Dr. Harbeck on Ki-67 as a Biomarker for Identifying High-Risk Early Breast Cancer

Nadia Harbeck, MD, PhD, head of the Breast Center and chair of Conservative Oncology, Department of Obstetrics and Gynaecology, at the University of Munich, discusses Ki-67 as a biomarker for identifying patients with high-risk early breast cancer who received treatment on the monarchE trial.

The evaluation of benefit with abemaciclib (Verzenio) in all cohorts of patients enrolled on the monarchE study was statistically pre-planned, Harbeck explains. Investigators assessed invasive disease-free survival (iDFS) in tumors that were Ki-67 high and noted a significant P value with a hazard ratio (HR) of 0.691, meeting the prespecified criteria in patients who received abemaciclib (Verzenio) and endocrine therapy. The intent-to-treat population had a significantly higher 2-year iDFS vs patients who received endocrine therapy alone.

After meeting these criteria, investigators launched an analysis that featured patients in cohort 1 who had tumors with high Ki-67. Additionally, the 2-year iDFS rate was 91.3% with the addition of abemaciclib to endocrine therapy vs 86.1% with endocrine therapy alone for a difference of 5.2 percentage points for a HR of 0.643, concludes Harbeck.