Effects of Triptorelin When Given Every 6-months Under the Skin to Adult Males With Cancer in the Prostate

Inclusion Criteria : * Participant is male and must be 18 years of age inclusive, at the time of signing the informed consent * Participant has histologically or cytologically proven prostate cancer with rising PSA after failed local therapy or metastatic disease, or requiring radiotherapy, and be a candidate for long-term (i.e. \>1 year) androgen deprivation therapy * Participant requires a GnRH analogue treatment for a minimum of 18 months, of which a minimum of 3 months of GnRH analogue treatment has already been provided prior to screening. (Note: participants must receive study intervention on Day 1 in accordance with the treatment schedule of their previously received GnRH analogue therapy). * Has serum testosterone levels \<1.735 nmol/L (50 ng/dL) at screening * Has Eastern Cooperative Oncology Group (ECOG) performance status score of 0 to 1 * Has a life expectancy of \>18 months * Male participants must agree that, if their partner is at risk of becoming pregnant (although highly unlikely in this study population), they will use an effective method of contraception. The participant must agree to use the contraception during the whole of the study and for 9 months after the last dose of study intervention * Capable of giving signed informed consent which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in the protocol Exclusion Criteria : * Presence of another neoplastic lesion or brain metastases * Metastatic hormone-sensitive prostate cancer with high tumour burden * Metastatic castration-resistant prostate cancer * Any concomitant disorder or resulting therapy that is likely to interfere with participant compliance or with the study in the opinion of the investigator * Use of finasteride (Proscar®) or dutasteride (Avodart®/Avolve®) within the past 6 months * Planned intermittent scheme of GnRH analogue * At the time of screening, planned use of any chemotherapy for prostate cancer during the study * Prior hypophysectomy or adrenalectomy * Participation in another study with an experimental drug within 3 months before signing informed consent or within five half-lives of the investigational drug (whichever was the longer), or any other type of medical research * Severe kidney or liver failure (creatinine \>2 times the normal range, aspartate aminotransferase and alanine aminotransferase \>3 times the normal range) * Any concomitant disorder or resulting therapy that is likely to interfere with participant's compliance, the subcutaneous administration of the drug or with the study in the opinion of the investigator * Previous history of QT prolongation or concomitant use of medicinal products known to prolong the QT interval or with a known risk of torsades de pointes * Known hypersensitivity to triptorelin or any of its excipients, GnRH, other GnRH agonist/analogues * Known active use of recreational drug or alcohol dependence in the opinion of the investigator * Inability to give informed consent or to comply fully with the protocol