An Updated Assessment of Chronic Hepatitis B Prevalence Among Foreign-Born Persons Living in the United States.

BACKGROUND AND AIMS: Although prevalence of chronic hepatitis B (CHB) in the USA includes 0.42 million (range, 0.28-0.67) U.S.-born persons, foreign-born (FB) persons contribute a substantially larger number to the burden of CHB in the USA. Over the past decade, patterns of U.S. immigration have changed and many countries have implemented HBV prevention programs. This study aims to estimate the number of FB persons with CHB in the USA by country of origin, updating our 2011 study. APPROACH AND RESULTS: We performed systematic searches for articles published in 2009-2019 reporting HBsAg seroprevalence in emigrants and in-country populations of 117 countries. Data meeting inclusion criteria were combined with data from our 2011 study to calculate pooled prevalence estimates for 99 countries using meta-analyses (total 2,800 surveys involving 112 million subjects). Combining country-specific CHB rate estimates with the number of FB in the USA in 2018, by country of origin from the U.S. Census Bureau, we estimate that the number of FB with CHB in the USA in 2018 was 1.47 million (95% CI, 1.21-1.73), substantially higher than previously reported. The weighted average CHB prevalence for all FB in the USA in 2018 was 3.07%. Approximately 59% of FB with CHB in the USA in 2018 emigrated from Asia, 19% from the Americas, and 15% from Africa. Subgroup analyses found that for many countries, CHB rates are higher in males than females and have declined over the past three decades, but no consistent pattern is observed between emigrant and in-country rates. CONCLUSIONS: Including FB and U.S.-born persons, the total prevalence of CHB in the USA may be as high as 2.4 million.

Reduction in liver transplant wait-listing in the era of direct-acting antiviral therapy.

Direct-acting antiviral (DAA) therapy, recently approved for patients with decompensated cirrhosis (DC) secondary to hepatitis C virus (HCV), is associated with improved hepatic function. We analyzed trends in liver transplant (LT) wait-listing (WL) to explore potential impact of effective medical therapy on WL registration. This is a cohort study using the Scientific Registry of Transplant Recipients database from 2003 to 2015. A total of 47,591 adults wait-listed for LT from HCV, hepatitis B virus (HBV), and nonalcoholic steatohepatitis (NASH) were identified. LT indication was defined as DC if the Model for End-Stage Liver Disease (MELD) at WL was ≥15 or hepatocellular carcinoma (HCC). Era of listing was divided into interferon (IFN; 2003-2010), protease inhibitor (PI; 2011-2013), and direct-acting antiviral (DAA; 2014-2015). Annual standardized incidence rates of WL were analyzed using Poisson regression. Adjusted incidences of LT WL for DC in HCV patients decreased by 5% in the PI era (P = 0.004) and 32% in the DAA era (P < 0.001) compared to the IFN era. Listing for DC in HBV also decreased in the PI (-17%; P = 0.002) and DAA eras (-24%; P < 0.001). Conversely, WL for DC in NASH increased by 41% in the PI era (P < 0.001) and 81% in the DAA era (P < 0.001). WL for HCC in both the HCV and NASH populations increased in both the PI and DAA eras (P < 0.001 for all) whereas HCC WL in HBV remained stable (P > 0.05 for all). CONCLUSION: The rate of LT WL for HCV complicated by DC has decreased by over 30% in the era of DAA therapy. Further reductions in WL are anticipated with increased testing, linkage to care, and access to DAA therapy. (Hepatology 2017;65:804-812).

Prevalence of chronic hepatitis B among foreign-born persons living in the United States by country of origin.

