The purpose of this phase II, randomized, double-blind placebo controlled, multi-center study is to evaluate the safety and efficacy of 10 mg atrasentan in hormone naive subjects as measured by rate of rise in the PSA (primary objective).

Inclusion Criteria:

• prostate adenocarcinoma,
• radical prostatectomy,
• PSA between 0.4 and 5 ng/mL,
• PSADT < 1 year

Exclusion Criteria:

• previous hormonal therapy,
• salvage therapy to the pelvis within 3 months prior to randomization