A Phase IIIb Study of Intermittent Versus Continuous Hormone Deprivation Treatment With ELIGARD

Inclusion Criteria: At study entry (visit 1): * Written informed consent * Male subjects aged \>=18 and \<80 years old * Locally advanced (stage T3 or T4) prostate cancer or Relapsing prostate cancer following radical prostatectomy or,Relapsing prostate cancer following radiotherapy * Gleason score of \>=6 * ECOG performance status of 0-2. * Life expectancy at least 5 years At randomization (visit 4): * Two successive decreasing serum PSA levels \<=1 ng/ml Exclusion Criteria: At study entry (visit 1): * Any suspected second primary tumors * Evidence of metastatic disease * Other malignancy within the last 5 years except * Acute spinal cord compression, uni- or bilateral ureteric obstruction * Any concurrent biological response modifier therapy * Concurrent chemotherapy * Less than 1 year since any prior neoadjuvant or adjuvant hormonal therapy * Less than 6 months since prior 5-alpha reductase inhibitor treatment * Other concurrent hormonal therapy * Any concurrent radiotherapy * Testosterone at screening \<= 1.7 mM or 50 ng/dL * Clinically significant elevation of serum creatinine or liver enzymes * Hypersensitivity to GnRH or other GnRH analogues or leuprorelin acetate * Hypersensitivity to CASODEXâ 50 mg.