Resistance of Hepatitis B Virus to Antiviral Drugs: Current Aspects and Directions for Future Investigation

Despite the existence of vaccines, chronic hepatitis B virus (HBV) infection remains a major health problem worldwide. Interferon therapy successfully controls infection in only a small percentage of chronically infected individuals. The recent approval of the nucleoside analogue lamivudine for the treatment of chronic HBV infection has ushered in a new era of antiviral therapy. While lamivudine is highly effective at controlling viral infection short-term, prolonged therapy has been associated with an increasing incidence of viral resistance. Thus, it appears that lamivudine alone will not be sufficient to control chronic viral infection in the majority of individuals. In addition to lamivudine, several new nucleoside and nucleotide analogues that show promising antihepadnaviral activity are in various stages of development. Lamivudine resistance has been found to confer cross-resistance to some of these compounds and it is likely that resistance to newer antivirals may also develop during prolonged use. Drug resistance therefore poses a major threat to nucleoside analogue-based therapies for chronic HBV infection. Fortunately, combination chemotherapy (antiviral therapy with two or more agents) can minimize the chance that resistance will develop and can be expected to achieve sustained reductions in viral load, provided that suitable combinations of agents are chosen. Here we review the basis of drug resistance in HBV, with emphasis on aspects that are likely to affect drug choice in future.

[1]  R. Schinazi,et al.  Pharmacodynamics of (−)-β-2′,3′-Dideoxy-3′-Thiacytidine in Chronically Virus-Infected Woodchucks Compared to Its Pharmacodynamics in Humans , 1998, Antimicrobial Agents and Chemotherapy.

[2]  G. Acs,et al.  Production of hepatitis B virus particles in Hep G2 cells transfected with cloned hepatitis B virus DNA. , 1987, Proceedings of the National Academy of Sciences of the United States of America.

[3]  M. Manns,et al.  Mutational pattern of hepatitis B virus on sequential therapy with famciclovir and lamivudine in patients with hepatitis B virus reinfection occurring under hbig immunoglobulin after liver transplantation , 1999, Hepatology.

[4]  D. Häussinger,et al.  Long-term follow-up of HBeAg-positive patients treated with interferon alfa for chronic hepatitis B. , 1996, The New England journal of medicine.

[5]  D. Pillay,et al.  Analysis of Hepatitis B Virus Quasispecies Changes during Emergence and Reversion of Lamivudine Resistance in Liver Transplantation , 1999, Antiviral therapy.

[6]  R. D. de Man,et al.  Lamivudine resistance in immunocompetent chronic hepatitis B. Incidence and patterns. , 1997, Journal of hepatology.

[7]  N. Enomoto,et al.  Prevalence and significance of naturally occurring mutations in the surface and polymerase genes of hepatitis B virus. , 1999, The Journal of infectious diseases.

[8]  C. Chu,et al.  Acute exacerbation and hepatitis B virus clearance after emergence of YMDD motif mutation during lamivudine therapy , 1999, Hepatology.

[9]  F. Zoulim,et al.  2',3'-dideoxy-beta-L-5-fluorocytidine inhibits duck hepatitis B virus reverse transcription and suppresses viral DNA synthesis in hepatocytes, both in vitro and in vivo , 1996, Antimicrobial agents and chemotherapy.

[10]  M. Wainberg,et al.  In vitro selection and molecular characterization of human immunodeficiency virus type 1 with reduced sensitivity to 9-[2-(phosphonomethoxy)ethyl]adenine (PMEA). , 1996, Antiviral research.

[11]  A. So,et al.  Unblocking of chain-terminated primer by HIV-1 reverse transcriptase through a nucleotide-dependent mechanism. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[12]  R. Lanford,et al.  Nucleotide priming and reverse transcriptase activity of hepatitis B virus polymerase expressed in insect cells , 1995, Journal of virology.

[13]  S. Locarnini,et al.  Combination chemotherapy for hepatitis B virus: The final solution? , 2000, Hepatology.

[14]  L. Stuyver,et al.  Early detection of viral resistance by determination of hepatitis B virus polymerase mutations in patients treated by lamivudine for chronic hepatitis B , 2000, Hepatology.

[15]  E. De Clercq,et al.  Enhanced 9-(2-phosphonylmethoxyethyl)adenine secretion by a specific, indomethacin-sensitive efflux pump in a mutant 9-(2-phosphonylmethoxyethyl)adenine-resistant human erythroleukemia K562 cell line. , 1998, Molecular pharmacology.

[16]  M. Buti,et al.  Rapid detection of lamivudine-resistant hepatitis B virus polymerase gene variants. , 1999, Journal of virological methods.

[17]  A. Bartholomeusz,et al.  Significance of mutations in the hepatitis B virus polymerase selected by nucleoside analogues and implications for controlling chronic disease , 1998 .

[18]  B. C. Wong,et al.  Lamivudine is effective in suppressing hepatitis B virus DNA in Chinese hepatitis B surface antigen carriers: A placebo‐controlled trial , 1997, Hepatology.

