This is a study to compare the efficacy and safety of 3 doses of DR-2031 to placebo when used as "add-on" therapy for prostate cancer patients with hot flashes following surgical or medical castration. All prostate cancer therapy must be stable for at least 45 days before entering the study and must remain stable throughout this 12-week study. Patients will maintain a daily paper diary to record the frequency and severity of hot flashes during the treatment period.

This is a study to compare the efficacy and safety of 3 doses of DR-2031 to placebo when used as "add-on" therapy for prostate cancer in patients with mild to moderate vasomotor symptoms (hot flashes) following surgical or medical castration. All prostate cancer therapy must be stable for at least 45 days before entering the study and must remain stable throughout this 12-week study. To be eligible for this study prostate cancer patients must have undergone bilateral orchiectomy or medical castration utilizing LHRH analogues (LHRH agonists or LHRH antagonists) with or without additional antiandrogen therapy. Patients must have at least 21 moderate to severe hot flashes weekly.

Patients will maintain a daily paper diary to record the frequency and severity of hot flashes during the treatment period. In addition, a brief physical evaluation will be done, diaries will be reviewed and any adverse events will be recorded at each follow-up evaluation.

Inclusion Criteria:

• Prostate cancer patients who have undergone chemical or surgical castration
• History of hot flashes for at least 30 days
• Stable prostate cancer therapy for at least 45 days

Exclusion Criteria:

• Uncontrolled diabetes or severe COPD
• History of thromboembolic disease
• Liver or kidney dysfunction
• History or presence of cancer other than prostate cancer within the last 5 years
• Surgery within the last 3 months