Ribociclib targets and inhibits the activity of CDK4 and CDK6, which are crucial for the progression of the cell cycle from the G1 phase to the S phase. By blocking these kinases, ribociclib effectively halts cell division, leading to reduced cancer cell growth and proliferation. This mechanism of action is particularly important in hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) breast cancer.
