KEYNOTE - 641: This phase III trial is evaluating the safety and effectiveness of using a combination of a targeted therapy (Pembrolizumab) and an anti-hormonal therapy (Enzalutamide) to treat patients with metastatic castration-resistant prostate cancer.Study of Pembrolizumab (MK-3475) plus Enalutamide versus placebo plus Enzalutamide in participants with metastatic castraion-resistant prostate cancer (mCRPC)

Exclusion

The main exclusion criteria include but are not limited to the following:

• Has a known additional malignancy that is progressing or has required active treatment in the last 3 years
• Has an active autoimmune disease that has required systemic treatment in past 2 years
• Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy
• Has undergone major surgery including local prostate intervention (excluding prostate biopsy) within 28 days prior to randomization and not recovered adequately from the toxicities and/or complications
• Has a gastrointestinal disorder affecting absorption or is unable to swallow tablets/capsules
• Has an active infection (including tuberculosis) requiring systemic therapy
• Has a history of (noninfectious) pneumonitis/interstitial lung disease that required steroids or current pneumonitis/interstitial lung disease
• Has known active human immunodeficiency virus (HIV), concurrent active hepatitis B virus (HBV) or known active hepatitis C virus (HCV) infection
• Has known active central nervous system (CNS) metastases and/or carcinomatous meningitis
• Has hypersensitivity to pembrolizumab and/or enzalutamide and/or any of their excipients
• Has a history of seizure or any condition that may predispose to seizure
• Has a history of loss of consciousness within 12 months of screening
• Has hypotension (systolic blood pressure <86 millimeters of mercury [mmHg]) or uncontrolled hypertension (systolic blood pressure >170 mmHg or diastolic blood pressure >105 mmHg) at the screening visit
• Has bradycardia (heart rate of <50 beats per minute) on the screening electrocardiogram (ECG)
• Has history of prostate cancer progression on ketoconazole
• Has had prior treatment with enzalutamide, apalutamide, darolutamide or cytochrome P450 (CYP) 17 inhibitor other than abiraterone acetate
• Has received prior therapy with an anti-programmed cell death-1 (anti-PD-1), anti-programmed cell death-ligand 1 (anti-PD-L1), or anti-PD-L2 agent or with an agent directed to another stimulatory or coinhibitory T-cell receptor
• Has received prior treatment with radium or other therapeutic radiopharmaceuticals for prostate cancer
• Has received prior treatment with docetaxel or another chemotherapy agent for mCRPC
• Has had a prior anti-cancer monoclonal antibody (mAb) prior to randomization
• Has used herbal products that may have hormonal anti-prostate cancer activity and/or are known to decrease PSA levels (eg, saw palmetto) prior to randomization
• Has received a live or live attenuated vaccine within 30 days prior to randomization
• Is currently participating in or has participated in a study of an investigational agent or has used an investigational device within 4 weeks prior to the first dose of study treatment
• Has a "superscan" bone scan
• Is expecting to conceive or father children within the projected duration of the study, starting with the screening visit through 90 days after the last dose of enzalutamide
• Has had an allogenic tissue/solid organ transplant