROUND & AIMS

NVR 3-778 is a first-in-class hepatitis B virus (HBV) capsid assembly modulator that can inhibit HBV replication. We performed a proof-of-concept study to examine the safety, pharmacokinetics, and antiviral activity of NVR 3-778 in patients with chronic HBV infection.

METHODS

We performed a phase 1 study in 73 hepatitis B envelope antigen (HBeAg)-positive patients with chronic HBV infection without cirrhosis. In a 2-part study (part 1 in New Zealand and part 2 in Hong Kong, Singapore, Taiwan, Korea, and the United States), patients were randomly assigned to groups that were given oral NVR 3-778 (100 mg, 200 mg, or 400 mg daily or 600 mg or 1000 mg twice daily) or placebo for 4 weeks. Additional groups received combination treatment with pegylated interferon (pegIFN) and NVR 3-778 (600 mg twice daily) or pegIFN with placebo.

RESULTS

Reductions in serum levels of HBV DNA and HBV RNA were observed in patients receiving ≥1200 mg/d NVR 3-778. The largest mean reduction in HBV DNA was observed in the group given NVR 3-778 plus pegIFN (1.97 log₁₀ IU/mL), compared with the groups given NVR 3-778 or pegIFN alone (1.43 log₁₀ IU/mL and 1.06 log₁₀ IU/mL, respectively). The mean reduction in HBV RNA was also greatest in the group given NVR 3-778 plus pegIFN (2.09 log₁₀ copies/mL), compared with the groups given NVR 3-778 or pegIFN alone (1.42 log₁₀ copies/mL and 0.89 log₁₀ copies/mL, respectively). There was no significant mean reduction in HBsAg during the 4-week treatment period. There were no discontinuations and no pattern of dose-related adverse effects with NVR 3-778.

CONCLUSIONS

In a phase 1 study of HBeAg-positive patients with chronic HBV infection without cirrhosis, NVR 3-778 was well tolerated and demonstrated antiviral activity. The agent reduced serum levels of HBV DNA and HBV RNA, to the greatest extent in combination with pegIFN. The observed reductions in HBV RNA confirmed the novel mechanism of NVR 3-778. Clinicaltrials.gov no. NCT02112799 (single-center) and NCT02401737 (multicenter).

Randomized prospective study showing the non-inferiority of tenofovir to entecavir in treatment-naïve chronic hepatitis B patients

AIM

The study aimed to evaluate the efficacy and safety of tenofovir disoproxil fumarate (TDF) and entecavir hydrate (ETV) in nucleos(t)ide analog (NA)-naïve Japanese chronic hepatitis B (CHB) patients.

METHODS

This multicenter, randomized, double-blinded study assessing the efficacy and safety of TDF 300 mg and ETV 0.5 mg in NA-naïve CHB subjects was carried out from November 2011 to November 2014, and funded by GlaxoSmithKline. The subjects were assigned to the TDF arm or ETV arm in a 2:1 ratio. The primary efficacy endpoint was the non-inferiority of TDF to ETV at week 24.

RESULTS

A total of 166 subjects (TDF arm, 110; ETV arm, 56) were enrolled. The change (mean ± SE) in serum hepatitis B virus (HBV)-DNA levels from baseline to week 24 was -4.63 ± 0.044 and -4.50 ± 0.063 log₁₀ copies/mL in the TDF and ETV arms, respectively, indicating the non-inferiority of TDF to ETV (P < 0.0001). The proportion of subjects with undetectable HBV-DNA increased from 54 to 77% and 39 to 66% in the TDF and ETV arms with continuation of the treatment from week 24 to 48, respectively. Reduction in hepatitis B surface antigen level was greater in subjects with hepatitis B envelope antigen (+) and high alanine aminotransferase levels (≥80 IU/L). Prevalence of drug-related adverse events at week 48 was 20% and 18% in the TDF and ETV arms, respectively.

CONCLUSIONS

The study is the first to report that TDF has non-inferiority to ETV in treatment effectiveness (lowering of serum HBV-DNA level) at week 24. ClinicalTrials.gov trial registration nos. NCT01480284 and GSK LOC115409.

Antiviral therapy with nucleotide/nucleoside analogues in chronic hepatitis B: A meta-analysis of prospective randomized trials