Estimates of the prevalence of chronic hepatitis B (CHB) in the United States differ significantly, and the contribution of foreign-born (FB) persons has not been adequately described. The aim of this study was to estimate the number of FB persons in the United States living with CHB by their country of origin. We performed a systematic review for reports of HBsAg seroprevalence rates in 102 countries (covering PubMed from 1980 to July 2010). Data from 1,373 articles meeting inclusion criteria were extracted into country-specific databases. We identified 256 seroprevalence surveys in emigrants from 52 countries (including 689,078 persons) and 1,797 surveys in the general populations of 98 countries (including 17,861,035 persons). Surveys including individuals with lower or higher risk of CHB than the general population were excluded. Data were combined using meta-analytic methods to determine country-specific pooled CHB prevalence rates. Rates were multiplied by the number of FB living in the United States in 2009 by country of birth from the U.S. Census Bureau to yield the number of FB with CHB from each country. We estimate a total of 1.32 million (95% confidence interval: 1.04-1.61) FB in the United States living with CHB in 2009; 58% migrated from Asia and 11% migrated from Africa, where hepatitis B is highly endemic. Approximately 7% migrated from Central America, a region with lower CHB rates, but many more emigrants to the United States. This analysis suggests that the number of FB persons living with CHB in the United States may be significantly greater than previously reported. Assuming 300,000-600,000 U.S.-born persons with CHB, the total prevalence of CHB in the United States may be as high as 2.2 million.

Trends in waiting list registration for liver transplantation for viral hepatitis in the United States.

BACKGROUND & AIMS: In the last decade, significant progress has been made in the treatment of liver disease associated with chronic hepatitis, especially in patients infected with the hepatitis B virus (HBV). To investigate whether the population-wide application of antiviral therapies has impacted liver transplant waiting list registration, we analyzed longitudinal trends in waiting list registration for patients with hepatitis B and C and those with nonviral liver disease. METHODS: This study represented a retrospective analysis of registry data containing all US liver transplant centers. All adult, primary liver transplantation candidates registered to the Organ Procurement and Transplantation Network between 1985 and 2006 were included in the analysis. Standardized incidence rates were calculated for waiting list registration for liver transplantation by underlying disease (HBV and HCV infection and other) and by indication for transplantation (fulminant liver disease, hepatocellular carcinoma [HCC], and end-stage liver disease [ESLD]). RESULTS: Of 113,927 unique waiting list registrants, 4793 (4.2%) had HBV, and 40,923 (35.9%) had HCV infections; the remaining 68,211 (59.9%) had neither. The incidence of waiting list registration for ESLD and fulminant liver disease decreased, whereas that for HCC increased. The decrease in ESLD registration was most pronounced, and the increase in HCC was least dramatic among registrants with hepatitis B. The decrease in registration for ESLD secondary to HCV infection was also significantly larger than that for ESLD patients with nonviral etiologies. CONCLUSIONS: The pattern of liver transplantation waiting list registration among patients with hepatitis B suggests that the widespread application of oral antiviral therapy for HBV contributed to the decreased incidence of decompensated liver disease.

Long-term therapy with adefovir dipivoxil for HBeAg-negative chronic hepatitis B.

BACKGROUND: Treatment with adefovir dipivoxil for 48 weeks resulted in histologic, virologic, and biochemical improvement in patients with hepatitis B e antigen (HBeAg)-negative chronic hepatitis B. We evaluated the effect of continued therapy as compared with cessation of therapy. METHODS: One hundred eighty-five HBeAg-negative patients with chronic hepatitis B were assigned to receive 10 mg of adefovir dipivoxil or placebo once daily for 48 weeks (ratio, 2:1). After week 48, patients receiving adefovir dipivoxil were again randomly assigned either to receive an additional 48 weeks of the drug or to switch to placebo. Patients originally assigned to placebo were switched to adefovir dipivoxil. Patients treated with adefovir dipivoxil during weeks 49 through 96 were subsequently offered continued therapy. The primary end points were changes in hepatitis B virus (HBV) DNA and alanine aminotransferase levels. RESULTS: Treatment with adefovir dipivoxil resulted in a median decrease in serum HBV DNA of 3.47 log copies per milliliter (on a base-10 scale) at 96 weeks and 3.63 log copies per milliliter at 144 weeks. HBV DNA levels were less than 1000 copies per milliliter in 71 percent of patients at week 96 and 79 percent at week 144. In the majority of patients who were switched from adefovir dipivoxil to placebo, the benefit of treatment was lost (median change in HBV DNA levels from baseline, -1.09 log copies per milliliter; only 8 percent of patients had levels below 1000 copies per milliliter at week 96). Side effects during weeks 49 through 144 were similar to those during the initial 48 weeks. Resistance mutations rtN236T and rtA181V were identified in 5.9 percent of patients after 144 weeks. CONCLUSIONS: In patients with HBeAg-negative chronic hepatitis B, the benefits achieved from 48 weeks of adefovir dipivoxil were lost when treatment was discontinued. In patients treated for 144 weeks, benefits were maintained, with infrequent emergence of viral resistance.

