Aug. 8, 2022—AstraZeneca and Daiichi Sankyo’s Enhertu (trastuzumab deruxtecan) has been approved in the U.S. for the treatment of adult patients with unresectable or metastatic HER2-low (IHC 1+ or IHC 2+/ISH-) breast cancer who have received a prior chemotherapy in the metastatic setting or developed disease recurrence during or within six months of completing adjuvant chemotherapy.
Enhertu is a specifically engineered HER2-directed antibody drug conjugate. The FDA’s approval was based on the results from the DESTINY-Breast04 phase three trial. In the trial, Enhertu reduced the risk of disease progression or death by 50 percent versus the physician’s choice of chemotherapy in patients with HER2-low metastatic breast cancer with hormone-receptor-positive disease or HR-negative disease (median progression-free survival 9.9 versus 5.1 months; hazard ratio 0.50; 95 percent CI 0.40–0.63; P < 0.0001). A median overall survival of 23.4 months was seen in patients treated with Enhertu versus 16.8 months in those treated with chemotherapy.
The expanded approval for Enhertu in the U.S., following its previous approval in second-line HER2-positive metastatic breast cancer, enables its use across a spectrum of HER2-expressing breast cancer, including patients with HER2-low disease.
The DESTINY-Breast04 phase three trial results were presented at this year’s American Society of Clinical Oncology annual meeting and published in July (Modi S, et al. N Engl J Med. 2022;387[1]:9–20).