[19]  W. Mason,et al.  Emergence of Drug-Resistant Populations of Woodchuck Hepatitis Virus in Woodchucks Treated with the Antiviral Nucleoside Lamivudine , 1999, Antimicrobial Agents and Chemotherapy.

[20]  F. Zoulim,et al.  Inhibitory Effect of Penciclovir-Triphosphate on Duck Hepatitis B Virus Reverse Transcription , 1997 .

[21]  S. Günther,et al.  Absence of mutations in the YMDD motif/B region of the hepatitis B virus polymerase in famciclovir therapy failure. , 1999, Journal of hepatology.

[22]  C. Gibbs,et al.  Mutations in hepatitis B DNA polymerase associated with resistance to lamivudine do not confer resistance to adefovir in vitro , 1998, Hepatology.

[23]  M A Nowak,et al.  Viral dynamics in hepatitis B virus infection. , 1996, Proceedings of the National Academy of Sciences of the United States of America.

[24]  William Lee,et al.  Chronic Hepatitis B Virus Infection: Treatment Strategies for the Next Millennium , 2000, Annals of Internal Medicine.

[25]  K. Matsubara,et al.  An in vitro system for screening anti-hepatitis B virus drugs. , 1989, Virology.

[26]  M. I. Barrasa,et al.  Apoptosis and Regeneration of Hepatocytes during Recovery from Transient Hepadnavirus Infections , 2000, Journal of Virology.

[27]  J. Walker,et al.  The human mitochondrial deoxynucleotide carrier and its role in the toxicity of nucleoside antivirals , 2001, Proceedings of the National Academy of Sciences of the United States of America.

[28]  E. Elias,et al.  Selection of hepatitis B surface “escape” mutants during passive immune prophylaxis following liver transplantation: potential impact of genetic changes on polymerase protein function , 1999, Gut.

[29]  J. Pollack,et al.  Hepatitis B virus reverse transcriptase and its many roles in hepadnaviral genomic replication. , 1994, Infectious agents and disease.

[30]  E. Holmes,et al.  Reconstructing the Complex Evolutionary History of Hepatitis B Virus , 1999, Journal of Molecular Evolution.

[31]  P. Angus,et al.  Hepatitis B virus polymerase mutations during antiviral therapy in a patient following liver transplantation. , 1997, Journal of hepatology.

[32]  M A Nowak,et al.  Viral dynamics in vivo: limitations on estimates of intracellular delay and virus decay. , 1996, Proceedings of the National Academy of Sciences of the United States of America.

[33]  J. Balzarini Suppression of resistance to drugs targeted to human immunodeficiency virus reverse transcriptase by combination therapy. , 1999, Biochemical pharmacology.

[34]  J. Hansen,et al.  Structure of the RNA-dependent RNA polymerase of poliovirus. , 1997, Structure.

[35]  M. Nassal Novel molecular approaches toward therapy of chronic hepatitis B , 1997, Archives of Virology.

[36]  M. Kukhanova,et al.  A Novel Action of Human Apurinic/Apyrimidinic Endonuclease , 2000, The Journal of Biological Chemistry.

[37]  J. Otsuka,et al.  Similarity relations of DNA and RNA polymerases investigated by the principal component analysis of amino acid sequences , 1999, Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology.

[38]  H. Thomas,et al.  A double blind, placebo‐controlled study to assess the effect of famciclovir on virus replication in patients with chronic hepatitis B virus infection , 1996, Journal of viral hepatitis.

[39]  B. Ames,et al.  Extensive oxidative DNA damage in hepatocytes of transgenic mice with chronic active hepatitis destined to develop hepatocellular carcinoma. , 1994, Proceedings of the National Academy of Sciences of the United States of America.

[40]  S. Locarnini,et al.  Antiviral chemotherapy for chronic hepatitis B infection: lessons learned from treating HIV-infected patients. , 1999, Journal of hepatology.

[41]  C. K. Chu,et al.  Antiviral activity of clevudine [L‐FMAU, (1‐(2‐fluoro‐5‐methyl‐β, L‐arabinofuranosyl) uracil)] against woodchuck hepatitis virus replication and gene expression in chronically infected woodchucks (Marmota monax) , 2001, Hepatology.

[42]  R. Colgrove,et al.  A combinatorial ledge: reverse transcriptase fidelity, total body viral burden, and the implications of multiple-drug HIV therapy for the evolution of antiviral resistance. , 1999, Antiviral research.

[43]  B. Rayner,et al.  Stereoisomers of Deoxynucleoside 5′-Triphosphates as Substrates for Template-dependent and -independent DNA Polymerases* , 1997, The Journal of Biological Chemistry.

[44]  K. Singh,et al.  A unified DNA- and dNTP-binding mode for DNA polymerases. , 1998, Trends in biochemical sciences.

[45]  M. Otto,et al.  The hepatitis B virus M539V polymerase variation responsible for 3TC resistance also confers cross-resistance to other nucleoside analogues. , 1998, Antiviral chemistry & chemotherapy.

