A Study of Pasritamig With Docetaxel Versus Docetaxel in Participants With Metastatic Castration-Resistant Prostate Cancer

Open to people ages 18 years and up

• Have histologically confirmed adenocarcinoma of the prostate
• Have disease that is metastatic at the time of screening by computed tomography (CT) or magnetic resonance imaging (MRI) and 99m^Tc bone scan as determined by the investigator
• Participants must receive ongoing androgen deprivation therapy (ADT) with a gonadotropin releasing hormone (GnRH) analog throughout the treatment or have had prior bilateral orchiectomy, and have serum testosterone less than or equal to (<=) 50 nanogram per deciliter (ng/dL) (<= 1.73 nanomoles per Liter [nmol/L]) at screening
• Have progressed by PSA or CT/MRI or 99m^Tc bone scan on at least 1 novel androgen receptor pathway inhibition (ARPI) but no more than 2 different ARPI for any stage of disease. Must have discontinued ARPI before randomization into the study
• Have an eastern cooperative oncology group (ECOG) performance status of 0 to 1

• Known history of either brain or leptomeningeal prostate cancer metastases
• Participants with known breast cancer gene 1/2 (BRCA 1/2) mutations (germline or somatic) who have not received treatment with a poly (ADP-ribose) polymerase (PARP) inhibitor, unless not available or contraindicated
• Prior or concurrent second malignancy (other than the disease under study)
• Received cytotoxic chemotherapy for prostate cancer in any setting
• Received prior treatment with human kallikrein 2 (KLK-2) directed therapies