Inclusion Criteria:

- Written informed consent has been obtained.

- Adults over 18 years of age.

- Histologically or cytologically proven adenocarcinoma of the prostate.

- Stage IV disease as evidenced by soft tissue, visceral and/or bony metastasis must be
Response Evaluation Criteria in Solid Tumors (RECIST) evaluable on CT scan and/or
bone scan

- Progressive disease while receiving hormonal therapy or after surgical castration
documented by at least one of the following: (1) Increase in measurable disease per
RECIST 1.1. (2) Appearance of new lesions on bone scan consistent with progressive
prostate cancer (>2 new lesions on bone scans if this is the only measure of PD) (3)
rising PSA defined as 2 sequential increases above a previous lowest reference value.
Each value must be obtained at least 1 week apart.

- PSA at least 2 ng/mL

- Received prior docetaxel chemotherapy

- Received prior abiraterone, but not within the 3 months prior to study drug dosing.
Prior therapy with abiraterone is not required for enrollment in the phase I study.

- Testosterone level <50 ng/mL. Patients receiving Leutinizing hormone releasing
hormone (LHRH) agonists must be continued to maintain castrate levels of testosterone
while on study.

- Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2.

- Adequate hematologic function (platelet >100, 000/uL; neutrophil count of >1500
cell/mm3; hemoglobin >9.0 g/dL)

- Adequate renal function (Creatinine clearance >60 mL/min)

- Adequate potassium level > 3.5 mEq/dL

- Adequate hepatic function (bilirubin < 1.5 X upper limit of normal (ULN), alanine
aminotransferase (ALT) < 1.5 X ULN, aspartate aminotransferase (AST) < 1.5 X ULN.
Have a serum albumin of ≥ 3.0 g/dL

- Must be able to take oral medication without crushing, dissolving or chewing tablets

- Willing to take abiraterone acetate on 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 must be willing and able to adhere to the prohibitions and restrictions
specified in the protocol.

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

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

Exclusion Criteria:

- Surgery or radiation therapy within 2 weeks. Cytotoxic anti-cancer therapy within 3
weeks. Non-cytotoxic anti-cancer therapy within 2 weeks, or 5 half-lives (whichever
is longer) of Study Day 1.

- Use of an investigational therapeutic within 30 days

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

- Prior treatment with cabazitaxel

- Known chronic infection with human immunodeficiency virus (HIV)

- Known active, or symptomatic, brain metastasis

- Blood pressure >140/90 on average (3 separate readings taken at screening visit in a
relaxed clinical environment and averaged)

- History of autoimmune disorder requiring daily corticosteroid therapy of greater than
prednisone 10mg daily, or its equivalent

- Baseline peripheral edema > grade 3

- Pre-existing diarrhea uncontrolled with supportive care; prior hemorrhagic diarrhea
due to ulcerative colitis, inflammatory bowel disease or other cause; active,
uncontrolled peptic ulcer disease even in the setting of proton-pump inhibitor or
Histamine2-blocker use.

- Pre-existing peripheral neuropathy grade > 2

- Documented hypersensitivity (CTCAE grade > 2) to any drug containing polysorbate 80

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

- Contraindications to steroid use

- Need for medications that strongly induce or inhibit cytochrome P450 3A4 (CYP3A4) or
cytochrome P450 2D6 (CYP2D6) activity

- Serious infection requiring parenteral antibiotics within 14 days of enrollment

- Poorly controlled diabetes (HgbA1C >9)

- 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 Class III-IV heart disease or cardiac ejection fraction
measurement of <50% at baseline.

- Consumption of food or beverages containing grapefruit juice within 7 days of study
drug dosing

- Use of a first-generation anti-androgen such as bicalutamide within 6 weeks of study
drug dosing. Use of flutamide within 4 weeks of study dosing with a continued rise
in PSA.

- Have 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