Original article
Hepatitis B virus genotype B has an earlier emergence of lamivudine resistance than genotype C
Ting-Hui Hsieh, Tai-Chung Tseng, Chun-Jen Liu, Ming-Yang Lai, Pei-Jer Chen, Hsin-Ling Hsieh, Ding-Shinn Chen, Jia-Horng Kao
Corresponding author name: Jia-Horng Kao
Corresponding author e-mail: kaojh@ntu.edu.tw
Citation: Antiviral Therapy 2009; 14:1157-1163
doi: 10.3851/IMP1454
Date published online: 27 November 2009
Abstract
Background: Hepatitis B virus (HBV) genotype B and C seem not to affect the therapeutic response to lamivudine (3TC). Whether a given genotype has an earlier emergence of 3TC resistance remains unclear. We thus conducted this study to elucidate the association of HBV genotype with the emergence of 3TC-resistant strains in Taiwanese patients.
Methods: Forty chronic hepatitis B patients who developed resistance after 3TC therapy were retrospectively enrolled. HBV genotype, serum alanine aminotransferase (ALT) and HBV DNA levels were determined at baseline. The presence of 3TC-resistant mutations was confirmed by direct sequencing whenever biochemical breakthrough developed.
Results: The distribution of HBV genotype B and C in 40 patients receiving 3TC therapy were 60% and 40%, respectively. The mean interval to detect 3TC-resistant strain was 19.6 ±1.7 months. By using multivariate analysis, HBV genotype B and higher pre-treatment HBV DNA level were independently associated with earlier detection of 3TC-resistant strains. In addition, genotype B was significantly associated with development of 3TC resistance within the first 12 months of 3TC therapy compared with genotype C (odds ratio 8.27; P=0.004).
Conclusions: Compared with HBV genotype C, genotype B appears to have an earlier biochemical resistance to 3TC than genotype C. Therefore, more frequent monitoring of viral load or genotypical resistance might be needed for patients with HBV genotype B infection receiving 3TC therapy, especially during the first year.