Nucleotide/nucleoside analogues (antiviral therapy) are used in the therapy of HBeAg positive and HBeAg negative chronic hepatitis B. We analyzed ten selected randomized controlled with 2557 patients to estimate the effect of antiviral drugs in chronic hepatitis B with compared to placebo. Virological response, biochemical response, histological response, seroconversion of HBeAg, and loss of HBeAg were estimated as primary efficacy measures. The included studies were subjected for heterogeneity and publication bias. The heterogeneity was assessed with χ2 and I(2) statistics. Publication bias was assessed by funnel plot. Greater rates of improvement obtained in antiviral group for virological response [43.96 % vs. 3.15 %, RR = 0.57, 95 % CI = 0.54-0.61, p-value <0.00001], biochemical response [58.37 % vs. 21.87 %, RR = 0.52, 95 % CI = 0.48-0.56, p-value <0.00001], histological response [58.99 % vs. 27.13 %, RR = 0.56, 95 % CI = 0.50-0.63, p-value <0.0001], seroconversion of HBeAg [10.66 % vs. 5.56 %, RR = 0.94, 95 % CI = 0.91-0.97, p-value = 0.0005], and HBeAg loss [14.59 % vs. 9.64 %, RR = 0.92, 95 % CI = 0.88-0.96, p-value = 0.0002]. The safety analysis were carried out for adverse events such as headache [17.22 % vs. 17.34 %, OR = 1.09, 95 % CI = 0.81-1.46, p-value = 0.58], abdominal pain [16.46 % vs. 14.34 %, OR = 1.24, 95 % CI = 0.90-1.72, p-value = 0.19], and pharyngitis [22.22 % vs. 18.23 %, OR = 1.12, 95 % CI = 0.86-1.45, p-value = 0.40]. Excluding adverse events, all primary efficacy measures shown statistical significant result for chronic hepatitis treatment (p-value <0.05). Antiviral therapy provided significant benefit for the treatment of chronic hepatitis B with no measurable adverse effects.

A genome-wide association study on chronic HBV infection and its clinical progression in male Han-Taiwanese

It is common to observe the clustering of chronic hepatitis B surface antigen (HBsAg) carriers in families. Intra-familial transmission of hepatitis B virus (HBV) could be the reason for the familial clustering of HBsAg carriers. Additionally, genetic and gender factors have been reported to be involved. We conducted a three-stage genome-wide association study to identify genetic factors associated with chronic HBV susceptibility. A total of 1,065 male controls and 1,623 male HBsAg carriers were included. The whole-genome genotyping was done on Illumina HumanHap550 beadchips in 304 healthy controls and HumanHap610 beadchips in 321 cases. We found that rs9277535 (HLA-DPB1, P = 4.87×10(-14)), rs9276370 (HLA-DQA2, P = 1.9×10(-12)), rs7756516 and rs7453920 (HLA-DQB2, P = 1.48×10(-11) and P = 6.66×10(-15) respectively) were significantly associated with persistent HBV infection. A novel SNP rs9366816 near HLA-DPA3 also showed significant association (P = 2.58×10(-10)). The "T-T-G-G-T" haplotype of the five SNPs further signified their association with the disease (P = 1.48×10(-12); OR = 1.49). The "T-T" haplotype composed of rs7756516 and rs9276370 was more prevalent in severe disease subgroups and associated with non-sustained therapeutic response (P = 0.0262). The "G-C" haplotype was associated with sustained therapeutic response (P = 0.0132; OR = 2.49). We confirmed that HLA-DPB1, HLA-DQA2 and HLA-DQB2 loci were associated with persistent HBV infection in male Taiwan Han-Chinese. In addition, the HLA-DQA2 and -DQB2 complex was associated with clinical progression and therapeutic response.

Similar response to entecavir 0.5 and 1.0 mg in treatment-naïve chronic hepatitis B patients: a case-control study

BACKGROUND AND AIMS

The dose recommendation for entecavir (ETV) is 0.5 mg daily for treatment-naïve chronic hepatitis B (CHB) patients and 1.0 mg daily for lamivudine-refractory patients; however, few data are available for the efficacy of a 1.0-mg daily dose in treatment-naïve CHB patients. Our goal is to examine the treatment outcome of treatment-naïve patients placed on ETV 0.5 mg or ETV 1.0 mg daily through week 48.

METHODS

Cases were 40 consecutive hepatitis B e antigen (HBeAg)-positive CHB patients treated with ETV 1.0 mg daily between January 2005 and September 2010, and controls were 40 consecutive CHB patients treated with ETV 0.5 mg daily between January 2005 and September 2010 at three US gastroenterology/liver clinics. Controls were matched for age (±5 years), sex, HBeAg, and baseline hepatitis B virus (HBV) DNA (±0.5 log10 IU/ml). Complete viral suppression was defined as undetectable HBV DNA by polymerase chain reaction (<100 IU/ml).

RESULTS

Both groups had similar distributions of age (38 ± 11 years), male patients (55 %), and mean HBV DNA (7.7 ± 1.1 log10 IU/ml). The complete viral suppression rate was similar in both cases and controls through week 24 (15 vs. 15 %, p = 1.00) and week 48 (22 vs. 36 %, p = 0.17). Non-adherence was reported in three patients in the ETV 1.0 mg daily cohort at week 48.

CONCLUSIONS

There were no significant differences in the proportion of patients with complete viral suppression in patients treated with ETV 0.5 mg daily or the higher daily dose of 1.0 mg.

