Study of 225Ac-PSMA-617 in Men With PSMA-positive Prostate Cancer

Total duration of study participation of each participant is approximately 18-24 months (12 months from enrollment to end of each treatment (EOT) plus 12 months of long-term follow up (LTFU). The total duration of the study, from first patient in (FPI) to last LTFU will be approximately 48 months. A minimum of 3 patients will be treated in each patient group at each dose level and evaluated for the occurrence of dose-limiting toxicity (DLT) during the first 6 weeks of treatment before consideration will be given to enrolling patients into the next dose level. Dose modifications for toxicity are allowed and defined per protocol. No more than 6 cycles of 225Ac-PSMA-617 will be administered. Patients may receive less than 6 cycles if they have disease progression, intolerable toxicity, started other anticancer therapy, or have withdrawn from treatment per participant or physician decision. Participants may also receive supportive care therapy, as determined by the study physician, however, participants cannot receive concurrent investigational agents, cytotoxic chemotherapy, biological agents, targeted therapy, immunotherapy, other systemic radioisotopes, and hemi-body radiotherapy until completion of treatment with 225Ac-PSMA-617.