Neutropenia was the only grade 4 adverse event reported in ≥5% of patients.47 Based on the results from this study, FDA recently approved the combination of ribociclib (KISQALI) with fulvestrant for treating postmenopausal women with HR+/HER2− advanced or metastatic BC, as initial endocrine‐based therapy or following disease progression on endocrine therapy.69 The list of ongoing phase II/III/IV trials combining CDK4/6 inhibitors with fulvestrant is summarized in Table 2. This evidence concerns the gene CDK4 and breast cancer.