15.8 percent lower risk for death seen with abemaciclib-ET versus ET in intent-to-treat population
By Elana Gotkine HealthDay Reporter
THURSDAY, Oct. 23, 2025 (HealthDay News) — For patients with hormone receptor (HR)-positive, human epidermal growth factor 2 (HER2)-negative, node-positive, high-risk early breast cancer (EBC), adjuvant abemaciclib combined with endocrine therapy (ET) yields significantly improved overall survival (OS) compared with ET, according to a study published online Oct. 17 in the Annals of Oncology to coincide with the annual meeting of the European Society for Medical Oncology, held from Oct. 17 to 21 in Berlin.
Stephen Johnston, Ph.D., from the Royal Marsden NHS Foundation Trust in London, and colleagues reported the primary OS results for patients with HR-positive, HER2-negative, node-positive, high-risk EBC receiving ET for at least five years with or without abemaciclib for two years. A total of 5,637 patients underwent randomization: 2,808 to abemaciclib-ET and 2,829 to ET.
The researchers found that abemaciclib-ET resulted in a 15.8 percent lower risk for death than ET in the intent-to-treat population, with a median follow-up of 76.2 months (hazard ratio, 0.842), meeting the prespecified boundary for significance. The seven-year OS was 86.8 and 85.0 percent with abemaciclib-ET and ET, respectively. Across prespecified subgroups, there was consistent OS benefit. Fewer patients in the abemaciclib-ET arm versus ET arm were living with metastatic disease (6.4 versus 9.4 percent). There were sustained improvements in invasive disease-free survival and distant relapse-free survival (hazard ratios, 0.734 and 0.746, respectively). Long-term safety data did not support concerns of delayed toxicities.
“For patients, survival is what matters most — and abemaciclib plus ET represents the first contemporary medicine in over two decades to deliver a clear improvement in overall survival in the adjuvant setting,” Johnston said in a statement.
Several authors reported financial ties to the pharmaceutical industry.
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