title: Lamivudine-resistant chronic hepatitis B: an observational study on adefovir in monotherapy or in combination with lamivudine.
abstract: OBJECTIVE
  In lamivudine-resistant patients with chronic hepatitis B (CHB), we compared efficacy, predictive response factors and changes in viral mutants in two antiviral approaches with adefovir.
  
  
  METHODS
  A prospective cohort study on therapy with adefovir alone (29 patients) or combined with ongoing lamivudine (23 patients) was performed.
  
  
  RESULTS
  A virological response was achieved in 55% of patients treated with adefovir and in 83% of those treated with the combination (p>0.05). This response was directly related to the basal viral load (p<0.0001) and obtained in 10 patients with basal HBV-DNA<17,200 IU/ml using both strategies. In patients with a higher basal viral load, the virological response was more frequent when treated with the combination (p<0.05). Mutation at locus rt181 predicted HBV-DNA persistence during therapy. A virological rebound was observed in 18% of non-responders while on adefovir monotherapy.
  
  
  CONCLUSIONS
  To achieve a complete virological response and reduce the risk of adefovir-resistant mutants in lamivudine-resistant patients, rescue therapy is preferable at early evidence of genotypic resistance. However, in subjects with a significant viral load, combination therapy is more effective. The presence of the rt181 mutation is associated with incomplete response.
authors.affiliation: Department of Gastroenterology and Hepatology, ASO San Giovanni Battista, C.so Bramante 88, 10126 Turin, Italy. silvia.gaia@fastwebnet.it
authors.forename: Silvia
authors.initials: S
authors.lastname: Gaia
authors.forename: Valeria
authors.initials: V
authors.lastname: Barbon
authors.forename: Antonina
authors.initials: A
authors.lastname: Smedile
authors.forename: Antonella
authors.initials: A
authors.lastname: Olivero
authors.forename: Silvia
authors.initials: S
authors.lastname: Carenzi
authors.forename: Marco
authors.initials: M
authors.lastname: Lagget
authors.forename: Carlo
authors.initials: C
authors.lastname: Alessandria
authors.forename: Mario
authors.initials: M
authors.lastname: Rizzetto
authors.forename: Alfredo
authors.initials: A
authors.lastname: Marzano
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D000998:Antiviral Agents / Q000627:therapeutic use*; D004279:DNA, Viral / Q000032:analysis; D024921:Drug Resistance, Multiple, Viral; D004359:Drug Therapy, Combination; D005260:Female; D005500:Follow-Up Studies; D005838:Genotype; D006515:Hepatitis B virus / Q000187:drug effects* / Q000235:genetics; D019694:Hepatitis B, Chronic / Q000188:drug therapy* / Q000821:virology; D006801:Humans; D019259:Lamivudine / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D063065:Organophosphonates / Q000627:therapeutic use*; D016133:Polymerase Chain Reaction; D011446:Prospective Studies; D018894:Reverse Transcriptase Inhibitors / Q000627:therapeutic use*; D013997:Time Factors; D016896:Treatment Outcome; D019562:Viral Load
chemical_list: D000998:Antiviral Agents; D004279:DNA, Viral; D063065:Organophosphonates; D018894:Reverse Transcriptase Inhibitors; D019259:Lamivudine; D000225:Adenine; C106812:adefovir dipivoxil