ABSTRACT
Introduction: Cyclin-dependent kinases (CDKs) 4 and 6 regulate the transition from G0/G1-phase to S-phase of the cell cycle and have been identified as key drivers of proliferation in hormone receptor (HR)-positive breast cancer. The CDK4/6 inhibitor palbociclib in combination with endocrine therapy has been approved for treatment of HR-positive/HER2-negative breast cancer patients.
Areas covered: In this article, we provide an update of the data on pharmacodynamics, pharmacokinetics, preclinical, and clinical studies of palbociclib in breast cancer. We performed a search of data on palbociclib in the PubMed and the clinicaltrials.gov databases, in the FDA website and in the ASCO and AACR proceedings.
Expert opinion: In order to optimize the clinical outcome of HR-positive breast cancer patients treated with palbociclib, predictive biomarkers allowing patient selection are urgently needed. A recent study suggested that early dynamics of PIK3CA mutations in circulating tumor DNA might be a potential predictive biomarker for CDK4/6 inhibitors. Several clinical trials are ongoing with the aim to explore the activity of combinations of palbociclib with targeted agents and/or immunotherapy in the different subtypes of breast cancer in both metastatic and early phases of the disease. These combinations might allow improving the sensitivity and overcoming mechanisms of resistance.
Declaration of interest
The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.
Reviewer disclosures
Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.