Modulation of cytochrome P450 and P-glycoprotein by Ashwagandha (Withania somnifera): implications for CDK4/6 inhibitor therapy

The approval of cyclin-dependent kinase 4/6 inhibitors (CDK4/6i), including palbociclib, ribociclib and abemaciclib, has transformed the prognosis of hormone receptor-positive, HER2-negative metastatic breast cancer. However, this therapeutic advance faces a growing challenge in daily clinical practice—the concomitant use of complementary medicine by patients. In particular, Withania somnifera, commonly known as Ashwagandha, has experienced unprecedented growth in popularity as an adaptogenic supplement aimed at alleviating cancer-related fatigue and psychological stress.1