Evaluation of Effects of Estetrol on Testosterone Suppression and Quality of Life in Prostate Cancer Patients Treated With an LHRH Agonist.

Inclusion Criteria: * Male patients with prostate cancer, qualifying for treatment with a LHRH agonist; * Age ≥ 18 years; * Body mass index (BMI) between ≥ 18.0 and ≤ 35.0 kg/m2 (inclusive); * Reasonable physical and mental health as judged by the Investigator determined by physical examination, clinical laboratory assessments and vital signs; * Eastern Cooperative Oncology Group (ECOG) Performance Status 0-1; * Life expectancy of at least 2 years. Exclusion Criteria: * Current or prior (during the last 12 months) hormonal therapy, immunotherapy or chemotherapy for prostate cancer. Allowed are 14 days concomitant treatment with an anti-androgen to prevent the flare-up, radiotherapy and low dose radiation to prevent gynecomastia; * History of deep vein thrombosis, pulmonary embolism, or cerebrovascular accident. However, patients with such history using anticoagulants for ≥ 6 months are eligible for the study provided anticoagulant treatment is continued throughout the whole study; * History of myocardial infarction or a coronary vascular procedure (e.g. percutaneous coronary intervention, coronary artery bypass graft). However, patients with such history using anticoagulants for ≥ 6 months are eligible for the study provided anticoagulant treatment is continued throughout the whole study; * Patients who have unstable angina or clinical congestive heart failure; * A defect in the blood coagulation system, assessed at screening: deficiencies in AT-III, protein C and protein S and elevated factor VIII; * Mutation in coagulation factor II and/or positive for factor V Leiden, assessed at screening; * Diabetes mellitus with poor glycaemic control in the past 6 months (haemoglobin A1c (HbA1c) above 7.5%); * Known primary hyperlipidaemias (Fredrickson); * Disturbance of liver function: cholestatic jaundice, a history of jaundice due to previous estrogen use, Rotor syndrome and Dubin-Johnson syndrome; * Known porphyria; * Uncontrolled hypertension, i.e. systolic blood pressure 160 mmHg and/or diastolic blood pressure 100 mmHg in the last 6 months with or without medication.