title: Viral dynamics in chronic hepatitis B patients during lamivudine therapy.
abstract: OBJECTIVE
  Recently, we described a first-order decay model for the description of a decrease in viral load during treatment with lamivudine for a chronic hepatitis B virus infection (HBV). However, more frequent sampling of viral load during the first month of treatment shows a bi-phasic viral decline. We therefore compared several mathematical models which are currently in use to describe the dynamics of various viruses and treatments.
  
  
  METHODS
  HBV DNA positive chronic hepatitis B patients were treated with lamivudine 150-600 mg daily for four weeks. During the first two days, blood samples were drawn every 6 h, then daily during the first week and weekly during the following three weeks. HBV DNA was measured with the Digene Hybrid Capture II HBV DNA test and the sensitive Roche PCR assay, both calibrated on the Eurohep standard.
  
  
  RESULTS
  Our HBV DNA data are most accurately described if we use the bi-phasic model previously described by Neumann et al. while introducing all consecutive data of all patients simultaneously (mixed effects model). This results in an effectiveness of blocking of viral replication of 93%, a half-life of free virus of 17 h and a half-life of infected hepatocytes of 7 day in patients treated with 150 mg of lamivudine.
  
  
  CONCLUSIONS
  HBV dynamics during treatment with lamivudine can be explained by blocking of virion production with or without blocking of de novo infection. The bi-phasic model as described by Neumann et al. in combination with frequent blood sampling provides the most accurate fit and can be used to compare new nucleoside analogue profiles to lamivudine therapy.
authors.affiliation: Department of Hepatogastroenterology, University Hospital Rotterdam, The Netherlands.
authors.forename: Lonieke M M
authors.initials: LM
authors.lastname: Wolters
authors.forename: Bettina E
authors.initials: BE
authors.lastname: Hansen
authors.forename: Hubert G M
authors.initials: HG
authors.lastname: Niesters
authors.forename: Stefan
authors.initials: S
authors.lastname: Zeuzem
authors.forename: Solko W
authors.initials: SW
authors.lastname: Schalm
authors.forename: Robert A
authors.initials: RA
authors.lastname: de Man
mesh_terms: D004279:DNA, Viral / Q000032:analysis; D006207:Half-Life; D006515:Hepatitis B virus / Q000187:drug effects / Q000235:genetics / Q000254:growth & development*; D019694:Hepatitis B, Chronic / Q000097:blood / Q000188:drug therapy* / Q000821:virology*; D006801:Humans; D019259:Lamivudine / Q000627:therapeutic use*; D008954:Models, Biological; D016133:Polymerase Chain Reaction; D018894:Reverse Transcriptase Inhibitors / Q000627:therapeutic use*; D019562:Viral Load; D014779:Virus Replication / Q000187:drug effects
chemical_list: D004279:DNA, Viral; D018894:Reverse Transcriptase Inhibitors; D019259:Lamivudine