Abstract PS5-04-27: Quality of life in patients with advanced breast cancer (aBC) treated with ribociclib (RIB) in the real-world RIBANNA trial

Abstract Background: In addition to disease control, maintaining a high health-related quality of life (QoL) is a major treatment goal for patients (pts) with advanced breast cancer (aBC). In the pivotal MONALEESA (ML) trials, the CDK4/6 inhibitor ribociclib (RIB) in combination with an aromatase inhibitor (AI) or fulvestrant (F) demonstrated significant improvement of survival in pre- and postmenopausal pts with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2−) aBC while maintaining QoL. Following approval of RIB in 2017, the non-interventional study (NIS) RIBANNA was initiated to collect real-world data on the safety and effectiveness of RIB plus endocrine therapy for first-line (1L) treatment of aBC. We have used the 7th interim analysis data to characterize the QoL of aBC pts treated with RIB in 1L. Methods: RIBANNA is a prospective, multicenter NIS investigating RIB for aBC in Germany. Here, we present patient-reported outcomes (PROs) based on the EORTC QLQ-C30 questionnaire as mean difference from baseline and mean first time to deterioration (TTD) by at least 10%. TTD is defined as the time from baseline to the first worsening by 10% of the baseline value. Furthermore, changes over time will also be reported for the EORTC subscales. All PROs constituted exploratory endpoints, and all analyses were descriptive and intended for hypothesis generation only. Results: At the data cutoff for the 7th interim analysis (Sep 30, 2024), 2,567 pts were enrolled in the study and followed up to 83.6 months. Enrolled pts were allocated to three treatment cohorts: RIB + AI/F (1,852 pts), endocrine monotherapy (183 pts) or chemotherapy (139 pts). Due to the small number of pts in the last two mentioned, the QoL analysis focuses solely on the RIB cohort. The study discontinuation rate due to any reason during 1L was 32.8% in the RIB cohort, while 20.8% of pts were still progression-free. The questionnaire completion rate was 83.5% at baseline and 42.6% at 72 months. In the overall RIB cohort, EORTC global health status (GHS) did not change significantly throughout the study, although an initial trend toward improvement (mean change from baseline at 7-12 months: + 3.9 points) was observed, followed by a gradual decrease over time (−2.5 points at 67-72 months). However, the magnitude of change did not reach the minimally important difference (MID) for the EORTC QLQ-C30 of 5-10 points change from baseline. In the overall RIB cohort, the median TTD of GHS by 10% was 12.2 months. Among EORTC subscales, role functioning (RF) in the total pt population showed a continuous decrease over time in the overall RIB cohort. However, only from 43-48 months onward, a deterioration of 7.8 points from baseline was observed, which, according to the EORTC guideline, is considered only a small change for RF. The median TTD for the RF subscale was 12.0 months. In addition to the analyses mentioned for the overall cohort, QoL results for pts subgroups will be presented. Conclusions: RIBANNA provides, for the first time, real-world QoL data on RIB in a large cohort of pts with HR+/HER2- aBC, confirming findings from the pivotal clinical ML trials. GHS changes over time were comparable to the randomized ML trials, where GHS was maintained throughout the study. Only after 12 months, 50% of pts experienced for the first time a deterioration in RF and GHS values of at least 10%. Stable mean changes from baseline in EORTC GHS and persistent RF over time suggest no relevant deterioration in QoL, which is a promising outcome in the real-world setting. Citation Format: P. A. Fasching, C. Brucker, T. Decker, A. Engel, T. Göhler, C. Jackisch, J. Janssen, A. Köhler, K. Lüdtke-Heckenkamp, D. Lüftner, F. Marmé, M. van Mackelenbergh, B. Rautenberg, R. Weide, P. Wimberger, E. Kisseleff, C. Pfister, C. Schneider-Walter, A. Wöckel, M. Schmidt. Quality of life in patients with advanced breast cancer (aBC) treated with ribociclib (RIB) in the real-world RIBANNA trial 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 PS5-04-27.