Inclusion Criteria:

          -  Willing and able to provide written informed consent and HIPAA authorization for the
             release of personal health information or have their legally authorized representative
             provide written informed consent. A signed informed consent must be obtained prior to
             performing screening procedures.

        NOTE: HIPAA authorization may be either included in the informed consent or obtained
        separately

          -  Males 18 years of age or above

          -  Histologically or cytologically confirmed adenocarcinoma of the prostate

          -  Bilateral orchiectomy or ongoing androgen deprivation therapy with a GnRH
             agonist/antagonist (surgical or medical castration)

          -  Progression of mCRPC on treatment with at least 1 second generation hormonal agent
             (e.g., enzalutamide and/or abirateroneacetate/prednisone)

          -  Documented progressive mCRPC based on at least one of the following criteria:

               -  PSA progression defined as at least 2 rises in PSA with a minimum of a 1-week
                  interval

               -  1.0 ng/mL is the minimal starting value if confirmed rise is only indication of
                  progression

               -  Soft-tissue progression per RECISTv1.1

               -  Progression of bone disease (evaluable disease) or tow or more new bone lesions
                  by bone scan

          -  Metastatic disease documented by bone lesions on whole-body radionuclide bone scan or
             soft tissue disease y computed tomography/magnetic-resonance imaging (CT/MRI).

          -  Consent to a fresh tumor biopsy during screening or have sufficient archival tumor
             tissue available for molecular profile and biomarker analyses

          -  ECOG status of 0 or 1 (Appendix A: Performance Status Criteria)

          -  Serum testosterone </= 50mg/dL at screening

          -  Adequate organ function with acceptable initial laboratory values within 14 days of
             treatment start:

        Absolute neutrophil count (ANC): >/= 1,500/ul Hemoglobin: >/= 9g/dL Platelet count: >/=
        100,00/ul Creatinine: >/= 60 mL/min estimated using the Cockcroft-Gault equation Potassium:
        >/= 3.5 mmol/L (within institutional normal range) Bilirubin: </= 1.5 ULN (unless
        documented Gilbert's disease) SGOT(AST): </= 2.5 x ULN SGPT (ALT): </= 2.5 x ULN

          -  Subjects must agree to use a highly effective method of contraception (e.g.,
             spermicide in conjunction with a barrier such as a condom) or sexual abstinence during
             treatment, and for at least 7 months after completing therapy. Furthermore, male
             patients with female partners of reproductive potential and pregnant partners must use
             a condom (even after vasectomy), during treatment and for at least 4 months after the
             final dose. Sperm donation is prohibited during the study and for 30 days after the
             last dose of study drug. Female partners must use hormonal or barrio contraception
             unless postmenopausal or abstinent.

        Exclusion Criteria:

          -  Prior treatment with a taxane-based chemotherapy for mCRPC (prior treatment with a
             taxane-based chemotherapy for metastatic non-castrate prostate cancer is permitted)

          -  Prior treatment with a PARP inhibitor, platinum, cyclophosphamide, mitozantrone
             chemotherapy, ortemozolmide

          -  Subject has received radiation therapy within 3 weeks (within 2 weeks, if single
             fraction of radiotherapy) of treatment start

          -  Documented carrier of a pathogenic or likely pathogenic germline or somatic mutation
             in BRCA 1, BRC 2 or ATM or known carrier (pathogenic or likely pathogenic) or one of
             the following DNA Damage Repair genes considered as sensitizing tumors to PARP
             inhibitors: FANCA, CHECK2, PALB2, MRE11A, NBN, RAD51C, ATR, MLH1, and CDK12. Testing
             is required for BRCA 1, BRCA 1, or ATM. If a subject has had next generation
             sequencing that did not include FANCA, CHECK2, PALB2, MRE11A, NBN, RAD51C, ATR, MLH1,
             or CDK12 he will not be excluded from the study if status is unknown.

        Note, if testing is germline negative, somatic testing is still required. If the subject is
        germline positive, the subject in ineligible.

          -  Use of systemic hormonal (except for GnRH analog), biologic, radium-223, or any
             investigational therapy for treatment of metastatic prostate cancer within 4 weeks
             prior to treatment start. Exceptions include abiraterone, which may not have been
             administered within 2 weeks of treatment start.

          -  Medical conditions such as uncontrolled hypertension, uncontrolled diabetes mellitus,
             or cardiac disease that would, in the opinion of the investigator, make this protocol
             unreasonably hazardous to the subject.

          -  Known or suspected brain metastasis or active leptomeningeal disease.

          -  Symptomatic or impending spinal cord compression or cauda equine syndrome

          -  Diagnosis of myelodysplastic syndrome (MDS)

          -  History of another cancer within 2 years of treatment start with the exception of
             nonmelanoma skin cancers or American Joint Committee on Cancer stage 0 or stage 1
             cancer that has a remote probability of recurrence in the opinion of the investigator
             and the Sponsor

          -  Use of any prohibited concomitant medications (Appendix C: Medications With the
             Potential for Drug-Drug Interactions) within 14 days prior to the first dose of
             talazoparib

          -  Grade > 2 treatment-related toxicity unresolved from prior therapy

          -  Known allergy to any of the compounds under investigation

          -  Any other condition which, in the opinion of the investigator, would preclude
             participation in this trial