Major

Inclusion Criteria:

- Be a male >= 18 years of age

- Have adenocarcinoma of the prostate

- Currently receiving continuous treatment with Gonadotropin-releasing hormone (GnRH)
monotherapy for at least 6 months before or have undergone surgical removal of the
testicles

- Serum testosterone of < 50 ng/dL(< 2.0 nM)

- Have rising PSA defined as a PSA of ≥ 10 ng/mL obtained at screening or PSADT of ≤ 10
months with the first of the 3 consecutive PSA values used to calculate PSADT ≥ 2.0
ng/mL

- Have an Eastern Cooperative Oncology Group (ECOG) performance status less than or
equal to 2

- Be capable of swallowing study agents whole as a tablet

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

Major Exclusion Criteria:

- Have prior or current evidence of local disease progression or metastatic disease as
defined by modified response evaluation criteria in solid tumors (RECIST) criteria

- Have received chemotherapy for treatment of castrate-resistant prostate cancer;
however, if a patient received chemotherapy in an adjuvant setting, prior to having
CRPC, for castrate-sensitive prostate cancer, the patient is still eligible

- Are currently receiving any antiandrogen therapy (eg, bicalutamide, flutamide, or
nilutamide).

- If previously treated with antiandrogen therapy, there must be documentation of at
least 2 consecutive rising PSA values at least 2 weeks apart obtained prior to
screening

- If previously treated with flutamide, at least 1 of the PSA values must be obtained 4
weeks or more after flutamide discontinuation.

- If previously treated with bicalutamide or nilutamide, at least 1 of the PSA values
must be obtained 6 weeks or more after antiandrogen discontinuation

- Have previously received agents having any CYP17 inhibitory activity for the
treatment of prostate cancer, such as ketoconazole

- Have previously received aminoglutethimide

- Have an active infection or other medical condition that would contraindicate
prednisone use

- Have uncontrolled hypertension

- Have active hepatitis or chronic liver disease

- Have clinically significant heart disease

- Have poorly controlled diabetes

- Have received an investigational therapeutic within 30 days of screening

- Have partners of childbearing potential and are not 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.

- Individuals with a history of a non-prostate malignancy are ineligible for this study
with the following exceptions. Individuals with a history of other malignancies are
eligible if they have been disease-free for at least 3 years and are deemed by the
investigator to be at low risk for recurrence of that malignancy. Individuals with
the following cancers are eligible if diagnosed and treated within the past 3 years:
basal cell or squamous cell carcinoma of the skin