FOSTER CITY, Calif.--(BUSINESS WIRE)--Gilead Sciences, Inc. (Nasdaq: GILD) today announced the publication of detailed 48-week data from two Phase III pivotal clinical trials evaluating the safety and efficacy of its once-daily Viread® (tenofovir disoproxil fumarate) for the treatment of chronic hepatitis B virus (HBV) infection in adults. The results of both studies (Studies 102 and 103), published in the December 4, 2008 issue of The New England Journal of Medicine (N Engl J Med 2008; #80-2878), show that Viread is significantly more effective in treating the virus that causes chronic hepatitis B than one of the most widely prescribed oral medications for HBV in the United States, Hepsera® (adefovir dipivoxil), also developed and marketed by Gilead.