• Willing and able to provide written informed consent (ICF) and HIPAA authorization for the release of personal health information. A signed informed consent must be obtained before screening procedures are performed.

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

• Males 18 years of age and above

• Histological or cytological proof of prostate cancer

• Documented progressive mCRPC based on at least one of the following criteria:

∙ PSA progression defined as 25% increase over baseline value with an increase in the absolute value of at least 1.0 ng/mL that is confirmed by another PSA level with a minimum of a 1 week interval and a minimum PSA of 1.0 ng/mL.

‣ Soft-tissue progression defined as an increase ≥ 20% in the sum of the LD of all target lesions based on the smallest sum LD since treatment started or the appearance of one or more new lesions.

‣ Progression of bone disease (evaluable disease) or two or more new bone lesions by bone scan.

• Two or more bone lesions

• ECOG 0- 1

• Normal organ function with acceptable initial laboratory values within 14 days of randomization:

‣ Albumin \> 30 g/L

⁃ ANC ≥ 1.5 x 10\^9/L

⁃ Hemoglobin ≥ 10 g/dL

⁃ Platelet count ≥ 100 x 10\^9/L

⁃ Creatinine ≤ 1.5 x the institutional upper limit of normal (ULN)

⁃ Bilirubin ≤ ULN (unless documented Gilbert's disease)

⁃ SGOT (AST) ≤ 1.5 x ULN

⁃ SGPT (ALT) ≤ 1.5 x ULN

⁃ WBC count ≥ 3 x 10\^9/L

• Subjects must agree to use a medically acceptable method of birth control (e.g., spermicide in conjunction with a barrier such as a condom) or sexual abstinence for the duration of the study, including 30 days after the last dose of study drug. Sperm donation is prohibited during the study and for 30 days after the last dose of study drug. Female partners must use hormonal or barrier contraception unless postmenopausal or abstinent.

• Serum testosterone \< 50 ng/dL. Subjects must continue primary androgen deprivation with an LHRH analogue (agonist or antagonist) if they have not undergone orchiectomy.

• All acute toxic effects of any prior treatment have resolved to NCI-CTCAE v4.0 Grade 1 or less.

• Willing and able to comply with the protocol, including follow-up visits and examinations