LAUSR

Key Points Question Can treatment with abemaciclib provide good clinical outcomes for patients with high-risk early breast cancer who received neoadjuvant chemotherapy? Findings In this prespecified analysis of the monarchE randomized clinical trial, treatment with abemaciclib and endocrine therapy demonstrated clinically meaningful benefit in invasive disease-free survival and distant relapse-free survival, with an absolute improvement of 6.6% in 2-year invasive disease-free survival rates and 6.7% in 2-year distant relapse-free survival rates. Consistent treatment benefit was observed by residual pathological breast tumor size or the number of positive lymph nodes at surgery. Meaning The results of this analysis of the monarchE randomized clinical trial found that treatment with adjuvant abemaciclib plus endocrine therapy demonstrated benefit for patients with hormone receptor–positive, ERBB2−, node-positive, and high-risk early breast cancer who received neoadjuvant chemotherapy before trial enrollment.