A dose ranging study of the pharmacokinetics, safety, and preliminary efficacy of lamivudine in children and adolescents with chronic hepatitis B

Fifty-three patients with chronic hepatitis B and active viral replication were studied for 4 weeks while on treatment and for 12 weeks after treatment with the oral nucleoside analogue lamivudine. Children aged 2 to 12 years were randomized to receive twice-daily doses of 0.35, 1.5, or 4 mg of lamivudine solution per kg of body weight or once-daily doses of 3 mg of lamivudine solution per kg. Adolescents aged 13 to 17 years received lamivudine at 100 mg (as tablets). Blood samples for pharmacokinetic assay were taken on days 1 and 28. Lamivudine was rapidly absorbed following oral administration, with the maximum concentration in serum being reached 0.5 to 1 h postdosing. Apparent oral clearance (CL/F) was higher in younger children and decreased with age, with CL/F values for adolescents reaching those seen for adults by the age of 12. All doses produced a dramatic fall in serum hepatitis B virus (HBV) DNA levels, with a median reduction of >/=99.5% after 4 weeks of treatment and with the levels returning to the baseline levels posttreatment. The correlation of dose, area under the concentration-time curve (AUC), and changes in HBV DNA levels, as measured by the Chiron Quantiplex assay, showed maximal antiviral effects (99.9% inhibition and a reduction of the amount of HBV DNA of approximately 3 log(10)) at 3 mg/kg/day, with no discernible increase in effect seen whether the drug was given at 4 mg/kg twice daily or whether it was given once daily or twice daily. The limit of detection of the assay (2.5 pg/ml) was reached for some but not all patients across the dose ranges, with the smallest number (n = 2) of those having values negative by the Chiron Quantiplex assay being in the lowest-dose group. The 13- to 17-year-olds showed a similar overall response in terms of the HBV DNA level reduction compared to that for patients younger than age 13. Analysis of the same samples by PCR, which has a lower limit of sensitivity than the Chiron Quantiplex assay, also showed average drops in HBV DNA levels of about 3 log(10) at 4 weeks for patients for which the AUC was >/=4,000 ng. h/ml, confirming the conclusions given above. Lamivudine treatment was well tolerated at all doses, with no significant adverse events or laboratory data changes. On the basis of pharmacokinetic and pharmacodynamic data, a 3-mg/kg/day dose in children (ages 2 to 12 years) with chronic hepatitis B provides levels of exposure and trough concentrations similar to those seen in adults following the receipt of doses of 100 mg. The 100-mg dose is being evaluated in a large phase III study with HBV-infected pediatric patients.     

Correction of argininosuccinate synthetase (AS) deficiency in a murine model of citrullinemia with recombinant adenovirus carrying human AS cDNA

Citrullinemia is an autosomal recessive disorder caused by the deficiency of argininosuccinate synthetase (AS). It is characterized by elevated levels of blood citrulline and ammonia, which often results in hyperammonemic coma and early neonatal death in affected children. We have explored the use of adenoviral vectors as a treatment modality in a murine model of citrullinemia, the Ass mouse. The Ass mouse has no endogenous AS activity due to a targeted interruption of the AS gene. Homozygous mutant animals develop high levels of blood citrulline, become hyperammonemic, and die within 24-48 h after birth. We demonstrated that the neonatal crisis in Ass mice can be ameliorated by the injection of a recombinant adenovirus carrying human AS cDNA (Ad.CMVhAS) within hours after birth. The average life span of the virus-treated animals was extended from 30 +/- 9.5 h to 16.1 +/- 1.6 days. A second viral infusion 14 days after the first dose further prolonged the life span to an average of 36.2 +/- 7.0 days, and to 40.7 +/- 3.3 days with a concurrent daily injection of arginine and sodium benzoate. Significantly increased liver AS activity (47.3 +/- 7.9% of normal) was detected 24 h after viral infusion, which reached peak levels (80-90% of normal) at day 7 and decreased to about 20% of normal within 2-3 weeks after viral infusion. Southern blot analysis of liver DNA revealed a transduction efficiency of about one viral genome per hepatocyte 7 days after viral infusion and a gradual decrease of viral genome per cell parallel to the loss of liver AS activity. Plasma glutamine levels were partially normalized in virus-treated animals and were completely normalized in animals receiving Ad.CMVhAS concurrently with alternative pathway therapy. Plasma arginine levels were also partially normalized. Together, these results demonstrated that the recombinant adenovirus was capable of conferring AS activity in the liver of the recipient animals within 24 h, and the neonatal crisis of hyperammonemia could be averted by acute treatment with the AS containing adenovirus.     

