Phase III Study of DCVAC/PCa Added to Standard Chemotherapy for Men With Metastatic Castration Resistant Prostate Cancer

Inclusion criteria: * Male 18 years and older. * Histologically or cytologically confirmed prostate adenocarcinoma. * Presence of skeletal, or soft-tissue/visceral/nodal metastases according to one of the following criteria: * Confirmed pathological fracture related to the disease OR * Confirmation of distant bone and/or soft-tissue and/or visceral metastases on CT or MRI scan or bone scintigraphy OR * Positive pathology report of metastatic lesion * Disease progression despite androgen-deprivation therapy (ADT) as indicated by: * Prostate-specific antigen (PSA) increase that is ≥ 2 ng/mL and ≥ 25% above the minimum PSA as reached during ADT or above the pre-treatment level, if no response was observed and which is confirmed by a second value 1 or more weeks later OR * Progression of measurable lymph nodes (short axis ≥ 15 mm) or visceral lesion measurable per RECIST v1.1 criteria, confirmation by an independent review facility (IRF) required OR * Two or more new lesions appearing on bone scan/imaging compared with a previous scan (confirmation by IRF required) * Maintenance of castrate conditions: patients, who have not had a surgical orchiectomy, must continue with hormone therapy with gonadotropin releasing hormone/ luteinizing hormone-releasing hormone (GnRH/LHRH) agonists or antagonists to reach levels of serum testosterone of ≤ 1.7 nmol/L (50 ng/dL). The duration of the castration period must be at least 4 months before screening as evidenced by combination of clinical/laboratory data (see section 6.8.1). * Laboratory criteria: * White blood cells (WBC) greater than 4,000/mm3 (4.0 x109/L) * Neutrophil count greater than 1,500/mm3 (1.5 x109/L). * Hemoglobin of at least 10 g/dL (100 g/L). * Platelet count of at least 100,000/mm3 (100 x 109/L). * Total bilirubin within normal limits (benign hereditary hyperbilirubinemias, e.g. Gilbert's syndrome, are permitted). * Serum alanine aminotransferase, aspartate aminotransferase, and creatinine \< 1.5x times the upper limit of normal (ULN). * Life expectancy of at least 6 months based on Investigator's judgment. * Eastern Cooperative Oncology Group (ECOG) Performance status 0-2. * At least 4 weeks after surgery or radiotherapy before randomization. * A minimum of 28 days beyond initiation of bisphosphonate or denosumab therapy before randomization. * Recovery from primary local surgical treatment, radiotherapy or orchiectomy before randomization. * Signed informed consent including patient's ability to comprehend its contents. Exclusion criteria: * Confirmed brain and/or leptomeningeal metastases (other visceral metastases are acceptable). * Current symptomatic spinal cord compression requiring surgery or radiation therapy. * Prior chemotherapy for prostate cancer. * Patient co-morbidities: * Subjects who are not indicated for chemotherapy treatment with first line Standard of Care chemotherapy (docetaxel and prednisone). * HIV positive, human T-lymphotropic virus positive. * Active hepatitis B (active hepatitis B), active hepatitis C (HCV), active syphilis. * Evidence of active bacterial, viral or fungal infection requiring systemic treatment. * Clinically significant cardiovascular disease including: * symptomatic congestive heart failure. * unstable angina pectoris. * serious cardiac arrhythmia requiring medication. * uncontrolled hypertension. * myocardial infarction or ventricular arrhythmia or stroke within a 6 months before screening, known left ventricular ejection fraction (LVEF) \< 40% or serious cardiac conduction system disorders, if a pacemaker is not present. * Pleural and pericardial effusion of any NCI CTCAE grade. * Peripheral neuropathy having a NCI CTCAE ≥ grade 2. * History of malignant disease (with the exception of non-melanoma skin tumors) in the preceding five years. * Active autoimmune disease requiring treatment. * History of severe forms of primary immune deficiencies. * History of anaphylaxis or other serious reaction following vaccination. * Known hypersensitivity to any constituent of the DCVAC/PCa or placebo product. * Uncontrolled co-morbidities including, psychiatric or social conditions which, in the Investigator's opinion, would prevent participation in the trial. * Systemic corticosteroids at doses greater than 40 mg hydrocortisone daily or equivalent for any reason other than treatment of PCa within 6 months before randomization. * Ongoing systemic immunosuppressive therapy for any reason. * Treatment with anti-androgens, inhibitors of adrenal-produced androgens or other hormonal tumor-focused treatment performed on the day of randomization (except for GnRH/LHRH agonists or antagonists) to exclude possible anti-androgen withdrawal response. This criterion is not applicable to subjects who have never responded to anti-androgen treatment, as there is no risk of anti-androgen withdrawal response. * Treatment with immunotherapy against PCa within 6 months before randomization. * Treatment with radiopharmaceutical within 8 weeks before randomization. * Participation in a clinical trial using non-immunological experimental therapy within 4 weeks before randomization. * Participation in a clinical trial using immunological experimental therapy (e.g., monoclonal antibodies, cytokines or active cellular immunotherapies) within 6 months before randomization. * Refusal to sign the informed consent.