Inclusion Criteria:

          -  Histologically or cytologically confirmed adenocarcinoma of prostate

          -  Documented progressive metastatic CRPC based on Prostate Cancer Working Group 3
             (PCWG3) criteria, which includes at least one of the following criteria: PSA
             progression, Objective radiographic progression in soft tissue, New bone lesions

          -  ECOG performance status of 0-2

          -  Have serum testosterone < 50 ng/dL. Subjects must continue primary androgen
             deprivation with an LHRH/GnRH analogue (agonist/antagonist) if they have not undergone
             bilateral orchiectomy

          -  Have previously been treated with at least one of the following: Androgen receptor
             signaling inhibitor (such as enzalutamide), CYP 17 inhibitor (such as abiraterone
             acetate)

          -  Have previously received taxane chemotherapy, been determined to be ineligible for
             taxane chemotherapy by their physician or refused taxane chemotherapy

          -  Age > 18 years

          -  Patients must have normal organ and marrow function as defined below: Absolute
             neutrophil count: >2,000 cells/mm3, Hemoglobin: ≥9 g/dL, Platelet count: >150,000 x
             109/uL, Serum creatinine: <1.5 x upper limit of normal (ULN) or calculated creatinine
             clearance ≥ 60 mL/min/1.73 m2 by Cockcroft-Gault, Serum total bilirubin: <1.5 x ULN
             (unless due to Gilbert's syndrome in which case direct bilirubin must be normal),
             Serum AST and ALT: <1.5 x ULN in the absence of liver metastases; <3 x ULN if due to
             liver metastases (in both circumstances bilirubin must meet entry criteria)

          -  Ability to understand, and the willingness to sign, a written informed consent
             document

        Exclusion Criteria:

          -  Implantation of investigational medical device ≤4 weeks of Treatment visit #1 (Day 1)
             or current enrollment in oncologic investigational drug or device study

          -  Use of investigational drugs ≤4 weeks or <5 half-lives of Treatment visit # 1(Day 1)
             or current enrollment in investigational oncology drug or device study

          -  Prior systemic beta-emitting bone-seeking radioisotopes. Prior radium-223 is allowed
             provided at least 90 days have lapsed since last dose

          -  Prior PSMA-targeted radionuclide therapy (prior PSMA-targeted isotopes used for
             imaging/diagnostic purposes are allowed, as is prior PSMA-targeted therapy that does
             not involve therapeutic radionuclides)

          -  Known active brain or leptomeningeal metastases

          -  History of deep vein thrombosis and/or pulmonary embolus within 1 month of Treatment
             visit #1

          -  Other serious illness(es) involving the cardiac, respiratory, CNS, renal, hepatic or
             hematological organ systems which might preclude completion of this study or interfere
             with determination of causality of any adverse effects experienced in this study

          -  Radiation therapy for treatment of PC ≤4 weeks of Treatment visit #1

          -  Patients on stable dose of bisphosphonates or denosumab, which have been started no
             less than 4 weeks prior to treatment start, may continue on this medication, however
             patients are not allowed to initiate bisphosphonate/Denosumab therapy during the
             DLT-assessment period of the study

          -  Having partners of childbearing potential and not willing to use a method of birth
             control deemed acceptable by the principle investigator and chairperson during the
             study and for at least 140 days after last study drug administration

          -  Currently active other malignancy other than non-melanoma skin cancer. Patients are
             considered not to have "currently active" malignancy if they have completed any
             necessary therapy and are considered by their physician to be at less than 30% risk of
             relapse

          -  Known history of myelodysplastic syndrome