Adjuvant abemaciclib plus endocrine therapy (ET) showed a significant but small improvement in overall survival compared to ET alone in HR-positive, HER2-negative, high-risk early breast cancer. At seven years, abemaciclib-ET showed sustained benefits in invasive disease-free survival and distant relapse-free survival. The treatment was well tolerated with no new safety concerns noted.
Study
|
Randomized, open-label, phase 3 study [monarchE] |
| Hormone receptor-positive, HER2-negative, node-positive, high-risk early breast cancer |
| Abemaciclib (2 yrs) + ET (n=2808) vs ET alone (5 yrs) (n=2829)
|
Efficacy
|
7-yr OS: 86.8% vs 85.0% (HR: 0.842 [0.722-0.981]) |
| 7-yr IDFS: 77.4% vs 70.9% (HR 0.734) |
| 7-yr DRFS: 80.0% vs 74.9% (HR 0.746)
|
Safety
|
Grade >=3 AEs: Infections (0.6% vs 0.4%), COVID-19 (0.3% vs 0.1%), Second primary neoplasm (0.5% vs 0.3%), Cardiac disorders (0.4% vs 0.3%) |
| Serious AEs: Higher in ET (8.1%) vs Abemaciclib-ET (7.5%)
|
Ann Oncol. Published online October 2025
Johnston S, Martin M, O’Shaughnessy J New Reference: Abemaciclib for Adjuvant Breast Cancer
http://doi.org/10.1016/j.annonc.2025.10.005
Reviewed by Ulas D. Bayraktar, MD on Oct 18, 2025
