AstraZeneca and Daiichi’s Datroway gets phase III breast cancer boost

Dividing breast cancer cell

Datroway (datopotamab deruxtecan) has become the first oncology drug to significantly improve overall survival compared to chemotherapy in an aggressive form of invasive breast cancer.

The late-stage clinical trial results will boost AstraZeneca and Daiichi Sankyo’s ambitions to position the antibody drug conjugate (ADC) drug as a first-line treatment, following its European approval for breast cancer in April.

In the phase III TROPION-Breast02 study Datroway showed statistically significant and clinically meaningful improvement in overall survival when given to patients with metastatic triple-negative breast cancer (TNBC) for whom immunotherapy was not an option.

The drug was also able to demonstrate a highly statistically significant and clinically meaningful improvement in the dual primary endpoint of progression-free survival.

Susan Galbraith, Executive Vice President, Oncology Haematology R&D at AstraZeneca, said: “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.”

The TROPION-Breast02 study involved 644 patients enrolled at sites in Africa, Asia, Europe, North America and South America. It saw Datroway compared to investigator’s choice of chemotherapy as first-line treatment for patients with locally recurrent inoperable or metastatic TNBC for whom immunotherapy was not an option.

Some 70 percent of patients with metastatic TNBC are unable to be treated with immunotherapy, including all patients whose tumours do not express PD-L1 as well as patients with PD-L1 expressing tumours who cannot receive immunotherapy due to other factors.

Ken Takeshita, Global Head of R&D at Daiichi Sankyo, said: “These landmark results from TROPION-Breast02 strengthen our confidence in our ongoing clinical development programme for Datroway in triple-negative breast cancer and other tumour types.”

An engineered TROP2-directed DXd ADC, Datroway was discovered by Daiichi Sankyo and is being jointly developed and commercialised by both companies under their $6 billion 2020 agreement. That deal sought to build on the partners’ success with the HER2-targeting ADC Enhertu, which made sales of $3.8 billion in 2024.

Datroway is also being evaluated in three phase III trials that combine it with Imfinzi (durvalumab)across multiple stages and treatment settings of TNBC.

To date the drug’s licenses includes a European one to treat metastatic HR-positive, HER2-negative breast cancer and FDA approvals for previously treated HR+/HER2- breast cancer and for metastatic EGFR-mutated non-small cell lung cancer.