Adefovir dipivoxil for the treatment of hepatitis B e antigen-positive chronic hepatitis B.

BACKGROUND: In preclinical and phase 2 studies, adefovir dipivoxil demonstrated potent activity against hepatitis B virus (HBV), including lamivudine-resistant strains. METHODS: We randomly assigned 515 patients with chronic hepatitis B who were positive for hepatitis B e antigen (HBeAg) to receive 10 mg of adefovir dipivoxil (172 patients), 30 mg of adefovir dipivoxil (173), or placebo (170) daily for 48 weeks. The primary end point was histologic improvement in the 10-mg group as compared with the placebo group. RESULTS: After 48 weeks of treatment, significantly more patients who received 10 mg or 30 mg of adefovir dipivoxil per day than who received placebo had histologic improvement (53 percent [P<0.001], 59 percent [P<0.001], and 25 percent, respectively), a reduction in serum HBV DNA levels (by a median of 3.52 [P<0.001], 4.76 [P<0.001], and 0.55 log copies per milliliter, respectively), undetectable levels (fewer than 400 copies per milliliter) of serum HBV DNA (21 percent [P<0.001], 39 percent [P<0.001], and 0 percent, respectively), normalization of alanine aminotransferase levels (48 percent [P<0.001], 55 percent [P<0.001], and 16 percent, respectively), and HBeAg seroconversion (12 percent [P=0.049], 14 percent [P=0.01], and 6 percent, respectively). No adefovir-associated resistance mutations were identified in the HBV DNA polymerase gene. The safety profile of the 10-mg dose of adefovir dipivoxil was similar to that of placebo; however, there was a higher frequency of adverse events and renal laboratory abnormalities in the group given 30 mg of adefovir dipivoxil per day. CONCLUSIONS: In patients with HBeAg-positive chronic hepatitis B, 48 weeks of 10 mg or 30 mg of adefovir dipivoxil per day resulted in histologic liver improvement, reduced serum HBV DNA and alanine aminotransferase levels, and increased the rates of HBeAg seroconversion. The 10-mg dose has a favorable risk-benefit profile for long-term treatment. No adefovir-associated resistance mutations were identified in the HBV DNA polymerase gene.

Adefovir dipivoxil for the treatment of hepatitis B e antigen-negative chronic hepatitis B.

BACKGROUND: Adefovir dipivoxil, a nucleotide analogue, demonstrated clinically significant antiviral activity in patients with chronic hepatitis B in phase 1 and 2 clinical trials. METHODS: We randomly assigned 185 patients with chronic hepatitis B who were negative for hepatitis B e antigen (HBeAg) to receive either 10 mg of adefovir dipivoxil or placebo once daily for 48 weeks in a 2:1 ratio and a double-blind manner. The primary end point was histologic improvement. RESULTS: At week 48, 64 percent of patients who had base-line liver-biopsy specimens available in the adefovir dipivoxil group had improvement in histologic liver abnormalities (77 of 121), as compared with 33 percent of patients in the placebo group (19 of 57, P<0.001). Serum hepatitis B virus (HBV) DNA levels were reduced to fewer than 400 copies per milliliter in 51 percent of patients in the adefovir dipivoxil group (63 of 123) and in 0 percent of those in the placebo group (0 of 61, P<0.001). The median decrease in log-transformed HBV DNA levels was greater with adefovir dipivoxil treatment than with placebo (3.91 vs. 1.35 log copies per milliliter, P<0.001). Alanine aminotransferase levels had normalized at week 48 in 72 percent of patients receiving adefovir dipivoxil (84 of 116), as compared with 29 percent of those receiving placebo (17 of 59, P<0.001). No HBV polymerase mutations associated with resistance to adefovir were identified. The safety profile of adefovir dipivoxil was similar to that of placebo. CONCLUSIONS: In patients with HBeAg-negative chronic hepatitis B, 48 weeks of adefovir dipivoxil treatment resulted in significant histologic, virologic, and biochemical improvement, with an adverse-event profile similar to that of placebo. There was no evidence of the emergence of adefovir-resistant HBV polymerase mutations.

