Results of lamivudine trials in Asia.

In summary, 100 mg daily lamivudine therapy is safe and effective in Asian patients in terms of HBV suppression, ALT normalization and improvement in histology. The complete response rate after 1 year of lamivudine therapy is only around 15% but increases with increasing duration of treatment and increasing pretherapy ALT levels. Similar results were observed in patients with HBeAg-negative chronic hepatitis but published data are limited. YMDD mutations may emerge after 6-9 months of lamivudine therapy and its incidence also increases with increasing duration of therapy. The emergence of YMDD mutations is associated with viral and biochemical breakthrough. Hepatitis flares, sometimes associated with hepatic decompensation, may develop after stopping lamivudine therapy and in patients with YMDD mutations during continuing lamivudine therapy. The benefit of long-term lamivudine therapy therefore must be weighed carefully against the concern about YMDD mutations and the durability of therapeutic response. The development of new strategies, including selection of patient and timing of therapy, and new drugs are needed to further improve the therapeutic efficacy.