title: Profile of HBV polymerase gene mutations during entecavir treatment in patients with chronic hepatitis B.
abstract: OBJECTIVE
  We investigated the efficacy of entecavir (ETV) monotherapy in 54 naïve patients and 27 lamivudine (LMV) and/or adefovir (ADV) experienced patients.
  
  
  METHODS
  Eighty-one chronic hepatitis B patients with a viral load above 4 log 10 copies/ml and high levels of serum alanine aminotransferase were treated with ETV 0.5mg daily. The viruses of patients were sequenced before ETV therapy and after every three months of ETV therapy.
  
  
  RESULTS
  Eight LAM-experienced and ADV-experienced patients emerged mutations in the ETV treatment. In one of these experienced patients, the ETV-resistant mutations were detected during ETV treatment, with the virological and the biochemical breakthrough. Two LAM-experienced and ADV-naïve patients were detected mutation during 1-2 years ETV therapy. All three LAM-naïve and ADV-experienced patients were detected mutations in the ETV treatment. Five in fifty for LAM-naïve and ADV-naïve patients showed mutations in the ETV monotherapy.
  
  
  CONCLUSIONS
  ETV has a high genetic barrier to resistance and the efficacy in LAM-experienced and/or ADV-experienced patients were much lower than in naïve patients.
authors.affiliation: The Second Hospital of Nanjing affiliated to Medical School of Southeast University, 210003 Nanjing, China.
authors.forename: Mei
authors.initials: M
authors.lastname: Sun
authors.affiliation: The Second Hospital of Nanjing affiliated to Medical School of Southeast University, 210003 Nanjing, China.
authors.forename: Guolei
authors.initials: G
authors.lastname: Tan
authors.affiliation: The Second Hospital of Nanjing affiliated to Medical School of Southeast University, 210003 Nanjing, China.
authors.forename: Jinyun
authors.initials: J
authors.lastname: Song
authors.affiliation: The Second Hospital of Nanjing affiliated to Medical School of Southeast University, 210003 Nanjing, China.
authors.forename: Jianfang
authors.initials: J
authors.lastname: Wang
authors.affiliation: The Second Hospital of Nanjing affiliated to Medical School of Southeast University, 210003 Nanjing, China. Electronic address: xuping_wu@yahoo.com.
authors.forename: Xuping
authors.initials: X
authors.lastname: Wu
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000627:therapeutic use; D000293:Adolescent; D000328:Adult; D000410:Alanine Transaminase / Q000097:blood; D000998:Antiviral Agents / Q000627:therapeutic use*; D024882:Drug Resistance, Viral; D005260:Female; D006147:Guanine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D006515:Hepatitis B virus / Q000187:drug effects / Q000235:genetics*; D019694:Hepatitis B, Chronic / Q000188:drug therapy*; D006801:Humans; D019259:Lamivudine / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009154:Mutation; D063065:Organophosphonates / Q000627:therapeutic use; D019562:Viral Load; D055815:Young Adult
chemical_list: D000998:Antiviral Agents; D063065:Organophosphonates; D019259:Lamivudine; C413685:entecavir; D006147:Guanine; C053001:adefovir; D000410:Alanine Transaminase; D000225:Adenine