Inclusion Criteria:

Each patient must meet all of the following inclusion criteria:

- Voluntary written consent

- Male patients 18 years or older

- Histologically or cytologically confirmed diagnosis of prostate adenocarcinoma

- Radiograph-documented metastatic disease

- Progressive disease

- Prior surgical castration or concurrent use of an agent for medical castration

- Either absence of pain or pain not requiring use of any opioid or narcotic analgesia
in the 2 weeks prior to study entry

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

- Even if surgically sterilized, patients must practice effective barrier contraception
during the entire study treatment and for 4 months after the last dose of study drug,
OR abstain from heterosexual intercourse

- Meet screening laboratory values as specified in protocol

- Stable medical condition

Exclusion Criteria:

Patients meeting any of the following exclusion criteria are not to be enrolled in the
study:

- Known hypersensitivity to orteronel, prednisone or gonadotropin-releasing hormone
(GnRH) analogue

- Received prior therapy with orteronel, aminoglutethimide, ketoconazole or abiraterone

- Received antiandrogen therapy within 6 weeks for bicalutamide and 4 weeks for all
others prior to first dose of study drug

- Continuous daily use of oral prednisone or oral dexamethasone for more than 14 days
within 3 months prior to study

- Received prior chemotherapy for prostate cancer with exception of
neoadjuvant/adjuvant therapy as part of initial primary treatment for local disease
that was completed 2 or more years prior to screening

- Exposure to radioisotope therapy within 4 weeks of receiving first dose of study
drug; exposure to external beam radiation within 2 weeks of start of screening until
receiving the first dose of study drug

- Documented central nervous system metastases

- Treatment with any investigational compound within 30 days prior to first dose of
study drug

- Current spinal cord compression, bilateral hydronephrosis or current bladder neck
outlet obstruction

- Diagnosis or treatment of another malignancy within 2 years preceding first dose of
study drug except nonmelanoma skin cancer or in situ malignancy completely resected

- Uncontrolled cardiovascular condition as specified in study protocol

- Known history of human immunodeficiency virus (HIV) infection, hepatitis B, or
hepatitis C

- Unwilling or unable to comply with protocol

- Uncontrolled nausea, vomiting or diarrhea

- Known gastrointestinal disease or procedure that could interfere with oral absorption
or tolerance of orteronel