HRS-6209 + HRS-9813 + letrozole

HRS-6209 + HRS-9813 + letrozole is an investigational combination regimen being developed by Hengrui Pharma for the treatment of advanced unresectable or metastatic breast cancer. The regimen consists of HRS-6209, a selective small molecule inhibitor of cyclin-dependent kinase 4 (CDK4); HRS-9813, a novel Class 1 innovative drug; and letrozole, an aromatase inhibitor. HRS-6209 is designed to improve upon existing CDK4/6 inhibitors by demonstrating higher selectivity for CDK4, which may reduce hematological toxicities like neutropenia. The combination is currently being evaluated in Phase Ib/II clinical trials to determine its safety, tolerability, and preliminary efficacy in patients with hormone receptor-positive breast cancer.