title: [Virological response to adefovir dipivoxil predicts the long-term development of resistance in previously untreated patients with HBeAg-negative chronic hepatitis B].
abstract: OBJECTIVE
  Adefovir dipivoxil monotherapy in lamivudine-resistant patients is associated with more frequent development of resistance than in naïve patients. The virological response during treatment predicts the risk of developing resistance. The aims of this study were to assess the efficacy of adefovir dipivoxil treatment in naïve and lamivudine-resistant patients and to determine whether virological response predicts the development of adefovir resistance.
  
  
  METHODS
  This study included 82 patients with HBeAg-negative chronic hepatitis B (CHB) who received adefovir dipivoxil therapy. During active treatment, HBV-DNA values were determined by polymerase chain reaction; in addition, the presence of adefovir resistance-associated mutations was studied in cases of virological breakthrough.
  
  
  RESULTS
  Virological response at 12 and 24 months was 59% and 73% in naive patients compared with 40% and 67% in lamivudine-resistant patients, whereas virological breakthrough at 24 months was 9.5% in naïve patients compared with 20% in lamivudine-resistant patients. A small percentage (4%) of patients with virological response at 12 months showed virological breakthrough between 12 and 40 months versus 29.4% of patients without virological response (P=.03). In lamivudine-resistant patients, virological response at 12 months was not a predictive factor for the development of virological breakthrough.
  
  
  CONCLUSIONS
  Adefovir dipivoxil monotherapy in lamivudine-resistant patients is associated with an increased tendency to develop virological breakthrough, which cannot be predicted by virological response at 12 months of treatment. In naive patients, an undetectable viral load at 12 months of treatment ensures the absence of virological breakthrough at 40 months of treatment.
authors.affiliation: Unidad de Gestión Clínica de Enfermedades Digestivas, Hospital Universitario Virgen de Valme, Sevilla, España. em121154@terra.es
authors.forename: Emilio
authors.initials: E
authors.lastname: Suárez
authors.forename: Ana
authors.initials: A
authors.lastname: Gila
authors.forename: Blanca
authors.initials: B
authors.lastname: Figueruela
authors.forename: Natalia
authors.initials: N
authors.lastname: Chueca
authors.forename: Pilar
authors.initials: P
authors.lastname: Muñoz Rueda
authors.forename: Beatriz
authors.initials: B
authors.lastname: Puche
authors.forename: Enrique
authors.initials: E
authors.lastname: Fraga
authors.forename: Federico
authors.initials: F
authors.lastname: García
authors.forename: Juan Manuel
authors.initials: JM
authors.lastname: Martín
authors.forename: Raúl J
authors.initials: RJ
authors.lastname: Andrade
authors.forename: Carmen
authors.initials: C
authors.lastname: Nogales
authors.forename: Manuel
authors.initials: M
authors.lastname: Romero-Gómez
authors.forename: Javier
authors.initials: J
authors.lastname: Salmerón
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D000998:Antiviral Agents / Q000627:therapeutic use*; D024882:Drug Resistance, Viral; D005260:Female; D006513:Hepatitis B e Antigens / Q000097:blood; D019694:Hepatitis B, Chronic / Q000097:blood / Q000188:drug therapy* / Q000821:virology; D006801:Humans; D008297:Male; D008875:Middle Aged; D063065:Organophosphonates / Q000627:therapeutic use*; D011379:Prognosis; D012189:Retrospective Studies; D013997:Time Factors; D055815:Young Adult
chemical_list: D000998:Antiviral Agents; D006513:Hepatitis B e Antigens; D063065:Organophosphonates; D000225:Adenine; C106812:adefovir dipivoxil