An open label, pilot study of veliparib (ABT-888) and lapatinib in patients with metastatic, triple negative (ER, PR, and HER-2 negative) breast cancer.

1095Background: Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer (BC), often resistant to standard of care therapies. We previously showed an induced synthetic lethal interaction with combined EGFR (epidermal growth factor receptor) and PARP (Poly (ADP-ribose)-polymerase) inhibition in TNBC cells. Therefore, we tested a pilot clinical trial using lapatinib and veliparib in patients with locally advanced unresectable or metastatic TNBC. Here we report safety results and clinical activity of the combination of veliparib and lapatinib. Methods: Key eligibility criteria include histologically confirmed TNBC (ER negative, PR negative, HER-2-Neu negative), measurable disease, failed anthracyclines and taxanes in the neoadjuvant, adjuvant, or metastatic setting, left ventricular ejection fracture ≥ 50, and ECOG PS of 0-2. Patients with known germline BRCA 1 or 2 mutations were excluded. Eligible patients received continuous doses of lapatinib 1250 mg PO daily and veliparib 200 mg PO...