GILEAD INITIATES PHASE III PROGRAM EVALUATING TENOFOVIR DISOPROXIL FUMARATE

Gilead Sciences has begun enrolling patients in its Phase III clinical program evaluating the oral antiviral drug tenofovir disoproxil fumarate (tenofovir DF) for the treatment of chronic hepatitis B.

Two Phase III clinical trials (Studies 102 and 103) will evaluate tenofovir DF among patients with either hepatitis B "e" antigen (HBeAg)-positive chronic hepatitis B or HBeAg-negative/anti-hepatitis B "e" positive (anti-HBe positive) chronic hepatitis B. Studies 102 and 103 are randomized, double-blind trials that will compare the efficacy, safety and tolerability of tenofovir DF versus Gilead's Hepsera (adefovir dipivoxil) over a 48-week period at more than 100 centers in 14 countries.

Study 102 will enroll approximately 300 patients with HBeAg-negative/anti-HBe positive (presumed pre-core mutant) chronic hepatitis B, with 200 patients receiving tenofovir DF (300 mg once daily) and 100 patients receiving Hepsera (10 mg once daily). Study 103 is designed to enroll approximately 240 patients with HBeAg-positive chronic hepatitis B, with 160 patients receiving tenofovir DF (300 mg once daily) and 80 patients receiving Hepsera (10 mg once daily).

The primary endpoint of both trials is the proportion of patients with a complete response at Week 48, defined as a serum HBV DNA level below 400 copies/mL, and improvement in liver histology scores, which is defined as at least a two-point reduction in the Knodell necroinflammatory score without worsening in fibrosis.