Study to Evaluate the Safety, Tolerability,Pharmacokinetics, and Anti-tumor Activity of a Thorium-227 Labeled Antibody-chelator Conjugate, in Patients With Metastatic Castration Resistant Prostate Cancer

Inclusion Criteria

- Ability to understand and sign an approved informed consent form.

- Male adult patients (≥ 18 years of age).

- ECOG PS of 0 or 1.

- Life expectancy ≥ 6 months.

- Histological, pathological and/or cytological confirmation of adenocarcinoma of the
prostate without small cell or neuroendocrine features.

- Previous treatment with at least one novel androgen axis drug (NAAD) (e.g.
enzalutamide and/or abiraterone).

- Patients must have prior orchiectomy and/or ongoing androgen deprivation therapy and a
castrate level of serum testosterone (<50 ng/dL or <1.7 nmol/L).

- Previous treatment with at least 1, but no more than 2 previous - taxane regimens. A
taxane regimen is defined as a minimum exposure of 2 cycles of a taxane. If a patient
has received only 1 taxane regimen, he is eligible, if refuses to receive a second
taxane regimen, or is considered unsuitable to receive a second taxane regimen (e.g.
intolerance).

- Documented progression of mCRPC, as defined according to the Prostate Cancer Working
Group 3 (PCWG3) guidelines.

- Adequate bone marrow, liver, and renal function, as assessed by the following
laboratory requirements, to be conducted within 14 days before start of study drug
administration:

- Hemoglobin > 9.0 g/dL

- Absolute neutrophil count (ANC) > 1500/mm3

- White blood cell (WBC) count > 3000/mL

- Platelet count > 100,000 /mm*3

- Total bilirubin < 1,5 x upper limit of normal (ULN) (except if confirmed history
of Gilbert's disease)

- ALT and AST ≤ 2.5 x ULN

- Serum creatinine ≤ 1.5 X ULN and glomerular filtration rate (GFR ≥ 45 mL/min/1.73
m2, according to the MDRD (Modified Diet in Renal Disease) abbreviated formula.

- Patients with partners of childbearing potential must be willing to use highly
effective methods of birth control for the time period between the first
administration of BAY 2315497 Injection to at least 6 months after the last
administration of the study drug.

Exclusion Criteria

- Diffuse bone or bone-marrow involvement (i.e. "superscan").

- Spinal cord compression or known brain metastases.

- Known incompatibility to CT/MRI, bone scan or uncontrolled pain, which results in
patient's lack of compliance with the CT/MRI and bone scan required for PCWG3 tumor
assessment.

- Clinically significant heart disease, as evidenced by myocardial infarction, arterial
thrombotic events in the past 6 months, severe or unstable angina, or uncontrolled
cardiovascular history.

- Patients known to be affected by genetic defects linked to radiation Hypersensitivity.

- Known history of myelodysplastic syndrome (MDS) / leukemia or with features suggestive
of MDS/AML at any time point.

- Concurrent or active cancer within the last 2 years with a distinct primary site or
histology from the cancer being evaluated in this study, with the exception of cancer
types with less than 30% likelihood of recurrence.

- Known allergies, hypersensitivity, or intolerance to the study drug including
excipients, or to contrast agents used in the diagnostic or exploratory imaging
procedures required per protocol.

- Any infection of National Cancer Institute Common Terminology Criteria for Adverse
Events (NCI-CTCAE) Version 5.0 Grade ≥ 2.

- Known human immunodeficiency virus (HIV) infection.

- Patients who have an active hepatitis B virus (HBV) or hepatitis C virus (HCV)
infection requiring treatment.

- Serious, non-healing wound, ulcer, or bone fracture.

- Any systemic anti-neoplastic therapy (e.g. chemotherapy, immunotherapy or biological
therapy [including monoclonal antibodies], PARP inhibitors) within at least 30 days
prior to day of randomization (except for Luteinizing Hormone-releasing Hormone [LHRH]
or Gonadotropin-releasing Hormone [GnRH]).

- Previous high-dose chemotherapy, needing hemopoietic stem cell rescue, is prohibited.

- Prior major surgery (excluding prostatic biopsies) must be at least 12 weeks prior to
study entry.

- Previous treatment with therapeutic PSMA-targeted agents.

- Previous treatment with radium-223 dichloride or other radiopharmaceuticals, including
but not limited to strontium-89 or samarium-153.

- Prior definitive radiotherapy completed less than 6 weeks before start of the study
drug administration.