177^Lu-PSMA-617 in Combination With Sipuleucel-T for the Treatment of Metastatic Castration-Resistant Prostate Cancer

This phase I trial compares the effect of lutetium Lu 177 (177\^Lu)-prostate-specific membrane antigen (PSMA)-617 in combination with Sipuleucel-T to 177\^Lu-PSMA-617 alone in treating patients with prostate that has spread from where it first started (primary site) to other places in the body (metastatic) and has continued to grow and spread despite surgical or medical intervention to block androgen production (castration-resistant). 177\^Lu-PSMA-617, a type of radioconjugate, binds to a protein called PSMA, which is found on some prostate tumor cells. It gives off radiation that may kill the tumor cells. Sipuleucel-T, a type of vaccine and a type of cellular adoptive immunotherapy, is made from immune system cells. The cells are treated with a protein that is made by combining a protein found on prostate tumor cells with a growth factor. When the cells are injected back into the patient, they may stimulate T cells to kill prostate tumor cells. Giving 177\^Lu-PSMA-617 in combination with sipuleucel-T may be safe, tolerable, and/or effective compared to 177\^Lu-PSMA-617 alone in treating patients with metastatic castration-resistant prostate cancer.