A Study of FG-3246 in Participants With Metastatic Castration-Resistant Prostate Cancer (mCRPC)

Required: AR castration resistance (serum testosterone <50 ng/dL)

serum testosterone levels <50 nanograms (ng)/deciliter (dL) during screening

Must have received: second-generation ARSI (abiraterone acetate, enzalutamide, apalutamide, darolutamide) — castration-sensitive or castration-resistant

progressed on one prior treatment with a second generation ARSI (abiraterone acetate, enzalutamide, apalutamide, or darolutamide) initiated in either the castration-sensitive or castration-resistant setting

Cannot have received: CD46-targeted therapy

previous treatment with a therapeutic targeting CD46

Cannot have received: second-generation ARSI (abiraterone acetate, enzalutamide, apalutamide, darolutamide)

Exception: more than one prior second-generation ARSI in any setting

received more than one prior second-generation ARSI in any setting

Cannot have received: systemic anticancer therapy

Exception: within 28 days prior to randomization

received any systemic anticancer therapy (for example, hormonal therapy, chemotherapy, immunotherapy, radioligand therapy, or biological therapy [including monoclonal antibodies], including investigational therapy) within 28 days prior to randomization

Cannot have received: radiation therapy

Exception: within 28 days prior to randomization

received any prior radiation therapy within 28 days prior to randomization

Cannot have received: chemotherapy

Exception: one prior taxane-based chemotherapy in the castration-sensitive setting is allowed if completed >12 months before randomization

received any prior chemotherapy; however, one prior taxane-based chemotherapy in the castration-sensitive setting is allowed if completed >12 months before randomization