Safety & Activity of P501-AS15 Vaccine as a First-line Treatment for Patients With Hormone-sensitive Prostate Cancer Who Show Rising PSA

Inclusion criteria: * Male, * Aged between 18 and 75 years, inclusive, * Histologically or cytologically proven adenocarcinoma of the prostate before the initiation of therapy of the primary tumor, * Radical prostatectomy before progression of disease by rising PSA was established, * Primary tumor presented a Gleason sum score ≤8, * Proven progressive hormone-sensitive prostate cancer, * Serum testosterone level above 50 ng/dl, * Free of clinically evaluable metastatic disease (other than the rising PSA), * ECOG Performance Status of 0 or 1, * Normal organ functions, * Negative HBV antigen test, * Negative HCV antibody test, * The investigator believes that the patient can and will comply with the requirements of the protocol, * Written, informed consent obtained before enrolment. Exclusion criteria: * Orchiectomy, * Received androgen-deprivation therapy, including neo adjuvant androgen-deprivation therapy, * Any radiotherapy (external beam radiotherapy and/or brachytherapy) for prostate cancer as primary management, * Receiving treatment with continuous systemic anticancer medications, * Received chronic administration of immunosuppressants or other immune-modifying drugs within six months before the first vaccine dose, * Received any investigational or non-registered product (drug or vaccine) other than the study vaccine(s) within 30 days preceding the first dose of study vaccine, or the administration of such a product is planned during the study period, * Receiving any immunoglobulins and/or other blood products or has received such products within the three months preceding the first dose of study vaccine or is planned to receive such products during the study period, * Received any commercial vaccine within the week before the first study vaccination, * Previous or concomitant malignancies at other sites, except (i) adequately treated non-melanoma skin cancers, and (ii) effectively treated malignancy that has been in remission for \>2 years and is considered by the investigator highly likely to have been cured, * Any clinical autoimmune disease (except vitiligo), * Family history of congenital or hereditary immunodeficiency, * HIV-positive, * Medical history includes splenectomy or irradiation to the spleen, * History of allergic disease or reactions likely to be exacerbated by any component of the vaccine, * Any known allergy or hypersensitivity to yeast or yeast products, * The patient presents with serious acute or chronic illness(es), e.g. active infections requiring antibiotics, bleeding/coagulation disorders, clinically significant heart disease (NCIC CTG III-IV), or other conditions requiring concurrent medications not allowed during this study, * Psychological, familial, sociological or geographical condition potentially hampering compliance with the study protocol and follow-up schedule, * History of chronic alcohol consumption and/or drug abuse, * Acute disease at the time of enrolment. All vaccines can be administered to persons with a minor illness.