A Study to Compare the Effect of ASP3550 With Goserelin in Patients With Prostate Cancer

This study consists of two parts. The purpose of PART 1 is to test non-inferiority of ASP3550 to goserelin acetate with respect to the cumulative castration rate in terms of serum testosterone when ASP3550 or goserelin acetate is administered for one-year in patients with prostate cancer.

The patients assigned to receive ASP3550 and completed the treatment in PART 1 are eligible for the treatment in PART 2, and will receive ASP3550 maintenance dose subcutaneously for additional term. The long-term safety, efficacy and PK of the continued ASP3550 treatment will be assessed in PART 2.

Inclusion criteria

• Male patient with histologically confirmed prostate cancer (adenocarcinoma).
• Patient in whom endocrine treatment is indicated. Patient having undergoing prostatectomy or radiotherapy with curative intention and has a rising serum PSA (PSA ≥ 2 ng/mL at screening) may be included.
• Has a serum testosterone level above 2.2 ng/mL at screening.
• Has an Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) score of 0 to 2 at screening.
• Has a serum PSA ≥ 2 ng/mL at screening.
• Has a life expectancy of at least 12 months.

Exclusion criteria

• Previous or present endocrine treatment for prostate cancer. Example: surgical castration, GnRH agonists, GnRH antagonists, antiandrogens or oestrogens, and 5α-reductase inhibitors.
• Received a 5α-reductase inhibitor within 25 weeks preceding screening.
• Is a candidate for curative therapy, i.e., radical prostatectomy or radiotherapy within 12 months.
• Has concurrent or a history of poorly controlled severe asthma, anaphylactic reactions, severe urticaria or angioedema.
• Has hypersensitivity towards mannitol.
• Has a marked prolongation of QT/QTc interval (two consecutive increases to >450 ms in QTc interval at retest) at screening.
• Has concurrent or a history of a disease (heart failure, hypokalemia, a family history of QT prolongation syndrome, etc.) that may induce Torsade de Pointes.