The drug can be used in adults with evidence of active viral replication and either elevations in serum alanine aminotransferase (ALT) or aspartate aminotransferase (AST), or histologically active disease.
Adefovir dipivoxil slows the progression of chronic hepatitis B by interfering with viral replication and causing DNA chain termination after its incorporation into viral DNA.
FDA based its approval of adefovir dipivoxil on the results of 2 randomized, double blind, placebo-controlled studies.
At week 48 of the studies, 53% of patients receiving adefovir dipivoxil in one study and 64% of patients in the other study showed significant improvement in the liver inflammation caused by HBV. This was compared to 25% and 35% of patients receiving placebo, respectively.
A statistically significant improvement in the degree of liver fibrosis was also observed in the patients who received the drug.
| Adefovir dipivoxil effectively treats lamivudine-resistant HBV infection.
Moreover, adefovir dipivoxil has been shown to be effective in treating patients with clinical evidence of HBV that is resistant lamivudine.
The major adverse events associated with the use of adefovir dipivoxil include severe, acute exacerbation of hepatitis B after discontinuation of the drug and kidney toxicity.
Patients who have discontinued other approved products for the treatment of chronic hepatitis B have also experienced severe, acute exacerbation of hepatitis.
This adverse event occurred in up to 25% of clinical trial participants after discontinuation of adefovir dipivoxil.
The labeling for adefovir dipivoxil states that patients who discontinue adefovir dipivoxil should be monitored at repeated intervals over a period of time for hepatic function.
Kidney toxicity was reported in patients at risk of or having underlying kidney dysfunction.
In addition, there is a theoretical concern associated with adefovir dipivoxil that HIV resistance could emerge in chronic hepatitis B patients with unrecognized or untreated HIV infection.