CDK4 and breast cancer: Similarly, the CAPItello-291 study reported doubled mPFS (7.2 vs. 3.6 months) for AKT inhibitor capivasertib plus fulvestrant in advanced HR+/HER2− breast cancer, with consistent benefits observed in CDK4/6 inhibitor-pretreated subgroups (5.5 vs. 2.6 months) (Turner et al., 2023).