[46]  S D Kemp,et al.  Rapid in vitro selection of human immunodeficiency virus type 1 resistant to 3'-thiacytidine inhibitors due to a mutation in the YMDD region of reverse transcriptase. , 1993, Proceedings of the National Academy of Sciences of the United States of America.

[47]  J. Roberts,et al.  Incidence and clinical consequences of surface and polymerase gene mutations in liver transplant recipients on hepatitis B immunoglobulin , 1998, Hepatology.

[48]  J. Colacino,et al.  The identification and development of antiviral agents for the treatment of chronic hepatitis B virus infection. , 1998, Progress in drug research. Fortschritte der Arzneimittelforschung. Progres des recherches pharmaceutiques.

[49]  C. Gibbs,et al.  Biphasic clearance kinetics of hepatitis B virus from patients during adefovir dipivoxil therapy , 1999, Hepatology.

[50]  S. Locarnini,et al.  Hepatic purine and pyrimidine metabolism: implications for antiviral chemotherapy of viral hepatitis. , 2008, Liver.

[51]  M A Nowak,et al.  Virus dynamics and drug therapy. , 1997, Proceedings of the National Academy of Sciences of the United States of America.

[52]  D. Tyrrell,et al.  Postliver transplant allograft reinfection with a lamivudine-resistant strain of hepatitis B virus: long-term follow-up. , 1998, Canadian journal of gastroenterology = Journal canadien de gastroenterologie.

[53]  C. Mandl,et al.  Monitoring the virus load can predict the emergence of drug-resistant hepatitis B virus strains in renal transplantation patients during lamivudine therapy. , 2000, The Journal of infectious diseases.

[54]  C. Seeger,et al.  Hepatitis B Virus Biology , 2000, Microbiology and Molecular Biology Reviews.

[55]  O. Yokosuka,et al.  In vivo study of the mechanism of action of antiviral agents against hepadna virus replication in the liver. Resistance of supercoiled viral DNA. , 1986, Journal of hepatology.

[56]  M. Roggendorf,et al.  The woodchuck: an animal model for hepatitis B virus infection in man. , 1995, Intervirology.

[57]  J. Schuetz,et al.  MRP4: A previously unidentified factor in resistance to nucleoside-based antiviral drugs , 1999, Nature Medicine.

[58]  J. Taylor,et al.  Asymmetric replication of duck hepatitis B virus DNA in liver cells: Free minus-strand DNA. , 1982, Proceedings of the National Academy of Sciences of the United States of America.

[59]  C. Seeger,et al.  The reverse transcriptase of hepatitis B virus acts as a protein primer for viral DNA synthesis , 1992, Cell.

[60]  S. Locarnini Hepatitis B virus surface antigen and polymerase gene variants: Potential virological and clinical significance , 1998, Hepatology.

[61]  C. Hannoun,et al.  An aberrant genotype revealed in recombinant hepatitis B virus strains from Vietnam. , 2000, The Journal of general virology.

[62]  E. De Clercq,et al.  Anti-Human Immunodeficiency Virus Drug Combination Strategies , 1998, Antiviral chemistry & chemotherapy.

[63]  P. Marcellin,et al.  A randomized, placebo‐controlled study to evaluate the efficacy of 12‐month famciclovir treatment in patients with chronic hepatitis B e antigen–positive hepatitis B , 2000, Hepatology.

[64]  J. Cullen,et al.  Lamivudine therapy of WHV-infected woodchucks. , 1998, Virology.

[65]  M. Wulfsohn,et al.  Efficacy and safety of adefovir dipivoxil with antiretroviral therapy: a randomized controlled trial. , 1999, JAMA.

[66]  A. Siddiqui,et al.  Hepatitis B Virus X Protein Colocalizes to Mitochondria with a Human Voltage-Dependent Anion Channel, HVDAC3, and Alters Its Transmembrane Potential , 2000, Journal of Virology.

[67]  H. Mitsuya,et al.  Differential influence of nucleoside analog-resistance mutations K65R and L74V on the overall mutation rate and error specificity of human immunodeficiency virus type 1 reverse transcriptase. , 2000, The Journal of biological chemistry.

[68]  Charles A. Lesburg,et al.  Crystal structure of the RNA-dependent RNA polymerase from hepatitis C virus reveals a fully encircled active site , 1999, Nature Structural Biology.

[69]  E. Elias,et al.  Selection of mutations in the hepatitis B virus polymerase during therapy of transplant recipients with lamivudine , 1996, Hepatology.

[70]  Nicholson,et al.  Inhibition of the replication of the DNA polymerase M550V mutation variant of human hepatitis B virus by adefovir, tenofovir, L‐FMAU, DAPD, penciclovir and lobucavir , 2000, Journal of viral hepatitis.

[71]  M. Otto,et al.  Inducible expression of human hepatitis B virus (HBV) in stably transfected hepatoblastoma cells: a novel system for screening potential inhibitors of HBV replication , 1997, Antimicrobial agents and chemotherapy.

