Dataset from neoMONARCH: A Phase 2 Neoadjuvant Trial Comparing the Biological Effects of 2 Weeks of Abemaciclib (LY2835219) in Combination With Anastrozole to Those of Abemaciclib Monotherapy and Anastrozole Monotherapy and Evaluating the Clinical Activity and Safety of a Subsequent 14 Weeks of Therapy With Abemaciclib in Combination With Anastrozole in Postmenopausal Women With Hormone Receptor Positive, HER2 Negative Breast Cancer

The purpose of this study is to evaluate the biological effects of abemaciclib in combination with anastrozole and compare those to the effects of abemaciclib alone and anastrozole alone in the tumors of postmenopausal women with hormone receptor positive (HR+), human epidermal growth factor receptor 2 (HER2) negative breast cancer.