Efficacy of BSI-201, a poly (ADP-ribose) polymerase-1 (PARP1) inhibitor, in combination with gemcitabine/carboplatin (G/C) in patients with metastatic triple-negative breast cancer (TNBC): Results of a randomized phase II trial

3 Background: TNBC is an aggressive breast cancer subtype that shares molecular and pathologic features with BRCA1-related breast cancers. BRCA-deficient cells are sensitive to inhibition of PARP1, a critical enzyme of cell proliferation and DNA repair, and thus represent a rational target of PARP inhibitor-based cancer therapy. The objectives of this study were to evaluate BSI-201, a potent PARP1 inhibitor, in combination with gemcitabine/carboplatin (G/C) in subjects with metastatic TNBC. Methods: Eligible subjects had measurable disease and had ≤2 prior cytotoxic regimens for ER-, PR-, and HER2-negative metastatic breast cancer. Patients were randomized (1:1) to G/C alone or G/C + BSI-201. Gemcitabine (1000 mg/m2) and carboplatin (AUC=2) were given on days 1 and 8, and BSI-201 (5.6 mg/kg; iv; biweekly) on days 1, 4, 8, and 11 every 21 days. Endpoints were clinical benefit rate (CBR = CR + PR + SD ≥6 months), progression-free survival (PFS) and overall survival (OS). Results: Analyses of the first 86 of...