ERBB2 and breast cancer: In the TUXEDO-1 phase II study, treatment with T-DXd resulted in an intracranial response rate of 73.3% (by RANO-BM; 11/15 patients) and a median PFS of 14 months in patients with HER2-positive breast cancer and newly diagnosed or progressive brain metastases; the response was 100% in patients with de novo brain metastases and 66.7% in patients with brain metastases that had progressed after previous local therapy [18].