Metastatic triple-negative breast cancer is an aggressive subtype of breast cancer with a very poor prognosis. Currently there is no standard therapy, although the inherent DNA repair defects make therapy based on PARP inhibition a rational target.
Iniparib, a PARP inhibitor, has shown promising anticancer activity in preclinical studies. In this multicentre, randomised, phase II study, US investigators assessed the safety and efficacy of gemcitabine and carboplatin chemotherapy with or without iniparib in 123 women with metastatic triple-negative breast cancer.
They found that clinical benefit improved from 34% to 56% with the addition of iniparib (p = 0.01) and overall response improved from 32% to 52% (p = 0.02). Median progression-free survival and median overall survival both increased with the addition of iniparib (p = 0.01).
No significant difference was observed between the groups regarding the rate of adverse events. On the basis of these results, a phase III trial of iniparib plus chemotherapy is being conducted to evaluate overall and progression-free survival.
O’Shaughnessy J, Osborne C, Pippen JE et al. Iniparib plus chemotherapy in metastatic triple-negative breast cancer. N Engl J Med January 5 2011