Talazoparib in Advanced Breast Cancer Patients With Homologous Recombinant Deficiency

This trial is testing a PARP inhibitor drug called talazoparib in patients with advanced or metastatic breast cancer whose tumors have DNA repair defects (such as BRCA1/2 mutations or other related gene abnormalities). PARP inhibitors work by blocking a mechanism cancer cells use to repair their DNA. **You may be eligible if...** - You are 19 or older with unresectable or metastatic breast cancer - Your tumor has been shown to have a homologous recombination deficiency (HRD) — a DNA repair defect — including BRCA1/2 mutations, or mutations in genes like ATM, CHEK1, CHEK2, PALB2, RAD51 family, or others - You have previously received a taxane chemotherapy (unless contraindicated) - Your cancer has measurably progressed on recent treatment - You have adequate blood counts and organ function **You may NOT be eligible if...** - You have previously received a PARP inhibitor drug (unless you relapsed 6+ months after an adjuvant PARP inhibitor in a clinical trial) - You have had more than 3 prior lines of chemotherapy for advanced/metastatic disease - You have brain metastases that are unstable or symptomatic - You have severe GI disease that affects oral medication absorption - You are pregnant or breastfeeding - You have active HIV, hepatitis B, or hepatitis C Talk to your doctor to see if this trial is right for you.