Efficacy and Safety of Ixabepilone and Capecitabine in Patients With Advanced Triple-negative Breast Cancer: a Pooled Analysis From Two Large Phase III, Randomized Clinical Trials.

INTRODUCTION: The purpose of this study was to evaluate the safety and efficacy of ixabepilone plus capecitabine in patients with metastatic or locally advanced triple-negative breast cancer (TNBC).

PATIENTS AND METHODS: We conducted a pooled analysis of patients with TNBC enrolled in 2 phase III trials (NCT00080301 and NCT00082433), pretreated or resistant to an anthracycline and a taxane. In each study, patients were randomized to receive ixabepilone 40 mg/m2 (3-hour intravenous infusion, day 1), plus oral capecitabine 1000 mg/m2 twice daily (days 1-14), or capecitabine alone 1250 mg/m2 twice daily (days 1-14), every 3 weeks. Treatment was continued until disease progression or unacceptable toxicity.

RESULTS: In the subset of patients with TNBC (N = 443), the addition of ixabepilone to capecitabine compared with capecitabine alone prolonged median progression-free survival from 1.7 months to 4.2 months (hazard ratio [HR], 0.64; 95% confidence interval [CI], 0.52-0.78; P < .0001), and doubled the objective response rate from 15% (95% CI, 10.4%-20.5%) to 31% (95% CI, 24.4%-38.0%). The median overall survival was similar (9.0 vs. 10.4 months; HR, 0.88; 95% CI, 0.72-1.08; P = .1802). A similar pattern of efficacy between arms was observed in the overall pooled population (N = 1973). The safety profile was comparable between the pooled TNBC subset and the overall pooled population. Adverse events observed with combination therapy were generally manageable and consistent with the safety profiles of the individual agents.

CONCLUSION: Adding ixabepilone to capecitabine is effective in prolonging progression-free survival and improving objective response rate compared with capecitabine alone in patients with advanced TNBC previously treated with anthracyclines and taxanes.