Insights into Effects of Adjuvant CDK4/6 Inhibitors in Breast Cancer

Each of the three available CDK4/6 inhibitors has uniformly improved outcomes in patients with ER-positive metastatic breast cancer. By extension, use of these agents in the setting of high-risk ER-positive, early-stage breast cancer would be predicted to similarly confer benefit in terms of reducing the risk of recurrence. Yet to date, only abemaciclib has been shown to confer such benefit, in the MonarchE trial. Three recent studies provide new findings about the effects of CDK4/6 inhibitors.

Researchers present updated results from the MonarchE trial, including an analysis of the subset of patients with high Ki-67. In the Monarch-E trial, 5637 patients with ER-positive, HER2-negative breast cancer were randomized to endocrine therapy alon…