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Background and Aim: The prediction of hepatocellular carcinoma (HCC) development during nucleotide/nucleoside analog (NA) therapy is clinically important in patients with chronic hepatitis B. Although several useful models for HCC prediction have been previously reported, their usefulness in the Japanese population is unclear. Therefore, this study examines the applicability of these models in Japanese patients., Methods: Four hundred forty-three patients with no history of HCC who were treated with entecavir, tenofovir alafenamide, or tenofovir disoproxil fumarate were enrolled. PAGE-B, modified-PAGE-B, and REACH-B scores were calculated, and subsequent HCC development was investigated., Results: The mean follow-up duration was 5.1 years, and a total of 33 patients (7.4%) developed HCC during the follow-up period. Multivariate analysis revealed that old age (hazard ratio [HR] 1.05, 95% confidence interval [CI] 1.01-1.09, P = 0.011), male gender (HR 2.62, 95% CI 1.06-6.49, P = 0.037), and low platelet count (HR 0.83, 95% CI 0.77-0.91, P < 0.001) were independent predictors of HCC development. These factors are the same as the factors identified in the PAGE-B model. Time-dependent area under the receiver operating characteristic (AUROC) curve revealed that the AUROCs for 3 and 7 years of PAGE-B (AUROC: 0.786 and 0.744 at 3 and 7 years, respectively) were continuously higher than those of REACH-B (0.658 and 0.543) and modified PAGE-B AUROC (0.772 and 0.731)., Conclusions: PAGE-B, which can easily identify high-risk cases, can be useful for predicting HCC development in Japanese patients treated with NA therapy., (© 2020 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.)

Background: Patients with hepatitis B virus (HBV) infection have a risk of reactivation after chemotherapy. All patients undergoing chemotherapy should be screened for HBV infection. No large-scale studies have been conducted to examine HBV screening practice in Japan., Methods: We analyzed health insurance claims equivalent data linked with a nationwide hospital-based cancer registry. Patients diagnosed with cancer in 2014, who were aged 20 years and older and those who underwent systemic anticancer treatment in 2014-15 were included. We assessed the HBV screening rates by the HBsAg or anti-HBc tests, HBV-DNA tests, and entecavir prescriptions. Multiple logistic regression models were used to identify factors related to the receipt of screening., Results: Of 177,597 patients (mean [SD] age, 65.6 [12.2] years), 82.6% and 12.9% patients had a solid tumor and hematologic malignancy, respectively. Among them, 88.1%, 6.3%, and 5.5% received cytotoxic chemotherapy, targeted therapy, and anti-CD20 antibodies, respectively. Overall, 70.6% of patients were screened. The positive predictor of HBV screening was receiving anti-CD20 antibodies [odds ratio (OR); 2.23, 95% confidence interval (CI) 2.06-2.41, p < 0.001] and negative predictors were age ≥ 85 (OR 0.76, 95% CI 0.71-0.81), age 75-84 (OR 0.77, 95% CI 0.75-0.79) and targeted therapy (OR 0.69, 95% CI 0.67-0.72). Among the screened patients, 13.2% were tested for HBV-DNA, and 1.49% were prescribed entecavir., Conclusions: The HBV screening rate in Japan is higher than in other countries. Further improvement of the HBV screening rate is needed to prevent reactivation and avoidable deaths of patients with HBV infection.

