Background: The novel therapeutic drug ¹⁷⁷Lu-PSMA-617 is a prostate-specific membrane antigen (PSMA) targeting agent that is used to deliver radionuclide therapy for the treatment of patients with mCRPC. Based on preclinical data that demonstrated high PSMA binding affinity and internalization, prolonged tumor uptake, rapid kidney clearance, and high tumor-to-background ratio, ¹⁷⁷Lu-PSMA-617 proceeded into clinical development. Preliminary clinical data indicates that ¹⁷⁷Lu-PSMA-617 may demonstrate clinical benefit in patients with mCRPC in a setting where patients had no clear standard of care. VISION (NCT03511664) is a phase 3 study designed to assess the efficacy of ¹⁷⁷Lu-PSMA-617 in patients with PSMA-positive mCRPC. Methods: Patients were randomized 2:1 to receive best standard of care with or without ¹⁷⁷Lu-PSMA-617. Eligibility criteria were: PSMA expressing tumor assessed by PSMA positron emission tomography imaging; prior exposure to a taxane and a novel androgen axis inhibitor (NAAI). The primary objective of this study is to compare the two alternative endpoints of progression-free survival (rPFS) and overall survival (OS). Stratification factors include lactate dehydrogenase, liver metastasis, ECOG PS, and use of an NAAI at time of randomization. On active treatment, median OS is assumed to be 13.7 months with a hazard ratio (HR) of 0.7306, and rPFS is assumed to be 6 months with an HR of 0.67. Enrollment began in June 2018 and the target of 814 patients has been reached. Clinical trial information: NCT03511664