[72]  M. Wainberg,et al.  The M184V Mutation in the Reverse Transcriptase of Human Immunodeficiency Virus Type 1 Impairs Rescue of Chain-Terminated DNA Synthesis , 2000, Journal of Virology.

[73]  S. Sarafianos,et al.  Molecular Modeling and Biochemical Characterization Reveal the Mechanism of Hepatitis B Virus Polymerase Resistance to Lamivudine (3TC) and Emtricitabine (FTC) , 2001, Journal of Virology.

[74]  M. Manns,et al.  Prostaglandin E plus famciclovir--a new concept for the treatment of severe hepatitis B after liver transplantation. , 1994, Transplantation.

[75]  J. Mackey,et al.  Nucleoside transporters of mammalian cells. , 1999, Pharmaceutical biotechnology.

[76]  T. Harrison,et al.  Functional analysis of mutations conferring lamivudine resistance on hepatitis B virus. , 1999, The Journal of general virology.

[77]  C. Kao,et al.  Analysis of RNA-dependent RNA polymerase structure and function as guided by known polymerase structures and computer predictions of secondary structure. , 1998, Virology.

[78]  R. Woodgate A plethora of lesion-replicating DNA polymerases. , 1999, Genes & development.

[79]  H. Isom,et al.  Use of the Hepatitis B Virus Recombinant Baculovirus-HepG2 System to Study the Effects of (−)-β-2′,3′-Dideoxy-3′-Thiacytidine on Replication of Hepatitis B Virus and Accumulation of Covalently Closed Circular DNA , 1999, Antimicrobial Agents and Chemotherapy.

[80]  D. Tyrrell,et al.  Mutation in HBV RNA‐dependent DNA polymerase confers resistance to lamivudine in vivo , 1996, Hepatology.

[81]  S. Locarnini,et al.  Long-Term Therapy with the Guanine Nucleoside Analog Penciclovir Controls Chronic Duck Hepatitis B Virus Infection In Vivo , 1998, Antimicrobial Agents and Chemotherapy.

[82]  S. Shiesh,et al.  Melatonin Prevents Pigment Gallstone Formation Induced by Bile Duct Ligation in Guinea Pigs , 2000, Hepatology.

[83]  A. Hizi,et al.  The processivity of DNA synthesis exhibited by drug-resistant variants of human immunodeficiency virus type-1 reverse transcriptase. , 1998, Nucleic acids research.

[84]  R. Schinazi,et al.  Antiviral l-Nucleosides Specific for Hepatitis B Virus Infection , 2001, Antimicrobial Agents and Chemotherapy.

[85]  Yung-chi Cheng,et al.  Excision of β-L- and β-D-Nucleotide Analogs From DNA by p53 Protein , 2000 .

[86]  M. Shapiro,et al.  Viral clearance without destruction of infected cells during acute HBV infection. , 1999, Science.

[87]  W. Mason,et al.  Lack of effect of antiviral therapy in nondividing hepatocyte cultures on the closed circular DNA of woodchuck hepatitis virus , 1997, Journal of virology.

[88]  B. Mitchell,et al.  Human Cytosolic 5′-Nucleotidase I , 2001, Journal of Biological Chemistry.

[89]  K. Walters,et al.  Identification and characterization of mutations in hepatitis B virus resistant to lamivudine , 1998 .

[90]  C. Katlama,et al.  Long‐term incidence of hepatitis B virus resistance to lamivudine in human immunodeficiency virus–infected patients , 1999, Hepatology.

[91]  S. Günther,et al.  Naturally occurring hepatitis B virus genomes bearing the hallmarks of retroviral G-->A hypermutation. , 1997, Virology.

[92]  H. Pelicano,et al.  Excision of β-D- and β-L-nucleotide analogs from DNA by the human cytosolic 3'-to-5' exonuclease , 2000 .

[93]  S. Murakami Hepatitis B Virus X Protein: Structure, Function and Biology , 1999, Intervirology.

[94]  O. Yokosuka,et al.  Emergence of YMDD motif mutants of hepatitis B virus during lamivudine treatment of immunocompetent type B hepatitis patients , 2000, Journal of medical virology.

[95]  T. Eickbush,et al.  Origin and evolution of retroelements based upon their reverse transcriptase sequences. , 1990, The EMBO journal.

[96]  M. Connelly,et al.  A human T lymphoid cell variant resistant to the acyclic nucleoside phosphonate 9-(2-phosphonylmethoxyethyl)adenine shows a unique combination of a phosphorylation defect and increased efflux of the agent. , 1995, Molecular pharmacology.

[97]  J. Schmidt,et al.  Dynamics of hepatitis B virus infection in vivo. , 1997, Journal of hepatology.

[98]  D. Tyrrell,et al.  In vitro and in vivo comparison of the abilities of purine and pyrimidine 2',3'-dideoxynucleosides to inhibit duck hepadnavirus , 1989, Antimicrobial Agents and Chemotherapy.

