Pre-Operative Radiation and Veliparib for Breast Cancer

The investigators' primary aim is to determine the safety, tolerability and maximum tolerated dose (within 50 - 200mg/BID dose range) when combining veliparib and radiation. The investigators' exploratory aim is to serially assess apoptosis/proliferation biomarkers, and gene and protein expression profiles for correlation with tumor response to POPI. Study Plan: It will be a standard 3+3 dose finding trial in which the MTD will be defined as the dose below the level at which \>1 DLT is observed in 3-6 patients. Women with node positive disease prior to NAC and \>1.0 cm residual breast disease and/or clinically positive nodal disease after NAC will be offered participation in the research phase of this study. Women with residual disease \>1cm or +/-LN after NAC (Med Onc's choice) will be offered pre-operative Veliparib and concurrent whole breast and regional nodal irradiation. Four (4) dose levels of Veliparib will be evaluated with concurrent whole breast and regional nodal irradiation (WB/RNI). The starting dose of Veliparib will be 50 mg BID, will increase in 50 mg increments to a maximum of 200 mg BID and be delivered concurrently with 235 cGy QD x 16 to the breast and SCV/Axilla. Accrual: Up to 41 patients