A Study of Lorigerlimab With Docetaxel or Docetaxel Alone in Participants With Metastatic Castration-Resistant Prostate Cancer

The purpose of this study is to determine whether the amount of time before disease progression can be prolonged in participants with metastatic castration-resistant prostate cancer (MCRPC) who receive lorigerlimab in addition to the standard of care (SOC) of docetaxel and prednisone. About 150 participants with mCRPC will be enrolled. Participants will be randomized in a 2:1 ratio to receive lorigerlimab with docetaxel and prednisone (experimental arm) or docetaxel and prednisone alone (standard-of-care arm). Lorigerlimab+docetaxel or docetaxel will be administered intravenously (IV) in clinic on Day 1 of each 3-week cycle. Prednisone will be administered orally twice daily. Lorigerlimab will be administered for up to 35 cycles. Docetaxel and prednisone will be administered up to 10 cycles until treatment discontinuation criteria are met. Participants will undergo regular testing for signs of disease progression using computed tomography (CT) scans, magnetic resonance imaging (MRI) and prostate-specific antigen (PSA) blood tests. Participants will be asked to complete questionnaires about their health and well-being. Routine examinations and blood tests will be performed and evaluated by the study doctor. Participants who have disease progression standard-of-care arm have the option of continuing on the study to receive lorigerlimab monotherapy.