Safety and Efficacy of Therapies for Metastatic Castration-resistant Prostate Cancer (mCRPC)

Inclusion Criteria

• ≥ 18 years of age (or legal adult age within country)
• Subject has provided informed consent prior to initiation of any study-specific activities/procedures
• Subjects with mCRPC with histologically or cytologically confirmed adenocarcinoma of the prostate
• Subjects should have undergone bilateral orchiectomy or should be on continuous androgen deprivation therapy with a gonadotropin releasing hormone agonist or antagonist (testosterone ≤ 50 ng/dL (or 1.7 nmol/L))

Exclusion Criteria

• Central nervous system (CNS) metastases or leptomeningeal disease
• History or presence of clinically relevant CNS pathology
• Confirmed history or current autoimmune disease or other diseases requiring permanent immunosuppressive therapy
• Myocardial infarction, uncontrolled hypertension, unstable angina, cardiac arrhythmia requiring medication, and/or symptomatic congestive heart failure (New York Heart Association > class II) within 12 months
• Prior treatment with a taxane for mCRPC
• Major surgery and/or Radiation within 4 weeks
• History or evidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection unless agreed upon with medical monitor and meeting the following criteria:
• Negative test for SARS-CoV-2 RNA by real time polymerase chain reaction (RT-PCR) within 72 hours of first dose of Acapatamab (or AMG 404 in Part 3)
• No acute symptoms of COVID-19 disease within 10 days prior to first dose of Acapatamab (or AMG 404 in Part 3) (counted from day of positive test for asymptomatic subjects) Prior/Concurrent Clinical Study Experience
• Currently receiving treatment in another investigational device or drug study, or less than 4 weeks since ending treatment on another investigational device or drug study(ies). Other investigational procedures while participating in this study are excluded with the exception of investigational scans. Subprotocol A only: Inclusion criteria • Subjects planning to receive enzalutamide for the first time for mCRPC Exclusion criteria
• Use of strong CYP2C8 inhibitors or strong CYP3A4 inducers
• Use of narrow therapeutic index drugs that are substrates of CYP3A4, CYP2C9 or CYP2C19 Subprotocol B only: