Study of Pembrolizumab Plus Enzalutamide Versus Placebo Plus Enzalutamide in Men with Advanced Prostate Cancer

Inclusion Criteria

• Diagnosed with prostate cancer confirmed by lab tests, without small cell cancer type.
• Cancer has progressed despite hormone therapy or after surgical removal of the testicles within the last 6 months.
• Evidence of cancer spread to bones or soft tissues as shown by scans.
• Either never used abiraterone, used it without cancer progression, or used it and cancer progressed after a certain period.
• Ongoing hormone therapy with low testosterone levels.
• Stable doses of bone-strengthening therapy if applicable.
• Agree to not donate sperm and use contraception during and for 90 days after treatment.
• Provide a recent biopsy sample from a tumor not previously treated with radiation.
• Good overall health with an ECOG performance status of 0 or 1.

Exclusion Criteria

• Have another active cancer needing treatment in the last 3 years.
• Have an autoimmune disease needing treatment in the last 2 years.
• Have an immune deficiency or are on long-term steroid therapy.
• Had major surgery recently and not fully recovered.
• Have digestive issues affecting medication absorption.
• Have an active infection needing treatment.
• Have lung disease needing steroids or current lung disease.
• Have active HIV, hepatitis B, or hepatitis C infections.
• Have cancer spread to the brain or spinal cord.
• Allergic to pembrolizumab or enzalutamide.
• Have a history of seizures or conditions causing seizures.
• Have had recent loss of consciousness.
• Have low or uncontrolled high blood pressure.
• Have a slow heart rate.
• Cancer progressed on ketoconazole.
• Previously treated with certain prostate cancer drugs.
• Previously treated with specific immune therapies.
• Previously treated with certain radioactive drugs for prostate cancer.
• Previously treated with chemotherapy for mCRPC.
• Previously treated with monoclonal antibodies.
• Used herbal products affecting prostate cancer or PSA levels.
• Received a live vaccine recently.
• Participating in another clinical trial recently.
• Have a specific type of bone scan result.
• Planning to have children during or shortly after the study.
• Had an organ transplant.