Abstract PS5-02-20: Treatment patterns and outcomes of sacituzumab govitecan in older versus younger patients with mTNBC: multinational real-world data

Abstract Background: Patients over 65 years constitute a substantial subset of those diagnosed with metastatic triple-negative breast cancer (mTNBC), yet are frequently underrepresented in clinical trials due to comorbidities, frailty, and polypharmacy. Sacituzumab govitecan (SG), approved for pretreated mTNBC, demonstrated comparable efficacy and tolerability in this age group in the ASCENT trial. However, real-world data remain limited. This multinational study investigates the safety and effectiveness of SG in patients aged 65 years treated in routine clinical practice. Materials and Methods: We retrospectively analyzed clinical data from female patients receiving SG across 18 oncology centers in Slovakia, Poland, and the Czech Republic between August 2021 and May 2025. Patients were stratified by age at SG initiation (≤65 vs. 65 years). Baseline characteristics, treatment patterns, and adverse events (graded according to CTCAE v5.0) were compared. Clinical information was extracted retrospectively from routine medical records. The analysis included progression-free survival (PFS; time from SG initiation to progression or death), overall survival (OS; time from SG initiation to death from any cause), objective response rate (ORR), and disease control rate (DCR) as clinical endpoints. Tumor responses were evaluated according to RECIST 1.1. Univariate Cox regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). P 0.05 was considered statistically significant. Results: Among 303 patients included, 76 (25.1%) were 65 years. Only 10 of them (13.2%) underwent geriatric assessment as part of routine clinical practice. Older patients had received a higher number of prior palliative systemic therapies (median 2 IQR 1-2 vs. 1 IQR 1-2, p=0.039). Visceral metastases (77.5% vs. 60.5%, p=0.006) and central nervous system (CNS) metastases (11.5% vs. 2.6%, p=0.038) were more frequent in the younger group. A reduced starting dose of SG (≤8 mg/kg at cycle 1 day 1) was used in 13.2% of older and 7.5% of younger patients (p=0.204). Adverse event-related dose reductions occurred in 46.1% of individuals 65 and 34.8% ≤65 (p=0.106). Delays in SG administration were observed in 71.1% and 60.4%, respectively (p=0.125). Grade ≥3 neutropenia occurred in 42.1% vs. 45.8% (p=0.733). No other significant differences in toxicity were detected. Median number of full SG cycles was similar across age groups (7 IQR 3-12 vs. 6 IQR 3-10, p=0.240). ORR was 30.3% vs. 30.8% (p0.999), and DCR was 72.4% vs. 61.7% (p=0.122). Survival analyses demonstrated that patients 65 years achieved significantly longer PFS and OS compared to younger individuals (median PFS: 5.42 vs. 4.07 months; HR=0.716; 95% CI: 0.534-0.960; p=0.026; and median OS: 12.81 vs. 10.91 months; HR=0.691; 95% CI: 0.485-0.985; p=0.041, respectively). Conclusions: Older women with mTNBC treated with SG in routine clinical practice achieved significantly longer PFS and OS than younger patients, despite similar treatment exposure, toxicity, and response rates. These findings challenge the assumption that age alone predicts poorer outcomes and support SG use in selected older individuals. However, only 13.2% of patients 65 years underwent formal geriatric assessment, suggesting a possible selection bias toward clinically fit individuals. The observed survival advantage may also reflect lower rates of CNS and visceral metastases or less aggressive tumor biology. Our findings emphasize the need for individualized treatment decisions based on clinical fitness rather than age and support broader integration of geriatric assessment into routine oncology practice. Prospective studies are warranted to clarify the biological and clinical drivers of age-related outcome differences. Citation Format: A. Konieczna, M. Holanek, M. Pieniazek, J. Zubrowska, A. Polakiewicz-Gilowska, R. Soumarova, H. Studentova, A. Mlodzinska, K. Winsko-Szczesnowicz, M. Lisik-Habib, A. Pekala, D. Krejci, J. Sustr, I. Kolarova, I. Kolouskova, I. Danielewicz, M. Szymanik-Resko, T. Ciszewski, L. Rusinova, B. Czartoryska-Arlukowicz, A. Lacko, M. Jarzab, R. Pacholczak-Madej, Z. Bielcikova, M. Malejcikova, M. Puskulluoglu. Treatment patterns and outcomes of sacituzumab govitecan in older versus younger patients with mTNBC: multinational real-world data abstract. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS5-02-20.