Cyclin-dependent kinase (CDK) 4/6 inhibitors are a class of agents recently introduced in the clinic for the treatment of advanced hormone receptor-positive (HR+) and HER2-negative (HER2-) BC. Palbociclib, ribociclib and abemaciclib have all been approved by the US Food and Drug Administration (FDA) and the European Medicines Agency among other regulatory bodies
1. Adult patients (≥18 years). 2. Confirmed diagnosis with MBC. 3. HR-positive/HER2-negative MBC as ascertained by immunohistochemistry (IHC) or fluorescence in situ hybridization in primary or metastatic tissue samples.
Prior exposure to fulvestrant or everolimus.
Patients with uncontrolled brain metastases or symptomatic visceral spread who are at risk of life-threatening complications.
Patients refusing to sign the written informed consent.