Pembrolizumab Plus 177Lu-PSMA-617 in Patients With Castration Resistant Prostate Cancer

This study is testing the combination of pembrolizumab (an immunotherapy) and lutetium PSMA-617 (a targeted radiation therapy) in men with advanced prostate cancer that has stopped responding to hormonal treatment — known as metastatic castration-resistant prostate cancer. **You may be eligible if...** - You are male, aged 18 or older - You have metastatic castration-resistant prostate cancer confirmed by biopsy - Your testosterone level is below 50 ng/dL (castrate level) - You have previously been treated with at least one hormonal therapy (e.g., enzalutamide or abiraterone) and it stopped working - You have adequate organ function **You may NOT be eligible if...** - You have not had prior hormonal therapy - You have poor overall health or serious organ problems - You have conditions that would interfere with immunotherapy or targeted radiation Talk to your doctor to see if this trial is right for you.