Abemaciclib is an oral anticancer drug primarily used in the treatment of hormone receptor (HR)-positive, HER2-negative advanced or metastatic breast cancer. It is often given in combination with endocrine therapies such as aromatase inhibitors or Fulvestrant, especially in patients whose disease has progressed after earlier treatments. In some cases, it is also used as monotherapy. The drug works by inhibiting cyclin-dependent kinases 4 and 6 (CDK4/6), which helps slow down the growth and division of cancer cells. It has been shown to improve progression-free survival and delay disease worsening. Abemaciclib can be used in both premenopausal and postmenopausal women when combined with appropriate hormonal therapy, and it is also approved for certain high-risk early breast cancer patients in the adjuvant setting. The medication is taken orally, typically twice a day, and ongoing research is exploring its potential applications in other cancers and combination regimens.
