Study Comparing Orteronel Plus Prednisone in Participants With Metastatic Castration-Resistant Prostate Cancer.

Inclusion Criteria:

Each participant must meet all of the following inclusion criteria:

* Voluntary written consent
* Male 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
* Progressive disease during or following 1 or 2 regimens of cytotoxic chemotherapy, 1 of which must have included docetaxel. Must have received greater than or equal to (\>=) 360 milligram per square meter (mg/m\^2) of docetaxel within a 6-month period. Participants who were clearly intolerant to docetaxel or develop progressive disease before receiving \>= 360 mg/m\^2 are also eligible if they have received at least 225 mg/m\^2 of docetaxel within a 6-month period and meet the other study entry criteria.
* Eastern Cooperative Oncology Group (ECOG) performance status 0 to 2
* Even if surgically sterilized, participants must practice effective barrier contraception during the entire study treatment period and for 4 months after the last dose of study drug, OR Abstain from heterosexual intercourse
* Screening laboratory values as specified in protocol
* Stable medical condition
* Life expectancy of 6 months or more
* Participants who have had up to 2 prior chemotherapy treatments are eligible to participate

Exclusion Criteria:

Participants 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
* Any other therapies for prostate cancer, except for GnRH analogue therapy, must be discontinued 2 weeks before the first dose of study drug
* Radioisotope therapy or external beam radiation therapy within 4 weeks of 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 (Participants who are in long-term follow-up following active treatment in other trials are eligible)
* 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
* Known gastrointestinal disease or procedure that could interfere with oral absorption or tolerance of orteronel
* Uncontrolled nausea, vomiting, or diarrhea despite appropriate medical therapy
* Prostate cancer confined to just the prostrate bed or immediate adjacent tissue