MonarchE Ki-67 Value

In this segment, the experts dive into the monarchE subanalysis evaluating how Ki-67 levels before and after neoadjuvant chemotherapy inform prognosis and treatment planning for high-risk HR+, HER2– early breast cancer. The discussion highlights why assessing Ki-67 at both time points offers important insight into residual disease biology, revealing that patients whose tumors remain Ki-67–high after NAC face the greatest recurrence risk. The panel explores how these findings intersect with abemaciclib’s mechanism of action, what the substantial post-NAC Ki-67 declines suggest about tumor responsiveness, and how pharmacists and oncologists can use this biomarker information to guide follow-up, refine adjuvant strategies, and better counsel patients.