amcenestrant + abemaciclib

Amcenestrant + abemaciclib is an investigational combination therapy for hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+/HER2-) advanced or metastatic breast cancer. Amcenestrant is an oral selective estrogen receptor degrader (SERD) that antagonizes and degrades the estrogen receptor, thereby inhibiting estrogen signaling pathways critical for the growth of ER+ breast cancer cells[6][9][10]. Abemaciclib is a small molecule inhibitor of cyclin-dependent kinases 4 and 6 (CDK4/6), which blocks cell cycle progression in cancer cells dependent on these kinases for proliferation[3]. The rationale behind combining these agents is to target both hormonal signaling and cell cycle regulation, potentially overcoming resistance to endocrine therapies. Clinical studies have evaluated this combination in postmenopausal women with ER+/HER2- advanced breast cancer; however, Sanofi discontinued global development of amcenestrant after negative results from phase 3 trials[5].