The phase III, open-label trial randomly assigned 519 patients who had received at least two prior cytotoxic regimens for metastatic triple-negative breast cancer to 21-day cycles of gemcitabine (1,000 mg/m2 IV) and carboplatin (area under the curve 2 IV), both on days 1 and 8, or the same chemotherapy doublet plus iniparib (5.6 mg/kg IV) on days 1, 4, 8 and 11.
The overall response rates by independent radiology review were 30% among the 258 chemotherapy patients and 34% among the 261 iniparib patients, Dr. O’Shaughnessy said. The clinical benefit rates were 36% and 41%.
The toxicity of iniparib plus gemcitabine and carboplatin was comparable with that of chemotherapy alone. One death from upper GI hemorrhage was attributed to iniparib therapy. Biomarker analyses are underway to evaluate patient populations that may benefit from iniparib, she said.
Sanofi-Aventis sponsored the trial in collaboration with BiPar Sciences. Dr. O’Shaughnessy disclosed honoraria from Sanofi-Aventis, which provided editorial support for the trial. A coauthor reported consulting/advising for Sanofi-Aventis. Dr. Carey disclosed consulting or advising for Sanofi-Aventis, Genentech, Novartis, GlaxoSmithKline, Pfizer, Schering-Plough and Wyeth.