Presurgical Phase II Study of Talazoparib in Combination With Enzalutamide in Prostate Cancer

To learn about the effectiveness of adding talazoparib to the standard of care treatment combination of androgen ablation therapy (hormone therapy, also known as ADT) and enzalutamide in patients with prostate cancer that has spread into the lymph nodes.

Inclusion Criteria: 1. Patients with adenocarcinoma of the prostate that in the opinion of the urologist could be resected after response to systemic therapy. Ductal adenocarcinoma is permitted. 2. Patients must be regarded as acceptable surgical risk and confirm their intention to undergo radical prostatectomy at the end of the pre-surgical therapy. 3. ECOG performance status 2 or better. 4. All patients must have tumor staging and meet at least one of the following criteria: 1. Either lymph node biopsy or lymph node dissection demonstrating lymph node metastasis by prostate cancer. 2. Non-bulky (\ 500 milliseconds. 9. Patients with any infectious process that, in the opinion of the investigator, could worsen or its outcome be affected as a result of the investigational therapy. 10. Patients with active or symptomatic viral hepatitis or chronic liver disease. 11. Patients with active pneumonitis or extensive bilateral lung disease of non-malignant etiology. 12. Patients with seizures or known condition that may pre-dispose to seizures (e.g., prior stroke or transient ischemic attack within 1 year to randomization, brain arteriovenous malformation, Schwannoma, meningioma, or other benign CNS or meningeal disease which may require treatment with surgery or radiation therapy). 13. Patients with symptomatic congestive heart failure, unstable angina or myocardial infarction, coronary/peripheral artery bypass graft or repair, clinically significant ventricular arrhythmias, deep vein thrombosis or pulmonary embolism in the 6 months prior to randomization. 14. Persistently uncontrolled diabetes mellitus or HIV infection. 15. Inadequately controlled hypertension (defined as systolic blood pressure \>160 mmHg and/or diastolic blood pressure \>95 mmHg) despite antihypertensive medication, or prior history of hypertensive encephalopathy. 16. Evidence of bleeding diathesis or significant coagulopathy (in the absence of therapeutic anticoagulation). 17. Anticipation of need for major surgical procedure during the course of the study other than as outlined by the protocol. 18. History of abdominal fistula or gastrointestinal perforation within 6 months prior to randomization. 19. Overt psychosis, mental disability, otherwise incompetent to give informed consent, or history of non-compliance. 20. Planned participation in any other experimental drug study.