Phase II Study of ASP3550 in Patients With Prostate Cancer

Inclusion Criteria: * Is a male patient with histologically proven prostate cancer (adenocarcinoma) of all stages * Is a patient in whom endocrine treatment is indicated. Patients with rising serum PSA after having prostatectomy or radiotherapy performed with curative intention may be included * Has a serum testosterone level above 1.5 ng/mL at screening * Has an ECOG (Eastern Co-operative Oncology Group) P.S. (Performance Status) score of 0 to 2 Exclusion Criteria: * Previous or present endocrine treatment for prostate cancer. However, patients who have undergone neoadjuvant/adjuvant endocrine therapy for a maximal duration of 6 months and in whom prostatectomy or radiotherapy was terminated at least 6 months preceding Screening Visit may be included * Is being treated with a 5α-reductase inhibitor * Is a candidate for curative therapy, i.e., radical prostatectomy or radiotherapy within 12 months * Has concurrent or a history of severe asthma (defined as a need for daily treatment with inhalation steroids), anaphylactic reactions, severe urticaria and angioedema