Real-world clinical outcomes of patients with early-stage TNBC and BRCAm who were treated with adjuvant capecitabine in the United States.

PURPOSE: Clinical benefit from adjuvant capecitabine in patients with early-stage triple-negative breast cancer (eTNBC) and deleterious BRCA1/BRCA2 mutation (BRCAm) is not well characterized. This retrospective, observational study explored the real-world effectiveness of adjuvant capecitabine in patients with eTNBC by BRCAm status. METHODS: Data from adults diagnosed with eTNBC from 2016 to 2024 were captured from electronic health records in the US Flatiron Health database. Patients who initiated adjuvant capecitabine within 6 months after primary surgery and had documented BRCA status (by germline/tumor testing) were included. RESULTS: Of 882 patients who received adjuvant capecitabine, 53 (6%) had BRCAm, and 829 (94%) had non-BRCAm tumors. Median age at eTNBC diagnosis was lower in patients with BRCAm versus non-BRCAm (47 vs. 55 years). Most patients received capecitabine after neoadjuvant treatment (BRCAm: n = 49/53, 92%; non-BRCAm: n = 755/829, 91%), and most received adjuvant capecitabine monotherapy (BRCAm: n = 52/53, 98%; non-BRCAm: n = 790/829, 95%). Survival rates from surgery to 36 months were numerically lower in patients with BRCAm versus non-BRCAm (invasive disease-free survival: 59% vs. 72%; distant disease-free survival: 59% vs. 73%; overall survival: 67% vs. 80%); these differences were maintained in sensitivity analyses of patients with profiles aligned with the CREATE-X clinical trial criteria. CONCLUSION: This analysis showed a trend for worse real-world survival in patients with BRCAm versus non-BRCAm eTNBC who received adjuvant capecitabine. Although descriptive, these findings suggest an unmet need for patients with BRCAm eTNBC despite adjuvant capecitabine treatment; this could be addressed through wider BRCA testing and subsequent targeted therapy for patients with BRCAm.