Current Treatments for Hepatitis B: An Overview
New optimism surrounds treatments for chronic hepatitis B (CHB). Interferon alfa-2b (Intron A), lamivudine (Epivir-HBV), and adefovir dipivoxil (Hepsera) are currently approved by the United States Food and Drug Administration for the treatment of CHB.
Peginterferon alfa-2a (Pegasys) monotherapy has shown promise as an effective treatment for CHB and is now in the final stages of Phase III testing. Entecavir is also expected to receive FDA approval in the near future. Other promising compounds are also in the HBV drug development pipeline.
Following is a brief summary of an article by Drs. G.V. Papatheodoridis and S.J. Hadziyannis that focuses on the three approved compounds. More Information on these therapies and on the HBV experimental drugs in development is available in the links following the summary.
The three treatments currently FDA-approved possess unique characteristics with respect to their side effect profiles, potencies, and treatment niches within the spectrum of CHB.
The newer agents, which are in various stages of clinical development, represent potential improvements within existing, as well as novel, classes of antiviral therapy, and they offer significant promise of a cure for the many patients with chronic and progressive hepatitis B.
However, there remain many challenges in understanding the implications of drug resistance, the role of combination therapy, and how to define the response to therapy within subsets of patients with hepatitis B.
Chronic hepatitis B can be diagnosed in patients with increased aminotransferases, hepatitis B virus viremia and necro-inflammation with fibrosis on liver biopsy. Although, ideally, all patients with chronic hepatitis B should be treated, therapeutic intervention is currently recommended for cases with a relatively satisfactory likelihood of response and/or advanced disease.
A realistic therapeutic approach aims to sustain hepatitis B e antigen (HBeAg) loss and hepatitis B e antibody (anti-HBe) seroconversion in HBeAg-positive chronic hepatitis B and to sustain biochemical and virological remission in HBeAg-negative chronic hepatitis B.
Currently, three drugs are licensed for chronic hepatitis B: interferon-alpha, lamivudine and adefovir dipivoxil. In patients with HBeAg-positive chronic hepatitis B, all of these drugs achieve HBeAg loss (24-33%) and anti-HBe seroconversion (12-30%) rates significantly superior to those observed in untreated placebo controls.
In patients with HBeAg-negative chronic hepatitis B, the sustained off-therapy response rate is 20-25% after a ≥12-month course of interferon-alpha and minimal (< 10%), if any, after a 12-month course of lamivudine or adefovir.
Long-term lamivudine induces an initial response in 70-90% of patients, but only 30-40% of patients remain in remission after the third year due to progressively increasing viral resistance to lamivudine.
Long-term adefovir achieves a response in approximately 70% of patients at 12 months, which is maintained at 24 months with rare (< 2%) drug resistance. Adefovir is also effective against lamivudine-resistant strains.
Many other anti-viral agents, immunomodulatory approaches and combination therapies are currently being evaluated in chronic hepatitis B.
Division of Infectious Diseases, University of California Davis Medical Center, Sacramento.
HIV and Hepatitis.com: FDA-approved Therapies for Chronic HBV
牋牋? Epivir-HBV (lamivudine; 3TC)
牋牋? Intron A (interferon alfa-2b)
牋牋? Hepsera (adefovir dipivoxil)
HIV and Hepatitis.com:
Experimental anti-HBV Treatments
Therapies (Approved and Experimental) and Vaccines for Chronic HBV
Hepatitis B Overviews, Guidelines, Reports
Reports on Major Hepatitis Research Conferences
10/22/04 Reference
G V Papatheodoridis and S J Hadziyannis. Current management of chronic hepatitis B. Alimentary Pharmacology & Therapeutics 19(1): 25-38. January 2004.
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发表于 2004-10-26 22:59
