A randomized, placebo-controlled, double-blind phase 2 study of docetaxel compared to docetaxel plus zosuquidar (LY335979) in women with metastatic or locally recurrent breast cancer who have received one prior chemotherapy regimen.

Purpose: To determine if concomitant administration of docetaxel plus zosuquidar.3HC1 can prolong progression-free survival in patients with metastatic breast cancer.
Methods: A randomized, double-blind, multicenter, placebo-controlled clinical trial comparing docetaxel plus 500 mg zosuquidar.3HCl (DZ) with docetaxel plus placebo (DP).
Results: A total of 170 patients were enrolled and randomly assigned to treatment. The median age was 53 years (range, 31-74 years). 81.7% of patients had prior chemotherapy in the adjuvant setting and 18.3% in the neoadjuvant setting. The median progression-free survival time was statistically different between groups [7.2 months (DZ) vs. 8.3 months (DP)]. Once the stratification factor relative to progression following prior chemotherapy was considered, no significant treatment difference existed.
Conclusion: The combination of zosuquidar.3HCl plus docetaxel is safe. The analysis of efficacy data is complex, but it can be concluded that there is no difference in progression-free survival, overall survival, or response rate in the study as a whole.