Highlight
– The FDA approved trastuzumab deruxtecan (T-DXd) for adult patients with unresectable or metastatic HR-positive breast cancer exhibiting HER2-low or HER2-ultralow expression after progression on endocrine therapy.
– This approval was based on DESTINY-Breast06, a pivotal multicenter randomized controlled trial demonstrating significant progression-free survival (PFS) improvement compared with chemotherapy.
– The indication includes a newly defined HER2-ultralow category (IHC 0 with membrane staining), supported by an approved diagnostic assay.
– T-DXd provides a novel treatment alternative in the metastatic setting without prior chemotherapy exposure, expanding options beyond standard endocrine and chemotherapy regimens.