Hormone Receptor Positive, HER2 Negative Metastatic Breast Cancer: Impact of CDK4/6 Inhibitors on the Current Treatment Paradigm

The document from 2018 reviewed the efficacy and impact of CDK4/6 inhibitors—ribociclib, palbociclib, and abemaciclib—on the treatment of HR+, HER2- metastatic breast cancer. These inhibitors, when used in combination with endocrine therapy, have improved progression-free survival (PFS), overall response rate (ORR), and clinical benefit rate (CBR) in both first and second-line settings, and have been effective across various patient subgroups. The review also addressed the management of adverse events, such as neutropenia and alopecia, and the need for dose adjustments due to interactions with CYP3A-metabolized drugs. While overall survival (OS) data was still immature, the document concluded that CDK4/6 inhibitors have significantly shifted the treatment paradigm, with a call for further research to explore their broader role in treatment.