HRS-6209 + letrozole

HRS-6209 + letrozole is an investigational combination therapy being studied for the treatment of advanced unresectable or metastatic breast cancer. HRS-6209 is a novel, orally administered small molecule inhibitor of cyclin-dependent kinase 4 (CDK4), developed by Jiangsu Hengrui Medicine. Letrozole is a third-generation aromatase inhibitor, widely used and approved for hormone receptor-positive breast cancer; it works by inhibiting the aromatase enzyme, thereby reducing estrogen production and limiting tumor growth in estrogen-dependent cancers. The combination aims to enhance antitumor efficacy by targeting both cell cycle progression (via CDK4 inhibition) and estrogen synthesis (via aromatase inhibition)[1][5][6][8].