AstraZeneca and Daiichi Sankyo have announced breakthrough results from the Phase III TROPION-Breast02 trial, showing that their antibody drug conjugate Datroway (datopotamab deruxtecan) significantly improved overall survival and progression-free survival in patients with metastatic triple-negative breast cancer (TNBC) who are not eligible for immunotherapy.
These results make Datroway the first and only therapy to demonstrate a survival advantage over standard chemotherapy in this high-risk patient population, marking a major advancement in treatment for a cancer type known for limited therapeutic options and poor prognosis.
TROPION-Breast02 compared Datroway to chemotherapy as a first-line treatment in patients with locally recurrent inoperable or metastatic TNBC who could not receive immunotherapy. The study met both of its dual primary endpoints—overall survival (OS) and progression-free survival (PFS)—with highly statistically significant and clinically meaningful improvements over chemotherapy.
“TROPION-Breast02 is the only trial ever to show an overall survival benefit in the first-line treatment of patients with metastatic triple-negative breast cancer for whom immunotherapy is not an option,” said Susan Galbraith, Executive Vice President of Oncology R&D at AstraZeneca. “We expect today’s results will mark an inflection point in the treatment of these patients who have the poorest prognosis of any type of breast cancer and urgently need better options.”
Triple-negative breast cancer accounts for approximately 15% of all breast cancer cases but is one of the most aggressive and difficult to treat, especially for the roughly 70% of patients with metastatic disease who are not eligible for immunotherapy. Current standard of care for this group remains chemotherapy, which is often associated with limited efficacy and significant side effects.
Ken Takeshita, Global Head of R&D at Daiichi Sankyo, emphasized the significance of the findings: “Datroway is the first antibody drug conjugate and the only therapy to significantly improve overall survival compared to chemotherapy in patients with metastatic triple-negative breast cancer for whom immunotherapy is not an option. These landmark results strengthen our confidence in the ongoing development programme for Datroway in TNBC and other tumour types.”
The safety profile of Datroway was consistent with previous trials in breast cancer. Full data from the study will be presented at an upcoming medical conference and submitted to regulatory authorities.
Datroway is a TROP2-directed DXd antibody drug conjugate developed by Daiichi Sankyo and co-developed and commercialised in partnership with AstraZeneca. The drug is also being evaluated in several other Phase III trials across various stages and treatment settings of TNBC, including combinations with AstraZeneca’s checkpoint inhibitor Imfinzi (durvalumab).
With these results, AstraZeneca and Daiichi Sankyo are expected to move forward with global regulatory filings, potentially bringing a new and much-needed treatment option to patients facing one of the most challenging forms of breast cancer.