This exploratory project is a prospective and multicenter study designed to evaluate the mechanisms of primary and acquired resistance to Kadcyla in a cohort of 50 progressive/recurrent HER2+ BC patients planned to be treated with Kadcyla within the approved indication in Spain.~This study will collect high quality molecular data derived from the analysis of serial biological samples (primary tumor and/or metastatic tissue, plasma, serum and whole blood samples), together with annotated clinical follow up, to reach a better understanding of the biological events that drive breast cancer progression and response/resistance to Kadcyla in ABC patients.
The study aim is to perform a comprehensive and integrated characterization of mechanisms of primary and acquired resistance to Kadcyla in a prospective cohort of progressive/recurrent HER2-positive breast cancer patients.