[99]  A. Dhillon,et al.  Lamivudine and alpha interferon combination treatment of patients with chronic hepatitis B infection: a randomised trial , 2000, Gut.

[100]  C. K. Chu,et al.  Molecular Modeling Approach to Understanding the Mode of Action of l-Nucleosides as Antiviral Agents , 2001, Antimicrobial Agents and Chemotherapy.

[101]  Efficacy of lamivudine in patients with hepatitis B e antigen-negative/hepatitis B virus DNA-positive (precore mutant) chronic hepatitis B. Lamivudine Precore Mutant Study Group. , 1999 .

[102]  M. Modak,et al.  Valine of the YVDD motif of moloney murine leukemia virus reverse transcriptase: role in the fidelity of DNA synthesis. , 2000, Biochemistry.

[103]  R. D. de Man,et al.  Lamivudine resistance inimmunocompetent chronic hepatitis B , 1997 .

[104]  M. Manns,et al.  Famciclovir treatment of hepatitis B virus recurrence after liver transplantation: a pilot study. , 1996, Liver transplantation and surgery : official publication of the American Association for the Study of Liver Diseases and the International Liver Transplantation Society.

[105]  J. Reardon Human immunodeficiency virus reverse transcriptase. A kinetic analysis of RNA-dependent and DNA-dependent DNA polymerization. , 1993, The Journal of biological chemistry.

[106]  J. Summers,et al.  Formation of the pool of covalently closed circular viral DNA in hepadnavirus-infected cells , 1986, Cell.

[107]  D. Pillay,et al.  Selection of multiresistant hepatitis B virus during sequential nucleoside-analogue therapy. , 2000, The Journal of infectious diseases.

[108]  I Sauvaget,et al.  Identification of four conserved motifs among the RNA‐dependent polymerase encoding elements. , 1989, The EMBO journal.

[109]  C. Hannoun,et al.  Long-term mutation rates in the hepatitis B virus genome. , 2000, The Journal of general virology.

[110]  P. Schlag,et al.  Efficient gene transfer into human hepatocytes by baculovirus vectors. , 1995, Proceedings of the National Academy of Sciences of the United States of America.

[111]  Y. Cheng,et al.  Role of additional mutations outside the YMDD motif of hepatitis B virus polymerase in L(-)SddC (3TC) resistance. , 1998, Biochemical pharmacology.

[112]  S. Lawrence,et al.  Chronic active hepatitis B exacerbations in human immunodeficiency virus-infected patients following development of resistance to or withdrawal of lamivudine. , 1999, Clinical infectious diseases : an official publication of the Infectious Diseases Society of America.

[113]  H. Agut,et al.  Hepatitis B Virus (HBV) Mutations Associated with Resistance to Lamivudine in Patients Coinfected with HBV and Human Immunodeficiency Virus , 1999, Journal of Clinical Microbiology.

[114]  S. Eriksson,et al.  Antiviral Guanosine Analogs as Substrates for Deoxyguanosine Kinase: Implications for Chemotherapy , 2001, Antimicrobial Agents and Chemotherapy.

[115]  A. Bartholomeusz,et al.  Clinical experience with famciclovir against hepatitis B virus. , 1997, Intervirology.

[116]  R. Schinazi,et al.  Site-specific Incorporation of Nucleoside Analogs by HIV-1 Reverse Transcriptase and the Template Grip Mutant P157S , 2000, The Journal of Biological Chemistry.

[117]  R. Miller,et al.  Mutation rate of the hepadnavirus genome. , 1989, Virology.

[118]  T. Steitz DNA Polymerases: Structural Diversity and Common Mechanisms* , 1999, The Journal of Biological Chemistry.

[119]  E. Schiff,et al.  Adefovir dipivoxil for the treatment of lamivudine‐resistant hepatitis B mutants , 2000, Hepatology.

[120]  S. Locarnini,et al.  Combination chemotherapy for hepatitis B virus: the path forward? , 2000, Drugs.

[121]  C. Gibbs,et al.  Combination therapy with lamivudine and famciclovir for chronic hepatitis B–infected Chinese patients: A viral dynamics study , 2000, Hepatology.

[122]  M. Kane Global programme for control of hepatitis B infection. , 1995, Vaccine.

[123]  T. Shike,et al.  Animal models. , 2001, Contributions to nephrology.

[124]  H. Schaller,et al.  Hepatitis B virus replication‐an update , 1996, Journal of viral hepatitis.

[125]  K. Chayama,et al.  Emergence and takeover of YMDD motif mutant hepatitis B virus during long‐term lamivudine therapy and re‐takeover by wild type after cessation of therapy , 1998, Hepatology.

[126]  S. Locarnini,et al.  In Vitro Antihepadnaviral Activities of Combinations of Penciclovir, Lamivudine, and Adefovir , 2000, Antimicrobial Agents and Chemotherapy.

[127]  S. L. Le Grice,et al.  Mutations in the Primer Grip Region of HIV Reverse Transcriptase Can Increase Replication Fidelity* , 1999, The Journal of Biological Chemistry.

