Results of a second interim analysis demonstrate real-world outcomes of treatment with ribociclib, a selective CDK4/6 inhibitor in combination with endocrine therapy.
Administered in conjunction with endocrine therapy (aromatase inhibitor or fulvestrant), the selective CDK4/6 inhibitor ribociclib has shown a significant prolongation of overall survival among patients with breast cancer, regardless of menopausal status and treatment line, based on the MONALEESA-3 and MONALEESA-7 clinical trials. In premenopausal or perimenopausal women, ribociclib plus an aromatase inhibitor or fulvestrant should be combined with a luteinizing hormone-releasing hormone agonist.
In real-world clinical practice, advocating the use of this combination must be based on real-world evidence in premenopausal or perimenopausal women, focusing on the safety, tolerability, and efficacy of ribociclib plus an aromatase inhibitor or fulvestrant.
Achim Wockel, MD, Director, Department of Gynecology and Obstetrics, University Hospital Würzburg, Germany, and colleagues reviewed results of an ongoing prospective, noninterventional study conducted since 2017 in Germany called the RIBANNA trial.
In this study, in accordance with German guidelines, a combination of pre-, peri-, and postmenopausal women totaling 3020 received treatment with ribociclib plus an aromatase inhibitor or fulvestrant, or endocrine monotherapy, or chemotherapy as first-line treatment for hormone receptor–positive, HER2-negative advanced breast cancer.
Patients (N = 1141) were enrolled until July 12, 2019, for the second interim analysis, but the full analysis set included 813 patients. Ribociclib exposure in patients receiving ribociclib plus an aromatase inhibitor compared with the total population, showed a median duration of 151 days compared with 150 days, respectively. At data cutoff, 1016 (89%) participants received first-line, 82 (7%) received second-line, and 11 (1%) received third-line treatments. Patients received a starting dose of ribociclib 600 mg per day in the first-line setting, and this was observed in 85% of the patients. At the time of the report, second-line patient data were not included.
Mean daily dose of ribociclib was 451.6 mg per day and was prescribed as first-line primarily in combination with other therapeutics, including anastrozole (7%), exemestane (6%), fulvestrant (12%), and letrozole (75%). In the study, 62% of the patients were treatment-naïve for endocrine monotherapy. Thirty percent of the 424 patients with early breast cancer had documented previous chemotherapy without endocrine monotherapy.
All-grade adverse events that were most commonly noted in ribociclib plus aromatase inhibitor or fulvestrant group compared with other groups were nausea (ribociclib [19%] vs endocrine monotherapy [9%] vs chemotherapy [11%]), neutropenia (19% vs 1% vs 10%, respectively), fatigue (17% vs 9% vs 14%, respectively), and leukopenia (14% vs 4% vs 12%, respectively).
The RIBANNA study showed real-world treatment outcomes in a diverse population of patients who received ribociclib therapy in routine clinical practice.
Source: Wockel A, Brucker C, Decker T, et al. Real-world efficacy of ribociclib + aromatase inhibitor/fulvestrant, or endocrine monotherapy, or chemotherapy as first-line treatment in women with HR-positive, HER2-negative locally advanced or metastatic breast cancer: third interim analysis from the RIBANNA study. Presented at: 2020 San Antonio Breast Cancer Symposium, December 8-11, 2020. Abstract PS10-16.