Mutations and deletions in core promoter and precore stop codon in relation to viral replication and liver damage in Singaporean hepatitis B virus carriers

BACKGROUND: The core promoter of hepatitis B virus (HBV) is crucial for the viral replication and mutations may lead to the establishment of chronic infection and development of liver diseases. We analysed this region in Singaporean HBV carriers and assessed their association with viral replication and liver damage. MATERIALS AND METHODS: Thirty-three Singaporean HBV carriers were selected. Serological markers for HBV infection and indicators for liver functions were analysed using commercial kits. Among these patients, 17 were chronic carriers, 10 had cirrhotic livers and 6 others had hepatocellular carcinoma (HCC). The region on the HBV genome covering the entire core promoter and core gene was amplified for each patient by polymerase chain reaction. The amplified DNA fragments were sequenced and analysed. RESULTS: The incidence of mutations in the core promoter or the precore gene product (stop codon at amino acid 28) was not significantly higher compared with the wild type sequences in patients with liver damage. Most mutations in either the core promoter or precore gene significantly reduced the viral replication, as indicated by HBV DNA levels. High levels of HBV DNA were found in three mutants with deletion in the same region, presumably the binding site of liver enriched factor, within the core promoter. CONCLUSION: Our findings revealed a different mutation pattern in the core promoter in Singaporean HBV carriers. While most mutations may not be directly associated with the development of liver diseases, deletions in the core promoter could contribute to enhanced viral replication and should be studied further.     

One-year entecavir or lamivudine therapy results in reduction of hepatitis B virus intrahepatic covalently closed circular DNA levels

Entecavir and lamivudine are potent nucleoside analogues that can suppress hepatitis B virus (HBV) replication. However, the effects of these two antiviral agents on intrahepatic total HBV DNA and covalently closed circular DNA (cccDNA) are not known. In this study, we aimed to assess the effect of 48 weeks of entecavir/lamivudine therapy on intrahepatic total HBV DNA and cccDNA levels. Forty chronic hepatitis B patients, participating in two Phase III entecavir trials at our centre, were randomized to receive 48 weeks of either 0.5 mg once daily of entecavir (n = 21) or 100 mg once daily of lamivudine (n = 19). Their serological, virological and biochemical responses, as well as intrahepatic HBV DNA levels were monitored. There was no significant difference between entecavir and lamivudine therapy in terms of post-treatment serological, virological and biochemical responses. Both nucleoside analogues reduced serum viral load, intrahepatic total HBV DNA, and cccDNA by about 4.8 logs, 2 logs, and 1 log respectively. An increase in the proportion of intrahepatic HBV DNA in the form of cccDNA was seen after 48 weeks of therapy. In conclusion, both entecavir and lamivudine can successfully reduce intrahepatic HBV DNA and cccDNA. CccDNA becomes the dominant form of HBV DNA during viral suppression and is possibly responsible for viral rebound after short-term antiviral therapy.     

