Abstract PS2-04-15: Real-world outcomes of sacituzumab govitecan in patients with pretreated triple-negative breast cancer and brain metastases: data from a central European cohort

Abstract Background: Patients with metastatic triple-negative breast cancer (mTNBC) and brain metastases (BM) constitute a subgroup with poor prognosis and limited treatment options. In the pivotal ASCENT trial, sacituzumab govitecan (SG) demonstrated clinical benefit in pretreated patients with mTNBC. An exploratory subgroup analysis of ASCENT trial included 61 patients with radiologically stable BM (32 in the SG arm), showing a modest improvement in progression-free survival (PFS) with SG versus chemotherapy (2.8 vs. 1.6 months), but no overall survival (OS) advantage (6.8 vs. 7.5 months). While suggestive of intracranial activity, these findings were derived from a small, highly selected population. Given the limited evidence in this setting, we aimed to evaluate the effectiveness and safety of SG in a real-world cohort of patients with active or treated BM Materials and Methods: This retrospective multicenter study included female patients with mTNBC and radiologically confirmed BM who initiated SG between August 2021 and May 2025 across 13 oncology centers in the Czech Republic, Poland and Slovakia. Clinical data were extracted from patients’ medical records. Collected variables included baseline characteristics, number and size of BM lesions, prior neurosurgical resection, use and timing of central nervous system (CNS)-directed radiotherapy, treatment response, and adverse events (AEs) (graded per CTCAE v5.0). Radiologic responses were assessed using RECIST 1.1. Overall response rate (ORR), PFS, and OS were evaluated. Survival outcomes were estimated using the Kaplan-Meier method. Univariable Cox proportional hazards models were used to assess the association between BM burden and survival. Statistical analyses were performed in R (v4.3.3); p 0.05 was set as significant. Results: A total of 29 patients with mTNBC and confirmed BM at SG initiation were included. The median number of BM was 3 with median size of the biggest lesion 16.5 mm. Neurosurgical resection had been performed in 4 (14.3%) and CNS-directed radiotherapy in 28 (89.3%) patients prior to SG initiation. The median number of prior palliative systemic therapy lines was 2 (range: 1-3). The median follow-up was 6.05 months (IQR: 3.66-11.06; range: 0.79-27.47). At the time of analysis, 22 patients had died and 26 had the treatment with SG discontinued. The median OS was 8.9 months. Estimated OS rates at 3, 6, 9, and 12 months were 85.2%, 60.3%, 42.3%, and 28.2%, respectively. Median PFS was 3.09 months, with 3-, 6-, 9-, and 12-month PFS rates of 53.6%, 31.4%, 22.5%, and 12.0%, respectively. ORR was observed in 8 of 26 evaluable patients (30.8%). CNS progression was documented in 6 patients (23.1%). Neither the number nor the size of CNS lesions showed a statistically significant association with OS or PFS. SG administration required dose delays due to AEs in 15 patients (51.7%), and dose reductions in 11 (37.9%). Two cases (7.7%) of treatment discontinuation due to toxicity were reported. No unexpected new safety signals were observed. Conclusions: SG demonstrated clinically meaningful activity and a manageable safety profile in this real-world cohort of patients with mTNBC and BM. Median PFS and OS outcomes appeared comparable or numerically favorable to those reported in the ASCENT BM subgroup analysis. Neither the number nor size of BM lesions significantly impacted outcomes, suggesting SG may be effective irrespective of intracranial disease burden. These data may support broader consideration of SG in routine management of CNS-involved TNBC. Citation Format: J. Żubrowska, M. Kubeczko, M. Pieniążek, A. Polakiewicz-Gilowska, I. Kolářová, M. Malejčíková, L. Rusinova, M. Holánek, R. Soumarová, K. Winsko-Szczęsnowicz, A. Konieczna, A. Młodzińska, D. Krejčí, I. Danielewicz, M. Szymanik-Resko, T. Ciszewski, M. Lisik-Habib, A. Pękala, H. Študentová, J. Šustr, A. Rudzińska, B. Czartoryska-Arłukowicz, A. Łacko, M. Jarząb, R. Pacholczak-Madej, Z. Bielčiková, M. Püsküllüoğlu. Real-world outcomes of sacituzumab govitecan in patients with pretreated triple-negative breast cancer and brain metastases: data from a central European cohort 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 PS2-04-15.