A granulomatous drug eruption induced by entecavir

Entecavir (Baraclude®, Bristol-Myers Squibb) is a potent and selective antiviral agent that has demonstrated efficacy in patients with chronic hepatitis B. The most frequent adverse events attributed to entecavir include increased alanine aminotransferase, upper respiratory tract infection, headache, abdominal pain, cough, pyrexia, fatigue, and diarrhea. Although quite a few randomized double-blind studies including ones investigating adverse events along with these general symptoms have been reported, few cases of cutaneous adverse events have been described in detail. We demonstrate a case of granulomatous drug eruption as a cutaneous adverse event induced by entecavir.

Response to higher dose of entecavir 1.0 mg daily in patients with partial response to entecavir 0.5 mg daily

BACKGROUND

Despite its high potency against hepatitis B virus (HBV), entecavir (ETV) 0.5 mg daily may not be sufficient to induce complete viral suppression in some patients with very high pretreatment viremia. It is not clear whether ETV 1.0 mg daily would have additive effect in such patients.

GOALS

Our goal was to examine virologic outcome of ETV 1.0 mg daily in patients with partial response to ETV 0.5 mg daily.

METHODS

We retrospectively studied 31 consecutive treatment-naive patients who were switched to ETV 1.0 mg daily after partial response [reduction of HBV DNA ≥2 log10 IU/mL but with detectable HBV DNA levels (>100 IU/mL) after 24 weeks of therapy or longer] with ETV 0.5 mg daily from January 2005 to January 2010 at 2 clinics.

RESULTS

All patients were Asians and 90% had positive hepatitis B e antigen. Mean HBV DNA was 8.04±0.65 log10 IU/mL before therapy and 3.64±0.91 log10 IU/mL at the time of switch. Overall rate of complete viral suppression were 29% (n=9/31) after 24 weeks of ETV 1.0 mg daily and 22% (n=5/23) after 48 weeks. Complete viral suppression after 24 weeks with ETV 1.0 mg daily was significantly higher in patients with lower HBV DNA (<3 log10 IU/mL) at time of switch: 75% versus 5%, P<0.0001.

CONCLUSIONS

The majority of patients with partial response to ETV 0.5 mg daily did not achieve complete viral suppression with the higher dose of ETV 1.0 mg daily except those with minimal residual viremia (HBV DNA <3 log10 IU/mL).

Prophylactic Lamivudine to Improve the Outcome of Breast Cancer Patients With HBsAg Positive During Chemotherapy: A Meta-Analysis

CONTEXT

Raising the chemotherapy-induced HBV reactivation is parallel to the increment of chemotherapy treatments in breast cancer patients. This meta-analysis aims to evaluate the efficacy of prophylactic use of lamivudine in breast cancer patients with HBsAg positive during chemotherapy.

EVIDENCE ACQUISITION

MEDLINE, Pubmed, Ovid and Embase were used to search for clinical studies comparing with or without prophylactic use of lamivudine for HBV reactivation in breast cancer patients receiving chemotherapy. Outcomes of interest were the rate of HBV reactivation, incidence of hepatitis and incidence of hepatitis attributable to HBV reactivation, severity of hepatitis and severity of hepatitis attributable to HBV reactivation, the rate of chemotherapy disruption, and the rate of chemotherapy disruption attributable to HBV reactivation, overall mortality, and mortality attributable to HBV reactivation.

RESULTS

Four studies with 285 patients were included in this meta-analysis. The rate of HBV reactivation, incidence of hepatitis and incidence of hepatitis related to HBV reactivation were reduced by use of prophylactic lamivudine compared to control group. Pooled Odds Ratios (ORs) were 0.09 (95% confidence intervals [CI] 0.03-0.26; P < 0.0001), 0.23 (95% CI 0.06-0.92; P = 0.04), and 0.10 (95% CI 0.03-0.32; P < 0.0001) respectively. There was a reduction in chemotherapy disruption related to HBV reactivation by use of prophylactic lamivudine (pooled OR = 0.11; 95% CI 0.02-0.58; P = 0.01). Chemotherapy disruption, overall mortality, and mortality attributable to HBV reactivation were not significantly different between two groups. Pooled ORs were 0.42 (95% CI 0.11-1.58; P = 0.20), 0.37 (95% CI 0.07-2.04; P = 0.25), and 0.25 (95% CI 0.01-6.82; P = 0.41) respectively. Lamivudine was well-tolerated, and no additional toxicity was observed.

CONCLUSIONS

Use of prophylactic lamivudine may have positive effect on the outcome of breast cancer patients with HBsAg positive during chemotherapy.