Introduction: It is unclear whether entecavir (ETV) and tenofovir disoproxil fumarate (TDF) differ in their effectiveness for preventing hepatocellular carcinoma (HCC) in patients with chronic hepatitis B (CHB)., Methods: This retrospective cohort study analyzed an international consortium that encompassed 19 centers from 6 countries or regions composed of previously untreated CHB patients then treated with either ETV or TDF monotherapy. Those who developed HCC before antiviral treatment or within 1 year of therapy were excluded. The association between antiviral regimen and HCC risk was evaluated using competing-risk survival regression. We also applied propensity score matching (PSM) to 1:1 balance the 2 treatment cohorts. A total of 5,537 patients were eligible (n = 4,837 received ETV and n = 700 received TDF) and observed for HCC occurrence until December 23, 2018. Before PSM, the TDF cohort was significantly younger and had generally less advanced diseases., Results: In the unadjusted analysis, TDF was associated with a lower risk of HCC (subdistribution hazard ratio [SHR], 0.45; 95% confidence interval [CI], 0.26-0.79; P = 0.005). The multivariable analysis, however, found that the association between TDF and HCC no longer existed (SHR, 0.81; 95% CI, 0.42-1.56; P = 0.52) after adjustment for age, sex, country, albumin, platelet, α-fetoprotein, cirrhosis, and diabetes mellitus. Furthermore, the PSM analysis (n = 1,040) found no between-cohort differences in HCC incidences (P = 0.51) and no association between regimens (TDF or ETV) and HCC risk in the multivariable-adjusted analysis (adjusted SHR, 0.89; 95% CI, 0.41-1.92; P = 0.77)., Discussion: TDF and ETV did not significantly differ in the prevention of HCC in patients with CHB.

The appropriate management of hepatitis B virus (HBV) infection during pregnancy has not been established in Japan. We herein report five HBV-infected pregnant Japanese women who received tenofovir disoproxil fumarate (TDF). Two of them had been born after the introduction of nationwide immunoprophylaxis and were vertically infected with HBV, highlighting the need to address mother-to-child transmission further. In both entecavir-experienced and nucleoside/nucleotide analog-naïve mothers, TDF suppressed HBV replication without serious adverse events. All five children were free from congenital disorders, growth impairment, and HBV infection. TDF showed safety and efficacy for pregnant woman with chronic hepatitis B and might have helped prevent mother-to-child transmission.

Background: We determined the antiviral potency and viral breakthrough rate after 10 years of continuous entecavir treatment in patients with chronic hepatitis B (CHB) infection., Methods: The cumulative rates of undetectable hepatitis B virus DNA (HBV-DNA, < 2.1 log copies/mL), alanine aminotransferase (ALT) normalization, hepatitis B e antigen (HBeAg) seroclearance, hepatitis B surface antigen (HBsAg) seroclearance, and viral breakthrough of 1094 nucleos(t)ide analogue-naïve CHB patients (HBeAg-positive: 47%) who were on continuous entecavir treatment for 10 years were calculated., Results: The median age was 50 years and follow-up period was 5.5 years, with 999, 804, 591, 390, 182 and 87 patients followed up for at least 1, 3, 5, 7, 9 and 10 years, respectively. Incremental increases were noted in the rates of undetectable HBV-DNA, ALT normalization, HBeAg seroclearance, and HBsAg seroclearance, reaching 96, 79, 38 and 3.7%, respectively, by the tenth year. The mean decline in HBsAg level from baseline was - 0.08 log IU/mL/year. Multivariate analysis identified HBsAg level and genotype (A) as independent predictors of HBsAg seroclearance. Sixteen patients experienced viral breakthrough. The cumulative percentages of patients with viral breakthrough analyzed by the Kaplan-Meier test were 1.5 and 2.5% at years 5 and 10, respectively. There were no serious adverse events during treatment., Conclusions: Long-term entecavir treatment of nucleos(t)ide analogue-naïve CHB patients was associated with an excellent viral response and a low rate of entecavir-resistant mutations at 10 years. Baseline HBsAg levels and genotype were predictors of HBsAg seroclearance during entecavir treatment.

