| Exclusion Criteria: | 1) Serious or uncontrolled co-existent, non-malignant disease, including active and uncontrolled infection
2) Abnormal liver functions consisting of any of the following: a) Serum bilirubin >/= 1.5 x ULN (except for patients with documented Gilbert's disease); b) AST or ALT >/= 2.5 x ULN
3) Uncontrolled hypertension within the screening period (systolic BP >/= 140 mmHg or diastolic BP >/= 90 mmHg). Patients with a history of hypertension are allowed provided blood pressure is controlled by anti-hypertensive therapy.
4) Requirement for corticosteroids greater than the equivalent of 5 mg of prednisone daily
5) Active or symptomatic viral hepatitis or chronic liver disease
6) History of pituitary or adrenal dysfunction
7) 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
8) Other active malignancy, except non-melanoma skin cancer and superficial transitional cell carcinoma, with a >/= 30% probability of recurrence within 12 months
9) History of gastrointestinal disorders (medical disorders or extensive surgery) which may interfere with the absorption of the study drug
10) Prior therapy with abiraterone acetate or other CYP17 inhibitor(s), or investigational agent(s) targeting the androgen receptor for prostate cancer
11) Prior hormone therapy for prostate cancer including LHRH agonists/antagonists, orchiectomy, antiandrogens, ketoconazole, or estrogens (5-alpha reductase inhibitors allowed)
12) Other concomitant systemic azole agents
13) Radiotherapy, chemotherapy or immunotherapy for prostate cancer
14) Current enrollment in an investigational drug or device study or participation in such a study within 30 days of Day 1
15) Condition or situation which, in the investigator's opinion, may put the patient at significant risk, may confound the study results, or may interfere significantly with patient's participation in the study
16) Not willing to comply with the procedural requirements of this protocol including repeat prostate biopsies
17) Patients who have partners of childbearing potential who 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 13 weeks after last study drug administration
18) Hypersensitivity to any ingredient in the abiraterone acetate, prednisone tablets, or leuprolide acetate
19) Gleason score </= 5 (total) |