Daiichi Sankyo Company, Limited (TYO: 4568) announced that Enhertu (trastuzumab deruxtecan) has been approved for a new indication in the European Union (EU) as a monotherapy for the adjuvant treatment of adult patients with resected HER2-positive (immunohistochemistry [IHC] 3+ or in-situ hybridization [ISH]+) breast cancer who have residual invasive disease after neoadjuvant taxane-based and HER2-targeted treatment.
Regulatory Milestone
| Item | Detail |
|---|---|
| Agency | European Union (EU), following positive CHMP opinion (EMA) |
| Approval Type | New indication – adjuvant monotherapy |
| Product | Enhertu (trastuzumab deruxtecan), HER2-directed DXd ADC |
| Indication | Adjuvant treatment of adult patients with resected HER2-positive (IHC 3+ or ISH+) breast cancer with residual invasive disease after neoadjuvant taxane-based and HER2-targeted treatment |
| Approval Date | Announced 27 Oct 2026 |
| Pivotal Evidence | DESTINY-Breast05 Phase 3 trial |
| Partners | Discovered by Daiichi Sankyo; jointly developed and commercialized with AstraZeneca (LSE/STO/NYSE: AZN) |
Drug Profile
- Modality: Enhertu is a specifically engineered HER2-directed DXd antibody-drug conjugate (ADC).
- Discovery & Partnership: Discovered by Daiichi Sankyo and jointly developed and commercialized by Daiichi Sankyo and AstraZeneca.
- Setting: The approval moves Enhertu into the adjuvant (post-surgical) setting for patients at elevated relapse risk due to residual invasive disease after neoadjuvant therapy.
Clinical Evidence – DESTINY-Breast05 Phase 3 Trial
| Endpoint | Enhertu | Comparator (T-DM1) | Relative Benefit |
|---|---|---|---|
| Risk of Invasive Disease Recurrence or Death | – | – | 53% reduction vs. T-DM1 |
| Three-Year IDFS Rate | 92.4% | 83.7% | +8.7 percentage points |
In the DESTINY-Breast05 trial in patients with HER2-positive breast cancer with residual invasive disease following neoadjuvant therapy, Enhertu significantly reduced the risk of invasive disease recurrence or death by 53% compared with trastuzumab emtansine (T-DM1), the prior standard of care in this setting, and demonstrated a three-year invasive disease-free survival (IDFS) rate of 92.4% versus 83.7% in the T-DM1 arm.
Market Impact & Outlook
- Standard-of-Care Shift: By displacing T-DM1 in the adjuvant setting, the approval positions Enhertu as a new benchmark for high-risk, resected HER2-positive breast cancer patients with residual disease after neoadjuvant treatment.
- Lifecycle Expansion: The new EU adjuvant indication broadens Enhertu’s footprint across earlier lines of treatment, extending the commercial runway for the Daiichi Sankyo–AstraZeneca franchise.
- Regulatory Pathway: The approval follows a positive opinion from the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA).
- Commercial Outlook: Launch timing across EU member states, pricing, and reimbursement details were not disclosed in the announcement.
Forward‑Looking Statements
This brief contains forward‑looking statements regarding the commercialization, market adoption, and reimbursement of Enhertu in the EU adjuvant breast cancer setting, as well as ongoing development activities by Daiichi Sankyo and AstraZeneca. Actual results may differ materially due to risks including national pricing and reimbursement decisions, competitive dynamics in HER2-targeted therapy, and evolving clinical guidelines.-Fineline Info & Tech
