Open-Label, Randomised Parallel-Group Study

Inclusion Criteria: * Patients, aged 18 years or older, with a histologically proven prostate cancer of all stages in whom endocrine treatment is indicated. * Screening testosterone level above the lower limit of normal range, globally defined as \> 2.2 ng/mL. * Screening PSA level of =2 ng/mL. ECOG score of =2. * Life expectancy of at least one year. CRITERIA FOR EVALUATION: Primary endpoint: * Probability of testosterone at castrate level (=0.5 ng/mL) from Day 28 through Day 364. Secondary endpoints: * Probability of testosterone at castrate level (=0.5 ng/mL) from Day 56 through Day 364. * Serum levels of testosterone, LH, FSH, and PSA over time. * Time to PSA failure - defined as two consecutive increases of 50%, and at least 5 ng/mL, compared to nadir. * Plasma levels of degarelix over time. * Frequency and severity of adverse events. * Clinically significant changes in laboratory safety parameters. * Clinically significant changes in physical examinations, ECGs, vital signs, and body weight.