RESUMO
BACKGROUND/AIMS: Clevudine is a nucleoside analogue that exhibits potent and sustained antiviral effects as a 24-week therapy for chronic hepatitis B (CHB). This study evaluated the efficacy and viral resistance of a 48-week course of clevudine treatment for CHB. METHODS: Data on patients with CHB and detectable serum hepatitis B virus (HBV) DNA who were treated with clevudine for 48 weeks or longer were collected retrospectively for this study. Patients who had taken lamivudine within the 3 years prior to this study were excluded. Serum HBV DNA was measured by polymerase chain reaction hybridization (lower detection limit=316 copies/mL). Serum HBV DNA and biochemical data were analyzed at weeks 24 and 48. Developments of viral breakthrough and resistance to the antiviral drug were also monitored. RESULTS: Data from 74 patients (mean age 44 years; M:F=54:20; HBeAg-positive, 47; HBeAg-negative, 27) were included in this study. Ten patients had experienced previous lamivudine treatment. Median HBV DNA at baseline was 6.49 log(10) copies/mL. Median serum HBV DNA reductions from baseline at week 48 were -4.34 log(10) copies/mL (HBeAg-positive, -4.84 log(10) copies/mL; HBeAg-negative, -3.74 log(10) copies/mL). At week 48, serum HBV DNA was not detected in 83.8% of the patients (HBeAg-positive, 76.6%; HBeAg-negative, 96.3%). Normalization of serum alanine aminotransferase levels was achieved in 84.7% of the patients. Viral breakthrough and antiviral resistance developed in two patients at week 48. The development of antiviral resistance was associated with the presence of previous lamivudine treatment and cirrhosis. CONCLUSION: A 48-week course of clevudine therapy was highly effective in patients with CHB. The risk of development of resistance to clevudine was increased in patients with previous exposure to lamivudine and cirrhosis.