Feb. 7, 2025—The FDA approved AstraZeneca and Daiichi Sankyo’s Enhertu (trastuzumab deruxtecan) for the treatment of adult patients with unresectable or metastatic HR-positive, HER2-low (IHC 1+ or IHC 2+/ISH-) or HER2-ultralow (IHC 0 with membrane staining) breast cancer, as determined by an FDA-approved test, that has progressed on one or more endocrine therapies in the metastatic setting.
The approval was based on results from the Destiny-Breast06 phase three trial in which Enhertu showed a 36 percent reduction in the risk of disease progression or death versus chemotherapy (hazard ratio, 0.64; 95 percent confidence interval, 0.54–0.76; P<0.0001) in the overall trial population of patients with chemotherapy-naive HER2-low or HER2-ultralow metastatic breast cancer. A median progression-free survival of 13.2 months was seen in patients randomized to Enhertu compared with 8.1 months in patients randomized to chemotherapy. The confirmed objective response rate in the overall trial population was 62.6 percent for Enhertu versus 34.4 percent for chemotherapy.
The trial enrolled 866 patients (n=713 for HER2-low; n=153 for HER2-ultralow) in Asia, Europe, Australia, North America, and South America.