The addition of abemaciclib to endocrine therapy was not found to negatively affect patient-reported outcomes (PROs) among patients with early breast cancer, according to data from the phase 3 monarchE trial presented at the 17th St. Gallen International Breast Cancer Conference 2021.

The monarchE trial ( Identifier: NCT03155997) enrolled patients with hormone receptor-positive, HER2-negative, high-risk, early breast cancer and randomly assigned them to receive abemaciclib plus endocrine therapy or endocrine therapy alone. The trial previously showed that adding abemaciclib to endocrine therapy improved invasive disease-free survival.

The investigators collected PROs from 5591 patients using 4 instruments administered at baseline; during treatment at 3, 6, 12, 18, and 24 months; and after treatment at 1, 6, and 12 months. The 4 instruments measured health-related quality of life (HRQOL), symptom burden, fatigue, and symptoms associated with endocrine therapy.

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The degree of bother by treatment side effects was similar between the treatment arms, with most patients in each arm reporting being bothered “a little” or “not at all” by treatment side effects.

Also, PROs in HRQOL, fatigue, and symptoms associated with endocrine therapy were similar for treatment arms.

Most patients who received abemaciclib plus endocrine therapy reported having diarrhea “a little bit” or “somewhat” at 3 months of treatment, but the study authors noted that PROs were not collected within the first 3 months of treatment, when the highest incidence and severity of diarrhea were reported.

The study authors concluded that the findings support a “tolerable” profile for abemaciclib in combination with endocrine therapy in patients with early breast cancer.

“However, the frequency of PRO assessments was not sufficient to capture patient-reported symptoms and HRQoL within the first 3 months post baseline,” they wrote.


Tolaney S, Blancas I, Im Y-H, et al. Patients’ quality of life and side-effect perceptions in monarchE, a study of abemaciclib plus endocrine therapy in adjuvant treatment of HR+, HER2−, node-positive, high-risk, early breast cancer. Poster presentation at: The 17th St. Gallen International Breast Cancer Conference 2021; March 17-21, 2021. Abstract P008.

This article originally appeared on Cancer Therapy Advisor