Efficacy and tolerability of veliparib (V; ABT-888) in combination with carboplatin (C) and paclitaxel (P) vs placebo (Plc)+C/P in patients (pts) with BRCA1 or BRCA2 mutations and metastatic breast cancer: A randomized, phase 2 study

Abstract

Background: Poly(ADP-ribose) polymerase (PARP) inhibitors block DNA damage repair and may thereby enhance the clinical activity of DNA-damaging chemotherapy. Homologous recombination is defective in BRCA1/2-mutated tumors, leading to more error-prone mechanisms of DNA repair and increased sensitivity to PARP inhibition. V is a potent PARP inhibitor that enhances the antitumor activity of platinum agents in preclinical models. This phase 2 trial (NCT01506609) investigated the safety and efficacy of V+C/P or V+ temozolomide (TMZ) vs Plc+C/P in pts with locally recurrent or metastatic breast cancer harboring a BRCA1 or BRCA2 mutation. Results of the V+C/P and Plc+C/P arms are presented; V+TMZ results will be presented separately. Methods: Pts ≥18 years with histologically confirmed locally recurrent or metastatic breast cancer were randomized 1:1:1 to: 1) V 40 mg BID D1–7+TMZ, 28-D cycle; 2) V 120 mg BID D1–7+C AUC 6, D3 and P 175 mg/m2, D3, 21-D cycle; or 3) Plc BID D1–7+C/P. Key eligibility criteria included deleterious BRCA1/2 mutation, ≤2 prior chemotherapies for metastatic disease, no prior platinum agent, and no CNS metastases. Randomization was stratified by hormone receptor status..