Evaluation of Response to Abiraterone/Prednisone by Race/Ethnicity and Other Factors in Metastatic Hormone Naive Prostate Cancer

This is a single arm study in metastatic hormone naïve prostate cancer. Standard of care in
these men is either to offer Androgen deprivation therapy (ADT) + abiraterone
acetate/low-dose prednisone or, in men with higher tumor burden, to offer ADT +
Docetaxel/prednisone. The investigator's experience is that even men with increased tumor
burden often opt for abiraterone because of the improved side effect protocol as compared to
chemotherapy.

Approximately 130 PSA response evaluable subjects will be enrolled, of which the
investigators expect 50% to be African American based on clinic population and previous
experience with clinical trial enrollment.

The study will enroll men with newly diagnosed hormone naïve prostate cancer within 42 days
of receiving the first dose of ADT (LHRH agonist) or undergoing orchiectomy. Patients will
continue ADT throughout the study. Abiraterone acetate and low dose prednisone will continue
until progression as defined by standard PCWG2 criteria.

Inclusion Criteria:

- All patients must have a histologically or cytologically proven diagnosis of
adenocarcinoma of the prostate. All patients must have metastatic disease as evidenced
by soft tissue and/or bony metastases prior to initiation of androgen deprivation
therapy (ADT). NOTE: ADT does not include treatment with anti-androgens such as
bicalutamide or flutamide or five alpha reductase inhibitors such as finasteride or
dutasteride.

- Patients must have radiographic assessments of all disease including bone scan (or PET
scan) within 42 days prior to registration. All disease will be assessed and
documented on the appropriate CRF.

- Patients must have had no more than 42 days of prior castration (medical or surgical)
for metastatic prostate cancer prior to starting abiraterone. The start date of
medical castration is considered the day the patient first received an injection of a
LHRH agonist/antagonist (or orchiectomy), not an oral antiandrogen. • If the method of
castration was luteinizing hormone releasing hormone (LHRH) agonists (i.e., leuprolide
or goserelin), the patient must be willing to continue the use of LHRH agonist and add
Abiraterone + Prednisone treatment. • If the patient was on an antiandrogen (e.g.
bicalutamide, flutamide), the patient must be willing to switch over to Abiraterone +
Prednisone treatment. There is no limit on how many days a patient may have been on an
antiandrogen (e.g. bicalutamide, flutamide) or a five alpha reductase inhibitor (e.g.
finasteride or dutasteride) prior to going on study and no washout is required.

- Patients may have received prior ADT - neoadjuvant and/or adjuvant setting only - but
it must not have lasted for more than 36 months. Single or combination therapy
allowed. At least 6 months must have elapsed since completion of ADT in the
neoadjuvant and/or adjuvant setting, and serum testosterone must be > 50 ng/dL
(non-castrate levels) within 28 days prior to registration. NOTE: Serum testosterone
assessment is required for eligibility for only those patients with prior treatment
with neoadjuvant or adjuvant ADT.

- Patients who are deemed to have high-risk or extensive metastatic, hormone sensitive
prostate cancer (mHSPC) per "clinical judgment" of the treating physician are eligible
for enrollment if the participants are unsuitable candidates for docetaxel or if the
participants have declined docetaxel therapy.

- Patients may have received prior surgery. For all major surgeries, at least 14 days
must have elapsed since completion and patient must have recovered from all major side
effects of surgery per investigator's assessment.

- Patients may have received or plan to receive concurrent bone targeting agents that do
not have an effect on PSA (e.g. denosumab or bisphosphonate).

- Patients must have no plans to receive any other experimental therapy while on the
protocol treatment. Previous experimental therapy must have been completed at least 28
days prior to registration.

- Patients must have a complete physical examination and medical history within 28 days
prior to registration.

- Patients must have a PSA ≥ 10 ng/mL obtained within 90 days prior to registration.

- Patients must have a QTc interval < 461 msec on the 12 lead ECG within 42 days prior
to registration. Patients with asymptomatic or incidental bundle branch blocks may
have QTc measured by a cardiologist or standard formulas such as Bazett's or
Fridericia's to adjust for pre-existing blocks.

- Patients must have adequate hepatic function, within 28 days prior to registration, as
evidenced by: • bilirubin ≤ 2 x institutional upper limit of normal (ULN), and • SGOT
(AST) and SGPT (ALT) ≤ 3 x institutional ULN, or ≤ 5 x institutional ULN if liver
metastases are present.

- Patients must have adequate renal function, within 28 days prior to registration, as
evidenced by calculated creatinine clearance ≥ 40 mL/min using a serum creatinine or
by 24-hour urine creatinine (using Cockroft-Gault equation).

- Patients must have adequate hematologic function, within 28 days prior to registration
as evidenced by:

- leukocytes ≥ 3,000/mcL,

- absolute neutrophil count (ANC) ≥ 1,500/mcL,

- hemoglobin ≥ 9 g/dL, and

- platelets ≥ 100,000/mcL.

- Patients must have a Zubrod performance status of 0-2. Zubrod performance status 3
will be allowed if from bone pain only.

- No other prior malignancy is allowed except for the following: adequately treated
basal cell or squamous cell skin cancer, adequately treated Stage I or II cancer from
which the patient is currently in complete remission, or any other cancer from which
the patient has been disease-free for 5 years.

- Patients must be ≥ 18 years of age.

- Patients or their legally authorized representative must be informed of the
investigational nature of this study and must sign and give written informed consent
in accordance with institutional and federal guidelines.

Voluntary written informed consent must be obtained before performance of any study-related
procedure not part of normal medical care, with the understanding that consent may be
withdrawn by the patient at any time without prejudice to future medical care.

Exclusion Criteria:

- Patients with known brain metastases are not eligible. Brain imaging studies are not
required for eligibility if the patient has no neurologic signs or symptoms suggestive
of brain metastasis. But, if brain imaging studies are performed, patients must be
negative for disease.

- Patients must not have received prior and/or must not have any plans for receiving
concomitant therapy with ketoconazole, aminoglutethimide, or enzalutamide (MDV3100).
Concurrent megestrol for hot flashes is allowed.

- Patients must not have received any prior cytotoxic chemotherapy for metastatic
prostate cancer. Prior cytotoxic chemotherapy with curative intent in the neoadjuvant
or adjuvant setting is allowed. At least 2 years must have elapsed since completion of
cytotoxic chemotherapy in the neoadjuvant and/or adjuvant setting.

- Patients must not have New York Heart Association Class III or IV heart failure at the
time of screening. Patients must not have any thromboembolic event, unstable angina
pectoris, myocardial infarction, or serious uncontrolled cardiac arrhythmia within 6
months prior to registration. (Note: Androgen deprivation therapy may prolong the
QT/QTc interval. Patients with congenital long AT syndrome, congestive heart failure,
frequent electrolyte abnormalities, and patients taking drugs known to prolong the QT
interval may be at increased risk.)

- Patients with a known history of primary and secondary adrenal insufficiency are not
eligible.

- Patients must not be known to have hypersensitivity to abiraterone or to LHRH agonist.

- Patients must not have known gastrointestinal (GI) disease or GI procedure that could
interfere with the GI absorption or tolerance of abiraterone, including difficulty
swallowing oral medications per investigator's clinical judgement.