Background: Nucleot(s)ide analogues (NA) can reduce the risk of hepatocellular carcinoma (HCC), but not completely prevent its development., Methods: Two hundred and thirty-four chronic hepatitis B patients virologically well controlled with entecavir or tenofovir disoproxil fumarate for more than 1 year were enrolled in this study. Over the median observation period of 51 (12-142) months, 24 of 234 patients developed HCC. We quantified HBV markers, alpha-fetoprotein (AFP) and Mac-2-binding protein glycosylation isomer (M2BPGi) at baseline and 48 weeks after therapy., Results: Serum AFP and M2BPGi tended to decline from baseline to 48 weeks after treatment both in patients who did and those who did not develop HCC. Univariate Cox regression analysis indicated that serum M2BPGi levels ≥ 1.215 COI at 48 weeks were associated with HCC development [hazard ratio (HR) 5.73; p ≤ 0.001]. Multivariate analysis showed that male sex (HR 5.6; p = 0.01), AFP ≥ 9.65 ng/ml (HR 22.01; p ≤ 0.001), M2BPGi ≥ 1.215 (HR 5.07; p = 0.004) at 48 weeks were significant independent predictive factors for HCC development. Based on a scoring system consisting of three factors above described, Kaplan-Meier analysis for four groups (score 0, 1, 2, ≥ 3), revealed significant differences in cumulative HCC occurrence for each group within 2 years. The rate of incidence of HCC was 0, 5.4, 23.4, and 75% in each group, respectively., Conclusions: In patients receiving NA therapy, higher M2BPGi at 48 weeks, as well as male sex and higher AFP at 48 weeks were independent risk factors for HCC development.

Background: Entecavir (ETV) is one of the first-line nucleoside analogs for treating patients with chronic hepatitis B virus (HBV) infection. However, the hepatocellular carcinoma (HCC) risk for ETV-treated patients remains unclear., Methods: A total of 496 Japanese patients with chronic HBV infection undergoing ETV treatment were enrolled in this study. The baseline characteristics were as follows: age 52.6 ± 12.0 years, males 58%, positive for hepatitis B e antigen 45 %, cirrhosis 19%, and median HBV DNA level 6.9 log copies (LC) per milliliter. The mean treatment duration was 49.9 ± 17.5 months., Results: The proportions of HBV DNA negativity (below 2.6 LC/mL) were 68% at 24 weeks and 86% at 1 year, and the rates of alanine aminotransferase (ALT) level normalization were 62 and 72%, respectively. The mean serum alpha-fetoprotein (AFP) levels decreased significantly at 24 weeks after ETV treatment initiation (from 29.0 ± 137.1 to 5.7 ± 27.9 ng/mL, p < 0.001). The cumulative incidence of HCC at 3, 5, and 7 years was 6.0, 9.6, and 17.2%, respectively, among all enrolled patients. In a multivariate analysis, advanced age [55 years or older, hazard ratio (HR) 2.84; p = 0.018], cirrhosis (HR 5.59, p < 0.001), and a higher AFP level (10 ng/mL or greater) at 24 weeks (HR 2.38, p = 0.034) were independent risk factors for HCC incidence. HCC incidence was not affected by HBV DNA negativity or by ALT level normalization at 24 weeks., Conclusions: The AFP level at 24 weeks after ETV treatment initiation can be the on-treatment predictive factor for HCC incidence among patients with chronic HBV infection.

At present, for adults with chronic hepatitis B virus (HBV) infection, two new analogues, entecavir (ETV) and tenofovir, are recommended as the first-line therapy by the EASL (European Association for the Study of the Liver), AASLD (American Association for the Study of Liver Diseases), and APASL (Asian Pacific Association for the Study of the Liver) guidelines. The use of pegylated interferon-α (PEG IFN-α) is recommended as the first-line therapy instead of standard IFN-α according to the above 3 guidelines. In this paper, the aim was to assess: (1) the long-term efficacy and safety as well as the resistance to ETV and tenofovir disoproxil fumarate (TDF); (2) the efficacy of PEG IFN-α; (3) the role of combination therapy with IFN plus two analogues, such as lamivudine and ETV; (4) the efficacy and safety of two analogues with cirrhosis, and (5) suppression of hepatocellular carcinoma (HCC) by ETV and IFN treatment. The results are as follows: (1) both ETV and TDF showed long-term efficacy and safety; (2) PEG IFN-α resulted in a greater decline in HBV DNA levels and a higher rate of HBeAg seroconversion; (3) combination therapy with IFN plus two analogues did not elevate the rate of sustained responses; (4) both ETV and TDF showed efficacy and safety with cirrhosis (ETV especially displayed efficacy and safety with decompensated cirrhosis), and (5) suppression of HCC was observed by ETV and IFN., (© 2015 S. Karger AG, Basel.)

