Primary resistance and treatment associated resistance to adefovir in four chronic hepatitis B patients

Abstract number: 1733_985

Fernandez-Olmos A., Tato M., Moreira V., Mateos M.

Background and Objectives: Adefovir dipivoxil is used for the treatment of patients with chronic hepatitis B infection who are infected with lamivudine-resistant hepatitis B virus. Mutations A181V, N236T, L217R, I233V, V214A and Q215S confer resistance to adefovir. We studied four patients in whom adefovir associated mutations were detected (N236T, V214A and Q215S). Two of these mutations were considered as primary resistance since patients had never received adefovir.

Methods: Serum samples of patients were studied by sequencing a 137-nucleotide fragment of the retrotranscriptase region of the hepatitis B virus (Trugene HBV Genotyping kit, Bayer Health Care, New York, USA). Clinical data are shown in Table 1.

CaseAST (U/I)ALT (U/I)Geno typeAdefovir resistance mutationViral load (UI/mL)Treatment
112976DN236T30,000,000Lamivudine, adefovir
24729DN236T5,484Lamivudine, adefovir
44353DV214A, Q215S39,152No

Discussion: In cases 1 and 2 adefovir was ineffective since no decrease in the viral load was observed after 16 and 17 months of treatment, respectively. Resistance to adefovir is considered unusual but it must be considered in patients who do not respond to adefovir. In cases 3 and 4, mutations N236T, V214A and Q215S were found when studying the genotype of the HBV in the patients. These patients had not received adefovir for the chronic hepatitis B and, therefore, these variants should be considered as primarily resistant to adefovir. In conclusion, the detection of resistance mutations is necessary to monitor and anticipate possible treatment failure.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Location: ICC, Munich, Germany
Presentation type:
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