The drug adefovir dipivoxil is effective in treating patients with both positive and negative hepatitis B e antigen (HbeAg), according to two separate studies reported in the Feb. 27 issue of the New England Journal of Medicine.
Adefovir dipivoxil is a nucleotide analogue that is marketed under the brand name of Hepsera. The U.S. Food and Drug Administration approved the drug last fall for the treatment of chronic hepatitis B.
In the first study, 185 patients with chronic hepatitis B who were negative for hepatitis B e antigen (HBeAg) received either 10 mg of adefovir dipivoxil or a placebo once daily for 48 weeks.
The researchers found that 48 weeks of adefovir treatment in such patients resulted in significant histologic, virologic and biochemical improvement with adverse effects similar to that of a placebo. No evidence of the emergence of adefovir-resistant hepatitis B virus polymerase mutations was found.
At week 48, 64 percent of patients who had base-line liver-biopsy specimens available in the adefovir dipivoxil group had improvement in histologic liver abnormalities, compared with 33 percent of patients in the placebo group.
Serum hepatitis B virus DNA levels were reduced to fewer than 400 copies per milliliter in 51 percent of patients in the adefovir dipivoxil group and in none of those in the placebo group.
The median decrease in log-transformed hepatits B virus DNA levels was greater with adefovir dipivoxil treatment than with the placebo (3.91 vs. 1.35 log copies per milliliter).
Alanine aminotransferase levels had normalized at week 48 in 72 percent of patients receiving adefovir dipivoxil, compared with 29 percent of those receiving placebo.
In the other study involving adefovir dipivoxil, researchers randomly assigned 515 patients with chronic hepatitis B who were positive for HBeAg to receive 10 mg of adefovir dipivoxil, 30 mg of adefovir dipivoxil or a placebo daily for 48 weeks.
Compared to a placebo, the researchers found that 10 mg or 30 mg of adefovir dipivoxil per day resulted in greater histologic liver improvement, reduced serum HBV DNA and alanine aminotransferase levels and increased the rates of HBeAg seroconversion. The drug did not result in the development of mutations in the hepatitis B virus polymerase gene that are associated with resistance.
Although the safety profile of the 10-mg dose of adefovir dipivoxil was similar to that of placebo, the researchers found a higher frequency of adverse events and renal laboratory abnormalities in the group given 30 mg of adefovir dipivoxil per day.
Other sources: New England Journal of Medicine