['castration-resistant prostate cancer']
['enzalutamide', 'flutamide']

        Inclusion Criteria:

          -  Testosterone of less than 50 ng/dL

          -  Participants who was detected of disease progression on image or relapse of PSA (All
             PSA values measured 3 time at least one week interval are consecutively increased and
             final value is 2 ng/mL or more. If third value is not higher than second one, fourth
             measurement will be undertaken and its value must be higher than second one.)

          -  Participants who relapsed after CAB with bicalutamide

          -  Eastern Cooperative Oncology Group (ECOG) performance status is 0 or 1

          -  Aged 20 years or older

          -  Participants who provided written informed consent

        Exclusion Criteria:

          -  Any prior treatment with enzalutamide, flutamide, abiraterone or chemotherapy, except
             for neoadjuvant therapy

          -  With active double cancer

          -  Any prior treatment with bicalutamide within 6 weeks

          -  Participants who received systemic biological therapy (except for existing approved
             drug for bone or treatment with luteinizing hormone-releasing hormone (LHRH) analogue)
             or received treatment with other antitumor agent for prostate cancer

          -  With serious complication

          -  History of hypersensitivity to enzalutamide or any other excipient of enzalutamide

          -  History of hypersensitivity to flutamide-containing agent

          -  With liver dysfunction

          -  Participants who are considered as inadequate by the investigator
      