A randomized phase III study of iniparib (BSI-201) in combination with gemcitabine/carboplatin (G/C) in metastatic triple-negative breast cancer (TNBC).

1007 Background: A randomized phase II study in mTNBC suggested that iniparib (I), an anticancer agent with PARP inhibitory activity, added to GC improved overall survival (OS), without potentiating GC toxicity (O’Shaughnessy et al. NEJM 2011). This confirmatory study evaluated the safety and efficacy of GC with or without I in a similar mTNBC pt population. Methods: This randomized, open-label phase III study enrolled pts ≥18 years with mTNBC, measurable disease, and ≤2 prior cytotoxic regimens for metastatic TNBC. Pts were stratified based on having 0 vs. 1–2 prior metastatic therapies. Pts were randomized (1:1) to GC alone or GCI. G (1000 mg/m2; IV) and C (AUC 2; IV) were given on days 1 and 8, and I (5.6 mg/kg; IV) on days 1, 4, 8, and 11 every 21 days. Upon central confirmation of disease progression on GC, crossover to GCI was permitted. Primary endpoints were OS and progression-free survival (PFS); secondary endpoints were objective response rate and safety. Results: Between July 2009 and March 201...