This Phase IV observational trial is intended to identify patients who are failing GnRH agonist therapy as evidenced by a rising PSA and who have yet to initiate secondary manoeuvres involving antiandrogens. This group may include both non-metastatic as well as metastatic patients. The trial will determine if these patients will benefit from switching to Degarelix. It will assess the effect of Degarelix's direct mode of action on androgen levels and whether continuous use of Degarelix improves disease progression.

As per the CUA Guidelines for the Management of CRPC, because the androgen receptor remains active in most patients who have developed castration resistant disease, it is recommended that ADT should be continued (LEVEL 3, GRADE C). Therefore, it is logical to continue patients on Degarelix throughout the castrate resistant period. This will allow for the gathering of data that is currently unknown within this setting, such as the effect of combined treatment with antiandrogens as well as chemotherapy and other castrate resistant treatments.

This trial will include hormone sensitive prostate cancer patients switched to Degarelix therapy after failing on GnRH agonists but prior to use of secondary hormonal treatments such as antiandrogens. The purpose of this trial is to determine the effect of Degarelix's direct mode of action on androgen levels and whether continuous use of Degarelix improves disease progression.

This is an open-label, multi-centre, Phase IV observational trial with s.c. injections of Degarelix one-month depot in patients with advanced prostate cancer.

The visit frequency is once a month (28-day intervals), with eCRF data entry at every 4 months. All patients will be treated with a one-month starting dose followed by 23 monthly maintenance doses for a duration of 672 days. The primary endpoints will be evaluated after 24 treatment months.

In total, 25 visits are scheduled for all patients.

Inclusion Criteria:

• Able to read and write, understand instructions related to trial procedures and give written informed consent before any trial-related activity is performed
• Histologically confirmed adenocarcinoma of the prostate (prostate cancer)
• Currently under hormonal management of prostate cancer with a GnRH agonist
• Confirmed biochemical PSA progression on GnRH agonist therapy, defined as ≥50% increase in PSA between 2 measurements, taken at least 1 week apart
• PSA ≥1.0 ng/ml
• ECOG score ≤2
• Able and willing to participate in the full duration of the clinical trial
• Male patient aged 18 years or older
• Life expectancy of at least 12 months

Exclusion Criteria:

• Prior treatment with chemotherapy, radiopharmaceuticals, estrogen, ketoconazole or other secondary hormonal treatments such as antiandrogens except for induction phase (<3 months)
• History of dermatitis, lupus, eczema, psoriasis affecting area used for Degarelix injections
• Allergy to Degarelix or its components
• Has a clinically significant disorder (other than prostate cancer) including, but not limited to, renal, haematological, gastrointestinal, endocrine, cardiac, neurological, or psychiatric disease, and alcohol or drug abuse or any other condition, which may affect the patient's health or the outcome of the trial as judged by the Investigator
• Has a history of bilateral orchiectomy, adrenalectomy, or hypophysectomy.
• Has a history of severe untreated asthma, anaphylactic reactions, or severe urticaria and/or angioedema
• Has a mental incapacity or language barrier precluding adequate understanding or co operation

Patients with prostate cancer failing androgen deprivation therapy can be investigated in this trial.