CDK4 and breast cancer: Lerociclib is a differentiated oral CDK4/6i, currently being evaluated in a phase I/II trial (NCT02983071) in combination with fulvestrant in HR-positive, HER2-negative metastatic BC patients; preliminary results presented at San Antonio Breast Cancer Symposium (SABCS) in December 2019 showed safety and efficacy profile consistent with other CDK4/6 inhibitors [75].