Viral interaction and responses in chronic hepatitis C and B coinfected patients with interferon-alpha plus ribavirin combination therapy

BACKGROUND/AIMS: We conducted a case-control study to investigate the efficacy of interferon-alpha (IFN-alpha) and ribavirin combination therapy for patients with chronic hepatitis C and B virus (HCV/HBV) coinfection and to elucidate the interaction of these two viruses. METHODS: Forty-two chronic HCV/HBV-coinfected patients (29 IFN-naive, 13 IFN-relapsed) and 84 HCV-monoinfected controls, matched for age, sex and previous history of IFN-alpha therapy, were enrolled. All patients were treated with IFN-alpha-2b 6 MU three-times weekly plus ribavirin 1000-1200 mg daily for 24 weeks. Serum HCV RNA and HBV DNA were determined every 24 weeks for 72 weeks. RESULTS: The rate of HCV sustained virological response (SVR) was comparable among IFN-naive and IFN-relapsed HCV/HBV-coinfected patients and IFN-naive and IFN-relapsed HCV-monoinfected patients (69.0%, 69.2%, 67.2% and 57.7%, respectively; intention-to-treat analysis). HCV genotype 1b, high pretreatment HCV RNA levels and liver fibrosis were significantly associated with a lower HCV SVR. Of 16 baseline HBV viraemic patients, five (31.3%) achieved HBV SVR, which correlated negatively to HCV genotype non-1b and HCV SVR. Only one (6.3%) had simultaneous seroclearance of HCV and HBV. Antibodies to HBV surface antigen seroconversion developed in five (11.9%) patients during long-term follow-up. HCV responders had significantly higher rates of HBV DNA resurgence than HCV non-responders during and after treatment. Reciprocal viral interference was noted between HCV and HBV after IFN-alpha/ribavirin therapy. CONCLUSIONS: IFN-alpha/ribavirin combination therapy is effective for HCV/HBV-coinfected patients in eradicating HCV infection and might promote HBV seroclearance, and there is a mutual viral response and reciprocal viral interaction between HBV and HCV.     

Effect of Hydrogen‐Rich Water on Oxidative Stress,Liver Function,and Viral Load in Patients with Chronic Hepatitis B

Objective

To investigate effects of hydrogen‐rich water (HRW) on oxidative stress, liver function and HBV DNA in patients with chronic hepatitis B (CHB).

Methods

Sixty patients with CHB were randomly assigned into routine treatment group or hydrogen treatment group in which patients received routine treatment alone or additional oral HRW (1200–1800 mL/day, twice daily), respectively, for 6 consecutive weeks. Serum oxidative stress, liver function, and HBV DNA level were detected before and after treatment. Thirty healthy subjects served as controls.

Results

When compared with controls, oxidative stress was obvious in CHB patients, and the liver function also significantly impaired. After treatment, the oxidative stress remained unchanged in routine treatment group, but markedly improved in hydrogen treatment group. The liver function was improved significantly and the HBV DNA reduced markedly after corresponding treatments. Although a significant difference was noted in the oxidative stress between two groups after treatment, the liver function and HBV DNA level were comparable after treatment and both had improved tendencies.

Conclusion

HRW significantly attenuates oxidative stress in CHB patients, but further study with long‐term treatment is required to confirm the effect of HRW on liver function and HBV DNA level. Clin Trans Sci 2013; Volume #: 1–4     

慢性乙型肝炎患者病毒基因组与乙型肝炎病毒e抗原、肝功能关系分析

目的探讨乙型肝炎病毒基因组(HBV-DNA)、乙型肝炎病毒e抗原(HBeAg)、肝功能的相关关系,为临床治疗提供参考。方法回顾分析401例患者的HBV-DNA、HBeAg、丙氨酸氨基转移酶(ALT)、天冬氨酸氨基转移酶(AST)水平,对HBVDNA与HBeAg进行相关性分析。根据患者的HBV-DNA、HBeAg水平进行分组,比较各组的ALT、AST水平差异。结果 (1)HBV-DNA与HBeAg的阳性率存在相关性,相关系数r=0.671(P0.01);(2)HBV-DNA载量达105 copies/mL时,血清ALT、AST较HBV-DNA阴性组及低载量组显著升高,差异有统计学意义(P0.05);(3)在HBV-DNA载量相当时,HBeAg阳性组与阴性组ALT、AST活性差异无统计学意义(P0.05)。结论 (1)HBeAg与HBV-DNA具有相关性;(2)HBV-DNA载量较高的患者容易出现肝功能异常;(3)HBeAg的存在情况与肝功能无显著相关性。     

