Daiichi SankyoDaiichi Sankyo announced that the first patient was dosed in the global TROPION-Breast02 phase 3 trial evaluating the efficacy and safety of datopotamab deruxtecan (Dato-DXd) versus investigator's choice of chemotherapy in patients with previously untreated locally recurrent inoperable or metastatic triple negative breast cancer (TNBC) not eligible to receive PD-1/PD-L1 inhibitor therapy. Datopotamab deruxtecan is a specifically designed TROP2 directed DXd antibody drug conjugate (ADC) being jointly developed by Daiichi Sankyo and AstraZeneca. Approximately 10 to 15% of breast cancers are considered triple negative, the most aggressive subtype of breast cancer.

Compared to patients with other breast cancer subtypes, the prognosis for patients with metastatic TNBC is generally worse, with five-year survival rates estimated at 12% and median overall survival generally less than two years. TNBC is defined by tumors that test negative for estrogen and progesterone hormone receptors (HRs) as well as human epidermal growth factor 2 receptor (HER2), as determined by an IHC test and/or an ISH test; HER2 negative cancers are currently defined as IHC 0, IHC 1+ or IHC 2+/ISH-.