Advancing the regulatory path on hepatitis B virus treatment and curative research: a stakeholders consultation.

Hepatitis B infection remains a significant disease burden around the world, with an estimated two billion individuals infected and 350 million living with chronic hepatitis B. Current antivirals are efficacious, but require lifelong treatment for the majority of infected individuals. The field is galvanised to improve diagnostics and treatment with the goal to develop shorter, finite treatments leading to viral control after treatment discontinuation. Achievement of complete and functional cure is challenged by the complexity of the virus life cycle, the lack of adequate preclinical models, the cccDNA-mediated persistence of HBV in liver cells, the lack of validated biomarkers to predict viral control and cure, and the probable need for combination treatment involving antiviral- and immune-based strategies. Experts from diverse stakeholder groups participating in the HBV Forum (a project of the Forum for Collaborative Research) contributed their expertise and perspective to resolving issues and overcoming barriers in the regulatory path for novel HBV therapeutic strategies; addressing gaps in preclinical models, diagnostics, clinical trial design, biomarkers and endpoints, and public health efforts. Interviewees highlighted the need for open and collaborative ongoing dialogues among stakeholders in a neutral space as a critical process to move the field forwards. The Forum model facilitates dialogue and deliberation of this nature, with dedicated experts from all stakeholder groups participating. The promise of an HBV cure is exciting. Now is the time to work together toward that goal.

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

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

HIV-1 genotype and phenotype correlate with virological response to abacavir, amprenavir and efavirenz in treatment-experienced patients.

OBJECTIVE: To assess the safety and efficacy of three new drugs in patients with antiretroviral failure and to correlate retrospectively baseline factors with virological response. DESIGN AND SETTING: Open-label, 48-week, single-arm, multi-center phase II trial conducted at nine US university or government clinics and private practices. PATIENTS AND INTERVENTIONS: Patients with HIV-1 RNA > or =500 copies/ml despite > or =20 weeks of treatment with at least one protease inhibitor received abacavir 300 mg twice a day, amprenavir 1200 mg twice a day and efavirenz 600 mg once a day. Other antiretrovirals were prohibited until week 16 except for substitutions for possible abacavir hypersensitivity. MAIN OUTCOME MEASURES: HIV RNA at weeks 16 and 48. RESULTS: A total of 101 highly treatment-experienced patients enrolled; 60 were naive to non-nucleoside analog reverse transcriptase inhibitors (NNRTI). HIV RNA < 400 copies/ml was attained in 25 out of 101 (25%) patients at 16 weeks (35% of NNRTI-naive and 10% of -experienced patients) and 23 (23%) patients at 48 weeks (33% of naive and 7% of experienced patients). CD4 cells increased by a median of 15 x 10(6) and 43 x 10(6) cells/l at weeks 16 and 48, respectively. Drug-related rash occurred in 50 out of 99 (51%) of patients, and 17 out of 99 (17%) permanently discontinued one or more drugs as a result. Lower baseline viral load, fewer NNRTI-related mutations, absence of decreased abacavir (> or =4-fold) and efavirenz (> or =10-fold) susceptibility, and greater number of drugs to which virus was susceptible were associated with virological response at week 16. CONCLUSIONS: Abacavir, amprenavir and efavirenz durably reduced HIV RNA and increased CD4 cell counts in a subset of treatment-experienced adults. Baseline viral load and some genotypic and phenotypic markers of resistance correlated with HIV RNA response.