The safety and effectiveness of pemetrexed(PEM)in patients with non-small cell lung cancer(NSCLC)were reviewed using data from post-marketing surveillance. Among 699 patients registered from June 2009 to May 2010, 683 patients were analyzed(343, first-line therapy: 340, second-line therapy or beyond). Patient backgrounds were as follows: median age=65 years(16.1%B75 years old); 64.7% male; 91.9% performance status 0-1; 83.2% Stage IV; 99.0% non-squamous cell cancer. Also, 86% of the first-line and 20% of the second-line cohort were receiving a concomitant anti-cancer drug(mostly platinum agents). The incidence rate of adverse drug reactions(ADR)was 76.7%, including serious cases(18.0%). The most common ADRs were decreased white blood cell count(26.8%), decreased neutrophil count(25.3%), anemia(19.2%), decreased platelet count(17.0%), and nausea(23.0%). The incidence of interstitial lung disease, which is a concern during chemotherapy, was 2.6%. Peripheral neuropathy and alopecia, events influencing a patient's quality of life, were less than 1%. The estimated median survival time was 23.2 months[95%CI: 19.8 months-not calculable]in the first-line cohort, and 11.8 months[95% CI: 10.5-13.7 months]in the B second-line cohort. The surveillance results showed no apparent difference in total ADRs in this current study compared to the safety profile established in clinical trials previously conducted in Japan and overseas. These results demonstrate the safety and effectiveness of PEM treatment for NSCLC patients in daily clinical settings.

Unlabelled: The proportion of patients who progress to chronicity following acute hepatitis B (AHB) varies widely worldwide. Moreover, the association between viral persistence after AHB and hepatitis B virus (HBV) genotypes in adults remains unclear. A nationwide multicenter study was conducted throughout Japan to evaluate the influence of clinical and virological factors on chronic outcomes in patients with AHB. For comparing factors between AHB patients with viral persistence and those with self-limited infection, 212 AHB patients without human immunodeficiency virus (HIV) coinfection were observed in 38 liver centers until serum hepatitis B surface antigen (HBsAg) disappeared or a minimum of 6 months in cases where HBsAg persisted. The time to disappearance of HBsAg was significantly longer for genotype A patients than that of patients infected with non-A genotypes. When chronicity was defined as the persistence of HBsAg positivity for more than 6 or 12 months, the rate of progression to chronicity was higher in patients with genotype A, although many cases caused by genotype A were prolonged cases of AHB, rather than chronic infection. Multivariate logistic regression analysis revealed only genotype A was independently associated with viral persistence following AHB. A higher peak level of HBV DNA and a lower peak of alanine aminotransferase (ALT) levels were characteristics of AHB caused by genotype A. Treatment with nucleotide analogs (NAs) did not prevent progression to chronic infection following AHB overall. Subanalysis suggested early NA initiation may enhance the viral clearance., Conclusion: Genotype A was an independent risk factor for progression to chronic infection following AHB. Our data will be useful in elucidating the association between viral persistence after AHB, host genetic factors, and treatment with NAs in future studies., (© 2013 by the American Association for the Study of Liver Diseases.)

Background: Although pemetrexed/cisplatin (P-C) is a standard treatment for advanced non-squamous non-small cell lung cancer (Nsq-NSCLC), neither its efficacy nor the effects of potential differences between driver mutations, such as the anaplastic lymphoma kinase (ALK) translocation and epidermal growth factor receptor (EGFR) mutations, have been thoroughly examined., Patients and Methods: A single-arm phase II study of P-C was conducted in Japanese patients with chemo-naïve advanced Nsq-NSCLC. Patients received four cycles of pemetrexed (500 mg/m(2)) combined with cisplatin (75 mg/m(2)) on day 1 every three weeks. The primary end-point was the response rate (RR) and the secondary end-points were toxicity, progression-free survival (PFS), and overall survival (OS)., Results: A total of 50 patients were analyzed (males, 68%; adenocarcinoma, 80%). The RR was 44.0%. The median PFS and OS were 4.3 months and 22.2 months, respectively. Toxicities were mild, and no new toxicity profiles were identified. Among the 39 out of 50 samples, six (15.4%) presented ALK translocation and nine (23.1%) presented EGFR mutations; of the remaining patients, 24 (61.5%) were wild-type for both ALK and EGFR. Objective response was observed in two out of six patients with ALK translocations, six out of nine with EGFR mutations, and in 11 (45.8%) wild-type patients., Conclusion: The combination of pemetrexed and cisplatin was effective and safe in Japanese patients with Nsq-NSCLC. We did not observe obvious differences in the efficacy of P-C between patients with ALK translocation or EGFR mutation and those with wild-type genotype.

