A Study in Patients With Metastatic Prostate Cancer to Assess How the Drug Eligard®, Affects Certain Markers in Blood and Urine, Which Are Indicators for the Disease

Inclusion Criteria: * Confirmed metastatic prostate cancer for whom androgen deprivation therapy (ADT) is indicated. * Non-castrate level of testosterone (≥ 8 nmol/L (230 ng/dL)) at screening. * Serum PSA ≥ 5 ng/mL at screening. * Eastern Cooperative Oncology Group (ECOG) score of 0-2 * A life expectancy of at least 12 months. * Is able to tolerate injection of study drug and comply with the study requirements. * Positive blood PSA mRNA at screening. A positive PSA mRNA in PBMCs (defined as exceeding the Limit of Detection \[LoD\] for the central lab assay, i.e. ≥ 10 copies per Polymerase Chain Reaction, PCR). Exclusion Criteria: * History of bilateral orchidectomy. * History of any hormonal treatment/therapy with GnRH agonist, GnRH anti-agonist within 6 months of enrolment. * Treatment with anti-androgens (except where used to prevent testosterone flare up, starting up to 2 weeks prior to Eligard injection, according to local treatment guidelines), 5-α reductase inhibitors, estrogens and/or other any investigational hormone-derivative within 3 months of enrolment or 5-times the half-life, whichever is longer. * Any previous treatment with chemotherapy treatment for prostate cancer prior to the screening visit or within 6 months prior to screening for any other cancer. * Patients previously treated for cancer with hormonal therapy in whom treatment was stopped due to lack of efficacy, progression of the disease or lack of tolerability. * Previous treatments for cancer (including prostate cancer) within 6 months prior to enrolment: immunotherapy, external beam radiotherapy, brachytherapy, thermotherapy, or biological response modifiers (e.g. cytokines). * Known or suspected spinal cord compression or evidence of spinal metastases with risk of spinal compression. * Uni- or bilateral ureteric obstruction. * Requiring concomitant use of anti-androgens during the course of the study (except where used to prevent testosterone flare up, starting up to 2 weeks prior to Eligard injection and continuing for up to 3 weeks, according to local treatment guidelines). * Previous or concomitant malignancies at other sites except effectively treated non-melanoma skin cancer or an effectively treated malignancy that has been in remission for at least 5 years. * Major surgery within 2 months prior to enrolment. * Total bilirubin \> 1.5 times the upper limit of normal (ULN) at screening. This will not apply to subjects with Gilbert's syndrome (persistent or recurrent hyperbilirubinemia that is predominantly unconjugated in the absence of evidence of hemolysis or hepatic pathology), who will be allowed in consultation with the sponsor. * Participation in any clinical study within ≤ 1 month prior to screening (or 5 half lives of the drugs under investigation, whichever is greater). * Not available for follow-up assessments or unable to comply with study requirements. * Known or suspected hypersensitivity to leuprorelin acetate, to other GnRH agonists or to any of the excipients of Eligard. * Male subjects who are intending to donate sperm within 9 months following the injection of Eligard * Male subjects and their female spouses/partners who are of childbearing potential and are NOT using highly effective contraception consisting of two forms of birth control (one of which must be a barrier method) starting at Screening and continuing for 9 months from the time of the Eligard injection. Acceptable forms include: * Established use of oral, injected or implanted hormonal methods of contraception. * Placement of an intrauterine device (IUD) or intrauterine system (IUS). * Barrier methods of contraception: Condom OR Occlusive cap (diaphragm or cervical/vault caps) with spermicidal foam/gel/film/cream/suppository * Absolute neutrophil count \< 1,500/μL, platelet count \< 100,000/μL, and hemoglobin \< 5.6 mmol/L (9 g/dL) at screening. * Alanine aminotransferase (ALAT) or aspartate aminotransferase (ASAT) \> 2 times ULN at screening. * Creatinine \> 177 μmol/L (2 mg/dL) at screening. * Albumin ≤ 30 g/L (3.0 g/dL) at screening.