Abstract RF6-05: Patient-reported outcomes (PROs) with sacituzumab govitecan (SG) vs chemotherapy in patients with previously untreated advanced triple-negative breast cancer (TNBC) who are not candidates for PD-(L)1 inhibitors in the phase 3 ASCENT-

Abstract Background: In the ASCENT-03 study (NCT05382299), SG led to a statistically significant improvement in progression-free survival vs chemotherapy in patients with previously untreated advanced TNBC who are not candidates for PD-(L)1 inhibitors. We report PROs from this study. Methods: Patients were randomized to SG or chemotherapy (gemcitabine + carboplatin, paclitaxel, nab-paclitaxel). Patients completed the EORTC QLQ-C30 at baseline, each cycle, and end of treatment. The key PRO-related secondary endpoints were change from baseline to week 25 in physical functioning and Time To first meaningful Deterioration (TTD) in fatigue. Changes from baseline and TTD in other domains, and Time To first meaningful Improvement (TTI) in all domains were assessed as exploratory endpoints. The meaningful within-patient changes from baseline for TTD and TTI analyses were defined as 13.33 points for physical functioning and 10 points for all other domains. Comparison between treatment arms was analyzed using a mixed-effect model for repeated measure for changes from baseline, the stratified Cox regression model for TTD, and the Fine-Gray subdistribution hazard regression model for TTI. Results: Analyses included 558 patients (279 in each arm). LS mean change from baseline favored SG for physical functioning, role functioning, global health status/quality of life (QOL), fatigue, pain, and dyspnea and favored chemotherapy for diarrhea; differences exceeded the minimum important differences (MID) for physical and role functioning ( Table ). TTD was comparable across most domains, including fatigue, but favored SG for dyspnea, and chemotherapy for nausea/vomiting and diarrhea, consistent with the known SG safety profile ( Table ). TTI favored SG for physical, role, cognitive, and social functioning, as well as fatigue, insomnia, appetite loss, and constipation and was comparable in both treatment arms for other domains ( Table ). Conclusions: The key secondary endpoints of LS mean changes from baseline to week 25 in physical functioning favored SG vs chemotherapy, while TTD in fatigue was similar in both treatment arms. These data, along with additional exploratory results reported here, suggest that SG was associated with more favorable and sustained benefits in QOL vs chemotherapy. The known gastrointestinal side effects of SG did not negatively impact global health status/QoL or functional domain scores in this analysis. Along with ASCENT-03 efficacy data, these data support SG as a potential new standard of care for patients with previously untreated advanced TNBC who are not candidates for PD-(L)1 inhibitors. Citation Format: K. Punie, S. M. Tolaney, A. Bardia, S. A. Hurvitz, C. Barrios, A. Schneeweiss, J. Sohn, E. Tokunaga, A. Brufsky, Y. Park, B. Xu, R. Hegg, M. Oliveira, A. Fabi, Y. Zhang, H. Wang, Y. Mu, R. Delaney, J. Cortés. Patient-reported outcomes (PROs) with sacituzumab govitecan (SG) vs chemotherapy in patients with previously untreated advanced triple-negative breast cancer (TNBC) who are not candidates for PD-(L)1 inhibitors in the phase 3 ASCENT-03 study [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 RF6-05.