AstraZeneca (AZ) and Daiichi Sankyo have shared positive results from a late-stage study of their HER2-directed antibody drug conjugate (ADC) Enhertu (trastuzumab deruxtecan) in a subset of early-stage breast cancer patients.
The phase 3 DESTINY-Breast11 trial has been evaluating the drug followed by paclitaxel, trastuzumab and pertuzumab (THP) against standard of care (SOC), dose-dense doxorubicin and cyclophosphamide followed by THP, in patients with high-risk, locally advanced HER2-positive early-stage breast cancer.
The Enhertu regimen demonstrated a statistically significant and clinically meaningful improvement in the rate of pathologic complete response (pCR), defined as no evidence of invasive cancer cells in the removed breast tissue and lymph nodes following treatment, compared to SOC.
Achieving pCR in early-stage HER2-positive breast cancer leads to improved long-term outcomes, however, many patients who receive neoadjuvant treatment with SOC combination chemotherapy regimens do not achieve this.
Event-free survival data also showed an early positive trend favouring the Enhertu regimen, but this was not mature at the time of analysis and will continue to be assessed.
Additionally, the Enhertu regimen was associated with an improved safety profile compared to SOC, with the profiles of Enhertu and THP found to be consistent with the known profiles of each individual medicine.
Breast cancer is the second most common cancer worldwide, and around one in three patients with early-stage cases of the disease are considered high risk.
Already approved to treat certain breast cancer patients in the metastatic setting, Enhertu is designed to target HER2, a tyrosine kinase receptor growth-promoting protein expressed on the surface of many tumours types.
Susan Galbraith, executive vice president, oncology haematology research and development (R&D), AZ, said: “Enhertu is already an important treatment option in the metastatic setting, and this data has the potential to allow this medicine to move into early stages of disease where cure is possible.”
Sharing a similar sentiment, Ken Takeshita, global head, R&D, Daiichi Sankyo, said: “These top-line results from DESTINY-Breast11 demonstrate that Enhertu followed by THP could offer patients with HER2-positive breast cancer a promising new treatment approach prior to surgery, setting more patients on a path towards a potential cure.”
Data from the trial will be presented at an upcoming medical meeting and shared with regulatory authorities, the partners outlined.