The purpose of the study is to evaluate the pharmacodynamic profile and safety of BN83495 in patients with prostate cancer with disease progression while on androgen ablative therapy

Evaluate the PD profile of BN83495 after 28 days of daily oral administration in patients with locally advanced or metastatic prostate cancer on androgen ablative therapy and with rising prostatic specific antigen

Inclusion Criteria:

• Confirmed and locally advanced or metastatic prostate cancer with rising prostate-specific antigen (PSA), while on androgen ablative therapy.
• Over age 18.
• Demonstrated PSA "biochemical failure".
• Adequate bone marrow and hepatic function

Exclusion Criteria:

• Luteinizing Hormone-Releasing Hormone analogue treatment and treated with more than one additional second line of endocrine therapy
• Prior treatment with ketoconazole
• Prior chemotherapy for hormone refractory prostate cancer
• Pre-existing cardiac failure and/or clinically significant abnormal ECG or Echo