abemaciclib + tamoxifen

Abemaciclib + tamoxifen is a combination therapy used primarily in the treatment of hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) breast cancer, including both early-stage and metastatic disease. Abemaciclib is an oral, selective inhibitor of cyclin-dependent kinases 4 and 6 (CDK4/6), which are key regulators of cell cycle progression. Tamoxifen is a selective estrogen receptor modulator (SERM) that acts as an antagonist on estrogen receptors in breast tissue, thereby inhibiting the proliferative action of estrogen on mammary epithelium. The combination leverages dual mechanisms—cell cycle arrest via CDK4/6 inhibition and hormonal blockade via estrogen receptor antagonism—to improve antitumor efficacy. Clinical studies have shown that adding tamoxifen to abemaciclib can provide greater overall survival benefit compared to abemaciclib monotherapy in patients with endocrine-refractory HR+, HER2- metastatic breast cancer[2][4][5]. This regimen has also demonstrated manageable safety profiles and promising antitumor activity[5][6].

Brand names

Verzenio (for abemaciclib)