Treatment of HBeAg positive chronic hepatitis B: interferon or nucleoside analogues

Interferon alpha has restricted efficacy in as much as only a proportion of patients show a response. However, in appropriately selected HBeAg-positive and HBeAg-negative patients, sustained suppression of viral replication can be achieved, and HBeAg or even HBsAg seroconversion can be attained. Thus, finite course of interferon alpha can be successful, and offer an advantage to patient. Interferon (IFN) remains a benchmark therapy for chronic hepatitis B. The main advantages of IFN-α over nucleoside analogues are the absence of resistance and the possibility of immune-mediated clearance of hepatitis B. Unfortunately, side effects preclude the use of interferon alpha in substantial proportions of patients, and prolonged maintenance therapy to suppress hepatitis B virus (HBV) is not feasible. Nucleoside analogues are given by mouth, once per day, and the safety, potency and efficacy have improved and facilitated treatment. However, maintenance of long-term suppression is required for the majority of patients. In general, treatment of chronic hepatitis B should target patients with active disease and viral replication, preferably before the signs and symptoms of cirrhosis or significant injury has occurred. Current EASL guidelines suggest that treatment be based on the evaluation of three criteria: Serum aminotransferase levels, serum HBV DNA levels and histological grade and stage. Many questions remain unanswered on the optimal treatment of patients with chronic hepatitis B with a nucleoside vs interferon alpha. Both forms of treatment have benefits and the choice should be selected and tailored. Stopping or futility rules can be implemented in patients who fail interferon. Recent data suggest the safety and efficacy of nucleoside analogues in the third trimester of pregnancy to reduce the risk of transmission from mothers to their children.

Optimal Management of the Hepatitis B Patient Who Desires Pregnancy or Is Pregnant

Women of childbearing age with recognized hepatitis B infection should have their liver disease assessed before pregnancy occurs since the management of hepatitis B virus (HBV) infection in this setting is complex. Initiation of treatment in a woman of child-bearing age will depend on when she intends on conceiving, as well as the severity of her liver disease. During pregnancy, all decisions about initiating, continuing or stopping HBV therapy must include an analysis of the risks and benefits for both mother and fetus. The trimester of the pregnancy and the stage of the mother's liver disease are important factors. Treatment in the third trimester may be considered to aid in prevention of perinatal transmission, which appears to be most pronounced in mothers with high viral loads. Consideration of initiation of third trimester treatment should occur after a high viral load is documented in the latter part of the second trimester, to allow adequate time for initiation of antiviral therapy with significant viral suppression before delivery. This discussion should include the topic of breastfeeding, since it is generally not recommended while on antiviral therapy. Until recently lamivudine and tenofovir appeared to be the therapeutic options with the most reasonable safety data in pregnancy. There are emerging data that telbivudine may also be considered in this setting.

Lamivudine with or without adefovir dipivoxil for postoperative hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a significant cause of death, especially in Asia and sub-Saharan Africa. Removal of the cancer through surgery or other techniques is considered the first-line therapy in early HCC, but relapse of HCC is the main postoperative problem. The main risk factor for HCC is hepatitis B virus (HBV) infection. Lamivudine and adefovir dipivoxil are effective and tolerable for chronic hepatitis B by suppressing the viral load and to reduce fibrosis in the liver.  

OBJECTIVES

To assess the benefits and harms of postoperative administration of lamivudine with or without adefovir dipivoxil in participants with surgically treated HCC and chronic HBV infection or HBV carrier state.

SEARCH METHODS

A systematic search was performed in The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded (SCI Exp) in October 2011. Further trials have been sought through scanning reference lists of relevant articles.

SELECTION CRITERIA

Randomised clinical trials comparing the administration of lamivudine with and without adefovir dipivoxil for participants with ablation treated HCC (surgical or through other techniques) and chronic HBV infection or HBV carrier state, regardless of publication status, language, blinding, and publication status, were to be included in this review. We planned to extract data on harms from quasi-randomised studies or cohort studies when retrieved with the search results.

DATA COLLECTION AND ANALYSIS

Two authors independently selected studies for inclusion, and extracted and analysed the data. The type and number of adverse events were reported descriptively.

MAIN RESULTS

No randomised trials could be included into this systematic review. Thus, we were unable to follow our pre-published protocol and perform meta-analyses.Through our searches for randomised clinical trials, four cohort trials with 230 participants were retrieved. We read them in order to find data on harm, ie, adverse events. Breakthrough hepatitis was a serious adverse event attributable to lamivudine. No other adverse events seemed to be caused by the administration of lamivudine or adefovir dipivoxil were reported in the four cohort studies.

AUTHORS' CONCLUSIONS

No evidence from randomised trials on the beneficial or harmful effects of lamivudine with or without adefovir dipivoxil for postoperative HCC was found. Randomised clinical trials with large number of participants and long follow-up period should be carried out to direct clinical practice.

Pooled model-based approach to compare the pharmacokinetics of entecavir between Japanese and non-Japanese chronic hepatitis B patients

This study evaluated the population pharmacokinetics (PK) of entecavir in Japanese patients with chronic hepatitis B infection enrolled in 2 Japanese phase IIb clinical trials and compared them to non-Japanese patients enrolled in global phase II trials. The objectives were to identify significant and clinically meaningful covariate effects on entecavir population pharmacokinetic parameters and assess whether differences exist between Japanese and non-Japanese patients. A total of 843 observations were obtained from 142 patients who received once daily administration of entecavir at 0.1, 0.5, and 1.0 mg doses in the 2 Japanese studies. Consistent with findings in non-Japanese patients, creatinine clearance estimated with ideal body weight (ICrCL) was found to be statistically significant for clearance in a 2-compartment model. Also, the entecavir dose was identified as a covariate on intercompartmental clearance. Age, gender, and hepatic function were not identified as covariate for clearance. The estimated population average of oral clearance in a typical patient with a reference ICrCL value of 100 mL/min was 26.4 L/h (interindividual variability: 19.4%). This model-based analysis indicates that the PK of entecavir are similar in Japanese and non-Japanese chronic hepatitis B patients.