Tenofovir therapy for lamivudine resistance following liver transplantation

BACKGROUND: Resistant hepatitis B virus (HBV) strains develop in 30% of liver transplant recipients treated with lamivudine within 2 years from the time of transplantation. OBJECTIVE: To assess safety and outcomes of tenofovir salvage therapy for patients with lamivudine resistance in a retrospective cohort of liver-transplanted patients. METHODS: Medical records were retrospectively evaluated for patients who received tenofovir. Data collected included demographics, HBV serologic information prior to and during tenofovir therapy, drug-related complications, and creatinine clearance. Criteria for lamivudine resistance included elevation of liver chemistries along with reappearance of hepatitis B surface antigen, hepatitis Be antigen, and/or HBV DNA. RESULTS: Sixteen patients showed resistance to lamivudine at 10-85 months (median 26) following liver transplantation. Tenofovir 300 mg/day orally was added in 8 patients 1-66 months after the development of viral lamivudine resistance and continued for 14-26 months (median 19.3). All 8 patients experienced HBV DNA viral suppression, with 7 currently nondetectable. No adverse events were reported, and creatinine clearance was not impaired. CONCLUSIONS: Our results suggest that tenofovir safely and markedly decreases replication of lamivudine-resistant HBV variants after liver transplantation and is another potential option for the treatment of HBV lamivudine resistance.     

In situ analysis of intrahepatic virological events in chronic hepatitis B virus infection

Persistent hepatitis B virus (HBV) infection is established by the formation of an intranuclear pool of covalently closed circular DNA (cccDNA) in the liver. Very little is known about the intrahepatic distribution of HBV cccDNA in infected patients, particularly at the single-cell level. Here, we established a highly sensitive and specific ISH assay for the detection of HBV RNA, DNA, and cccDNA. The specificity of our cccDNA probe set was confirmed by its strict intranuclear signal and by a series of Southern blot analyses. Use of our in situ assay in conjunction with IHC or immunofluorescence uncovered a surprisingly mosaic distribution of viral antigens and nucleic acids. Most strikingly, a mutually exclusive pattern was found between HBV surface antigen–positive (HBsA-positive) and HBV DNA– and cccDNA-positive cells. A longitudinal observation of patients over a 1-year period of adeforvir therapy confirmed the persistence of a nuclear reservoir of viral DNA, although cytoplasmic DNA was effectively depleted in these individuals. In conclusion, our method for detecting viral nucleic acids, including cccDNA, with single-cell resolution provides a means for monitoring intrahepatic virological events in chronic HBV infection. More important, our observations unravel the complexity of the HBV life cycle in vivo.     

DNA vaccines.

Chronic infections with hepatitis B (HBV) and hepatitis C (HCV) virus are worldwide problems often leading to the development of chronic liver disease and hepatocellular carcinoma. Genetic immunizations with DNA encoding for structural and nonstructural proteins of HCV and HBV in experimental mice generate a broad base CD4+ and CD8+ cellular immune response which may be required for viral clearance from the host. DNA based immunization is a promising antiviral approach for the development of therapeutic and prophylactic vaccine against HBV and HCV.     

Lengths of hepatitis B viremia and antigenemia in blood donors: preliminary evidence of occult (hepatitis B surface antigen-negative) infection in the acute stage

