Companies hope benefits can be confirmed in some subsets of patients.

BiPar Sciences and parent company sanofi-aventis confirmed that a Phase III trial evaluating iniparib (BSI-201) in patients with metastatic triple-negative breast cancer (mTNBC) failed to meet its primary endpoint. The 519-patient study failed to show benefits on overall survival and progression-free survival from adding iniparib to standard chemotherapy comprising gemcitabine and carboplatin.

The firms say, however, a prespecified analysis of patients treated in the second- and third-line setting did suggest that adding iniparib to chemotherapy led to improvements in overall survival and progression-free survival consistent with those observed in a previous Phase II trial.

“While this trial did not meet its primary goal, we believe that the improvement in overall survival and progression-free survival in patients in the second-and third-line setting are important findings,” states Debasish Roychowdhury, Ph.D., senior vp and head of sanofi-aventis oncology. “We are conducting an in-depth analysis to gain further insight into these Phase III results.”

Iniparib is separately undergoing Phase III trials in patients with squamous non-small-cell lung cancer, and Phase II studies in patients with breast, lung, and other cancers. BiPar’s pipeline also includes follow-on PARP inhibitor BSI-401, and an antitubulin agent BSI-302, which has been developed to target cancer cells based on the role of thyroid hormones in cell proliferation and death. Both these candidates are in preclinical development.