Safety and Efficacy of Tucatinib, Letrozole, and Palbociclib in Patients with Previously Treated HR./HER2. Breast Cancer
Tumors that express hormonal receptors (HR) and amplified human epidermal growth factor receptor 2 (HER2) comprise 11% of all breast cancer cases, with a higher frequency among young patients. To overcome resistance to antihormonal and HER2-targeted agents mediated by cyclin D1-CDK4/6 complex, we proposed an oral combination of the HER2 inhibitor tucatinib, aromatase inhibitor letrozole, and CDK4/6 inhibitor palbociclib (TLP combination) for treatment of HR./HER2. metastatic breast cancer (MBC).