In this sense, co-targeting HER2 and ER may therefore help to optimize survival outcomes for patients with HER2+, ER+ BC; the heredERA BC study is aiming to address this unmet need by evaluating the combination of PH FDC SC with giredestrant as maintenance therapy, following an induction phase of PH FDC SC and a taxane. This evidence concerns the gene ESR1 and breast cancer.