The active ingredient of Pamorelin® 11,25 mg is Triptorelin. Triptorelin is a substitute for a natural hormone produced in the body called Gonadotrophin-releasing hormone (GnRH). GnRH is a hormone secreted by hypothalamus (a gland located in brain) and controls the production of sex hormones (eg testosterone in men) in other organs in the body. The growth of prostate cancer cells, one of the most common cancers in men, is induced by the hormone testosterone. Hormonotherapy is one of treatments available to treat this type of disease by controlling the testosterone serum level. Pamorelin® 11,25 mg is normally injected in the muscle but this type of injection is not suitable for every patient. Therefore the primary purpose of this study is to assess the non-inferiority of the 12-week triptorelin formulation Pamorelin® 11,25 mg administered via subcutaneous (SC) injection as compared to Pamorelin® 11,25 mg administered via standard intramuscular (IM) injection based on the percentage of patients presenting a testosterone level ≤ 50 ng/dl at week 24.