HBV resistant to lamivudine: experimental and clinical studies.

Objective: To identify the impact of lamivudine on HBV e antigen (HBeAg) seroconversion and HBV DNA level, and the appearance of Tyr-Met-Asn-Asp (YMDD) resistants.

Methods: Forty-seven hepatitis B patients were treated with oral lamivudine. ALT level and HBeAg were detected in the treatment on the zero, 3rd, 6th and 9th month respectively. The levels of HBV DNA and YMDD resistants were analyzed with PCR microplate hybridization-ELISA.

Results: After 9 months of treatment, HBV DNA became negative and ALT level was normal in 74% patients. Among these patients, 17% patients had HBeAg converted to negative and anti-HBe antibody positive, whereas another 15% patients showed HBeAg negative. YMDD resistants appeared in 19% patients (9/47). One, three and five resistants were detected in the treatment on the 3rd, 6th and 9th month respectively.

Conclusions: Most HBV DNA in serum became negative after 9 months of treatment, and the rate of HBeAg seroconversion was 17% (HBV DNA level was lower than 100 pg/ml before treatment). YMDD resistants appeared in 19% patients.