RecruitingPhase 1Genetic interventionA Phase 1 Study of BPX-601 CAR T-Cell Therapy in Adult Participants With Prostate Cancer That Has Returned, is Resistant to Treatment and Has SpreadThis study will test a study drug called BPX-601, a CAR-T cell product manufactured from the patient's own T-cells, to see if it can help treat advanced prostate cancer. BPX-601 is a drug that is only used in clinical studies. The study is looking at: * What side effects BPX-601 might cause * What is the best dose of BPX-601 * How well BPX-601 may work to destroy prostate cancer