Talapro-1: This phase II trial is evaluating an oral drug (Talazoparib) in men who have previously received treatment for metastatic Castration-Resistant Prostate Cancer (CRPC)A Phase 2, Open-label, 2-arm, Response Rate Study Of Talazoparib In Men With Dna Repair Defects And Metastatic Castration-resistant Prostate Cancer Who Previously Received Taxane-based Chemotherapy And Progressed On At Least 1 Novel Hormonal Agent (Enzalutamide And/or Abiraterone Acetate/Prednisone)

Exclusion

1. 1. Use of systemic chemotherapeutic (including but not limited to taxanes), hormonal, biologic, or radionuclide therapy for treatment of metastatic prostate cancer (other than approved bone targeting agents and GnRH agonist/antagonist) or any other investigational agent within 4 weeks before day 1.
2. Prior treatment with a PARP inhibitor, cyclophosphamide, or mitoxantrone chemotherapy. Patients who discontinued prior platinum based chemotherapy <=6 months prior to screening or whose disease previously progressed on platinum based therapy at any time in the past are also excluded.
3. Treatment with any concurrent cytotoxic chemotherapy or investigational drug(s) within 4 weeks or 5 half lives of the drug (whichever is longer) before Day 1 and/or during study participation
4. Radiation therapy within 3 weeks (within 2 weeks, if single fraction of radiotherapy) before day 1.
5. Major surgery within 2 weeks before day 1.
6. Clinically significant cardiovascular disease.
7. Significant renal, hepatic, or bone marrow organ dysfunction.
8. Known or suspected brain metastasis or active leptomeningeal disease.
9. Symptomatic or impending spinal cord compression or cauda equina syndrome.
10. Prior diagnosis of myelodysplastic syndrome or acute myeloid leukemia
11. History of another cancer within 3 years before enrollment 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.
12. Gastrointestinal disorder affecting absorption.
13. Current or anticipated use within 7 days prior to first dose of study drug or anticipated use during the study of the following P gp inhibitors (amiodarone, carvedilol, clarithromycin, cobicistat, darunavir, dronedarone, erythromycin, indinavir, itraconazole, ketoconazole, lapatinib, lopinavir, propafenone, quinidine, ranolazine, ritonavir, saquinavir, telaprevir, tipranavir, verapamil, and valspodar).
14. Any other acute or chronic medical or psychiatric condition (concurrent disease, infection, or comorbidity) that interferes with ability to participate in the study, causes undue risk, or complicates the interpretation of data, in the opinion of the investigator or sponsor, including recent (within the past year) or active suicidal ideation or behavior or laboratory abnormality that may increase the risk associated with study participation or investigational product administration or may interfere with the interpretation of study results and, in the judgment of the investigator, would make the patient inappropriate for entry into this study.
15. Investigator site staff members directly involved in the conduct of the study and their family members, site staff members otherwise supervised by the investigator, or patients who are Pfizer employees, including their family members, directly involved in the conduct of the study.
16. Fertile male subjects who are unwilling or unable to use a highly effective method of contraception as outlined in this protocol for the duration of the study and for at least 4 months after the last dose of investigational product.