SAN ANTONIO – The investigational selective PARP-1 and PARP-2 inhibitor veliparib failed to significantly improve progression-free or overall survival, compared with placebo, when added to carboplatin and paclitaxel in patients with BRCA1 or BRCA2 mutations and locally recurrent or metastatic breast cancer in the randomized phase II BROCADE study.
The potent, orally bioavailable drug did, however, show a trend toward improvement on these measures, as well as a significant improvement in overall response-rate findings that warrant further investigation in a phase III trial, Hyo Han, MD, said at the San Antonio Breast Cancer Symposium.
Patients were randomized to receive placebo (98 patients) or 120 mg veliparib twice daily on days 1-7 (95 patients) in addition to carboplatin and 175 mg/m2 of paclitaxel every 3 weeks.
Median progression-free survival – the primary endpoint of the study – was 12.3 months in the placebo group and 14.1 months in the veliparib group (hazard ratio, 0.789), and overall survival was 25.9 and 28.3 months, respectively (HR, 0.750), said Dr. Han of Moffitt Cancer Center, Tampa, Fla.
The overall response rate was 61.3% vs. 77.8% in the groups, respectively.
Although the study did not meet its primary endpoint, the findings are encouraging as it was powered to detect only dramatic differences between the groups, Dr. Han said.
In a video interview, she discussed veliparib, its safety, the BROCADE findings – including data from a third study arm looking at veliparib in combination with temozolomide, and plans for evaluating veliparib in the ongoing phase III BROCADE3 trial.