Ribociclib Plus Endocrine Therapy Found to Improve Progression-Free Survival and Overall Survival in Elderly Patients

The MONALEESA-2, -3, and -7 clinical trials found that ribociclib + endocrine therapy was associated with significant progression-free survival (PFS) and overall survival (OS) in patients with HR+/HER2–advanced breast cancer (ABC). The use of ribociclib + endocrine therapy in elderly patients and its efficacy, safety, and quality of life was further investigated. Data were pooled from the 3 studies of pre- and postmenopausal patients with HR+/HER2–ABC who were treated with front-line ribociclib + endocrine therapy or placebo + endocrine therapy. Patients who experienced early relapse and those who were in the tamoxifen cohort of the MONALEESA-7 trial were excluded from this evaluation. Time to first chemotherapy, PFS, and OS were analyzed for 3 patient groups: <65 years, 65 to <75 years, and ≥75 years.

There were a total of 1229 patients included in this study. There were 773 patients <65 years of age, 335 patients aged 65 to <75 years, and 121 patients who were aged ≥75 years. The ≥75 years group had a slightly higher percentage with an Eastern Cooperative Oncology Group (ECOG) status of 1 while those patients age <65 years had a slightly higher percentage of de novo disease. All 3 groups had a PFS and OS benefit and a delay in time to chemotherapy with the use of ribociclib + endocrine therapy versus placebo + endocrine therapy. For patients receiving ribociclib + endocrine therapy, the most common antineoplastic therapy was hormonal therapy. For patients aged ≥75 years receiving ribociclib + endocrine therapy, chemotherapy alone was used by 6.3% while 24.5% who received placebo + endocrine therapy used chemotherapy alone as the first antineoplastic treatment. When safety was analyzed, results for patients <65 years were similar to the overall patient population. The most common adverse effects for patients 65 to <75 years and ≥75 years were neutropenia, nausea, fatigue, and diarrhea in both treatment groups. Rates of grade 3/4 febrile neutropenia, all-grade QT prolongation, and all-grade interstitial lung disease were lower in patients <65 years. Discontinuation rates due to adverse events were 14.6% in patients <65 years, 19.7% in patients 65 to <75 years, and 41.2% in patients ≥75 years receiving ribociclib + endocrine therapy, and 3.1% in patients <65 years, 6.8% in patients 65 to <75 years, and 7.7% in patients ≥75 years receiving placebo + endocrine therapy. The time to deterioration in global health status was prolonged in patients <65 years receiving ribociclib + endocrine therapy versus those receiving placebo + endocrine therapy. The time to deterioration was similar between the 2 treatment groups in those patients 65 to <75 years and ≥75 years although these patients had a greater benefit with the use of ribociclib + endocrine therapy.

Source:

Hart L, Seock-Ah I, Tolaney S, et al. Efficacy, safety, and quality of life with ribociclib + endocrine therapy in elderly patients with HR+/HER2– advanced breast cancer across the MONALEEA-2,-3, and -7 trials. Poster presented at: San Antonio Breast Cancer Symposium. December 5, 2023; San Antonio, TX. Abstract # PS02-01.