Site Editor

William J. Gradishar, MD, FACP, FASCO


SABCS 2022: monarchE Update on Endocrine Therapy Plus Abemaciclib for High-Risk Breast Cancer

By: Vanessa A. Carter, BS
Posted: Tuesday, December 13, 2022

Stephen Johnston, MBBS, of The Royal Marsden Hospital, London, United Kingdom, and colleagues conducted a study that combined adjuvant abemaciclib with endocrine therapy in patients with hormone receptor–positive, HER2-negative, early-stage breast cancer. The 4-year overall survival analysis with the combination of this CDK4/6 inhibitor and hormonal therapy was presented during the 2022 San Antonio Breast Cancer Symposium (SABCS; Abstract GS1-09).

“The clinically meaningful benefit of adjuvant abemaciclib added to endocrine therapy in [this] cancer persists beyond completion of abemaciclib therapy, yielding an increase in absolute invasive disease–free survival and distant relapse–free survival benefit at 4 years,” concluded the investigators. “While overall survival remains immature at this time, the lower number of deaths in the abemaciclib arm compared to the endocrine therapy arm suggest that a survival signal favoring abemaciclib is emerging.”

A total of 5,637 patients with hormone receptor–positive, HER2-negative, node-positive, early-stage breast cancer were enrolled. Participants were randomly assigned on a 1:1 basis to receive endocrine therapy for up to 10 years with or without abemaciclib for 2 years.

All patients had ceased receiving abemaciclib at the median follow-up of 42 months. The hazard ratios were 0.664 for invasive disease–free survival and 0.659 for distant relapse–free survival. Additionally, there was an observed improvement in both invasive disease–free survival (79.4% to 85.8%) and distant relapse–free survival (82.5% to 88.4%) rates at 4 years.

A lower number of deaths observed with the combination therapy versus endocrine therapy alone (157 vs. 173) suggests the benefit in invasive disease–free survival and distant relapse–free survival may translate into a numerically favorable overall survival hazard ratio. In addition, a Ki67 index of at least 20% was associated with a worse prognosis among patients with positive axillary lymph nodes or who had grade 3 disease. No new safety signals were observed.

Disclosure: For full disclosures of the study authors, visit

By continuing to browse this site you permit us and our partners to place identification cookies on your browser and agree to our use of cookies to identify you for marketing. Read our Privacy Policy to learn more.