Clinical outcome in cases of viral breakthrough during lamivudine therapy in chronic hepatitis B patients

BACKGROUND/AIMS: Long-term lamivudine therapy can induce the emergence of lamivudine resistant hepatitis B virus (HBV) mutants. Clinically emergence of the mutant is expressed by the reappearance of disappeared HBV DNA in serum. Continued lamivudine treatment has been usually recommended in cases of viral breakthrough. However, the clinical outcome in patients with viral breakthrough is not clear. The aim of this study was to investigate the clinical course of chronic hepatitis B patients after viral breakthrough during lamivudine therapy. METHODS: A total of 74 patients with chronic hepatitis B who showed viral breakthrough after at least 6 months of lamivudine treatment were included in this study. They had positive HBeAg and HBV DNA before treatment. The median follow-up duration after breakthrough was 13 months. RESULTS: After viral breakthrough, only 8 patients (11%) maintained normal ALT levels and 66 patients (89%) showed elevation of ALT. 30 patients (41%) showed acute exacerbation of hepatitis (ALT increase over five-times upper normal limit). These acute exacerbations occurred within three months after breakthrough in 19 patients (63%). In the cases of acute exacerbation, 6 patients showed decompensated progression such as elevation of serum total bilirubin. One of them died of hepatic failure. A predictive factor for acute exacerbation was not found. HBeAg seroconversion occurred in 8 patients after viral breakthrough but their clinical course was highly variable. CONCLUSIONS: Chronic hepatitis B patients who had viral breakthrough during lamivudine therapy should be followed carefully and regularly in mind of potential clinical deterioration. New strategies are needed to manage the cases of acute exacerbation after viral breakthrough.