The European Medicines Agency (EMA) has validated the Type II Variation marketing authorization application for ENHERTU^® (trastuzumab deruxtecan) as a monotherapy for adult patients with HER2 positive (immunohistochemistry [IHC] 3+ or in-situhybridization [ISH]+) breast cancer who have residual invasive disease after neoadjuvant HER2 targeted treatment.

ENHERTU is a specifically engineered HER2 directed DXd antibody drug conjugate (ADC) discovered by Daiichi Sankyo (TSE: 4568) and being jointly developed and commercialized by Daiichi Sankyo and AstraZeneca (LSE/STO/NYSE: AZN).

The validation confirms the completion of the application and commences the scientific review process by the EMA’s Committee for Medicinal Products for Human Use (CHMP). The application is based on data from the DESTINY-Breast05 phase 3 trial presented at the 2025 European Society for Medical Oncology (#ESMO25) Congress and subsequently published in The New England Journal of Medicine. In the trial, ENHERTU demonstrated a statistically significant and clinically meaningful improvement in invasive disease-free survival (IDFS) versus trastuzumab emtansine (T-DM1) in patients with HER2 positive breast cancer with residual invasive disease following neoadjuvant therapy.

“Patients who have residual invasive disease despite neoadjuvant therapy face a heightened risk of recurrence and are in need of better options following neoadjuvant treatment and surgery,” said Ken Takeshita, MD, Global Head, R&D, Daiichi Sankyo. “This validation in the EU is an important step toward bringing ENHERTU to eligible patients earlier in the treatment journey to help reduce the risk of disease recurrence and progression to metastatic disease.”

Additional regulatory submissions for ENHERTU also are underway in the EU, including in combination with pertuzumab for the first-line treatment of adult patients with unresectable or metastatic HER2 positive breast cancer based on data from DESTINY-Breast09 and for previously treated HER2 positive unresectable or metastatic solid tumors based on data from DESTINY-PanTumor02, DESTINY-CRC02 and DESTINY-Lung01.