Epidemiology of primary and secondary liver cancers

Primary liver cancer is the sixth most common cancer worldwide with a wide geographic distribution. The incidence of primary liver cancer is increasing and there is still a higher prevalence in developing countries. Early recognition remains an obstacle and lack of it results in poor outcomes for hepatocellular carcinoma (HCC), the most prevalent primary liver cancer, and cholangiocarcinoma. The most common risk factors associated with HCC are hepatitis B and chronic hepatitis C infections, alcohol use, smoking, and aflatoxin exposure. Emerging risk factors such as obesity might play an important role in the future because of the increasing prevalence of this condition.

Treatment of hepatitis B in decompensated liver cirrhosis

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

Clinical profile, genotype and management updates of hepatitis B virus

Hepatitis B virus (HBV) is a well known agent of acute and chronic hepatitis, liver cirrhosis and hepatocellular carcinoma. Around 400 million people worldwide carrier of HBV of which more than 250 million reside in Asia, and 1-2 million people have died from it. It has a partially double-stranded DNA, having 3.2-kb genome size and replicate via reverse transcription of RNA intermediate. In the natural history or during the antiviral therapy of chronic HBV infection, seroconversion from HBeAg to anti-HBeAg is usually accompanied by a decrease in viral replication and remission of liver disease. Based on genomic sequence data HBV is classified into eight genotypes A-H and four major serotypes ayw, ayr, adw and adr on the basis of complete genome and S gene sequence analysis. Genotypes and serotypes are useful tools in understanding the epidemiology of HBV infection. HBV genotypes have distinct geographical distributions. The HBV variants appear during HBeAg seroconversion and they bring mutations in the precore region (PC) that prevent HBeAg synthesis. Another common HBeAg variant is the basal core promoter mutant (BCP) characterized by point mutation in the promoter of both HBeAg mRNA and core protein mRNA. The most frequent core promoter mutation is the double A1762T and G1764A nucleotide exchange, which results in a substantial decrease in HBeAg expression but enhanced viral genome replication. The approved antiviral drugs such as Interferon, lamivudine, adefovir dipivoxil, entecavir and telbivudine for purpose of treating chronic HBV infection is to prevent or stop the progression of liver injury by suppressing viral replication or eliminating infection. Sustained losses of viral markers of active viral replication (HBeAg and HBV DNA) are the standard end point of the therapies.

[The efficacy of adefovir dipivoxil, entecavir and telbivudine for chronic hepatitis B treatment: a systematic review]

INTRODUCTION

Chronic hepatitis B is one of the most frequent infectious disease in the world and represents a serious problem of public health

METHODS

A systematic review of randomized clinical trials was conducted to evaluate the efficacy of the nucleoside/nucleotide analogues (adefovir, entecavir and telbivudine) used for the treatment of chronic hepatitis B. The databases PubMed and LILACS were consulted, among others

RESULTS

Twenty nine articles published between January/1970 to December/2009 were selected

CONCLUSIONS

All nucleoside/nucleotide analogues demonstrate upper or similar efficacy to lamivudine. The entecavir can be appropriate for patients with chronic hepatitis B, HBeAg positive and negative treatment-naive as alternative to lamivudine, considering its low potential of viral resistance. The addition of adefovir to lamivudine presented good results in lamivudine resistant patients. The use of entecavir and telbivudine in those patients presents risk of crossed resistance. TBV is one of the most recent antivirals available, but antiviral resistance already documented represents limitation to its use as therapeutic option to LAM. Adverse events of nucleoside/nucleotide analogues were similar in characteristics, gravity and incidence when compared to the lamivudina and placebo.

Safety and efficacy of entecavir for the treatment of chronic hepatitis B

Entecavir is a cyclopentyl deoxyguanosine analog that was approved for the treatment of the hepatitis B virus (HBV) in 2005. In Phase III trials, it showed potent HBV suppression with drops of 6- to 7-log copies/mL in HBV DNA at 1 year. In addition, rates of genotypic resistance in nucleos(t)ide-naïve patients are low, reaching only 1.2% after 6 years. Safety and efficacy have been established in compensated cirrhosis and HIV-coinfected patients. Studies in decompensated cirrhosis also show efficacy. Because of potent viral suppression and a large genetic barrier to resistance, entecavir is now a first-line choice in most HBV treatment guidelines and has become an integral part of the HBV treatment armamentarium.

