title: Safety and efficacy of entecavir in adefovir-experienced patients.
abstract: OBJECTIVE
  Suboptimal viral suppression with adefovir (ADV) poses a challenge in managing chronic hepatitis B. Few studies have evaluated the efficacy of entecavir (ETV) in ADV-experienced patients. Our aim is to assess treatment effectiveness of ETV in ADV-experienced patients.
  
  
  METHODS
  ADV-experienced patients switched to ETV were enrolled from six US clinics. Patients completed a median of 24 months of ETV after switch. Patients were categorized into partial responders (detectable HBV-DNA at switch) or complete responders (undetectable HBV-DNA at switch) to ADV. Primary and secondary outcome measurements were complete viral suppression (CVS, HBV-DNA < 60 IU/mL) and biochemical response (BR, alanine aminotransferase [ALT] < 40 U/L), respectively.
  
  
  RESULTS
  A total of 120 patients were included in the analysis (80 ADV partial responders; 40 ADV complete responders). In partial responders, CVS rate was 84% after 24 months of ETV. BR rate was 58% at switch to ETV and increased to 90% after 24 months. All complete responders continued to experience CVS after switch. On multivariate analysis inclusive of age, male gender, ALT level at switch, and history of lamivudine (LAM) exposure, we identified positive, hepatitis B e antigen status before ADV and higher HBV-DNA level at time of switch as significant independent negative predictors of CVS. In eight patients with ADV resistance, seven achieved CVS after 24 months of ETV, and all achieved BR.
  
  
  CONCLUSIONS
  In ADV-experienced patients, high rates of CVS and BR can be achieved/sustained after switching to ETV, including those with ADV resistance or with prior exposure to LAM.
authors.affiliation: School of Medicine, University of California San Diego, San Jose, California, USA.
authors.forename: Nghia H
authors.initials: NH
authors.lastname: Nguyen
authors.forename: Huy N
authors.initials: HN
authors.lastname: Trinh
authors.forename: Thuan T
authors.initials: TT
authors.lastname: Nguyen
authors.forename: Son T
authors.initials: ST
authors.lastname: Do
authors.forename: Phuong
authors.initials: P
authors.lastname: Tran
authors.forename: Huy A
authors.initials: HA
authors.lastname: Nguyen
authors.forename: Khanh K
authors.initials: KK
authors.lastname: Nguyen
authors.forename: Ruel T
authors.initials: RT
authors.lastname: Garcia
authors.forename: Glen A
authors.initials: GA
authors.lastname: Lutchman
authors.forename: Mindie H
authors.initials: MH
authors.lastname: Nguyen
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D000328:Adult; D000410:Alanine Transaminase / Q000097:blood; D000998:Antiviral Agents / Q000627:therapeutic use*; D015415:Biomarkers / Q000097:blood; D057915:Drug Substitution; D005260:Female; D005500:Follow-Up Studies; D019694:Hepatitis B, Chronic / Q000175:diagnosis / Q000188:drug therapy* / Q000821:virology; D006801:Humans; D019259:Lamivudine / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D063065:Organophosphonates / Q000627:therapeutic use*; D013997:Time Factors; D016896:Treatment Outcome; D019562:Viral Load
chemical_list: D000998:Antiviral Agents; D015415:Biomarkers; D063065:Organophosphonates; D019259:Lamivudine; C053001:adefovir; D000410:Alanine Transaminase; D000225:Adenine
keywords: HBV; HBeAg; adefovir resistance; lamivudine experienced; viral suppression