The finding of our study that abemaciclib is a cost-saving option over ribociclib was not consistent with other two published findings from the two studies that we could identify to address the cost-effectiveness of abemaciclib plus aromatase inhibitors versus ribociclib plus aromatase inhibitors in HR+/HER2- advanced breast cancer patients (44, 45). This evidence concerns the gene CYP19A1 and breast cancer.