Extended treatment with lamivudine and adefovir dipivoxil in chronic hepatitis B patients with lamivudine resistance.

PURPOSE: We and others have reported that adding adefovir dipivoxil (adefovir) to lamivudine results in virological and biochemical improvement in cases of lamivudine resistance. The current study assessed the efficacy and safety of combined therapy after 104 weeks of combined treatment and analyzed the frequency of persistent lamivudine resistant HBV. METHODS: A total of 78 patients with compensated CHB (Group A) were maintained on either adefovir 10 mg daily (n = 38) or placebo (n = 40) while continuing lamivudine. An additional 38 patients with decompensated cirrhosis or post liver transplantation (Group B) received lamivudine plus adefovir. The primary endpoint was HBV DNA response at year 2. RESULTS: At week 104 of therapy, a significantly greater proportion of patients in Group A on combination therapy (76%) had a decline in serum HBV DNA to ≤10(5) copies or >2 log(10) reduction from baseline compared to those receiving lamivudine alone (13%; p < 0.001). Fifty-two percent of Group A patients on combination treatment continued to have the M204V/I HBV mutation compared to 92% receiving lamivudine alone (p = 0.0013). Virologic response occurred less frequently in patients expressing persistent lamivudine resistant HBV. In Group B, 87% of patients had HBV DNA response at week 104 (median change from baseline of -5.84 log(10) copies/mL). CONCLUSIONS: The combination of lamivudine and adefovir for 2 years generally proved effective in lamivudine-resistant cases, but there was a persistently high rate of detection of lamivudine resistant mutants and impaired virologic response in compensated patients.

Hepatitis B virus e antigen loss during adefovir dipivoxil therapy is associated with enhanced virus-specific CD4+ T-cell reactivity.

Weak T-cell reactivity to hepatitis B virus (HBV) is thought to be the dominant cause for chronic HBV infection. Treatment with adefovir dipivoxil (ADV) increases the rate of HBV e antigen (HBeAg) loss; however, the immune mechanisms associated with this treatment response are not understood. Serial analysis of HBV-specific CD4+ T-cell reactivity was performed during 48 weeks of therapy with ADV and correlated with treatment outcome for 19 HBeAg-positive patients receiving ADV (n = 13) or the placebo (n = 6). We tested T-cell reactivity to HBV at seven protocol time points by proliferation, cytokine production, and enzyme-linked immunospot assays. A panel of serum cytokines was quantitated by cytokine bead array. ADV-treated patients showed increased CD4+ T-cell responses to HBV and lower serum levels of cytokines compared to those of placebo-treated patients. Enhanced CD4+ T-cell reactivity to HBV, which peaked at treatment week 16, was confined to a subgroup of ADV-treated patients who achieved greater viral suppression (5.3 +/- 0.3 log(10) copies/ml [mean +/- standard error of the mean {SEM}] serum HBV DNA reduction from baseline) and HBeAg loss, but not to ADV-treated patients with moderate (3.4 +/- 0.2 log(10) copies/ml [mean +/- SEM]) viremia reduction who remained HBeAg positive or to patients receiving the placebo. In conclusion, T-cell reactivity to HBV increases in a proportion of ADV-treated patients and is associated with greater suppression of HBV replication and HBeAg loss.

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

BACKGROUND/AIMS: We aimed to evaluate nucleoside/nucleotide combination therapy in treatment-naïve HBeAg-positive patients with chronic hepatitis B (CHB). METHODS: One hundred and fifteen HBeAg-positive patients received lamivudine 100 mg daily plus placebo (monotherapy) or lamivudine 100 mg plus adefovir dipoxil 10 mg daily (combination therapy) for 104 weeks in a randomized double-blind study. RESULTS: Time-weighted average change in serum HBV DNA from baseline up to week 16 was -4.20 log(10)copies/mL for both groups (p=0.936). At week 104, median serum HBV DNA change from baseline (log(10)copies/mL) for monotherapy and combination therapy was -3.41 versus -5.22, respectively. HBV DNA breakthrough was detected in 44% of monotherapy and 19% of combination therapy patients. The M204V/I mutation was detected in 43% (15/35) and 15% (6/41) of each group, respectively. ALT normalization at week 100 and 104 was 34% (19/56) in the monotherapy group and 45% (23/51) in the combination therapy group (p=0.018). By week 104, HBeAg seroconversion occurred in 20% of monotherapy and 13% of combination therapy patients. Both regimens were well tolerated. CONCLUSIONS: Lower rates of resistance to lamivudine, lower serum HBV DNA levels and higher rates of ALT normalization were seen in the combination therapy group after two years. However, serological outcomes were similar.

