WILMINGTON, DE — AstraZeneca and Daiichi Sankyo reported breakthrough results from the Phase III DESTINY-Breast05 trial, showing that their drug ENHERTU (fam-trastuzumab deruxtecan-nxki) cut the risk of disease recurrence or death by 53% compared with the current standard therapy, T-DM1, in patients with high-risk HER2-positive early breast cancer following neoadjuvant treatment.
The findings, unveiled during the European Society for Medical Oncology’s 2025 Congress, mark a major advance for patients who face a heightened risk of recurrence after initial therapy. At three years, 92.4% of patients receiving ENHERTU remained free of invasive disease versus 83.7% of those treated with T-DM1.
“For patients with residual disease after neoadjuvant treatment, this represents a critical second opportunity to prevent relapse,” said Dr. Charles Geyer of the UPMC Hillman Cancer Center and principal investigator for the study. “The data suggest ENHERTU could redefine post-surgical care for HER2-positive breast cancer.”
The study’s secondary endpoints also favored ENHERTU, which demonstrated a 51% reduction in distant recurrence and a 36% reduction in the risk of brain metastases. Overall survival data remain immature but trend in favor of the drug.
Safety results were consistent with prior studies, with Grade 3 or higher adverse events comparable between treatment arms (50.6% for ENHERTU versus 51.9% for T-DM1). Interstitial lung disease occurred in fewer than 10% of patients treated with ENHERTU, with most cases classified as mild.
AstraZeneca’s executive vice president for oncology R&D, Dr. Susan Galbraith, described the findings as “landmark data” that could establish ENHERTU as a foundational therapy in early-stage breast cancer.
The antibody-drug conjugate, jointly developed by AstraZeneca and Daiichi Sankyo, is already approved in multiple metastatic settings and is being studied across a range of HER2-driven cancers, including lung, gastric, and colorectal tumors.
With these results, ENHERTU could soon move from treating advanced disease to becoming a standard therapy in early-stage, curative-intent breast cancer — a shift with the potential to improve survival outcomes for thousands of patients worldwide.
Support the local news that supports Chester County. MyChesCo delivers reliable, fact-based reporting and essential community resources—free for everyone. If you value that, click here to become a patron today.