Management of patients with chronic hepatitis B.
Better understanding of hepatitis B virus (HBV) replication and the natural history and immunopathogenesis of chronic hepatitis B, together with the introduction of effective agents with different mechanisms of action, is the basis for better therapeutic strategies against chronic hepatitis B. Substantial experience has now been accumulated in the use of some of these drugs, and an Asia-Pacific Consensus has been reached on indications for their use. The goals of therapy and aspects of general management will be reviewed here. Among currently available drugs, alpha-interferon therapy gives a response rate (hepatitis B e antigen (HBeAg) seroconversion) of 30-40% compared with 10-20% in matched controls, but patients with lower alanine aminotransferase (ALT), higher HBV-DNA, and immunosuppressed patients have a poorer response, and alpha-interferon can be dangerous in cirrhosis. Meta-analysis of four controlled trials also suggests that thymosin-alpha1 is effective, but more studies are needed. Lamivudine has been most extensively studied. It is effective in terms of HBV-DNA loss, ALT normalization, HBeAg seroconversion, and improvement in histology, as well as being well tolerated. After 1 year of treatment, HBeAg seroconversion rate increased with higher pretherapy ALT levels, suggesting that patients with stronger endogenous antiviral defenses to kill hepatocytes harboring covalently closed circular DNA have a better response to direct antiviral effects. Lamivudine is also beneficial in HBeAg negative chronic hepatitis B, and patients with decompensated cirrhosis and HBV replication. However, genotypic-resistant tyrosine-methionine-aspartate-aspartate (YMDD) mutations start to emerge after 9-10 months of lamivudine therapy, and their incidence increases more quickly than the HBeAg seroconversion rate durating prolonged therapy. Thus the benefits of long-term lamivudine must be balanced against concern about YMDD mutations, and the durability of treatment response. There are encouraging preliminary results for adefovir dipivoxil, entecavir, emtricitabine, clevudine and other nucleoside/nucleotide analogs in the early stages of appraisal; entecavir and adefovir dipivoxil appear effective in patients with YMDD mutants. Further development of new drugs and new strategies, such as combination or sequential therapy, may help to better achieve the goals of treatment for chronic hepatitis B in the new century.
Liaw
Yun-Fan
YF
Liver Research Unit, Chang Gung University Memorial Hospital, 199 Tung Hwa North Road, Taipei, Taiwan. liveryfl@so-net.net.tw
D000998:Antiviral Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D004334:Drug Administration Schedule; D019694:Hepatitis B, Chronic / Q000188:drug therapy*; D006801:Humans; D007372:Interferons / Q000008:administration & dosage / Q000627:therapeutic use*; D019259:Lamivudine / Q000008:administration & dosage / Q000627:therapeutic use*; D018579:Patient Selection; D018894:Reverse Transcriptase Inhibitors / Q000008:administration & dosage / Q000627:therapeutic use*
D000998:Antiviral Agents; D018894:Reverse Transcriptase Inhibitors; D019259:Lamivudine; D007372:Interferons