Japanese healthcare company Daiichi Sankyo Co Ltd (TYO:4568) announced on Thursday that the European Medicines Agency has validated a Type II variation application for Enhertu (trastuzumab deruxtecan) as monotherapy for adults with HER2-positive early breast cancer with residual invasive disease after neoadjuvant therapy.

Enhertu is an antibody drug conjugate discovered by Daiichi Sankyo and jointly developed and commercialised with AstraZeneca plc (STO:AZN) (LON:AZN) (Nasdaq:AZN). Validation confirms dossier completeness and initiates scientific review by the EMA's Committee for Medicinal Products for Human Use.

The filing is based on the Phase 3 DESTINY-Breast05 trial, in which Enhertu reduced the risk of invasive disease recurrence or death by 53% versus trastuzumab emtansine (T-DM1) in patients with residual invasive disease following neoadjuvant treatment. Results were presented at the 2025 European Society for Medical Oncology Congress and published in The New England Journal of Medicine.

If approved, Enhertu could become a new standard of care in this early breast cancer setting. Additional EU submissions are underway, including combinations and indications in metastatic HER2-positive and previously treated solid tumours.