• HBV core promoter mutation;
  • HBV precore mutation;
  • hepatitis B virus genotypes;
  • lamivudine resistance

Summary.  Lamivudine has demonstrated efficacy for the treatment of hepatitis B e antigen-negative chronic hepatitis B (e-CHB). However, treatment withdrawal after 1 year has been associated with a high rate of relapse while long-term treatment is associated with increasing risks of drug resistance. We report our treatment experience of 50 Chinese-Canadian patients with e-CHB. All patients received lamivudine for 2 years. Treatment was withdrawn at month 24 in patients who had undetectable hepatitis B virus (HBV) DNA by PCR and normal aminotransferases during the second year of therapy. All patients had HBV genotype B or C. Biochemical response at months 6, 12 and 24 was 74%, 71% and 66%, respectively. HBV DNA was undetectable at months 6, 12 and 24 by hybrid capture and PCR assays in 100%, 92% and 86%; and 94%, 88% and 74% patients, respectively. The cumulative rates of genotypic resistance (GR) after 1 and 2 years were 15% and 25%, respectively. Four (44%) patients with GR experienced a hepatitis flare. The probability of clinical and virological relapse 6, 12, and 18 months after treatment withdrawal were 12% and 30%, 18% and 50%, and 30% and 50%, respectively. Reinstitution of lamivudine resulted in prompt virological and biochemical responses. Our study demonstrates that a sustained response can be achieved after a 2-year course of lamivudine in a subset of patients with e-CHB.