WILMINGTON, DE — AstraZeneca and Daiichi Sankyo reported that their antibody-drug conjugate ENHERTU® (fam-trastuzumab deruxtecan-nxki), when used before surgery and followed by standard therapy, achieved a pathologic complete response in 67 percent of patients with high-risk HER2-positive early-stage breast cancer. The findings come from the DESTINY-Breast11 Phase III trial and were presented at the European Society for Medical Oncology (ESMO) 2025 Congress in Berlin.
The trial compared ENHERTU followed by paclitaxel, trastuzumab, and pertuzumab (THP) against the standard regimen of dose-dense doxorubicin and cyclophosphamide followed by THP. Results showed an 11.2 percent improvement in complete response rates, marking the highest seen in a Phase III study for HER2-positive early breast cancer with a favorable safety profile.
“For patients with early breast cancer who are at high risk of recurrence, using the most effective treatment at the earliest opportunity is critical,” said Dr. Nadia Harbeck, Director of the Breast Center at LMU University Hospital in Munich and principal investigator of the trial. “In this study, more than two-thirds of patients achieved a pathologic complete response with trastuzumab deruxtecan followed by THP, suggesting a potential new standard of care in the neoadjuvant setting.”
The trial also reported improvements across both hormone receptor–positive and –negative subgroups, with corresponding rates of 61.4 and 83.1 percent compared with 52.3 and 67.1 percent in the control arm. Additionally, 81.3 percent of patients who received ENHERTU followed by THP had no or minimal residual invasive cancer detected after surgery, compared with 69.1 percent in the comparator group.
“The impressive pathologic response rates and favorable safety profile seen with ENHERTU followed by THP have the potential to transform treatment in the neoadjuvant setting,” said Dr. Susan Galbraith, Executive Vice President of Oncology R&D at AstraZeneca. “These results reinforce the importance of bringing ENHERTU into earlier stages of HER2-positive disease.”
Ken Takeshita, Global Head of R&D at Daiichi Sankyo, emphasized the significance of these outcomes, noting that the regimen represents the first in over a decade to significantly improve results for patients with early-stage HER2-positive breast cancer.
The safety profile for ENHERTU followed by THP was consistent with previous data and demonstrated fewer serious and high-grade adverse events compared with standard chemotherapy. Incidences of interstitial lung disease were low and similar between treatment groups.
A supplemental Biologics License Application for ENHERTU followed by THP is now under review by the U.S. Food and Drug Administration.
AstraZeneca and Daiichi Sankyo described the results as reinforcing ENHERTU’s potential to become a foundational treatment in curative-intent early breast cancer therapy, extending its role beyond metastatic disease and positioning it as a cornerstone in HER2-targeted oncology care.
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