Adefovir dipivoxil: new preparation. A third-line option in chronic hepatitis B.

(1) Without treatment, between 15% and 25% of patients with chronic hepatitis B die prematurely, usually of cirrhosis or hepatocellular carcinoma. Two treatments are already available to prevent these complications, namely interferon alfa (2a and 2b), and lamivudine, a nucleotide analogue. (2) Marketing authorization has now been granted in the European Union for another antiviral agent, adefovir dipivoxil, a prodrug of the nucleotide analogue adefovir. (3) Two double-blind placebo-controlled trials in treatment-naive patients with active viral replication showed that adefovir dipivoxil 10 mg/day orally reduced viral load and improved hepatic histology. (4) In lamivudine-resistant patients with active viral replication, the preliminary results of two trials comparing adefovir dipivoxil with continued lamivudine therapy, and data from two non comparative trials (one in HIV-coinfected patients), showed that adefovir dipivoxil reduced viral load by about 4 log after 48 weeks. (5) In clinical trials, creatinine levels rose in 2-5% of patients treated with 10 mg/day adefovir dipivoxil, reflecting renal toxicity. Other possible risks, and especially lactic acidosis, must be monitored closely. (6) In practice, adefovir dipivoxil is currently a third-line option for patients with chronic hepatitis B, when interferon alfa-2 and lamivudine fail or are poorly tolerated.