Complete Clinical Response in Locally Advanced Metastatic de novo Breast Cancer after Front-Line Treatment with Ribociclib/Letrozole within the RIBANNA Study.

Introduction: Ribociclib is an orally bioavailable cyclin-dependent kinase 4/6 inhibitor. In combination with aromatase inhibitor letrozole, it has approval for treatment of hormone receptor positive (HR+) and human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer. First-line therapy with ribociclib + letrozole significantly improves progression-free survival compared to placebo + letrozole in patients with HR+/HER2- advanced breast cancer.