Reuters Health Information (2004-01-29): Adefovir effective in lamivudine-resistant chronic hepatitis B
Adefovir effective in lamivudine-resistant chronic hepatitis B
Last Updated: 2004-01-29 12:35:36 -0400 (Reuters Health)
NEW YORK (Reuters Health) - Adefovir, alone or in combination with ongoing lamivudine therapy, is effective treatment for lamivudine-resistant chronic hepatitis B virus (HBV) infection, according to a report in the January issue of Gastroenterology.
The incidence of lamivudine resistance can reach 69% after 5 years of treatment, the authors explain. Adefovir has been shown in vitro to suppress lamivudine-resistant HBV and in vivo to suppress wild-type HBV.
Dr. Marion G. Peters from University of California, San Francisco and colleagues for the GA-00-461 Study Group assessed the safety and effectiveness of adefovir dipivoxil in 59 patients with chronic HBV infection and compensated liver disease and lamivudine-resistant HBV.
Serum HBV DNA levels declined significantly in patients receiving adefovir alone or in combination with lamivudine, the authors report, but not in patients receiving lamivudine monotherapy.
Sixteen percent of patients receiving adefovir monotherapy and 11% of patients receiving adefovir and lamivudine became HBeAg-negative by week 48, the researchers note, but no lamivudine monotherapy patients lost HBeAg.
Clinical status (as measured by Child-Pugh-Turcotte scores) and adverse events did not differ significantly across treatment groups, the report indicates.
Adefovir therapy continued to suppress HBV DNA levels following cessation of lamivudine treatment, the investigators report, even in patients whose HBV reverted to wild-type HBV.
"The antiviral response seen between the combination of adefovir dipivoxil plus lamivudine compared with adefovir dipivoxil monotherapy was similar," the authors conclude, "suggesting that lamivudine provides little or no antiviral benefit in patients with lamivudine resistance and confirming the activity of adefovir dipivoxil against both wild-type and lamivudine-resistant HBV."
Dr. Peters told Reuters Health that there appears to be no reason to continue lamivudine after initiating adefovir therapy in most of these patients. Combination therapy, however, should be continued in patients with cirrhosis.
"Adefovir is an alternative and lamivudine does not need to be continued provided that the patient is not decompensated," Dr. Peters concluded. "Flares do occur on treatment and are usually benign."