On May 15, 2026, the Food and Drug Administration (FDA) approved fam-trastuzumab deruxtecan-nxki (T-DXd, Enhertu, Daiichi Sankyo, Inc.) for two separate indications in adults with HER2-positive early-stage breast cancer. The first indication is for T-DXd followed by a taxane, trastuzumab, and pertuzumab (THP), for the neoadjuvant treatment of adult patients with HER2-positive (IHC 3+ or ISH+) Stage II or III breast cancer, as determined by an FDA-authorized test. The second indication is for T-DXd for the adjuvant treatment of adult patients with HER2-positive (IHC 3+ or ISH+) breast cancer who have residual invasive disease following neoadjuvant treatment with trastuzumab (with or without pertuzumab) and taxane-based treatment.
FDA also approved two companion diagnostic devices, the PATHWAY anti-HER-2/neu (4B5) Rabbit Monoclonal Primary Antibody and the VENTANA HER2 Dual ISH DNA Probe Cocktail, both for identifying HER2-positive (IHC3+ or ISH+) patients for treatment with T-DXd, consistent with the approved drug labeling.