Medium throughput drug-screening platform (METPlatform) based on organotypic cultures that allows evaluation of inhibitors against metastases growing in situ. 

17 participants with active brain mets (median 14 mos since  radiation therapy): iORR 73% (11/15 with measureable dz) 

Additional modeling illustrates efficacy of T-DXd in HER2+ brain   metastases murine (PDX) models – both ER+ and ER -