BACKGROUND: The Japanese Red Cross (JRC) implemented a fully automated pooling and nucleic acid amplification test (NAT) system for testing seronegative donations. The JRC sample repository and repeat blood donations allowed for lookback and follow-up studies of hepatitis B virus (HBV) DNA-positive donors, who tested negative for hepatitis B surface antigen (HBsAg) and anti-hepatitis B core antigen in the JRC screening system. STUDY DESIGN AND METHODS: From February 1, 2000, to March 31, 2003, 17,314,486 units were tested in 50-sample pools with a semiautomated multiplex assay system (AMPLINAT MPX test, Roche). During this period, 328 HBV DNA-positive donations were found. From 26 of these donors, sequential samples were available at short intervals. This enabled us to examine the dynamics of viral markers in acute HBV infection. The length of detectable periods of plasma viremia and antigenemia were estimated by regression analysis from the results obtained in the quantitative polymerase chain reaction assay (JRC) and HBsAg enzyme immunoassay (Auszyme II, AxSYM, Abbott) and chemiluminescence immunoassay (Abbott). RESULTS: The median length of detectable HBV DNA in individual donation and 20-sample minipool (MP) NAT format was estimated to be 74 and 50 days, respectively, whereas the median length of detectable HBsAg was estimated to be 42 days. Six of the 26 donors were infected with mutant viruses, and 3 of these 6 donors did not develop detectable HBsAg during the entire observation period, despite a moderately high viral load of 10(4) to 10(5) HBV DNA copies per mL. CONCLUSION: Transmission of mutant virus may cause occult HBV infection in the acute stage. HBV NAT, even in MP configuration, is more effective than HBsAg testing and capable of interdicting infected donors in the pre- and post-HBsAg window periods.     

Natural killer T cell activation inhibits hepatitis B virus replication in vivo

We have previously reported that hepatitis B virus (HBV)-specific CD8(+) cytotoxic T lymphocytes and CD4(+) helper T lymphocytes can inhibit HBV replication in the liver of HBV transgenic mice by secreting interferon (IFN)-gamma when they recognize viral antigen. To determine whether an activated innate immune system can also inhibit HBV replication, in this study we activated natural killer T (NKT) cells in the liver of HBV transgenic mice by a single injection of alpha-galactosylceramide (alpha-GalCer), a glycolipid antigen presented to Valpha14(+)NK1.1(+) T cells by the nonclassical major histocompatibility complex class I-like molecule CD1d. Within 24 h of alpha-GalCer injection, IFN-gamma and IFN-alpha/beta were detected in the liver of HBV transgenic mice and HBV replication was abolished. Both of these events were temporally associated with the rapid disappearance of NKT cells from the liver, presumably reflecting activation-induced cell death, and by the recruitment of activated NK cells into the organ. In addition, prior antibody-mediated depletion of CD4(+) and CD8(+) T cells from the mice did not diminish the ability of alpha-GalCer to trigger the disappearance of HBV from the liver, indicating that conventional T cells were not downstream mediators of this effect. Finally, the antiviral effect of alpha-GalCer was inhibited in mice that are genetically deficient for either IFN-gamma or the IFN-alpha/beta receptor, indicating that most of the antiviral activity of alpha-GalCer is mediated by these cytokines. Based on these results, we conclude that alpha-GalCer inhibits HBV replication by directly activating NKT cells and by secondarily activating NK cells to secrete antiviral cytokines in the liver. In view of these findings, we suggest that, if activated, the innate immune response, like the adaptive immune response, has the potential to control viral replication during natural HBV infection. In addition, the data suggest that therapeutic activation of NKT cells may represent a new strategy for the treatment of chronic HBV infection.     

