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

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. 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. 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. 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.