By Fineline Cube 
AstraZeneca (AZ, NASDAQ: AZN) and Daiichi Sankyo (TYO: 4568) disclosed the Phase III DESTINY‑Breast11 results at the 2025 European Society for Medical Oncology (ESMO) Congress. The study demonstrated that Enhertu (trastuzumab deruxtecan, T‑DXd), administered sequentially to the THP regimen (paclitaxel, trastuzumab, pertuzumab) as a neoadjuvant therapy, produced a clinically meaningful 11.2 % rise in pathological complete response (pCR) rates.
Study Highlights
| Metric | T‑DXd + THP | ddAC‑THP (Control) | Δ |
|---|---|---|---|
| pCR rate | 67.3 % | 56.3 % | +11.2 % |
| HR⁺ subgroup | 61.4 % | 52.3 % | +9.1 % |
| HR⁻ subgroup | 83.1 % | 67.1 % | +16.0 % |
| Residual Cancer Burden 0 + I | 81.3 % | 69.1 % | +12.2 % |
- Overall improvement: 67.3 % vs. 56.3 % pCR.
- Subgroup benefit: Significant gains seen in both hormone‑receptor positive and negative cohorts.
- Post‑surgery outcome: 81.3 % of the T‑DXd arm achieved RCB 0 + I versus 69.1 % in the control arm.
About Enhertu (T‑DXd)
- Mechanism: HER2‑targeting antibody‑drug conjugate (ADC) combining a humanized anti‑HER2 mAb with the topoisomerase‑I inhibitor DXd via a cleavable tetrapeptide linker.
- Technology: Built on Daiichi Sankyo’s proprietary DXd ADC platform; the most advanced ADC in AstraZeneca’s oncology pipeline.
- Global Approval: Licensed in >85 countries for HER2‑positive metastatic or early‑stage breast cancer after ≥1 prior anti‑HER2 therapy.
Implications for Clinical Practice
- Neoadjuvant Advantage: The higher pCR rate suggests a stronger likelihood of long‑term disease control.
- Broad Applicability: Benefit spans HR‑positive and HR‑negative disease, supporting use across the HER2‑positive spectrum.
- Strategic Collaboration: Demonstrates the synergistic potential of combining AstraZeneca’s ADC platform with Daiichi Sankyo’s drug‑delivery expertise.
Forward‑Looking Statements
This release contains forward‑looking statements that involve risks and uncertainties. Actual results may differ materially.-Fineline Info & Tech