[128]  S. Locarnini,et al.  Animal Models for Hepatitis B Infections — Duck Hepatitis , 1999 .

[129]  C. Gibbs,et al.  In vitro evaluation of hepatitis B virus polymerase mutations associated with famciclovir resistance , 2000, Hepatology.

[130]  Elias S. J. Arnér,et al.  Mammalian deoxyribonucleoside kinases. , 1995, Pharmacology & therapeutics.

[131]  J. Cherrington,et al.  Novel mutation (K70E) in human immunodeficiency virus type 1 reverse transcriptase confers decreased susceptibility to 9-[2-(phosphonomethoxy)ethyl]adenine in vitro , 1996, Antimicrobial agents and chemotherapy.

[132]  R. Beasley Hepatitis B virus. The major etiology of hepatocellular carcinoma , 1988, Cancer.

[133]  G. Maury The Enantioselectivity of Enzymes Involved in Current Antiviral Therapy Using Nucleoside Analogues: A New Strategy? , 2000, Antiviral chemistry & chemotherapy.

[134]  R. King,et al.  The M539V Polymerase Variant of Human Hepatitis B Virus Demonstrates Resistance to 2′-Deoxy-3′-Thiacytidine and a Reduced Ability to Synthesize Viral DNA , 1998, Antimicrobial Agents and Chemotherapy.

[135]  S. Locarnini,et al.  The covalently closed duplex form of the hepadnavirus genome exists in situ as a heterogeneous population of viral minichromosomes , 1995, Journal of virology.

[136]  F. Zoulim,et al.  Transient selection of a hepatitis B virus polymerase gene mutant associated with a decreased replication capacity and famciclovir resistance , 1999, Hepatology.

[137]  C. Chang,et al.  Production of hepatitis B virus in vitro by transient expression of cloned HBV DNA in a hepatoma cell line. , 1987, The EMBO journal.

[138]  S. Locarnini,et al.  In vitro antiviral activity of penciclovir, a novel purine nucleoside, against duck hepatitis B virus , 1994, Antimicrobial Agents and Chemotherapy.

[139]  C. Rogler,et al.  Increase in the frequency of hepadnavirus DNA integrations by oxidative DNA damage and inhibition of DNA repair , 1997, Journal of virology.

[140]  B. Tennant,et al.  Treatment of chronic woodchuck hepatitis virus infection in the eastern woodchuck (marmota monax) with nucleoside analogues is predictive of therapy for chronic hepatitis B virus infection in humans , 2000, Hepatology.

[141]  I. Gust,et al.  Antiviral strategies in chronic hepatitis B virus infection: II. Inhibition of duck hepatitis B Virus in vitro using conventional antiviral agents and supercoiled‐DNA active compounds , 1990, Journal of medical virology.

[142]  E. Schiff,et al.  Lamivudine as initial treatment for chronic hepatitis B in the United States. , 1999, The New England journal of medicine.

[143]  F. Zoulim,et al.  Evolution of hepatitis B virus polymerase gene sequence during famciclovir therapy for chronic hepatitis B. , 2000, The Journal of infectious diseases.

[144]  K. Reddy,et al.  Hepatitis-B-virus resistance to lamivudine given for recurrent infection after orthotopic liver transplantation , 1997, The Lancet.

[145]  L. Stuyver,et al.  Line Probe Assay for Monitoring Drug Resistance in Hepatitis B Virus-Infected Patients during Antiviral Therapy , 2000, Journal of Clinical Microbiology.

[146]  C. Harris,et al.  Hepatitis B virus X protein inhibits nucleotide excision repair , 1999, International journal of cancer.

[147]  M. Manns,et al.  Cross-Resistance Testing of Antihepadnaviral Compounds Using Novel Recombinant Baculoviruses Which Encode Drug-Resistant Strains of Hepatitis B Virus , 2001, Antimicrobial Agents and Chemotherapy.

[148]  C. Gibbs,et al.  Fulminant hepatic failure resulting from lamivudine-resistant hepatitis B virus in a renal transplant recipient: durable response after orthotopic liver transplantation on adefovir dipivoxil and hepatitis B immune globulin. , 1999, Transplantation.

[149]  M. Kukhanova,et al.  L- and D-Enantiomers of 2′,3′-Dideoxycytidine 5′-Triphosphate Analogs as Substrates for Human DNA Polymerases , 1995, The Journal of Biological Chemistry.

[150]  C. Chu,et al.  Identification and characterization of a prevalent hepatitis B virus X protein mutant in Taiwanese patients with hepatocellular carcinoma , 2000, Oncogene.

[151]  M. Nassal Hepatitis B Virus Replication: Novel Roles for Virus-Host Interactions , 1999, Intervirology.

[152]  A. Detsky,et al.  Effect of Alpha-Interferon Treatment in Patients with Hepatitis B e Antigen-Positive Chronic Hepatitis B , 1993, Annals of Internal Medicine.

