Denosumab Plus Enzalutamide, Abiraterone and Prednisone Compared to Denosumab Plus Enzalutamide Alone for Men With Castrate Resistant Prostate Cancer (CRPC) With Bone Metastases

Inclusion Criteria: * Histologic proof of adenocarcinoma of the prostate with clinical evidence of metastatic disease to the bone. * Castrate resistant progression of prostate carcinoma, as shown by: * Serum testosterone level \<50 ng/dL or prior bilateral orchiectomy. Treatment to maintain castrate levels of testosterone should continue, and * Either symptomatic progression, or, if patient is asymptomatic then a rising serum PSA in two occasions at least 1 week apart, with minimum pre-treatment serum PSA of 5 ng/dL. * Patients with nodal disease are eligible. * Bi-dimensionally measurable disease within the bone. * Life expectancy of at least 12 weeks. * ECOG Performance status \< 2 * Adequate: * Bone marrow function; absolute neutrophil count \> 1,500 mm3, platelet count of \> 100,000 mm3 and hemoglobin \> 9.0 gm/dl. * Hepatic function; SGOT/SGPT and conjugated bilirubin less than twice the upper limit of normal. * Renal function; serum creatinine ≤ 2 mg/dL (or, if creatinine \> 2 mg/dL, then a creatinine clearance of at least 35 ml/min (measured or estimated by the Cockroft formula: CLcr = \[(140-age) x wt (kg)\]/\[72 x serum creatinine (mg/dL)\]. * No evidence of coagulopathy as indicated by PT \< 1.5X upper limit of normal. * Serum calcium (corrected) from 8 to11.5 mg/dL (2 to 2.9 mmol/L) - Patients must sign an informed consent indicating that they are aware of the investigational nature of the study. Exclusion Criteria: * Patients with variant histologies (e.g., ductal or small cell carcinoma). * Patients with visceral disease are ineligible. * Patients who have had prior Sipuleucel-T, docetaxel, cabazitaxel, abiraterone or enzalutamide as a single agent, or in combination therapy. * Concurrent cancer chemotherapy, radiotherapy or surgery. * Concurrent serious infection. * Life threatening illness (e.g., congestive heart failure, uncontrolled angina or myocardial infarction in the prior six months). * Hypertension uncontrolled by medication. * Patients who are known to require invasive dental procedures. * No known or suspected brain metastases (NOTE: patients with treated epidural disease are allowed) * Administration of any investigational drug within 28 days prior to receipt of denosumab. * Age ≤ 18 years of age