Efficacy of Talazoparib in Asian Metastatic Breast Cancer Patients With a Homologous Recombinant Deficiency (HRD) Signature

This is an open label, non randomised, investigator-initiated Phase II study of single agent talazoparib (Talzenna®) in metastatic triple negative breast cancer patients with enriched HRD signature. Approximately 55 subjects will be enrolled in this study to examine the efficacy of talazoparib when given orally 1mg daily for days 1 to 28 for up to 28 months. The study will be conducted using the Simon two-stage phase II design, whereby this study will initially enroll 19 patients with RECIST v1.1 measurable disease with enriched HRD signature (stage I). There will be one interim analysis at the end of stage I and if 3 of the 19 have a response, then no further patient will be accrued. If 4 or more of the 19 patients have a response, then accrual would continue to stage II until a total of 55 patients have been enrolled. This study will be conducted in conformance with Good Clinical Practices. Specific procedures to be performed during the trial, as well as their prescribed times and associated visit windows, are outlined in the Trial Flow Chart.