[153]  M. Sherman,et al.  Loss of serum HBV DNA and HBeAg and seroconversion following short-term (12 weeks) adefovir dipivoxil therapy in chronic hepatitis B: two placebo-controlled phase II studies. , 1998 .

[154]  S. Locarnini,et al.  Preclinical aspects of lamivudine and famciclovir against hepatitis B virus , 1999, Journal of viral hepatitis.

[155]  F. Baldanti,et al.  Two Sensitive PCR-Based Methods for Detection of Hepatitis B Virus Variants Associated with Reduced Susceptibility to Lamivudine , 1999, Journal of Clinical Microbiology.

[156]  Y. Cheng,et al.  Sensitivity of L-(-)2,3-dideoxythiacytidine resistant hepatitis B virus to other antiviral nucleoside analogues. , 1999, Biochemical pharmacology.

[157]  A. Lok,et al.  Hepatitis B infection: pathogenesis and management. , 2000, Journal of hepatology.

[158]  M. Manns,et al.  In Vitro Susceptibilities of Wild-Type or Drug-Resistant Hepatitis B Virus to (−)-β-d-2,6-Diaminopurine Dioxolane and 2′-Fluoro-5-Methyl-β-l-Arabinofuranosyluracil , 2001, Antimicrobial Agents and Chemotherapy.

[159]  Y. Shiratori,et al.  YMDD motif in hepatitis B virus DNA polymerase influences on replication and lamivudine resistance: A study by in vitrofull‐length viral DNA transfection , 1999, Hepatology.

[160]  M. Seifer,et al.  Recombinant human hepatitis B virus reverse transcriptase is active in the absence of the nucleocapsid or the viral replication origin, DR1 , 1993, Journal of virology.

[161]  J. Wands,et al.  Hepatitis B virus mutants associated with 3TC and famciclovir administration are replication defective , 1998, Hepatology.

[162]  J. Gerin,et al.  Use of a standardized cell culture assay to assess activities of nucleoside analogs against hepatitis B virus replication. , 1992, Antiviral research.

[163]  R. D. de Man,et al.  Development of a Quantitative Real-Time Detection Assay for Hepatitis B Virus DNA and Comparison with Two Commercial Assays , 2000, Journal of Clinical Microbiology.

[164]  R. Miller,et al.  Inhibition of duck hepatitis B virus replication by 2',3'-dideoxycytidine. A potent inhibitor of reverse transcriptase. , 1989, Gastroenterology.

[165]  R. D. de Man,et al.  Efficacy of famciclovir treatment in chronic hepatitis B patients with different mutations at position 552 of the DNA polymerase gene. , 1998, Journal of hepatology.

[166]  B. Slagle,et al.  Hepatitis B Virus X Protein Interferes with Cellular DNA Repair , 1998, Journal of Virology.

[167]  F. Baas,et al.  Multidrug-resistance protein 5 is a multispecific organic anion transporter able to transport nucleotide analogs. , 2000, Proceedings of the National Academy of Sciences of the United States of America.

[168]  R. Hamatake,et al.  Generation of Replication-Competent Hepatitis B Virus Nucleocapsids in Insect Cells , 1998, Journal of Virology.

[169]  M. Bakhanashvili,et al.  Mutational studies of human immunodeficiency virus type 1 reverse transcriptase : the involvement of residues 183 and 184 in the fidelity of DNA synthesis , 1996, FEBS letters.

[170]  Y. Shiratori,et al.  Susceptibility of lamivudine-resistant hepatitis B virus to other reverse transcriptase inhibitors. , 1999, The Journal of clinical investigation.

[171]  H. Thomas,et al.  Lamivudine therapy for chronic hepatitis B: a six-month randomized dose-ranging study. , 1997, Gastroenterology.

[172]  D. Ilsley,et al.  Acyclic guanosine analogs inhibit DNA polymerases alpha, delta, and epsilon with very different potencies and have unique mechanisms of action. , 1995, Biochemistry.

[173]  S. Bowyer,et al.  Relationships within and between genotypes of hepatitis B virus at points across the genome: footprints of recombination in certain isolates. , 2000, The Journal of general virology.

[174]  H. Isom,et al.  Hepatitis B virus replication in human HepG2 cells mediated by hepatitis B virus recombinant baculovirus , 1998, Hepatology.

[175]  E. Schiff,et al.  A preliminary trial of lamivudine for chronic hepatitis B infection. , 1995, The New England journal of medicine.

[176]  W. Jilg,et al.  High genetic variability of the group-specific a-determinant of hepatitis B virus surface antigen (HBsAg) and the corresponding fragment of the viral polymerase in chronic virus carriers lacking detectable HBsAg in serum. , 2000, The Journal of general virology.

[177]  C. Seeger,et al.  Novel mechanism for reverse transcription in hepatitis B viruses , 1993, Journal of virology.

[178]  H. Will,et al.  Increased hepatocyte turnover and inhibition of woodchuck hepatitis B virus replication by adefovir In vitro do not lead to reduction of the closed circular DNA , 2000, Hepatology.

