Inclusion Criteria:

- Have signed an informed consent document indicating that the subjects understands the
purpose of and procedures required for the study and are willing to participate in
the study

- Written authorization for use and release of health and research study information
has been obtained

- Be willing/able to adhere to the prohibitions and restrictions specified in this
protocol

- Able to swallow the study drug whole as a tablet

- Willing to take abiraterone acetate on an empty stomach; no food should be consumed
at least two hours before and for at least one hour after the dose of abiraterone
acetate is taken

- Patients who have partners of childbearing potential must be willing to use a method
of birth control with adequate barrier protection as determined to be acceptable by
the principal investigator and sponsor during the study and for 1 week after last
dose of abiraterone acetate

- Histologically proven adenocarcinoma of the prostate

- Eastern Cooperative Oncology Group (ECOG) performance status =< 2

- Metastatic castration resistant prostate cancer as defined by serum testosterone < 50
ng/ml and one of the following:

- Prostate specific antigen (PSA) level of at least 2 ng/ml that has risen on at
least 2 successive occasions at least 1 week apart

- Evaluable disease progression by modified RECIST (Response Evaluation Criteria
in Solid Tumors)

- Progression of metastatic bone disease on bone scan with > 2 new lesions

- Maintenance of Lupron or antagonist unless previously treated with orchiectomy

- The presence of metastatic disease amenable to computed tomography (CT) or ultrasound
guided biopsy; this may include thoracolumbar vertebral bodies, pelvis, femur or
humerus, or soft tissue or nodal metastasis amenable to biopsy (excluding lung or
pleural lesions)

- Patients may have received secondary hormonal manipulations (excluding prior
Abiraterone acetate, MDV3100 or TAK700) or up to two cycles of chemotherapy; all
prior therapy except Lupron must have been discontinued for more than 4 weeks before
enrollment

- Serum potassium of >= 3.5 mEq/L

- Aspartate aminotransferase (AST), alanine aminotransferase (ALT) =< 1.5 x upper limit
of normal (ULN)

- Serum albumin of >= 3.0 g/dL

- Total bilirubin =< 1.5 x ULN

- Calculated creatinine clearance >= 60 mL/min

- Platelet count of >= 100,000/uL

- Absolute neutrophil count of > 1,500 cell/mm^3

- Hemoglobin >= 9.0 g/dL

Exclusion Criteria:

- Active infection or other medical condition that would make prednisone/prednisolone
(corticosteroid) use contraindicated

- Patients who are currently receiving active therapy for other neoplastic disorders
will not be eligible

- Patients with histologic evidence of small cell carcinoma of the prostate will not be
eligible

- Known brain metastasis

- Uncontrolled hypertension (systolic blood pressure [BP] >= 160 mmHg or diastolic BP
>= 95 mmHg); patients with a history of hypertension are allowed provided blood
pressure is controlled by anti-hypertensive treatment

- Active or symptomatic viral hepatitis or chronic liver disease

- History of pituitary or adrenal dysfunction

- Clinically significant heart disease as evidenced by myocardial infarction, or
arterial thrombotic events in the past 6 months, severe or unstable angina, or New
York Heart Association (NYHA) Class II-IV heart disease or cardiac ejection fraction
measurement of < 50 % at baseline

- Atrial fibrillation, or other cardiac arrhythmia requiring medical therapy

- Administration of an investigational therapeutic within 30 days of screening

- Patients with dementia/psychiatric illness/social situations that would limit
compliance with study requirements or would prohibit the understanding and/or giving
of informed consent will not be eligible

- Patients with any condition that, in the opinion of the investigator, would
compromise the well-being of the subject or the study or prevent the subject from
meeting or performing study requirements

- Patients requiring therapeutic anticoagulation (e.g., warfarin, Dabigatran, heparin,
or low molecular weight heparins [Lovenox, dalteparin])

- Patients with poorly controlled diabetes

- Patients with a history of gastrointestinal disorders (medical disorders or extensive
surgery) that may interfere with the absorption of the study agents

- Patients with a pre-existing condition that warrants long-term corticosteroid use in
excess of study dose

- Patients with known allergies, hypersensitivity, or intolerance to abiraterone
acetate or prednisone or their excipients