Recently, preliminary results for abemaciclib in combination with fulvestrant for the treatment of postmenopausal women with HR+/HER2− advanced breast cancer based on phase III study MONARCH-3 are published.30 However, abemaciclib had not received FDA or EMA approval at the point of model development, and therefore was not included in the study.31 Given the approval of abemaciclib in the same patient population would require a fully incremental analysis of the cost-effectiveness of all the CDK4/6 inhibitors. This evidence concerns the gene CDK4 and breast cancer.