Celiac disease and its effect on human reproduction: a review

All decisions about initiating, continuing, or stopping therapy of the hepatitis B virus (HBV) during pregnancy must include an analysis of the risks and benefits for mother and fetus. The trimester of the pregnancy and the stage of the mother’s liver disease are important factors. Treatment in the third trimester may be initiated to aid in preventing perinatal transmission, which appears to be most pronounced in mothers with high viral loads. Consideration of initiating treatment in the third trimester should occur after a high viral load is documented in the latter part of the second trimester, to allow adequate time for initiation of antiviral therapy with significant viral suppression before delivery. This discussion should include the topic of breastfeeding, because it is generally not recommended while receiving antiviral therapy. Currently, lamivudine and tenofovir appear to be the therapeutic options with the most reasonable safety data in pregnancy.

N-6 Substituted Deoxygenated Derivatives of L-like 5'-Noraristeromycin

Several N-6 substituted derivatives (4-11) of (+)-4'-deoxy-5'-noraristeromycin (2) and its unsaturated counterpart (3) have been prepared. The derivatives are designed to systematically vary the hydrophobic/hydrophilic balance of the lead compounds. These compounds were evaluated against a large number of viruses but, no significant antiviral activity was observed. Also, no cytotoxicity to host cells was found.

Chronic Hepatitis B Infection: Principles of Therapy

Chronic hepatitis B is a global health concern in many resource-limited settings due to perinatal or pediatric hepatitis B virus transmission. In the United States, pediatric infection has been virtually eliminated due to maternal screening during pregnancy and the availability of an effective vaccine. However, young adults remain an at-risk group for hepatitis B virus infection due to sexual transmission and injection drug use. The frequency of progression from acute hepatitis B virus infection to chronic hepatitis B infection depends on multiple factors, including host immune function and age at time of hepatitis B virus infection. Fortunately, there are 7 currently approved therapies for chronic hepatitis B infection, and several emerging therapies that show promise. Despite the availability of these agents, many clinical questions still surround chronic hepatitis B therapy including when to start therapy, which agent is ideal for first and second line therapy, the appropriate duration of therapy, and the role of combination antiviral therapy. This review focuses on agents available for chronic hepatitis B management, including pharmacology, safety and efficacy data, monitoring parameters, and the role for each in chronic hepatitis B therapy in adult patients.

Doctor-to-patient transmission of Hepatitis B virus: the potential of antiviral therapy for prevention

Hepatitis B virus (HBV)-infected health-care workers (HCWs) have infected patients during medical procedures. In many countries HBV-infected HCWs are restricted in performing exposure prone procedures based on either HBeAg status or serum HBV DNA level. To prevent loss of skilled HCWs and to minimize transmission risk, highly viraemic HCWs can be offered antiviral therapy. Nucleoside analogues have proven to be effective in reducing transmission of HIV and HBV in the setting of vertical mother-to-infant transmission. Following the same rationale, suppression of viral load in HBV-infected HCWs could minimize the risk of doctor-to-patient transmission to such an extent that job modifications are no longer indicated. To limit the risk of drug resistance, the use of combination therapy is advocated. We describe two chronic HBV-infected HCWs treated with antiviral therapy, eventually leading to well-tolerated and highly effective combination therapy with lamivudine and tenofovir, with continuation of medical practice.

Viral dynamics of hepatitis B virus DNA in human immunodeficiency virus-1-hepatitis B virus coinfected individuals: similar effectiveness of lamivudine, tenofovir, or combination therapy

Following treatment of hepatitis B virus (HBV) infection with nucleos(t)ide reverse transcriptase inhibitors (NRTIs), there is a biphasic clearance of HBV, similar to that seen following treatment of human immunodeficiency virus-1 (HIV-1) and hepatitis C virus. Little is known about the impact of combination NRTIs and HIV-1 coinfection on HBV viral kinetic parameters following the initiation of HBV-active highly active antiretroviral therapy (HAART). HIV-1-HBV coinfected patients (n = 21) were enrolled in a viral kinetics substudy of the Tenofovir in HIV-1-HBV Coinfection study (TICO). TICO was a randomized (1:1:1) trial of tenofovir disoproxil fumarate (TDF, 300 mg) versus lamivudine (LMV, 300 mg) versus TDF/LMV within an efavirenz based HAART regimen initiated in HIV-1-HBV coinfected antiretroviral naïve individuals in Thailand. HBV DNA was measured frequently over the first 56 days. To fit the viral load data, we used a model of HBV kinetics that allows the estimation of treatment effectiveness, viral clearance and infected cell loss. We observed a biphasic decline in HBV DNA in almost all patients. We did not observe any significant differences in HBV viral dynamic parameters between the three treatments groups. Overall, median (interquartile range) HBV treatment effectiveness was 98% (95%-99%), median HBV virion half-life was 1.2 days (0.5-1.4 days), and median infected cell half-life was 7.9 days (6.3-11.0 days). When we compared hepatitis B e antigen (HBeAg)-positive and HBeAg-negative individuals, we found a significantly longer infected cell half-life in HBeAg-positive individuals (6.2 versus 9.0 days, P = 0.02).

