AstraZeneca, Daiichi Sankyo announce results from DESTINY-Breast09 Phase III

Positive results from the DESTINY-Breast09 Phase III trial showed AstraZeneca (AZN) and Daiichi Sankyo’s ENHERTU plus pertuzumab demonstrated a highly statistically significant and clinically meaningful improvement in progression-free survival compared to a taxane, trastuzumab and pertuzumab as a 1st-line treatment for patients with HER2-positive metastatic breast cancer. Results will be presented today during a special late-breaking oral session at the 2025 American Society of Clinical Oncology Annual Meeting in Chicago, IL. In a prespecified interim analysis, ENHERTU plus pertuzumab reduced the risk of disease progression or death by 44% versus THP. Median PFS was 40.7 months with ENHERTU plus pertuzumab compared to 26.9 months for THP, as assessed by blinded independent central review. The PFS benefit for ENHERTU plus pertuzumab versus THP was consistent across subgroups, including for the prespecified stratification factors of de novo or recurrent disease, hormone receptor status and PIK3CA mutation status.