A Gene Panel Associated With Abemaciclib Utility in <i>ESR1</i>-Mutated Breast Cancer After Prior Cyclin-Dependent Kinase 4/6-Inhibitor Progression

Abstract

For ESR1-MUT MBC with resistance to ET and palbociclib, PFS on abemaciclib is longer for patients with CDKi-R(-) than CDKi-R(+). Although a small and retrospective data set, this is the first demonstration of a genomic panel associated with abemaciclib sensitivity in the postpalbociclib setting. Future directions include testing and improving this panel in additional data sets, to guide therapy selection for patients with HR+/HER2- MBC.