Researchers have announced information revealing how patients with metastatic breast cancer develop resistance to the treatment Enhertu (trastuzumab deruxtecan, T-DXd) in Nature’s npj Breast Cancer journal. Main data that support the findingsThe research identified two primary genetic predictors that influence how long a patient with breast cancer may survive while being treated with Enhertu. Trial detailsThe study utilized an expansive real-world clinico-genomic database to perform a population-level analysis of 2,799 patients with breast cancer who were treated with Enhertu. Scientists used a statistical method called multivariate Cox proportional hazards to analyze a cohort of patients with breast cancer. In patients where samples were collected before starting Enhertu treatment, they measured how ERBB2 and ABCC1 expression levels impacted survival.