CDK4/6 Inhibitors

CDK4/6 inhibitors are a class of medicines used to treat certain types of hormone receptor-positive, HER2-negative breast cancer. These medicines interrupt the process through which breast cancer cells divide and multiply. To do this, they target specific proteins known as the cyclin-dependent kinases 4 and 6, abbreviated as CDK4/6. That's why you may hear them referred to as targeted therapies. If a breast cancer is hormone receptor-positive, it means the cancer’s growth is fueled by the hormones estrogen, progesterone, or both. HER2-negative cancers have tested negative for a protein called human epidermal growth factor receptor 2, or HER2, which promotes cancer cell growth. So HER2-negative cancers don’t respond to treatments that target the HER2 protein (such as Herceptin). More than two out of every three breast cancers are both hormone receptor-positive and HER2-negative.