A drug used to treat hormone-receptor positive (HR+), HER2-negative (HER2-) breast cancer that is advanced or has spread to other parts of the body. It is used with an aromatase inhibitor in postmenopausal women who have not been treated with hormone therapy. It is used with fulvestrant in women whose disease got worse after treatment with hormone therapy. Abemaciclib is also used alone in men and women whose disease got worse after treatment with hormone therapy and previous chemotherapy. It is also being studied in the treatment of other types of cancer. Abemaciclib blocks certain proteins, which may help keep cancer cells from growing. It is a type of cyclin-dependent kinase inhibitor. Also called Verzenio.