New Drug for Triple-Negative Breast Cancer

Researchers at Baylor and affiliated institutions reported in the January issue of the New England Journal of Medicine that the addition of iniparib to chemotherapy improves the clinical benefit and survival of patients with metastatic triple-negative breast cancer, without significantly increased toxic effects.

Triple-negative breast cancer accounts for roughly 15% to 20% of all cases of breast cancer and is one of the more aggressive forms of the disease, characterized by frequent and aggressive metastasis and poor survival rates and a median survival of about one year. Because there is no standard of care in this subtype of breast cancer, the field is wide open for clinical advances.

O'Shaughnessy and her colleagues conducted a phase II study comparing gemcitabine and carboplatin with and without iniparib, which is a PARP inhibitor, in 123 patients with metastatic triple-negative breast cancer. Primary end points were the rate of clinical benefit and the rate of stabilization of disease, and other endpoints included progression-free survival and overall survival.

Results showed that the addition of iniparib to gemcitabine and carboplatin resulted in an improvement in clinical benefit from 24% to 56%; prolonged progression-free survival from 3.6 months to 5.9 months; and overall survival from 7.7 months to 12.3 months, with no notable difference in side effects between the two groups. This group is following up with a phase III trial that will evaluate overall survival and progression-free survival. 

This article (DOI: 10.1056/NEJMoa1011418) was published on January 5, 2011, at www.NEJM.org.