BGB-43395 + elacestrant

**BGB-43395 + elacestrant** is an investigational oral combination therapy for advanced solid tumors and hormone receptor positive (HR+) / human epidermal growth factor receptor 2 negative (HER2-) breast cancer. BGB-43395 is a highly potent and selective cyclin-dependent kinase 4 (CDK4) inhibitor, designed to preferentially inhibit CDK4 over CDK6, potentially minimizing hematologic toxicity seen with traditional CDK4/6 inhibitors. Elacestrant is a selective estrogen receptor degrader (SERD), acting on estrogen receptor (ER)-positive breast cancers. The combination is intended to synergistically inhibit tumor cell cycle progression and hormone-driven tumor proliferation in solid tumors dependent on CDK4 and ER signaling, particularly after progression on other endocrine or CDK4/6 inhibitor therapies[3][4][5][1].