AstraZeneca, Daiichi Sankyo announce Enhertu demonstrated improvement in IDFS

AstraZeneca (AZN) and Daiichi Sankyo (DSNKY) announced positive results from the DESTINY-Breast05 Phase III trial showed Enhertu demonstrated a highly statistically significant and clinically meaningful improvement in invasive disease-free survival, IDFS, in patients with a high risk of disease recurrence. The trial compared Enhertu with trastuzumab emtansine, T-DM1, as a post-neoadjuvant treatment in patients with HER2-positive early breast cancer with residual invasive disease in the breast and/or axillary lymph nodes after neoadjuvant treatment. Results showed Enhertu significantly reduced the risk of invasive disease recurrence or death by 53% compared with T-DM1 as a post-neoadjuvant treatment. At three years, 92.4% of patients in the Enhertu arm were alive and free of invasive disease, compared with 83.7% of those in the T-DM1 arm. The IDFS results were consistent across all prespecified subgroups. Enhertu also significantly reduced the risk of disease recurrence or death, a key secondary endpoint, by 53%. Further, Enhertu lowered the risk of distant disease recurrence by 51% and the risk of brain metastases by 36% versus T-DM1. Overall survival was not mature at the time of this planned interim analysis and will be assessed in future analyses.