441P Real-world efficacy of ribociclib (RIB) + aromatase inhibitor (AI)/fulvestrant (FUL) in subgroups of special interest: 5th interim analysis (IA) of the RIBANNA study

RIBANNA (CLEE011ADE03) is a prospective, noninterventional study assessing the efficacy and safety of RIB+AI/FUL, or endocrine therapy (ET) or chemotherapy (CT) in pre-, peri- and postmenopausal women with hormone receptor-positive (HR+), human epidermal growth factor receptor-2-negative (HER2-) advanced breast cancer (ABC) in a broad patient population. Real-world data on the efficacy of RIB in subgroups of special interest resulting from the 5th IA from the RIBANNA study will be presented at the conference. Efficacy outcomes in subgroups of special interest will be determined. Adjusted progression-free survival (PFS) for 1L RIB will be separately analyzed for patients with visceral vs. non-visceral metastases (lung, liver, central nervous system), pre- vs postmenopausal patients, patients receiving AI vs FUL as Ribociclib combination partner, de novo vs. recurrent and endocrine-resistant vs. -sensitive disease. In addition, conditional PFS (this is, the probability of survival without progression for further months given a previous survival for a defined number of months) will be analyzed for patients without progression at 6, 12, and 24 months in the overall study population. At data cutoff Sep 6, 2022, 2581 patients were enrolled in the study (RIB+AI/FUL, n = 2163; ET, n = 237; CT, n = 181). At baseline there were 189 pre/peri and 1605 postmenopausal patients and 750 patients with visceral metastases in the RIB cohort included in the study. 1566 patients received AI and 415 received FUL in the RIB cohort at baseline. At study start 381 de novo and 1765 recurrent patients were included over all treatment cohorts. The unadjusted KM estimate for median PFS was 32.2 months (95% CI, 29.3–34.8) in the RIB + AI/FUL cohort. Herein, efficacy data (PFS, conditional PFS) in the specified patient subgroups will be presented. The RIBANNA study analyses the use of RIB in a diverse patient population in the clinical routine. RIB showed efficacy superiority over ET and CT in the overall patient population. Data on the real-world efficacy of specific patient subgroups will be presented at the conference.