Docetaxel/Prednisone Versus Docetaxel/Prednisone and Enzalutamide in Castration-Resistant Prostate Cancer

Inclusion Criteria:

- Willing and able to provide written informed consent and HIPAA authorization for the
release of personal health information.

NOTE: HIPAA authorization may be either included in the informed consent or obtained
separately.

- Males 18 years of age and above

- Histologically or cytologically confirmed adenocarcinoma of the prostate without
neuroendocrine differentiation or small cell features

- Having documented disease progression on enzalutamide defined by 1 or more of the
following criteria:

- PSA progression according to PCWG2 criteria with 3 consecutive rising PSA
measurements, all collected at least 1 week apart

- Radiographic progression in soft tissue or bone by modified RECIST 1.1 for subjects
with measurable disease; or

- Bone disease progression defined by 2 or more new lesions on 2 consecutive bone scans
in the absence of falling PSA

- Patients who have not had a bilateral orchiectomy must have a plan to maintain
effective GnRG-analogue therapy for the duration of the trial

- Serum testosterone level < 50 ng/dL at Screening visit

- ECOG PS: 0-1

- Throughout the study, male patients and their female partners of childbearing
potential must use 2 acceptable methods of birth control (1 of which must include a
condom as a barrier method of contraception) starting at screening and continuing
throughout the study period and for 3 months after final study drug administration.
Two acceptable methods of birth control thus include the following:

- Condom (barrier method of contraception even if having sex with a pregnant woman)

- One of the following is required:

- Established use of oral, injected, or implanted hormonal method of contraception
by the female partner

- Placement of an intrauterine device (IUD) or intrauterine system (IUS) by the
female partner

- Additional barrier method: Occlusive cap (diaphragm or cervical/vault caps) with
spermicidal foam/gel/film/cream/suppository by the female partner

- Tubal litigation in the female partner

- Vasectomy or other procedure resulting in infertility (eg, bilateral orchiectomy)
for >6 months

- Patients must have adequate organ and marrow function as defined below

- Leukocytes >3,000/mm3

- absolute neutrophil count >1,500/mm3

- platelets >100,000/mm3

- total bilirubin within normal institutional limits (or <2X the upper limit of normal
in those with Gilbert's disease)

- AST(SGOT)/ALT(SGPT) <1.5 X institutional upper limit of normal

- creatinine within normal institutional limits OR

- creatinine clearance* >45 mL/min/1.73 m2 for patients with creatinine levels above
institutional normal

- Estimated life expectancy of > 6 months

- Able to swallow the study drug as prescribed and comply with study requirements

Exclusion Criteria:

- Prior treatment with docetaxel-based chemotherapy

- Prior treatment with abiraterone acetate

- Prior treatment with cabazitaxel

- Severe concurrent disease, infection, or co-morbidity that, in the judgment of the
Investigator, would make the patient inappropriate for enrollment

- Ongoing investigational treatment

- Medical conditions such as uncontrolled hypertension, uncontrolled diabetes mellitus,
cardiac disease that would, in the opinion of the investigator, make this protocol
unreasonably hazardous

- Major surgery within 4 weeks of enrollment

- Use of an investigational therapeutic agent with 4 weeks of enrollment

- History of seizure or any condition that may predispose to seizure.

- History of loss of consciousness or transient ischemic attack within 12 months of
enrollment

- Gastrointestinal disorder affecting absorption (e.g., gastrectomy, active peptic ulcer
disease) within last 3 months

- Grade > 2 treatment-related toxicity from prior therapy

- History of hypersensitivity to polysorbate 80

- Any known allergy to the compounds under investigation

- Any other condition which, in the opinion of the Investigator, would preclude
participation in this trial