Food Effect Study of Abiraterone Acetate for Treatment of Patients With Castration-Resistant Prostate Cancer

PRIMARY OBJECTIVES:

I. To compare the pharmacodynamic effect of reduced dose (250mg daily) abiraterone acetate
in the prandial state (250mg-Fed) to the full, standard 1000mg daily dose in the fasting
state (1000mg-Fasting) as assessed by change in serum prostate-specific antigen (PSA).

SECONDARY OBJECTIVES:

I. To evaluate the effect of prandial states on plasma levels and the intra-patient
pharmacokinetic variability of abiraterone acetate.

II. To evaluate the safety profile of reduced dose abiraterone acetate taken in the prandial
state.

III. To evaluate the pharmacodynamic effect of reduced dose abiraterone acetate in the
prandial state as assessed by reduction in the extra-gonadal androgen dihydroepiadrosterone
sulfate (DHEA-S) and dihydroepiandrostenedione (DHEA).

IV. To evaluate the effect of prandial state on time to disease progression (Working group
criteria).

OUTLINE: Patients are randomized to one of two treatment arms.

ARM I: Patients receive abiraterone acetate orally (PO) daily first thing in morning after
an overnight fast of at least 8 hours.

ARM II: Patients receive abiraterone acetate PO daily within 30 minutes of a conventional
low-fat breakfast.

In both arms, courses repeat every 28 days in the absence of disease progression or
unacceptable toxicity. Both arms will also be treated with prednisone 5mg twice daily.

After completion of study treatment, patients are followed up within 30 days.

Inclusion Criteria:

- Histologically or cytologically confirmed prostate cancer with progressive disease
defined as either:

- 2 or more new lesions on bone scan or

- Progressive disease on computed tomography (CT)/magnetic resonance imaging (MRI)
according to Response Evaluation Criteria In Solid Tumors (RECIST) 1.1 criteria
or

- Rising prostate-specific antigen (PSA): PSA evidence for progressive prostate
cancer consists of a minimum PSA level of at least 2 ng/ml, which has
subsequently risen on at least 2 successive occasions, at least 2 weeks apart

- Evidence of castration resistance defined as disease progression despite a
testosterone level < 50 ng/dL (or surgical castration)

- Any prior therapy for castrate disease is acceptable except prior abiraterone, which
is excluded; a minimum washout of 28 days for any other anticancer therapy prior to
first dose of study drug is required

- Any other radiotherapy or radionuclide require 28-day washout prior to first
dose of study drug

- Denosumab or zoledronic acid are allowed

- Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1

- Total bilirubin =< 1.5 x the upper limit of normal

- Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase
[SGOT])/alanine aminotransferase (ALT) (serum glutamic pyruvate transaminase [SGPT])
=< 2.5 X institutional upper limit of normal

- Ability to understand and the willingness to sign a written informed consent document

Exclusion Criteria:

- Therapy with other hormonal therapy, including any dose of megestrol acetate
(Megace), finasteride (Proscar), dutasteride (Avodart), or any herbal product known
to decrease PSA levels (e.g., saw palmetto and PC-SPES), or any systemic
corticosteroid (other than prednisone =< 10 mg/day) within 4 weeks prior to first
dose of study drug

- Therapy with supplements or complementary medicines/botanicals within 4 weeks of
first dose of study drug is excluded with the following exceptions:

- Conventional multivitamin supplements

- Selenium

- Lycopene

- Soy supplements

- Inability to swallow capsules or known gastrointestinal malabsorption

- History of other malignancies, with the exception of adequately treated non-melanoma
skin cancer or adequately treated superficial bladder cancer or other solid tumors
curatively treated with no evidence of disease for >= 5 years from enrollment

- Blood pressure that is not controlled despite > 2 oral agents (systolic blood
pressure [SBP] > 160 and diastolic blood pressure [DBP] > 90 documented during the
screening period with no subsequent blood pressure readings < 160/100)

- Serum potassium (K)+ < 3.5 mmoL/L on more than one reading within the screening
period

- Serious intercurrent infections or non-malignant medical illnesses that are
uncontrolled

- Active psychiatric illness/social situations that would limit compliance with
protocol requirements

- New York Heart Association (NYHA) class II, NYHA class III, or IV congestive heart
failure (any symptomatic heart failure)

- Concurrent therapy with strong inhibitors or inducers of Cytochrome P450 (CYP)3A4 due
to concerning possible drug-drug interactions with abiraterone