Background: The combination of paclitaxel and carboplatin is widely used for the treatment of patients with advanced solid tumors of diverse histologies. In breast cancer patients, a weekly regimen of paclitaxel has shown greater efficacy with comparable safety, when compared to every-three-weeks dosing (ECOG 1199). ABT-888 (veliparib) is an oral inhibitor of poly-ADP-ribose polymerase (PARP). Inhibition of PARP has been shown in preclinical studies to potentiate the effect of cytotoxic agents which induce DNA damage, such as platinum agents. The preclinical synergy of carboplatin with veliparib and the efficacy of the combination of paclitaxel with carboplatin supports exploration of this triplet regimen. Methods: This 3+3 phase I trial will seek to determine the maximum tolerated dose (MTD) of the combination of carboplatin (AUC 2), paclitaxel (80 mg/m²), and veliparib in patients with advanced solid tumors. Veliparib will be escalated beginning at 50 mg PO BID to a maximum of 200mg PO BID. Treatment will be given on a weekly basis over a 21-day cycle. There will be an expansion cohort of 6-12 patients with triple negative breast cancer at the maximum tolerated dose. This group of patients will undergo mandatory pre- and post-cycle 1 tumor biopsies. Secondary aims of the study include safety and toxicity of the combination, its pharmacokinetic and pharmacodynamic effects, documentation of any anti-tumor response, and assessment of the characteristics of the tumor specimens obtained in the expansion cohort that may contribute to efficacy. The latter will include whole genome microarray analysis to evaluate expression of genes involved in DNA repair pathways. Currently, the recommended phase II dose has not been determined and enrollment is ongoing on the last planned dose level (veliparib 200 mg BID).