Real-world clinical outcomes of capecitabine by BRCAm status in patients with early-stage triple-negative breast cancer.

Abstract

e12503 Background: The clinical benefit of adjuvant capecitabine (cape) in patients (pts) with early triple-negative breast cancer (eTNBC) and BRCA1 / BRCA2 mutation (BRCAm) is not well characterized. This retrospective, observational study explored the real-world effectiveness of cape in pts with eTNBC by BRCAm status. Methods: Data from pts ≥18 years old diagnosed with eTNBC from 2016–2024 were captured in the US Flatiron Health electronic health record-derived deidentified database. Included pts had initiated adjuvant cape ≤6 months after primary surgery and had known BRCA test results (BRCAm/non-BRCAm by germline or tumor testing). Pts who received neoadjuvant cape or any adjuvant therapy ≤30 days from metastatic diagnosis were excluded. Pts who received any adjuvant hormone therapy, PARP inhibitor, or immunotherapy were excluded to reduce bias when assessing the effectiveness of adjuvant cape. Demographics, clinical characteristics, and treatment patterns were described. Invasive disease-free survival (IDFS), distant disease-free survival (DDFS), and real-world overall survival (rwOS) rates were calculated from the first curative breast surgery to the earliest of death, last activity date, or database cutoff (May 1, 2024). Sensitivity analyses were performed in pts who met CREATE-X trial eligibility criteria (received neoadjuvant chemotherapy and adjuvant cape). Results: Of 882 pts who received adjuvant cape, 53 (6%) had BRCAm, and 829 (94%) had non-BRCAm. Median follow-up time was 31 (range: 1–92) months. Median age at eTNBC diagnosis was younger in pts with BRCAm vs non-BRCAm (47 vs 55 years). Among the 882 pts, cape initiation decreased from 2021 onwards. Most pts received cape after neoadjuvant treatment (BRCAm: n=49/53, 92%; non-BRCAm: n=755/829, 91%) and most received adjuvant cape monotherapy (BRCAm: n=52/53, 98%; non-BRCAm: n=790/829, 95%). Survival rates at 24 and 36 months were numerically lower in pts with BRCAm vs non-BRCAm; this was maintained in sensitivity analyses of pts who met CREATE-X trial eligibility criteria. Conclusions: This real-world analysis showed a trend for poorer survival in pts with eTNBC and BRCAm vs those with non-BRCAm. While this study is descriptive, data suggest an unmet need for pts with eTNBC and BRCAm who receive adjuvant cape; this could be addressed through wider BRCA testing and subsequent targeted therapy for pts with BRCAm. Survival rate, % (95% CI) All BRCAm (n=53) All non-BRCAm (n=829) BRCAm (CREATE-X eligible; n=47) Non-BRCAm (CREATE-X eligible; n=667) 24-month IDFS 69 (57–83) 77 (74–81) 68 (56–83) 79 (76–82) 36-month IDFS 59 (47–75) 72 (68–75) 60 (47–77) 74 (70–78) 24-month DDFS 71 (59–85) 79 (76–82) 70 (58–85) 80 (77–84) 36-month DDFS 59 (46–75) 73 (69–76) 60 (47–77) 75 (71–79) 24-month rwOS 77 (66–90) 86 (0.83–89) 77 (66–91) 87 (84–90) 36-month rwOS 67 (55–83) 80 (0.77–83) 70 (57–85) 82 (79–85) CI, Greenwood’s confidence interval.