title: Lamivudine and adefovir resistance in children and young adults with chronic hepatitis B.
abstract: OBJECTIVE
  Long-term lamivudine (LAM) and adefovir (ADV) treatment has been found to induce the emergence of drug-resistant hepatitis B virus (HBV) in a significant number of patients with chronic hepatitis B (CHB) infection. The aim of our study was to evaluate the LAM and ADV mutations detected in our patient group.
  
  
  METHODS
  Twenty-four patients diagnosed with CHB were enrolled in this study. The patient group consisted of those who had received 6 months of treatment with interferon-alpha and who did not response to this therapy. Patients were evaluated based on virologic and serologic response to therapy, and were classified as responders or non-responders. The treatment of non-responders continued with LAM (3mg/kg/d, maximum 100mg/d). Due to a lack of response to treatment, ADV (10mg/g) was added to the treatment regimen of eight young adult patients. The mutations associated with HBV drug resistance were investigated using reverse hybridization methods and PCR.
  
  
  RESULTS
  The mutation studies indicated that 14 (58.4%) of the patients had resistance. Three patients developed ADV-associated mutations (A181T), one after 18 months of ADV; the other two had undergone 18 and 36 months of LAM therapy without ADV exposure. Although the average LAM treatment period of the patients with LAM resistance was longer than for those in whom no resistance was detected, no statistically significant difference was found.
  
  
  CONCLUSIONS
  HBV treatment with nucleoside analogues results in the development of mutant strains, leading to drug resistance. Therefore genotypic resistance testing is important in planning and monitoring HBV treatment.
authors: Department of Pediatric Gastroenterology, The Ministry of Health Tepecik Training and Research Hospital, Izmir, Turkey. sezin.akman@gmail.com
authors: Sezin Asik
authors: SA
authors: Akman
authors: Sukran
authors: S
authors: Kose
authors: Oya
authors: O
authors: Halicioglu
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D000293:Adolescent; D000998:Antiviral Agents / Q000494:pharmacology* / Q000627:therapeutic use; D002648:Child; D004334:Drug Administration Schedule; D024882:Drug Resistance, Viral / Q000235:genetics*; D005260:Female; D005838:Genotype; D006515:Hepatitis B virus / Q000187:drug effects* / Q000235:genetics; D019694:Hepatitis B, Chronic / Q000188:drug therapy / Q000821:virology*; D006801:Humans; D019259:Lamivudine / Q000494:pharmacology* / Q000627:therapeutic use; D008297:Male; D009154:Mutation; D063065:Organophosphonates / Q000494:pharmacology* / Q000627:therapeutic use; D018894:Reverse Transcriptase Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D013997:Time Factors; D055815:Young Adult
chemical_list: D000998:Antiviral Agents; D063065:Organophosphonates; D018894:Reverse Transcriptase Inhibitors; D019259:Lamivudine; C053001:adefovir; D000225:Adenine