Randomized, doubleblind, phase 3 study of tucatinib or placebo in combination with T-DM1 for subjects with unresectable locally-advanced or metastatic HER2 breast cancer

Abstract

Abstract Background: Tucatinib is an orally-available, reversible HER2 small molecule tyrosine kinase inhibitor (TKI) being developed as a novel treatment for patients with HER2+ metastatic breast cancer (mBC), including patients with brain metastases. Two key features of tucatinib are its potency and selectivity for HER2, compared to the epidermal growth factor receptor (EGFR). Ado-trastuzumab emtansine (T-DM1) is approved for the treatment of patients with HER2+ mBC after prior treatment with trastuzumab and a taxane. While treatment with T-DM1 has led to significant improvements in progression-free survival (PFS) and overall survival, further improvements in therapy are nee..