Abstract P1-18-15: Real-world efficacy of ribociclib + aromatase inhibitor/fulvestrant, or endocrine monotherapy, or chemotherapy as first-line treatment in women with hormone receptor-positive (HR+), human epidermal growth factor receptor-2-negative (HER2-) locally advanced or metastatic breast cancer: Fourth interim analysis from the RIBANNA study
Authors: Lüftner Diana , Brucker Cosima , Decker Thomas , Fasching Peter , Göhler Thomas , Jackisch Christian , Janssen Jan , Köhler Andreas , Lüdtke-Heckenkamp Kerstin , van Mackelenbergh Marion , Marmé Frederik , Nusch Arnd , Rautenberg Beate , Reimer Toralf , Schmidt Marcus , Weide Rudolf , Wimberger Pauline , Nabieva Naiba , Roos Christian , Wöckel Achim 
Published: March 2022

Background: Ribociclib (RIB; a selective CDK4/6 inhibitor) + endocrine therapy (ET; aromatase inhibitor or fulvestrant along with ovarian suppression in pre- and perimenopausal patients [pts]) received USFDA and EMA approval for pre-, peri- and postmenopausal pts with HR+, HER2- advanced breast cancer (ABC) based on results from phase 3 MONALEESA (ML) trials. In ML-2 trial, first-line treatment (tx) with RIB + letrozole (LET) vs placebo (PBO) + LET significantly improved median progression-free survival (mPFS) in postmenopausal pts with HR+, HER2- ABC. In ML-3 and ML-7 trials, RIB + ET vs PBO + ET showed a significant improvement in mPFS and overall survival among pts with HR+, HER2- ABC, irrespective of menopausal status, line of tx and combination partner. Real-world evidence on the effectiveness, safety, and tolerability of RIB + ET in pts with HR+, HER2- ABC would help to gain insight into routine clinical practice. Methods: RIBANNA is a prospective, noninterventional study ongoing in Germany since October 2017. Pre-, peri- and postmenopausal pts who received first-line tx with RIB + ET, or ET alone or chemotherapy (CT) for HR+, HER2- ABC in accordance with German tx guidelines were included. Data from routine clinical practice in all 3 cohorts, including further lines of sequential therapy, were collected. The third interim analysis data from RIBANNA study was presented in SABCS 2020. Fourth interim analysis data will be presented during SABCS 2021. Results: Till February 11, 2021, 2594 pts were included in the study (RIB + ET, n = 2183; ET, n = 229; CT, n = 182) and the enrollment was stopped; however, pt follow-up will be continued for an additional 4 years. For the fourth interim analysis, full analysis set (comprising all pts, except screening failures and locked pts, who received at least one dose of study medication [safety analysis set] and for whom ≥ 1 post-baseline evaluation was recorded) included 2131 pts (RIB + ET, n = 1814 [81.2%]; ET, n = 175 [73.8%]; CT, n = 142 [72.1%]), while the safety analysis set comprised 2452 pts (RIB + ET, n = 2062 [92.3%]; ET, n = 216 [91.1%]; CT, n = 174 [88.3%]). Until last patient first visit, among 2594 treated pts (including screening failures), data from first-line (1L) tx are available for 2452 pts (94.5%), from second-line (2L) tx for 343 pts (13.2%), and from third-line (3L) tx for 74 pts (2.9%, Table 1). Overall, 23.9%, 27.9%, and 43.4% of pts discontinued the study in RIB + ET, ET, and CT cohorts, respectively. The fourth interim analysis is planned in October 2021, and the final baseline demographic data as well as updated information on safety will be presented during SABCS 2021. Conclusion: RIBANNA study showed diverse population characteristics among pts who received RIB tx in a real-world setting. The data from fourth interim analysis, which is planned in October 2021, including final baseline demographic data and updated safety data will be presented.

Table 1. Patient disposition following last patient first visit on February 11, 2021PatientsTotal. (N = 2594). n (%)RIB + AI/FUL (n = 2183). n (%)ET (n = 229). n (%)CT. (n = 182). n (%)Includeda2594 (100.0)2183 (100.0)229 (100.0)182 (100.0)Treated (including screening failures)2452 (94.5)2062 (94.5)216 (94.3)174 (95.6)1L therapyb2452 (94.5)2062 (94.5)216 (94.3)174 (95.6)2L therapyb343 (13.2)264 (12.1)36 (15.7)43 (23.6)3L therapyb74 (2.9)53 (2.4)10 (4.4)11 (6.0)4L therapyb7 (0.3)7 (0.3)0 (0.0)0 (0.0)Discontinued studyc664 (25.6)521 (23.9)64 (27.9)79 (43.4)aAll pts signing informed consent form, bNumber of data set available till February11, 2021, cEnd of documentation with reason other than ‘end of study.

Citation Format: Diana Lüftner, Cosima Brucker, Thomas Decker, Peter Fasching, Thomas Göhler, Christian Jackisch, Jan Janssen, Andreas Köhler, Kerstin Lüdtke-Heckenkamp, Marion van Mackelenbergh, Frederik Marmé, Arnd Nusch, Beate Rautenberg, Toralf Reimer, Marcus Schmidt, Rudolf Weide, Pauline Wimberger, Naiba Nabieva, Christian Roos, Achim Wöckel. Real-world efficacy of ribociclib + aromatase inhibitor/fulvestrant, or endocrine monotherapy, or chemotherapy as first-line treatment in women with hormone receptor-positive (HR+), human epidermal growth factor receptor-2-negative (HER2-) locally advanced or metastatic breast cancer: Fourth interim analysis from the RIBANNA study [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-18-15.