409P Treatment of elderly patients (pts; > 75 years) with 1st-line ribociclib (RIB) + endocrine therapy (ET) or endocrine monotherapy in clinical routine: Real-world data from the RIBANNA study (5th interim analysis (IA))

RIB+ET has demonstrated a statistically significant survival benefit across three phase 3 MONALEESA trials, irrespective of menopausal status, line of therapy, or combination partner. RIBANNA (CLEE011ADE03), a prospective, noninterventional study assessing the efficacy and safety of 1st-line treatment options including RIB+ET in pre-, peri- and postmenopausal women with HR+, HER2– ABC is ongoing in Germany since October 2017. In this 5th IA from RIBANNA, efficacy, safety, and tolerability for elderly pts will be presented. Pts were included in accordance with the German tx guideline. For individual age subgroups (≤75 years; >75-80 years; >80 years) efficacy of RIB+ET vs. endocrine monotherapy will be compared by adjusting for baseline characteristics including Charlson comorbidity index. Furthermore, data for patient-reported outcomes (PRO) and treatment-emergent adverse events including time to onset, frequency, dose adjustment and outcome will be analyzed. At data cutoff Sep 6, 2022, for age subgroup ≤ 75 years, >75-80 years and for age subgroup >80 years data from n=1377 (RIB+ET) respectively n=109 (ET), n=281 (RIB+ET) respectively n=42 (ET), and n=153 (RIB+ET) respectively n=41 (ET) are available. The mean Charlson comorbidity index (standard deviation [SD]) increases with increasing age subgroup in the RIB+ET cohort (0.5 [1.2]; 0.8 [1.4]; 0.8 [1.3]) vs. ET cohort (0.6 [1.2]; 0.9 [1.5]; 0.9 [1.4]) respectively. Excluding interruptions, the mean daily RIB dose decreases with increasing age subgroups (527.7 mg vs. 504.8 mg vs. 471.3 mg). Most relevant differences in mPFS are seen in subgroup >75-80 (HR=0.555; 95% CI: 0.307-1.001; p=0.05). Overall number of treatment-emergent adverse events (all grade) in the RIB+ET cohort were similar between age subgroups (32.33% vs. 29.34% vs. 25.71%). RIBANNA study showed diverse population characteristics among pts who received RIB tx in a real-world setting. For investigated age subgroups RIB+ET showed high efficacy over ET alone with manageable safety profile without new signals in the clinical routine.