First-Line Bevacizumab-Containing Therapy for Triple-Negative Breast Cancer: Analysis of 585 Patients Treated in the ATHENA Study

Background: The prognosis for patients with triple-negative breast cancer (TNBC) is poor and treatment options are limited. Bevacizumab improves the efficacy of standard first-line therapy in locally recurrent/metastatic breast cancer (LR/mBC). The benefit of bevacizumab seen in patients with TNBC appears similar to that observed in the overall population. We conducted an exploratory analysis of patients with TNBC treated in the single-arm routine oncology practice ATHENA study. Methods: Patients with previously untreated LR/mBC received standard first-line chemotherapy combined with bevacizumab (10 mg/kg every 2 weeks or 15 mg/kg every 3 weeks, until progression, unacceptable toxicity, or patient/physician decision). Results: Of 2,264 patients treated in ATHENA, 585 (26%) had TNBC. Most patients received single-agent taxane with bevacizumab. In the TNBC subgroup, the overall response rate was 49%, including complete responses in 10%; only 16% had primary resistant disease. Median time to progression was 7.2 months (95% CI 6.6–7.8) and median overall survival was 18.3 months (95% CI 16.4–19.7). The 1-year overall survival rate was 60%. The safety profile in TNBC was consistent with results in the overall population. Conclusion: This exploratory subgroup analysis suggests that first-line chemotherapy in combination with bevacizumab is an active regimen in patients with metastatic TNBC.