Patient population

For this phase II, randomized, double-blind, placebo-controlled study, we enrolled chemotherapy-naïve patients with CRPC from ten medical centers in Japan. The subjects must satisfy the following conditions: (1) patients must be diagnosed as prostate cancer pathologically at the initial treatment; (2) patients who had progressive disease after androgen deprivation therapy (ADT) either by surgical castration, gonadotropin-releasing hormone or antagonist treatment. Progressive disease while receiving ADT, defined by any 1 of the following: (1) at least two consecutive rises in serum PSA obtained at a minimum of 1-week intervals; (2) measurable disease with ≥ 50% increase in the sum of the cross products of all measurable lesions, or the development of new measurable lesions by RESIST; (3) non-measurable (bone) disease consisting of new areas of uptake by bone scan consistent with metastatic disease compared to previous imaging; (4) patients have serum PSA level ≥ 2 ng/m; (5) anti-androgen therapy is discontinued for at least 4 weeks before the first vaccination for patients receiving flutamide and 6 weeks for those receiving bicalutamide; (6) patients continue to stay on medical treatment such as LHRH agonists or LHRH antagonists to maintain testosterone level of 0.5 ng/m; (7) patients must be positive for HLA-A2, HLA-A24, HLA-A26 or HLA-A3 super type (A3, A11, A31, A33); (8) written informed consent must be obtained from patients; (9) patients must be more 20 year-old; (10) patients must be at a score level of 0 or 1 of an Eastern Cooperative Oncology Group (ECOG) performance status; (11) patients must be expected to survive more than 6 months; (12) patients must satisfy bone marrow function (white blood cell count ≥ 2500/mm³, lymphocyte count ≥ 1000/mm³, hemoglobin ≥ 8 g/dl, and platelets ≥ 100,000/mm³), hepatic function [total bilirubin ≤ 1.5 × the upper limit of normal (ULM), transaminase ≤ 2 × ULM], and renal function (serum creatinine ≤ 2 × ULM). Patients without previous bilateral orchiectomy continued receiving luteinizing hormone-releasing agonists. Exclusion criteria included acute infection, history of severe allergic reactions, pulmonary, cardiac or other systemic diseases, or other inappropriate conditions for enrollment as judged by clinicians.