肝功能指标正常慢性乙型肝炎患者的肝功能与HBV-DNA病毒载量关系研究

目的 探讨肝功能指标正常慢性乙型肝炎患者（CHB）的肝功能与HBV-DNA病毒载量的关系,为临床治疗提供依据.方法 选择2012年7月至12月肝功能指标均在参考范围内的95例CHB患者为CHB组,健康体检者46例为对照组,用生化仪测定总胆红素（TBi）、直接胆红素（DBi）、间接胆红素（IBi）、丙氨酸氨基转移酶（ALT）、天门冬氨酸氨基转移酶（AST）和白蛋白/球蛋白（A/G）比值指标的水平,并进行统计学处理;将肝功能指标正常的95例CHB患者按HBV-DNA病毒载量分三组（Ⅰ组：HBV-DNA〈103 IU/ml;Ⅱ组：103 IU/ml ≤HBV DNA〈104 IU/ml;Ⅲ组：HBV-DNA ≥104 IU/ml）,比较各组间肝功能指标水平的差异,并分析HBV-DNA不同载量和肝功能指标的相关性.结果 GHB组ALT和AST高于对照组,差异均有统计学意义（P均＜0.05）,A/G低于对照组,差异有统计学意义（P＜0.05）,GHB组TBi、DBi和IBi与对照组比较,差异均无统计学意义（P均＞0.05）;Ⅱ组和Ⅲ组ALT水平均高于Ⅰ组,差异均有统计学意义（U分别为620.5和 526.5,P分别为0.042和0.004）,Ⅱ组和Ⅲ组ALT差异无统计学意义（U=238.5,P=0.360）,HBV-DNA病毒载量在TBi、DBi、IBi、AST水平和A/G比值之间差异均无统计学意义（H分别为0.428、0.811、1.221、4.250、2.614,P均＞0.05）;HBV-DNA病毒载量与ALT呈正相关（r=0.243,P=0.018）,而与TBi、DBi、IBi、AST水平和A/G无相关性（P均＞0.05）.结论 肝功能指标正常CHB患者的部分人群仍可能存在肝细胞的损害,ALT是反映肝细胞损害的最敏感指标之一,HBV-DNA病毒载量与ALT呈正相关,而与TBi、DBi、IBi、AST水平和A/G无相关性.     

Frequent genital herpes simplex virus 2 shedding in immunocompetent women. Effect of acyclovir treatment.

Reactivation of herpes simplex virus type 2 (HSV-2) occurs intermittently as perceived clinically and by viral culture. We performed a series of studies to evaluate the frequency and pattern of HSV-2 reactivation using both viral isolation and HSV PCR assay. Daily samples of genital secretions were obtained from 27 HSV-2 seropositive women; a subset of subjects obtained samples while receiving oral acyclovir 400 mg PO twice a day. HSV DNA was detected in genital swab specimens on 28% of 1,410 d compared with 8.1% of days by viral isolation. 11 of 20 women had HSV DNA detected on > 20% of days, 4 on > 50%, and 2 on > 75% of days; in contrast, none of the women shed on > 21% of days by viral isolation. The daily administration of oral acyclovir promptly reduced the frequency of HSV DNA detection by a median of 80%. Within 3-4 d of discontinuing daily acyclovir, HSV DNA again appeared in the genital area. HSV-2 shedding in the genital mucosa occurs much more frequently than previously appreciated. This frequent reactivation likely plays a role in the epidemic spread of genital herpes worldwide.     

Long-term lamivudine monotherapy in renal-transplant recipients with hepatitis-B-related cirrhosis

BACKGROUND: Chronic hepatitis B virus (HBV) infection is an important cause of morbidity and mortality in renal-transplant recipients. The aim of the study was to assess the efficacy and safety of long-term lamivudine monotherapy in renal-transplant recipients with HBV-related cirrhosis. METHODS: Seventeen such patients [median age: 45 years; 7 with hepatitis B e antigen (HBeAg)] received daily oral doses of 75-150 mg lamivudine for a median of 48 (range 11-81) months. All patients had baseline serum levels of HBV DNA of over 6 log10 copies per ml and of alanine transaminase (ALT) of over 1.5 times the upper normal limit (UNL). Clinical lamivudine resistance was defined as a rebound of serum HBV DNA above 5.3 log10 copies per ml and of serum ALT of over 1.5 times the UNL in patients who initially responded with HBV DNA levels of less than 5.3 log10 copies per ml and normal ALT values. Controls were 14 renal-transplant patients (median age 44 years; 3 with HBeAg) with HBV-related cirrhosis, naive to any anti-HBV therapy, followed for 58 months (4-135). RESULTS: Thirteen (77%) treated patients had a persistent response throughout the study period, including three (18%) who developed genotypic resistance, compared with none of the untreated controls (77% versus 0%, P < 0.0001). Four (23%) developed clinical resistance. Two of three patients with initially decompensated cirrhosis had a durable response and clinical improvement compared with the transient responder, whose liver function worsened following lamivudine resistance. Two responders developed chronic rejection requiring chronic haemodialysis. Overall, one treated patient developed liver-related complications, compared with eight untreated controls (6% versus 57%, P < 0.01). CONCLUSIONS: Most renal-transplant patients treated with lamivudine achieved a rapid and durable suppression of HBV, which substantially lowered the risk of liver decompensation and death.     

