ESMO 2020: Adding Abemaciclib to Hormonal Therapy in High-Risk Early Breast Cancer
Posted: Tuesday, September 22, 2020
Adding abemaciclib to hormonal therapy significantly reduced the risk of an invasive disease free–survival event by 25% in patients with high-risk early hormone receptor–positive HER2-negative breast cancer, according to results of the international phase III monarchE trial presented at the European Society for Medical Oncology (ESMO) Virtual Congress 2020 (Abstract LBA5_PR). “This is the first time in more than 20 years that we have seen an advance in the adjuvant treatment of this form of breast cancer,” stated author Stephen R.D. Johnston, MD, of the Royal Marsden Hospital NHS Foundation Trust, London, in an ESMO press release.
The open-label global study included 5,637 patients with hormone receptor–positive HER2-negative early breast cancer with high-risk clinical or pathologic factors. After completing primary treatment, patients were randomly assigned to receive either abemaciclib at 150 mg twice daily for 2 years plus endocrine therapy or endocrine therapy alone.
During the study period, 11.3% of patients in the control group had invasive disease recurrence compared with 7.8% of those in the abemaciclib group, corresponding to a 25.3% reduction in the risk of recurrence (P = .0096). A similar improvement was observed for 2-year distant relapse–free survival, with rates of 93.6% and 90.3% in the abemaciclib and control arms, respectively. The most frequent adverse events were diarrhea, neutropenia, and fatigue in the abemaciclib arm and arthralgia, hot flush, and fatigue in the control arm.
“This is a very important trial, and the findings will change practice,” explained Giuseppe Curigliano, MD, PhD, Chair of the ESMO Guidelines Committee, who was not involved in the study. “Once approved for high-risk [hormone receptor–positive HER2-negative] early breast cancer, the new standard of care for these patients will be to add 2 years of abemaciclib to endocrine therapy.”
Disclosure: For full disclosure of the study authors, visit esmo.org.
