Ribociclib is a kinase inhibitor. the mechanism of action of ribociclib is as a kinase inhibitor, and cytochrome p450 3a inhibitor.ribociclib in combination with an aromatase inhibitor is indicated for the treatment of postmenopausal women with hormone receptor (hr) positive, human epidermal growth factor receptor 2 (her2) negative locally advanced or metastatic breast cancer as initial endocrine based therapy.dose: 600mg daily.