title: Strong antiviral activity of the new l-hydroxycytidine derivative, l-Hyd4FC, in HBV-infected human chimeric uPA/SCID mice.
abstract: BACKGROUND
  Suppression of viral replication with nucleoside/nucleotide inhibitors has been shown to greatly improve the outcome of chronic HBV infection. β-l-nucleoside analogues, especially β-l-deoxycytidine derivatives represent one of the most efficient groups of antiretroviral compounds. We recently described that hydroxylation of the amino group of these β-l-deoxycytidine derivatives preserved their strong HBV inhibitory activity in vitro, but strongly reduced their cytotoxicity. From this new group of compounds we selected β-l-2',3'-didehydro-2',3'-dideoxy-N(4)-hydroxy-5-fluorocytidine (l-Hyd4FC) for a first in vivo investigation. The aim of this study was to determine the antiviral activity of l-Hyd4FC in HBV-infected human liver chimeric urokinase plasminogen activator (uPA)/SCID mice.
  
  
  METHODS
  Stably infected animals (median 6×10(7) HBV DNA/ml) were injected daily with either l-Hyd4FC (50 mg/kg) or saline as controls. Mice treated with lamivudine served to compare the in vivo antiviral potency of l-Hyd4FC. Virological changes were determined by quantitative PCR.
  
  
  RESULTS
  Treatment with l-Hyd4FC for 4 weeks induced a 2-log reduction of viraemia, while a median 1.5-log decline was achieved with lamivudine. Intrahepatically, l-Hyd4FC induced a median eightfold decline of viral activity (relaxed circular DNA/covalently closed circular DNA), and threefold reduction of pregenomic RNA/GAPDH levels. No significant decline of subgenomic HBV transcripts, as well as of circulating hepatitis B e antigen and hepatitis B surface antigen was detected. Maintenance of human serum albumin concentrations throughout the study, negative TUNEL staining and occurrence of viral rebound after drug withdrawal indicated that l-Hyd4FC was not toxic in human hepatocytes.
  
  
  CONCLUSIONS
  Administration of l-Hyd4FC in uPA/SCID mice harbouring HBV-infected human hepatocytes demonstrated the high antiviral potency of this drug in vivo. Such characteristics make l-Hyd4FC a good candidate for further investigations a as potential HBV therapeutic agent.
authors.affiliation: Department of Internal Medicine, University Medical Center Hamburg, Hamburg, Germany.
authors.forename: Tassilo
authors.initials: T
authors.lastname: Volz
authors.forename: Marc
authors.initials: M
authors.lastname: Lütgehetmann
authors.forename: Lena
authors.initials: L
authors.lastname: Allweiss
authors.forename: Michael
authors.initials: M
authors.lastname: Warlich
authors.forename: Jeanette
authors.initials: J
authors.lastname: Bierwolf
authors.forename: Joerg M
authors.initials: JM
authors.lastname: Pollok
authors.forename: Joerg
authors.initials: J
authors.lastname: Petersen
authors.forename: Eckart
authors.initials: E
authors.lastname: Matthes
authors.forename: Maura
authors.initials: M
authors.lastname: Dandri
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000627:therapeutic use*; D002678:Chimera; D003562:Cytidine / Q000031:analogs & derivatives* / Q000737:chemistry; D004279:DNA, Viral; D006509:Hepatitis B / Q000188:drug therapy*; D006801:Humans; D019259:Lamivudine / Q000627:therapeutic use; D051379:Mice; D016513:Mice, SCID; D015394:Molecular Structure; D014568:Urokinase-Type Plasminogen Activator / Q000235:genetics*; D014766:Viremia; D016047:Zalcitabine / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: C574702:2',3'-didehydro-2',3'-dideoxy-N4 -hydroxy-5-fluorocytidine; D000998:Antiviral Agents; D004279:DNA, Viral; D019259:Lamivudine; D003562:Cytidine; D016047:Zalcitabine; D014568:Urokinase-Type Plasminogen Activator