New monarchE trial data shows long-term survival gains for high-risk early breast cancer patients receiving abemaciclib with hormone therapy

New monarchE trial data shows long-term survival gains for high-risk early breast cancer patients receiving abemaciclib with hormone therapy

(IN BRIEF) Long-term data from the international monarchE trial has confirmed that patients with HR+ and HER2- node-positive high-risk early breast cancer achieve better survival outcomes when treated with the targeted therapy abemaciclib in combination with standard hormone therapy. Presented by Professor Stephen Johnston of The Royal Marsden NHS Foundation Trust and The Institute of Cancer Research, London, at the ESMO 2025 Congress and published in Annals of Oncology, the study shows a 15.8% reduction in the risk of death and 32% fewer metastatic cases compared to hormone therapy alone. These results mark the first major survival improvement in the adjuvant treatment of breast cancer in over 20 years. The research, funded by Eli Lilly and Company, highlights the ongoing commitment of The Royal Marsden, ICR, and NIHR to advancing therapies that extend survival and enhance quality of life for patients with early breast cancer.

(PRESS RELEASE) LONDON, 21-Oct-2025 — /EuropaWire/ — Patients with hormone receptor-positive (HR+) and human epidermal growth factor receptor 2-negative (HER2-) node-positive, high-risk early breast cancer are experiencing significantly improved long-term survival seven years after treatment, according to new findings from the international monarchE Phase III trial. The latest results, simultaneously published in Annals of Oncology and presented at the European Society for Medical Oncology (ESMO) 2025 Congress, demonstrate that adding the targeted therapy abemaciclib to standard hormone treatment continues to yield durable benefits in overall survival.

Led by Professor Stephen Johnston, Head of the Breast Unit and Consultant Medical Oncologist at The Royal Marsden NHS Foundation Trust and Professor of Breast Cancer Medicine at The Institute of Cancer Research (ICR), London, the monarchE trial investigated whether abemaciclib could enhance outcomes for women with HR+/HER2- breast cancer who are at higher risk of recurrence. The study enrolled patients with node-positive disease and tumours that were large, high-grade, or otherwise at elevated risk of returning after initial treatment.

The seven-year follow-up data revealed that patients who received abemaciclib alongside hormone therapy had a 15.8% reduction in the risk of death compared to those given hormone therapy alone, marking a statistically significant and clinically meaningful improvement. Furthermore, the combination therapy led to 32% fewer cases of metastatic disease — with 6.4% of patients developing or living with metastatic cancer compared to 9.4% in the control group.

Professor Johnston described the results as a milestone in breast cancer treatment: “The most recent data from our monarchE study reaffirms that this is the first medicine in over two decades to deliver a clear improvement in overall survival for patients in the adjuvant setting. It is wonderful to see these patients in my clinic who continue to remain disease free and are able to live their lives fully.”

With roughly 70% of all breast cancer patients presenting HR+ and HER2- tumours, the findings have broad implications for global cancer care. The study underscores how early integration of targeted therapies in high-risk cases can dramatically reduce recurrence and mortality rates.

The monarchE trial was funded by Eli Lilly and Company, with breast cancer research at The Royal Marsden supported by The Royal Marsden Cancer Charity and the National Institute for Health and Care Research (NIHR). Continued long-term monitoring of participants will determine whether the survival benefits extend further with time.

Media Contact:

Tel: 0203 437 3502
email: mediaoffice@icr.ac.uk

SOURCE: The Institute of Cancer Research