Long-term therapy with adefovir dipivoxil for HBeAg-negative chronic hepatitis B for up to 5 years.

BACKGROUND & AIMS: Treatment with adefovir dipivoxil for 48 weeks resulted in clinical improvement in patients with hepatitis B e antigen (HBeAg)-negative chronic hepatitis B that was lost when treatment was discontinued. We investigated the efficacy, safety, and resistance profile of adefovir dipivoxil treatment for up to 240 weeks. METHODS: HBeAg-negative patients were treated double blind with placebo or adefovir dipivoxil 10 mg once daily for 48 weeks, followed by adefovir dipivoxil from week 49 to 96. At week 97, 125 patients enrolled in a 144-week, open-label phase. Patients received adefovir dipivoxil for up to 192 or 240 weeks. RESULTS: Serum hepatitis B virus (HBV) DNA levels were less than 1000 copies per milliliter in 67% of patients, and alanine aminotransferase (ALT) levels normalized in 69% after 240 weeks. After 192 or 240 weeks of treatment, over 83% of patients had improvement in necroinflammation, and over 73% had improvement in fibrosis. Ishak fibrosis scores improved compared with baseline in 35%, 55%, and 71% of patients after 48, 192, and 240 weeks of adefovir dipivoxil, respectively. After 240 weeks, the cumulative probability of HBV polymerase mutations was 29%, but the cumulative probability of mutations with virologic resistance was 20% and of mutations, virologic resistance, and ALT elevations was 11%. Slight elevations in creatinine were confirmed in 4 (3%) patients. CONCLUSIONS: Treatment with adefovir dipivoxil for up to 240 weeks was well tolerated and produced significant, increasing improvement in hepatic fibrosis, durable suppression of HBV replication, normalization of liver enzymes, and delayed development of resistance.

Randomized controlled study of tenofovir and adefovir in chronic hepatitis B virus and HIV infection: ACTG A5127.

Chronic hepatitis B virus (HBV) infection is an important cause of morbidity and mortality in subjects coinfected with HIV. Tenofovir disoproxil fumarate (TDF) and adefovir dipivoxil (ADV) are licensed for the treatment of HIV-1 and HBV infection, respectively, but both have in vivo and in vitro activity against HBV. This study evaluated the anti-HBV activity of TDF compared to ADV in HIV/HBV-coinfected subjects. ACTG A5127 was a prospective randomized, double-blind, placebo-controlled trial of daily 10 mg of ADV versus 300 mg of TDF in subjects with HBV and HIV coinfection on stable ART, with serum HBV DNA >/= 100,000 copies/mL, and plasma HIV-1 RNA

Week 48 resistance surveillance in two phase 3 clinical studies of adefovir dipivoxil for chronic hepatitis B.

