AstraZeneca and Daiichi Sankyo Announce Phase 3 Results for Enhertu in HER2-Ultralow Breast Cancer

AstraZeneca and Daiichi Sankyo today announced positive results from the Phase 3 DESTINY-Breast06 trial evaluating trastuzumab deruxtecan (Enhertu) in patients with HER2-ultralow (IHC 0 with incomplete membrane staining) hormone receptor-positive breast cancer. The trial met its primary endpoint, demonstrating a statistically significant improvement in progression-free survival compared to chemotherapy. The median PFS was 13.2 months for Enhertu versus 8.1 months for chemotherapy. These results expand the potential use of Enhertu into HER2-ultralow breast cancer, a population previously not considered for HER2-targeted therapy.