Role of lamivudine in the treatment of chronic hepatitis B virus infection.

OBJECTIVE: To examine the evidence regarding the therapeutic effectiveness of lamivudine in the treatment of chronic hepatitis B virus (HBV) infection in immunocompetent patients. DATA SOURCES: Using chronic hepatitis B and lamivudine as MeSH headings, MEDLINE was searched from 1966 to September 1998 for all published randomized controlled trials evaluating lamivudine in chronic HBV infection. Relevant articles from selected bibliographies were also retrieved. STUDY SELECTION: Only randomized, single- and double-blind trials in human HBV carriers published in the English language were included. DATA SYNTHESIS: Evidence from the controlled trials suggests that lamivudine has a therapeutic effect in suppressing HBV replication in immunocompetent patients. Lamivudine 100 mg/d appears to suppress HBV replication in as many as 97% of patients within two weeks after the initiation of therapy and is capable of suppressing histologic damages. However, viral suppression is effective only during the therapy; on discontinuation of lamivudine therapy, most patients return to the pretreatment condition. Viral resistance to lamivudine has been observed. Most patients with chronic HBV infection appear to tolerate 100 mg/d of lamivudine therapy. CONCLUSIONS: Evidence has shown that oral lamivudine 100 mg/d will produce rapid and significant suppression of viral replication in immunocompetent patients with chronic HBV infections. Treatment periods up to one year have been effective and well tolerated. The suppression of viral replication may not be sustained after cessation of lamivudine therapy, and very few patients have complete elimination of HBV during therapy. Therefore, long treatment periods may be necessary. Efficacy and tolerability of treatment beyond one year need to be investigated. Resistance to lamivudine has been reported in patients receiving therapy. A combination anti-HBV regimen using lamivudine and other agents with different mechanisms of action should be investigated to maximize the elimination of the viral infection while minimizing or preventing damage to the liver cells and tissues and the development of viral resistance.