The reported durability of virologic response after successful lamivudine monotherapy is variable, and the question remains as to whether virologic responses can be maintained over an extended follow-up period. The aim of this study was to investigate posttreatment durability, the optimal duration of additional treatment after HBeAg clearance or seroconversion, and determinants for sustained virologic response (SVR) following lamivudine monotherapy in patients with HBeAg-positive chronic hepatitis B (CHB). From January 1999 to August 2004, 178 Korean patients with HBeAg-positive CHB were treated with lamivudine and achieved complete responses, defined as a loss of serum HBeAg and hepatitis B virus DNA, and alanine aminotransferase normalization. The mean duration of lamivudine monotherapy was 26 months (range, 12-77). SVR was maintained in 138 patients (77.5%). Host and viral factors were compared between 138 patients with SVR and 40 patients whose response was not sustained. The cumulative relapse rates increased from 15.9% at 1 year to 30.2% at 5 years, with a mean time to relapse after cessation of lamivudine of 12 months (range, 7-42). Most relapses occurred within 2 years after discontinuation of lamivudine (33/40, 82.5%). On multivariate analysis, age <or=40 years and additional treatment for more than 12 months after HBeAg clearance or seroconversion were independent factors for SVR.
Conclusion: The lamivudine-induced virologic response was durable in patients under 40 years old and those receiving lamivudine for more than 12 months after HBeAg clearance or seroconversion. Age and additional treatment were major predictive factors for SVR.