Abemaciclib is an oral, selective inhibitor of cyclin-dependent kinase (CDK) 4 and 6 that is indicated for the treatment of hormone receptor positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced or metastatic breast cancer. In previous reports of the phase III MONARCH 2 trial, the addition of abemaciclib to fulvestrant was shown to result in a significant improvement of the progression-free (PFS) and overall survival (OS) of women with HR+/HER2- advanced breast cancer and significantly delayed the time to the initiation of chemotherapy. In recent months, Professor Patrick Neven (University Hospitals Leuven) presented two interesting exploratory analyses of this trial.