CONCLUSION

HBV viral dynamic parameters are similar following anti-HBV NRTI monotherapy and dual combination therapy in the setting of HIV-1-HBV coinfection. HIV-1 coinfection has minimal effect on HBV viral dynamics, even in the setting of advanced HIV-1-related immunosuppression.

Efficacy and safety of entecavir in nucleoside-naive, chronic hepatitis B patients: phase II clinical study in Japan

BACKGROUND AND AIM

Entecavir has demonstrated clinical efficacy for chronic hepatitis B. This study evaluated the efficacy and safety of entecavir in nucleoside-naive Japanese chronic hepatitis B patients.

METHODS

In this multicenter, double-blind study, 66 nucleoside-naive Japanese chronic hepatitis B patients were randomized to 0.1 mg entecavir (n = 32) or 0.5 mg entecavir (n = 34) daily for 52 weeks. The primary endpoint was the proportion of patients whose serum hepatitis B virus (HBV) DNA decreased from baseline by > or =2 log(10) copies/mL or became undetectable (<400 copies/mL by polymerase chain reaction assay) at week 48.

RESULTS

One hundred percent of patients in both treatment groups achieved the primary efficacy endpoint, with 81% and 68% of patients achieving undetectable HBV DNA in the 0.1 mg and 0.5 mg treatment groups, respectively. Mean changes from baseline in HBV DNA were -4.49 log(10) and -4.84 log(10) copies/mL for the 0.1 mg and 0.5 mg groups, respectively. Significant improvements in necroinflammation were seen in both groups, as assessed by Knodell and New Inuyama classifications. Most adverse events were transient and classified as grade 1 or 2. There were no clinically significant differences in adverse events across the two treatment groups and no discontinuations due to adverse events in either group.

CONCLUSIONS

In Japanese nucleoside-naive patients with chronic hepatitis B, 0.1 mg or 0.5 mg entecavir daily provided excellent efficacy and was well tolerated. The 0.5 mg dose was selected for the treatment of nucleoside-naive patients.

[Entecavir]

Chronic hepatitis B continues to be a serious problem worldwide. Because a high viral load is associated with greater progression to cirrhosis and hepatocarcinoma in these patients, new drugs that achieve rapid, potent and lasting suppression of viral replication must be sought. Entecavir is a new, highly potent antiviral agent; phase II and III studies have demonstrated this drug to be superior to placebo and lamivudine in patients with chronic hepatitis B virus in terms of histological improvement, efficacy in achieving suppression of viral replication and normalizing transaminase counts. The drug is well tolerated, since its adverse effects are usually mild or moderate and their incidence is similar to that found with placebo or lamivudine. Moreover, in treatment-naïve patients, no resistance has been observed after 3 years of therapy. However, in patients with prior resistance to lamivudine, the incidence of resistance is approximately 15% at 3 years. Further studies are required that compare this drug with other currently available therapeutic options, as well as longer term trials to evaluate its safety. It seems that entecavir will occupy a major place in the treatment of patients with chronic hepatitis B virus infection.

Entecavir: a potent antiviral with minimal long-term resistance in nucleoside-naive chronic hepatitis B patients

Entecavir has demonstrated safety and efficacy in the treatment of chronic hepatitis B infection. It is the prototype for the cyclopentane class of nucleoside/nucleotide chronic hepatitis B antiviral agents. It has a high potency and, due to its structural formula and mechanism of action, entecavir is associated with emergence of minimal resistance in the long-term treatment of nucleoside-naive patients. Research suggests that long-term treatment may be required for chronic hepatitis B patients, especially those who acquire HBV early in life, to achieve maximum viral suppression and improve outcomes. Several recent studies have evaluated the long-term safety, efficacy and development of resistance in nucleoside-naive patients treated with entecavir. Results indicate that the long-term use of entecavir is well tolerated and associated with continuous clinical improvement -- with an increasing number of patients achieving undetectable levels of HBV DNA, HBeAg seroconversion and minimal resistance. These data underscore the position of entecavir for first-line therapy and highlight its role in the long-term treatment of chronic hepatits B.

