Abemaciclib is a type of targeted cancer drug. You pronounce it as a-bee-ma-sye-klib. 

It is a treatment for breast cancer that has:

spread to another part of the body (secondary or metastatic breast cancer)

spread to the area and structures surrounding the breast, such as nearby lymph nodes Open a glossary item, muscle and skin, but not to other parts of the body (locally advanced breast cancer)

You might also have it if you have an early breast cancer Open a glossary item that has a high risk of coming back.

You usually have abemaciclib in combination with a type of hormone therapy. This might include fulvestrant or an aromatase inhibitor Open a glossary item for example.

Abemaciclib is only for a type of breast cancer that is hormone receptor positive (HR+) and human epidermal growth factor receptor negative Open a glossary item (HER2 -). You have tests on your breast cancer cells to check for this.

How does abemaciclib work?

Abemaciclib is a type of cancer growth blocker that targets the proteins cyclin dependant kinase 4 and 6 (CDK4 and CDK6) on breast cancer cells.

CDK 4 and CDK 6 are proteins that stimulate cancer cells to divide and grow.

Abemaciclib works by blocking these proteins. It aims to slow or stop the growth of the cancer.