Non-fucosylated Anti-CTLA-4 (BMS-986218) + Degarelix Acetate vs. Degarelix Acetate Alone in Men With High-risk Localized Prostate Cancer

Inclusion Criteria: * Histologically confirmed adenocarcinoma of the prostate (clinical stage T1c-T3b, N0, M0) without involvement of lymph nodes, bone, or visceral organs * Initial prostate biopsy is available for central pathologic review, and is confirmed to show at least 2 positive cores and a Gleason sum of ≥4+3 * Radical prostatectomy has been scheduled at Columbia University Irving Medical Center * Age ≥18 years * Eastern Cooperative Oncology Group (ECOG) performance status 0-1, or Karnofsky score ≥ 70% (see Appendix A) * Adequate bone marrow, hepatic, and renal function: * White blood cell count (WBC) \>3,000 cells/mm3 * Absolute neutrophil count (ANC)\>1,500 cells/mm3 * Hemoglobin \>9.0 g/dL * Platelet count \>100,000 cells/mm3 * Serum creatinine \<1.5 × upper limit of normal (ULN) * Serum bilirubin \<1.5 × ULN * Alanine transaminase (ALT) \<3 × ULN * Aspartate aminotransferase (AST)\<3 × ULN * Alkaline phosphatase \<3 × ULN * Willingness to provide written informed consent and HIPAA authorization for the release of personal health information, and the ability to comply with the study requirements (note: HIPAA authorization will be included in the informed consent) * Willingness to use barrier contraception from the time of first dose of BMS-986218 until 165 days from the last dose of BMS-986218. Exclusion Criteria: * Presence of known lymph node involvement or distant metastases * Other histologic types of prostate cancers such as ductal, sarcomatous, lymphoma, small cell, and neuroendocrine tumors * Prior radiation therapy, hormonal therapy, biologic therapy, or chemotherapy for prostate cancer * Prior immunotherapy/vaccine therapy for prostate cancer * Concomitant treatment with other hormonal therapy or 5α-reductase inhibitors (prior use of these agents is allowed). * Conditions requiring systemic treatment with either corticosteroids \> 10 mg daily prednisone equivalents or other immunosuppressive medications within 14 days of study treatment administration, except for adrenal replacement steroid doses \> 10 mg daily prednisone equivalent in the absence of active autoimmune disease. (1) Treatment with a short course of steroids (\< 5 days) up to 7 days prior to initiating study treatment is permitted. * History of known or suspected autoimmune disease with the following exceptions: * Vitiligo * Resolved childhood atopic dermatitis * Psoriasis (with exception of psoriatic arthritis) not requiring systemic treatment (within the past 2 years). * Patients with Grave's disease or Hashimoto's thyroiditis that are now euthyroid clinically and by laboratory testing. * History of malignancy within the last 2 years, with the exception of non-melanoma skin cancers and superficial bladder cancer * Known uncontrolled or significant cardiovascular disease including, but not limited, to any of the following: 1. Myocardial infarction or stroke/transient ischemic attack within the past 6 months. 2. Uncontrolled angina within the past 3 months. 3. Any history of clinically significant arrhythmias (such as ventricular tachycardia, ventricular fibrillation, or torsades de pointes). 4. History of other clinically significant heart disease (eg, cardiomyopathy, congestive heart failure with New York Heart Association functional classification III to IV, pericarditis, or significant pericardial effusion). 5. History of myocarditis, regardless of etiology. 6. Cardiovascular disease-related requirement for daily supplemental oxygen therapy. * Known prior or current history of HIV. * Patients with known untreated hepatitis B/C or those with a detectable viral load. * Active infection ≤7 days prior to start of treatment. * Live vaccine within 30 days of start of treatment. * Prior history of hypersensitivity to a monoclonal antibody.