Understanding the molecular basis of HBV drug resistance by molecular modeling

Despite the significant successes in the area of anti-HBV agents, resistance and cross-resistance against available therapeutics are the major hurdles in drug discovery. The present investigation is to understand the molecular basis of drug resistance conferred by the B and C domain mutations of HBV-polymerase on the binding affinity of five anti-HBV agents [lamivudine (3TC, 1), adefovir (ADV, 2), entecavir (ETV, 3), telbivudine (LdT, 4) and clevudine (l-FMAU, 5)]. In this regard, homology modeled structure of HBV-polymerase was used for minimization, conformational search and induced fit docking followed by binding energy calculation on wild-type as well as on mutant HBV-polymerases (L180M, M204V, M204I, L180M+M204V, L180M-M204I). Our studies suggest a significant correlation between the fold resistances and the binding affinity of anti-HBV nucleosides. The binding mode studies reveals that the domain C residue M204 is closely associated with sugar/pseudosugar ring positioning in the active site. The positioning of oxathiolane ring of 3TC (1) is plausible due the induced fit orientation of the M204 residue in wild-type, and further mutation of M204 to V204 or I204 reduces the final binding affinity which leads to the drug resistance. The domain B residue L180 is not directly close ( approximately 6A) to the nucleoside/nucleoside analogs, but indirectly associated with other active-site hydrophobic residues such as A87, F88, P177 and M204. These five hydrophobic residues can directly affect on the incoming nucleoside analogs in terms of its association and interaction that can alter the final binding affinity. There was no sugar ring shifting observed in the case of adefovir (2) and entecavir (3), and the position of sugar ring of 2 and 3 is found similar to the sugar position of natural substrate dATP and dGTP, respectively. The exocyclic double bond of entecavir (3) occupied in the backside hydrophobic pocket (made by residues A87, F88, P177, L180 and M204), which enhances the overall binding affinity. The active site binding of LdT (4) and l-FMAU (5) showed backward shifting along with upward movement without enforcing M204 residue and this significant different binding mode makes these molecules as polymerase inhibitors, without being incorporated into the growing HBV-DNA chain. Structural results conferred by these l- and d-nucleosides, explored the molecular basis of drug resistance which can be utilized for future anti-HBV drug discovery.

Lack of an effect of human immunodeficiency virus coinfection on the pharmacokinetics of entecavir in hepatitis B virus-infected patients

Entecavir is a guanosine nucleoside analogue approved for the treatment of chronic hepatitis B virus (HBV) infection. The impact of human immunodeficiency virus (HIV) coinfection on the pharmacokinetics (PK) of entecavir was examined by nonlinear mixed-effects modeling. Plasma concentration data from HIV- and HBV-coinfected patients were analyzed in conjunction with data from HBV-monoinfected patients, and HIV coinfection was tested as a covariate on oral clearance (CL/F). The estimated population averages of intercompartmental clearance and the volumes of distribution in the central and peripheral compartments obtained with a 1-mg dose were 34.2 liters/h (interindividual variability, 30.2%), 115 liters (interindividual variability, 39.2%), and 1,830 liters (interindividual variability, 74%), respectively. CL/F was found to be a function of creatinine clearance, but HIV confection did not show any effect on CL/F. The geometric mean (GM) of individual Bayesian estimates of the steady-state area under the concentration-time curve following 1-mg daily doses were 39.3 and 38.8 ng x h/ml in HIV- and HBV-coinfected and HBV-monoinfected patients, respectively. The adjusted GM ratio (1.01; 90% confidence interval, 0.91 to 1.12) was within the bioequivalence criteria boundary (0.80 to 1.25). In conclusion, the proposed model adequately described the entecavir PK in HBV- and HIV-coinfected patients and HBV-monoinfected patients, and the entecavir exposures were comparable in the two patient populations.

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

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

Genotyping and genomic sequencing in clinical practice

The global prevalence of chronic hepatitis B and its associated serious sequelae demand technologically advanced techniques of management. Nucleic acid testing (NAT) plays a key role in the diagnosis, surveillance, and treatment of chronic hepatitis B. NAT includes quantitative PCR-based HBV DNA assays, HBV genotyping, tests for mutations associated with resistance to antiviral medications, and assays to detect precore and core promoter mutations. This article reviews the uses of NAT in the diagnosis and management of chronic hepatitis B.

Improving outcomes for patients with chronic hepatitis B

A focused meeting on hepatitis B virus (HBV) infection was held at the United States National Institutes of Health in Washington, DC, in April 2006. This meeting focused on new and historical data and served as a review for basic scientists and clinicians, as well as representatives from the pharmaceutical industry. Understanding HBV disease must include up-to-date information concerning virology, immunology, animal models, natural history, prevalence, and transmission risk, as well as an understanding of the evolving therapies for this life-threatening infection. Serious outcomes such as advanced fibrosis, cirrhosis, liver failure and hepatocellular carcinoma from hepatitis B infection appear to be closely tied to both historical and current serum levels of HBV DNA, and elevated serum levels of liver enzymes. Decreasing risk events and vaccinating susceptible individuals are key steps in managing this global scourge. New oral treatments for patients withchronic hepatitis B infection characterized by more potent antiviral effects, less toxicity, and minimal or no risk of resistance were reviewed and emphasized. Entecavir and pegylated interferons have recently been approved for treatment of chronic hepatitis B. Further expansion of our information about lamivudine and adefovir were highlighted. Several other new anti-HBV agents are also in phase II or III clinical trials or have been submitted for licensing including LdT (telbivudine). The NIH review meeting is summarized in this review and new and emerging areas of information are highlighted.