PALBOCICLIB: CDK4/6 INHIBITION IN THE TREATMENT OF ER-POSITIVE BREAST CANCER

Maintaining cell-cycle control has become a mainstay in treatment for many cancers. Cell-cycle manipulation can be especially valuable in breast cancer tumor cells that will often express hormone receptors that are amenable to anti-hormone receptor-targeted therapies. Despite these treatments, patients often progress, leading to other targeted agents being investigated to help promote progression-free survival. Cyclin-dependent kinases (CDKs) have been identified as contributors in the process of cell division. Combining inhibitors of CDKs with traditional endocrine treatments has shown significant progression-free survival in patients with metastatic breast cancer. One such CDK inhibitor, palbociclib, has shown great promise in the treatment of hormone receptor-positive breast cancer. In this article we review the traditional hormonal treatments of breast cancer, how CDK inhibition is beneficial in the treatment of this disease, and the preclinical and clinical data supporting the use of this medication.