Inclusion Criteria:

• Willing and able to provide written informed consent
• Written Authorization for Use and Release of Health and Research Study Information (USA sites only) or Data Protection Consent (European sites only)has been obtained
• Age ≥ 18 years and male
• Histologically or cytologically confirmed adenocarcinoma of the prostate, but not with neuroendocrine differentiation or of small cell histology
• Prior chemotherapy for prostate cancer with regimen(s) containing docetaxel.
• Patients may have had up to two previous chemotherapy regimens.
• Documented PSA progression according to PSAWG eligibility criteria with a PSA > 5 ng/mL
• On-going androgen deprivation with serum testosterone < 50 ng/dL (< 2.0nM/L)
• Eastern Cooperative Oncology Group (ECOG) Performance Status of ≤ 2. (Karnofsky Performance Status ≥ 50%)
• Any acute toxicities of prior chemotherapy, radiotherapy have resolved to a NCI CTCAE (version 3) grade of ≤ 1. Chemotherapy induced alopecia and grade 2 neuropathy are excluded from this consideration.
• Life expectancy > 12 weeks
• Able to swallow CB7630 whole as a tablet
• Able to follow study instructions, accessible for treatment and follow-up, and likely to complete all study requirements

Exclusion Criteria:

• Active or uncontrolled autoimmune disease that may require corticosteroid therapy
• Serious or uncontrolled co-existent non-malignant disease, including active and uncontrolled infection
• Uncontrolled hypertension
• Hemoglobin ≤ 9.0 g/dL without growth factor or transfusion support
• Abnormal liver function tests consisting of any of the following:Serum bilirubin > 1.5 x ULN; ALT > 2.5 x ULN; AST > 2.5 x ULN
• Serum creatinine > 2.0 x UNL or a calculated creatinine clearance < 50 mL/min
• Serum potassium < 3.5 mmol/L
• Clinically significant heart disease as evidenced by a myocardial infarction in the past twelve months, severe or unstable angina, or New York Heart Association(NYHA) Class III or IV heart disease. Patients with a history of atherosclerotic vascular disease requiring coronary or peripheral artery bypass surgery may be enrolled provided the surgery occurred at least two years prior to enrollment and after consultation with a cardiologist to insure that the disease is stable.
• Abnormal electrocardiogram, including any finding which would interfere with assessment of intervals (patients with long QT syndrome, bundle branch blocks or hemiblocks are prohibited)
• Malignancy within the previous 5-years other than basal cell or squamous cell carcinomas of skin with a >30% probability of recurrence within 12 months.
• History of adrenal insufficiency or hyperaldosteronism
• History of gastrointestinal disorders (medical disorders or extensive surgery)which may interfere with the absorption of the study medication