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

All parts

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:

Inclusion criteria

Subjects planning to receive abiraterone for the first time for mCRPC Exclusion criteria
Baseline moderate and severe hepatic impairment (Child-Pugh Class B and C)
Presence of uncontrolled hypertension, hypokalemia, or fluid retention
History or presence of adrenocortical insufficiency
Use of concomitant medications that are sensitive substrates for CYP2D6 with a narrow therapeutic index
Use of strong CYP3A4 inducers

Subprotocol C only:

Inclusion criteria

Subjects who are refractory to a novel antiandrogen therapy. Subjects must be ineligible for or refuse taxane therapy.
Evidence of progressive disease, defined as 1 or more PCWG3 criteria: PSA level >/=1 ng/mL that has increased on at least 2 successive occasions at least 1 week apart, nodal or visceral progression as defined by RECIST 1.1 with PCGW3 modifications, and/or appearance of 2 or more new lesions in bone scan Exclusion criteria
History or evidence of interstitial lung disease or active, non-infectious pneumonitis
Subjects on a prior PD-1 or PD-L1 inhibitor who experienced a grade 3 or higher immune-related adverse event prior to first day of dose

Subprotocol D only:

Inclusion criteria

Subjects may have had novel hormonal therapies (NHT; eg, abiraterone, enzalutamide, apalutamide, or darolutamide) for prostate cancer, but no more than 1 NHT for metastatic prostate cancer
Ineligible for or refuse taxane therapy