BACKGROUND: Actinium-225 (^(225)Ac) prostate-specific membrane antigen (PSMA) radioligand therapy (RLT) is a novel therapy for metastatic castration-resistant prostate cancer (mCRPC). We aimed to report the safety and antitumour activity of ^(225)Ac-PSMA RLT of mCRPC in a large cohort of patients treated at multiple centres across the …