Dr. Ellis on Abemaciclib in HR-Positive Breast Cancer

Matthew J. Ellis, MD, PhD, professor and director, Lester and Sue Smith Breast Center, associate director of precision medicine, Dan L. Duncan Comprehensive Cancer Center, Baylor College of Medicine, discusses the use of abemaciclib (Verzenio) in hormone receptor-positive breast cancer.

Following the frontline approval of abemaciclib, Ellis’s interest lies in its potential use as a later-line therapy in patients who have not had an opportunity to be treated with a CDK4/6 inhibitor. Because of that approval, Ellis says that he may favor its use in patients with multiple resistance to multiple endocrine agents. These patients would have already had fulvestrant alone or fulvestrant and an aromatase inhibitor (AI).

Preclinical data with ESR1 mutations and ESR1 fusions indicate that downstream inhibition is very effective with CDK4/6 even when the estrogen receptor is mutationally interrupted, states Ellis. Some of these diagnoses are also being made with liquid biopsy analysis. The presence of an ESR1 mutation and prior AI therapy with fulvestrant might be a situation where in it is logical to consider abemaciclib as third-line monotherapy.