[179]  H. Nasheuer,et al.  Eukaryotic DNA polymerases, a growing family. , 2000, Trends in biochemical sciences.

[180]  S. Locarnini,et al.  Antiviral strategies in chronic hepatitis B virus infection: I. Establishment of an in vitro system using the duck hepatitis B virus model , 1990, Journal of medical virology.

[181]  D. Tyrrell,et al.  Generation of duck hepatitis B virus polymerase mutants through site-directed mutagenesis which demonstrate resistance to lamivudine [(--)-beta-L-2', 3'-dideoxy-3'-thiacytidine] in vitro , 1996, Antimicrobial agents and chemotherapy.

[182]  B. Rayner,et al.  Stereochemical control of DNA biosynthesis. , 2000, Nucleic acids research.

[183]  B. Berkhout,et al.  Increased polymerase fidelity of the 3TC-resistant variants of HIV-1 reverse transcriptase. , 1997, Nucleic acids research.

[184]  J. Cullen,et al.  In vivo antiviral activity and pharmacokinetics of (-)-cis-5-fluoro-1-[2-(hydroxymethyl)-1,3-oxathiolan-5-yl]cytosine in woodchuck hepatitis virus-infected woodchucks , 1997, Antimicrobial agents and chemotherapy.

[185]  B. Korba,et al.  A cell culture assay for compounds which inhibit hepatitis B virus replication. , 1991, Antiviral research.

[186]  P Argos,et al.  An attempt to unify the structure of polymerases. , 1990, Protein engineering.

[187]  J. Cherrington,et al.  Genotypic and Phenotypic Characterization of Human Immunodeficiency Virus Type 1 Variants Isolated from AIDS Patients after Prolonged Adefovir Dipivoxil Therapy , 1998, Antimicrobial Agents and Chemotherapy.

[188]  J. Summers,et al.  Replication of the genome of a hepatitis B-like virus by reverse transcription of an RNA intermediate , 1982, Cell.

[189]  A. Fujiyama,et al.  Stable expression and replication of hepatitis B virus genome in an integrated state in a human hepatoma cell line transfected with the cloned viral DNA. , 1987, Proceedings of the National Academy of Sciences of the United States of America.

[190]  Ally,et al.  A ONE-YEAR TRIAL OF LAMIVUDINE FOR CHRONIC HEPATITIS B , 2000 .

[191]  K. Koike,et al.  Hepatitis B virus (HBV) particles are produced in a cell culture system by transient expression of transfected HBV DNA. , 1987, Proceedings of the National Academy of Sciences of the United States of America.

[192]  D. Richman,et al.  Nomenclature for antiviral‐resistant human hepatitis B virus mutations in the polymerase region , 2001, Hepatology.

[193]  R. D. de Man,et al.  The sequential occurrence of viral mutations in a liver transplant recipient re-infected with hepatitis B: hepatitis B immune globulin escape, famciclovir non-response, followed by lamivudine resistance resulting in graft loss. , 1998, Journal of hepatology.

[194]  J. Tainer,et al.  Abasic site recognition by two apurinic/apyrimidinic endonuclease families in DNA base excision repair: the 3' ends justify the means. , 2000, Mutation research.

[195]  M. Shapiro,et al.  Replicative intermediates of hepatitis B virus in HepG2 cells that produce infectious virions , 1988, Journal of virology.

[196]  J. Li,et al.  Roles of the three major phosphorylation sites of hepatitis B virus core protein in viral replication. , 1999, Virology.

[197]  L. Boone,et al.  DNA polymerase activity of hepatitis B virus particles: differential inhibition by L-enantiomers of nucleotide analogs. , 1996, Antiviral research.

[198]  J. Cherrington,et al.  Human immunodeficiency virus type 1 reverse transcriptase expressing the K70E mutation exhibits a decrease in specific activity and processivity. , 1998, Molecular pharmacology.

[199]  J. Pawlotsky,et al.  Routine detection and quantification of hepatitis B virus DNA in clinical laboratories: performance of three commercial assays. , 2000, Journal of virological methods.

[200]  D. Earnshaw,et al.  Mode of antiviral action of penciclovir in MRC-5 cells infected with herpes simplex virus type 1 (HSV-1), HSV-2, and varicella-zoster virus , 1992, Antimicrobial Agents and Chemotherapy.

[201]  R. Schinazi,et al.  The polymerase L528M mutation cooperates with nucleotide binding-site mutations, increasing hepatitis B virus replication and drug resistance. , 2001, The Journal of clinical investigation.

[202]  M A Nowak,et al.  The dynamics of hepatitis B virus infection. , 1996, Proceedings of the National Academy of Sciences of the United States of America.

[203]  L. Fu,et al.  Characterization of Novel Human Hepatoma Cell Lines with Stable Hepatitis B Virus Secretion for Evaluating New Compounds against Lamivudine- and Penciclovir-Resistant Virus , 2000, Antimicrobial Agents and Chemotherapy.