MONALEESA Pooled Analyses Show Quality of Life Is Maintained in Elderly Patients Receiving Ribociclib, Endocrine Therapy

Pooled analyses of data from the MONALEESA-2, -3, and -7 trials found that the combination of ribociclib and endocrine therapy was well tolerated throughout age groups, with a safety profile consistent with what is anticipated for an older patient population. The data were presented in a poster at the 2023 San Antonio Breast Cancer Symposium (SABCS), taking place December 5 through 9 in Texas.

Ribociclib and endocrine therapy have been shown to improve progression-free survival (PFS) and overall survival (OS) statistically significantly in patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer, based on data from the MONALEESA-2, -3, and -7 trials. In the new analyses, investigators reported efficacy, safety, and quality of life (QOL) with the combination in elderly patients.

“As we know, the incidence of comorbidities and potential toxicity will increase with age, so it’s obviously very important [to answer] questions about patients in the elderly age groups,” said presenter Lowell Hart, MD, FACP.

Data were pooled from the 3 trials of pre- and post-menopausal patients with HR-positive, HER2-negative advanced breast cancer who had been treated with either ribociclib plus endocrine therapy or placebo plus endocrine therapy. PFS, OS, and time to first chemotherapy (TTC) were analyzed in patients younger than 65 years, those aged 65 to less than 75 years of age, and those aged 75 years and older. Time to definitive deterioration (TTD) by ³10 points in global health status was analyzed across age subgroups.

In total, 1229 patients were included in the analysis, 773 (62.9%) of whom were under 65 years, 335 (27.3%) were 65 to 74 years, and 121 (9.8%) were 75 years or older. Hart said the researchers did find minor differences in baseline characteristics between the age groups. There was a higher percentage of fragile patients in the 75 years or older age group, and a slightly higher percentage of de novo metastatic disease in the under 65 years group.

There was a higher percentage of fragile patients in the 75 years or older age group, and a slightly higher percentage of de novo metastatic disease in the under 65 years group. Image Credit: © pikselstock - stock.adobe.com

Regardless of age, benefits in PFS and OS were seen in the ribociclib plus endocrine therapy arm vs the control arm. The investigational combination also delayed the median TTC in all age groups.

In the investigational combination group, the most common first subsequent antineoplastic treatment was hormonal therapy alone (<65 years, 26.3%; 65-<75 years, 41.6%; ³75 years, 38.1%). In the ³75 years age group, patients in the ribociclib plus endocrine therapy arm (6.3%) less frequently received chemotherapy alone as the first subsequent antineoplastic treatment vs the control arm (24.5%).

In patients under 65 years, safety results were consistent with the overall trial population. In patients aged 65 to 74 years and 75 years or older, the most common adverse events (AEs) of any grade with ribociclib plus endocrine therapy were neutropenia, nausea, fatigue, and diarrhea. For the investigational combination vs the control arm, rates of grade 3/4 febrile neutropenia, all grade interstitial lung disease, and all grade QT prolongation were numerically higher in patients ages 65 to 74 years and 75 years or older compared to those under 65 years of age.

Based on these pooled results, Hart said the researchers concluded that PFS and OS benefit with ribociclib plus endocrine therapy in elderly patients are consistent with those observed in younger patients. Across the age subgroups, treatment with the investigational combination also delayed TTC. Further, the safety profile was consistent with what is anticipated in an older patient population, and there was no difference in TTD in global health status with ribociclib plus endocrine therapy vs placebo plus endocrine therapy in patients aged 65 years and older.

“We know from other studies that you can reduce the dose and keep the survival benefits, so I think this study shows that there is an opportunity to optimize [AE] management in the elderly patients by reducing the dose—not necessarily having to stop [treatment],” Hart said.

Reference

Hart L. Efficacy, safety, and quality of life with ribociclib plus endocrine therapy in elderly patients with hormone receptor-positive, HER2-negative advanced breast cancer across the MONALEESA-2, -3, and -7 trials. Presented at: San Antonio Breast Cancer Symposium. December 5-9, 2023.