Clinical

Tenofovir better than adefovir for chronic hepatitis B

Last Updated: 2008-12-03 17:00:13 -0400 (Reuters Health)

By Anthony J. Brown, MD

NEW YORK (Reuters Health) - Tenofovir disoproxil fumarate (Viread) is more effective than and just as safe as adefovir dipivoxil (Hepsera) for treating chronic hepatitis B virus infection, according to a report in The New England Journal of Medicine for December 4.

"This is the first time that a drug has shown superiority to Hepsera in an adequately powered head-to-head comparison; Hepsera has been the market leader for chronic HBV in the US," senior author Dr. Franck Rousseau, from Gilead Sciences, Durham, North Carolina, told Reuters Health.

The results come from two phase 3 studies involving over 600 patients with Hepatitis B e antigen (HBeAg)-negative or -positive disease who were randomized to receive tenofovir 300 mg or adefovir 10 mg once daily for 48 weeks. The primary endpoint was a plasma HBV DNA level <400 copies/mL and histologic improvement at week 48.

Compared with adefovir, tenofovir significantly increased the likelihood of attaining the primary endpoint (p < 0.001). Moreover, viral suppression was more commonly achieved with tenofovir in both HBeAg-negative patients (93% vs. 63%) and HBeAg-positive patients (76% vs. 13%).

Moreover, in HBeAg-positive patients, tenofovir therapy was also more likely than adefovir to promote normalization of alanine aminotransferase level and loss of hepatitis B surface antigen, the report indicates.

HBV testing at week 48 showed no evidence of resistance to tenofovir or other anti-HBV agents in any patients. Tenofovir appeared to perform equally well in patients previously treated or not treated with lamivudine.

The safety profiles of tenofovir and adefovir were comparable.

The message for clinicians, Dr. Rousseau said, is that "there is a new drug available for treatment of chronic HBV and this drug works in the vast majority of patients regardless of what treatment history they have because of its potency and lack of resistance/cross resistance, unlike all other antivirals approved so far." He added that tenofovir is "kind of a one-size-fits-most therapy."

N Engl J Med 2008;359:2442-2455.