Japanese healthcare company Daiichi Sankyo Co Ltd (TYO:4568) and British-Swedish biopharmaceutical company AstraZeneca plc (STO:AZN) (LON:AZN) (Nasdaq:AZN) on Monday reported positive topline results from the phase 3 DESTINY-Breast05 trial of ENHERTU (trastuzumab deruxtecan).

The antibody drug conjugate demonstrated a highly statistically significant and clinically meaningful improvement in invasive disease-free survival compared with trastuzumab emtansine (T-DM1) in patients with high-risk HER2 positive early breast cancer following neoadjuvant therapy.

This marks the second positive phase 3 trial for ENHERTU in this setting, following results from the DESTINY-Breast11 study earlier this year. Both datasets will be presented at the ESMO 2025 Presidential Symposium.

Overall survival was not mature at the interim analysis and will be assessed at a later time. The safety profile observed in DESTINY-Breast05 was consistent with prior data, with no new concerns identified.

Regulatory submissions are planned, with ENHERTU positioned to potentially become a foundational curative-intent treatment for HER2 positive early breast cancer. The trial was conducted in collaboration with the National Surgical Adjuvant Breast and Bowel Project Foundation (NSABP), the German Breast Group (GBG), Arbeitsgemeinschaft Gynäkologische Onkologie (AGO-B), and SOLTI Breast Cancer Research Group.