Hsieh T.-H.TAI-CHUNG TSENGCHUN-JEN LIULai M.-Y.PEI-JER CHENHsieh H.-L.DING-SHINN CHENJIA-HORNG KAO2021-07-032021-07-0320091359-6535https://www.scopus.com/inward/record.uri?eid=2-s2.0-84984535933&doi=10.3851%2fIMP1454&partnerID=40&md5=985140a7a31ebd539ec74879e66f978fhttps://scholars.lib.ntu.edu.tw/handle/123456789/568595Background: 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. ?2009 International Medical Press.[SDGs]SDG3alanine aminotransferase; lamivudine; virus DNA; adolescent; adult; aged; alanine aminotransferase blood level; antiviral resistance; article; clinical article; controlled study; female; gene mutation; gene sequence; genotype; hepatitis B; Hepatitis B virus; human; male; priority journal; retrospective study; Taiwan; virus load; virus strainjournal article10.3851/IMP14542-s2.0-84984535933