AcTFirstAAA817 and ARPI for PSMA-positive Metastatic Castration Resistant Prostate Cancer

This study is designed to see if a new treatment called 225Ac-PSMA-617, when combined with either enzalutamide or abiraterone, is more effective than the current standard treatments for adult men with a type of prostate cancer known as PSMA-positive metastatic castration-resistant prostate cancer. The main goal is to find out if this new treatment can help patients live longer without the cancer getting worse. This is important because finding more effective treatments can improve the quality of life and outcomes for patients who have few options due to the advanced stage of their cancer. Participants in the study will first undergo scans to confirm their eligibility and ensure their cancer is PSMA-positive. Those who qualify will be randomly assigned to receive either the new treatment of 225Ac-PSMA-617 through an IV infusion, potentially with oral ARPI medications, or the standard care treatment, which could involve other oral ARPI drugs or chemotherapy. The study will closely monitor the safety of the treatments and measure how long patients go without their cancer progressing. Supportive care, including therapies to reduce certain hormone levels, is available to all participants as needed. The study does not allow switching between treatment groups, and safety checks are a routine part of the process.