Background: Single-agent chemotherapy with third-generation non-platinum agents, such as docetaxel, vinorelbine, is a standard therapeutic option for elderly patients with non-small-cell lung cancer (NSCLC). Subset analysis of a previous phase III study comparing pemetrexed with docetaxel in the second-line setting showed the superiority of pemetrexed in an elderly (≥70) population in both efficacy and toxicity., Patients and Methods: This was a single-arm phase II study of pemetrexed in elderly (≥75) Japanese patients with advanced non-squamous NSCLC. Patients received four cycles of pemetrexed (500 mg/m(2)) every 3 weeks. The primary endpoint was the response rate, and secondary endpoints were safety and survival., Results: Twenty-eight patients were enrolled between January 2010 and April 2012. The median age of the patients was 77 years (range 75-88). All but one patient had adenocarcinoma histology. The median number of chemotherapy cycles administered was 4 (range, 1-12). Seventeen (60 %) patients completed four cycles of chemotherapy. Partial response was achieved in 7 patients (response rate: 25 %) and stable disease in 11 patients (disease control rate: 64 %). Median progression-free survival and overall survival were 3.3 and 17.5 months, respectively. Grade 3/4 neutropenia and thrombocytopenia were observed in 8 patients (29 %) and 2 (7 %), respectively. Non-hematologic toxicities were generally mild, and there were no treatment-related deaths., Conclusions: Although this study did not meet our primary endpoint, pemetrexed showed favorable antitumor activity with mild toxicity in elderly patients with non-squamous NSCLC. Further investigations of pemetrexed in this population are warranted (UMIN-CTR number, 000002452).

Purpose: To determine whether nucleoside analogue therapy is associated with improved survival in patients with hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) who are treated solely with transarterial chemoembolization., Materials and Methods: A retrospective chart review of patients diagnosed with HBV-associated HCC was performed to identify patients treated solely with chemoembolization. Relevant demographic and clinical data were extracted and recorded. The influence of therapy with nucleoside analogues (lamivudine, adefovir dipivoxil, or entecavir) was determined by estimating the survival function using the Kaplan-Meier product-limit method., Results: The inclusion criteria for chemoembolization were met by 81 patients (67 men and 14 women, mean age 60.6 years ± 9.2); 21 (25.9%) of these patients had been treated with nucleoside analogues. The number of chemoembolization treatments was significantly greater in the patients who were treated with nucleoside analogues (3.43 ± 2.32) than in the patients who did not receive nucleoside analogues (1.82 ± 0.95; P = .0022). The 1-year, 3-year, and 5-year survival rates were 89.5%, 66.8%, and 40.5% in the patients treated with nucleoside analogues and 72.6%, 27.5%, and 14.3% in the patients not treated with nucleoside analogues. The survival rate was significantly higher in the patients who received nucleoside analogues (P = .0051). Nucleoside analogue intake was an independent factor that was associated with increased survival (P = .0063)., Conclusions: Administration of nucleoside analogues was associated with longer survival in patients with HBV-associated HCC who were treated with transarterial chemoembolization., (Copyright © 2012 SIR. Published by Elsevier Inc. All rights reserved.)