Seven hundred nucleoside treatment-naive patients were enrolled in two phase 3 trials of adefovir dipivoxil (ADV) for the treatment of chronic hepatitis B. To monitor for the emergence of potential adefovir resistance mutations over the first 48 weeks, all intent-to-treat patients (467 ADV-treated and 228 placebo patients) were included in a prospectively defined, treatment-blinded, virology substudy. The study protocol mandated genotypic analysis for all patients with detectable hepatitis B virus (HBV) DNA by Roche Amplicor polymerase chain reaction (PCR) at baseline and week 48, and in vitro phenotypic analyses for patients with conserved site substitutions in HBV polymerase or 1.0 log(10) or greater increase in HBV DNA from nadir. Paired sequences of the entire HBV reverse transcriptase were obtained for 271 ADV-treated and 227 placebo patients by using a sequencing method that detects down to 30% of minor species present within mixtures. Four substitutions (rtS119A, rtH133L, rtV214A, and rtH234Q) developed once each at conserved sites in HBV polymerase in 4 ADV-treated patients. Seven conserved site substitutions developed in 6 placebo patients. HBV mutants encoding the 4 substitutions that emerged in ADV-treated patients remained fully susceptible to adefovir in vitro. Furthermore, these 4 ADV-treated patients had HBV-DNA reductions of 3.3 to 5.9 log(10) copies/mL by week 48 with no rebound. All other substitutions occurred at very low frequencies (<1.6%) at polymorphic sites and were not associated with HBV-DNA increases in patients or adefovir resistance in vitro. In conclusion, no adefovir resistance mutations were identified in a large group of chronic hepatitis B patients treated with ADV for 48 weeks.

Renal safety of adefovir dipivoxil in patients with chronic hepatitis B: two double-blind, randomized, placebo-controlled studies.

BACKGROUND: The incidence of adefovir dipivoxil (ADV) nephrotoxicity has been previously reported with the 60 and 120 mg daily dose in human immunodeficiency virus (HIV). We report a complete analysis on the renal tolerance of ADV at the currently approved dose of 10 mg daily for the treatment of chronic hepatitis B. METHODS: To investigate the efficacy, safety, and the tolerability of two dosing regimens of ADV (10 mg daily or 30 mg daily), two double-blind, placebo-controlled studies were performed in patients with chronic hepatitis B and compensated liver disease who were not undergoing current treatment and who had evidence of hepatitis B virus (HBV) replication. RESULTS: There was no overall median change from baseline at week 48 in serum creatinine or serum phosphorus levels in the ADV 10 mg group. In the ADV 30 mg group there was a slight increase of 0.2 mg/dL in median serum creatinine levels, and decrease of 0.1 mg/dL in serum phosphorus levels at week 48. Serum creatinine increase and hypophosphatemia were more frequently observed in patients receiving ADV 30 mg daily compared with ADV 10 mg and placebo. There were no grade 4 proteinuria, hematuria, or glycosuria events. CONCLUSION: Mild nephrotoxicity was demonstrated with the dose of 30 mg daily. Nephrotoxicity, as defined by an increase >/=0.5 mg/dL from baseline in serum creatinine or a serum phosphorus value of <1.5 mg/dL on two consecutive occasions, was not observed in patients treated with ADV 10 mg for a median follow-up period of approximately 64 weeks.

Selection of a hepatitis B virus strain resistant to adefovir in a liver transplantation patient.

BACKGROUND/AIMS: In contrast to lamivudine, adefovir dipivoxil (ADV) therapy is associated with delayed and infrequent selection of drug resistant hepatitis B virus (HBV). METHODS: A 52 year-old man was treated with lamivudine for an HBV recurrence on his liver graft. A viral breakthrough was observed and the patient received ADV. Serum HBV DNA decreased rapidly and lamivudine was discontinued while ADV monotherapy was maintained. Serum HBV DNA levels remained suppressed until a second breakthrough was observed. Lamivudine was then reintroduced together with ADV, and serum HBV DNA became undetectable by polymerase chain reaction. RESULTS: Sequence analyses of the HBV polymerase gene revealed a sequential selection of lamivudine resistance mutations L180M+M204V, followed by a reversion to wild-type, and subsequently the selection of a novel adefovir resistance mutation N236T. Phenotypic analyses in cell culture assays demonstrated that the HBV isolates at the time of ADV breakthrough had reduced susceptibility to ADV. This mutant remained sensitive to lamivudine, entecavir and emtricitabine in vitro. CONCLUSIONS: We describe the first case of sequential selection of lamivudine and adefovir resistant strains of HBV in a liver transplantation patient. The selection of the N236T polymerase mutant was associated with resistance to ADV but remained sensitive to lamivudine in vitro and in vivo.