Inhibitory Effect of Adefovir on Viral DNA Synthesis and Covalently Closed Circular DNA Formation in Duck Hepatitis B Virus-Infected Hepatocytes In Vivo and In Vitro

The elimination of viral covalently closed circular DNA (CCC DNA) from the nucleus of infected hepatocytes is an obstacle to achieving sustained viral clearance during antiviral therapy of chronic hepatitis B virus (HBV) infection. The aim of our study was to determine whether treatment with adefovir, a new acyclic nucleoside phosphonate, the prodrug of which, adefovir dipivoxil, is in clinical evaluation, is able to suppress viral CCC DNA both in vitro and in vivo using the duck HBV (DHBV) model. First, the effect of adefovir on viral CCC DNA synthesis was examined with primary cultures of DHBV-infected fetal hepatocytes. Adefovir was administered for six consecutive days starting one day before or four days after DHBV inoculation. Dose-dependent inhibition of both virion release in culture supernatants and synthesis of intracellular viral DNA was observed. Although CCC DNA amplification was inhibited by adefovir, CCC DNA was not eliminated by antiviral treatment and the de novo formation of CCC DNA was not prevented by pretreatment of the cells. Next, preventive treatment of experimentally infected ducklings with lamivudine or adefovir revealed that both efficiently suppressed viremia and intrahepatic DNA. However, persistence of viral DNA even when detectable only by PCR was associated with a recurrence of viral replication following drug withdrawal. Taken together, our results demonstrate that adefovir is a potent inhibitor of DHBV replication that inhibits CCC DNA amplification but does not effectively prevent the formation of CCC DNA from incoming viral genomes.     

Comparative sensitivity of HBV NATs and HBsAg assays for detection of acute HBV infection

BACKGROUND: A study was designed to estimate relative analytic sensitivity and window-period (WP) closure and to project incremental yield of newer HBsAg tests, pooled-sample NAT, and single-sample NAT, compared to currently licensed HBsAg tests. STUDY DESIGN AND METHODS: HBV DNA and HBsAg test results for 23 HBV seroconversion (SC) panels were first analyzed to construct a model of primary HBV viremia. One-hundred representative samples were then selected from 10 panels and coded with 28 analytical controls. All 128 samples were tested by seven HBsAg tests and by four pooled-sample and three single-sample NAT assay formats. Results were analyzed to obtain differential times to HBV detection and combined with HBV incidence rates to project comparative yields. RESULTS: HBV doubling time during the ramp-up phase was estimated at 2.56 days. HBsAg concentrations at cutoff for new tests ranged from 0.07 to 0.12 ng per mL, compared with 0.13 to 0.62 ng per mL for licensed tests. Estimated viral load at cutoff ranged from 102 to 267 IU per mL for new tests and from 363 to 1069 IU per mL for licensed tests. HBsAg tests detected 31 to 63 percent of early ramp-up phase samples in the 100-member seroconversion panel study, while pooled-sample NAT detected 55 to 71 percent and single-sample NAT, 82 to 99 percent. Compared with currently licensed HBsAg assays, newer HBsAg assays would reduce the WP by 2 to 9 days; pooled-sample NAT would reduce the WP by 9 to 11 days; and single-sample NAT would reduce the WP by 25 to 36 days. CONCLUSION: Newer HBsAg tests would be expected to detect an additional 15 to 21 infected units per 107 donations, compared to licensed HBsAg tests. Sensitivity, WP closure, and yield projections for newer HBsAg assays and pooled-sample NAT are comparable. Single-sample NAT would increase yield by 13 to 15 units per 107 donations over pooled-sample NAT and newer HBsAg assays and by 35 to 50 units per 107 donations over currently licensed HBsAg assays.