Objective: Currently, five nucleos(t)ide analogues (NUCs) are available for the treatment of chronic hepatitis B in the world. We examined the prevalence of hepatitis B virus (HBV) DNA and alanine aminotransferase normalization in patients receiving entecavir (ETV) and the frequency of ETV-resistant mutations during an approximately 27-month use of ETV in chronic hepatitis B patients in an urban hospital in Japan., Materials and Methods: A retrospective analysis of 81 NUC-naive chronic hepatitis B patients who received 0.5 mg of ETV daily was performed. HBV DNA was measured and sequence analysis of HBV DNA was performed in virological breakthrough patients., Results: Hepatitis B e antigen (HBeAg)-positive patients with HBV DNA 5.0-7.0 log IU/mL group and all HBeAg-negative patients achieved serum HBV DNA negativity by 12 months. Four patients experienced virological breakthrough during ETV therapy. Two patients had no genotypic mutations, and medical interviews revealed that they had poor adherence to ETV., Conclusions: We found that some of the HBV virological breakthroughs during ETV treatment were related to poor adherence to medication, highlighting that clinicians should pay attention to the emergence of resistant mutants as well as adherence to ETV.

Background/aims: The recurrence rate of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) is high even in patients receiving curative therapy. In this study, we analysed the risk factors for tumour recurrence after curative therapy for HBV-related HCC while under treatment with nucleot(s)ide analogues (NAs) by measuring serum HBcrAg and intrahepatic covalently closed circular DNA (cccDNA) levels to elucidate the viral status associated with HCC recurrence., Methods: We enrolled 55 patients who developed HCC during NA therapy and underwent either curative resection or percutaneous ablation for HCC., Results: Hepatocellular carcinoma recurred in 21 (38%) of the patients over a period of 2.2 (range, 0.2-7.4) years. In multivariate analysis, serum HBcrAg levels ≥4.8 log U/ml at the time of HCC diagnosis (hazard ratio, 8.96; 95% confidential interval, 1.94-41.4) and portal vein invasion (3.94, 1.25-12.4) were independent factors for HCC recurrence. The recurrence-free survival rates of the high cccDNA group were significantly lower than those of the low cccDNA group only in patients who underwent resection (P=0.0438). A positive correlation (P=0.028; r=0.479) was observed between the intrahepatic cccDNA and the serum HBcrAg levels at the incidence of HCC., Conclusion: HBcrAg is a predictor of the post-treatment recurrence of HCC during antiviral therapy. Serum HBcrAg and intrahepatic cccDNA suppression by NAs may be important to prevent HCC recurrence., (© 2010 John Wiley & Sons A/S.)

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.

Background and Aim: Entecavir is a potent inhibitor of both wild-type and lamivudine-resistant hepatitis B virus (HBV) with proven clinical efficacy. We conducted a randomized, double-blind, multicenter study in Japan (ETV-052) evaluating the efficacy and safety of two doses of entecavir in adult patients with lamivudine-refractory chronic hepatitis B infection., Methods: Eighty-four patients with chronic hepatitis B who were refractory to lamivudine therapy were switched from lamivudine to daily oral doses of 0.5 mg entecavir (41 patients) or 1 mg entecavir (43 patients) for 52 weeks., Results: The proportions of patients achieving the primary end-point (>or=2 log(10) reduction in HBV-DNA from baseline by polymerase chain reaction assay or undetectable HBV-DNA levels [<400 copies/mL] at week 48) were 90% and 93% for entecavir 0.5 mg and 1 mg, respectively, with 33% of patients in each dosing group achieving <400 copies/mL. The mean reduction in HBV-DNA from baseline was 3.58 and 3.75 log(10) copies/mL for entecavir 0.5 mg and 1 mg, respectively. High proportions of patients achieved alanine aminotransferase normalization at week 48 (0.5 mg 86%, 1 mg 78%). Histological improvement was observed in most patients (0.5 mg 52%, 1 mg 60%). Virological breakthrough (increase in HBV-DNA of >or=1 log(10) copies/mL from nadir) was observed in one patient but was not associated with selection of entecavir-associated resistance substitutions. Entecavir was well tolerated, with no patients discontinuing study drug due to adverse events., Conclusions: These findings indicate that entecavir is safe and effective for the treatment of Japanese adults with lamivudine-refractory chronic hepatitis B.