In the DESTINY‐Breast09 trial, combining T‐DXd with pertuzumab significantly prolonged progression‐free survival (median 40.7 vs. 26.9 months) compared with standard first‐line therapy (taxane plus trastuzumab and pertuzumab) in patients with metastatic HER2‐positive breast cancer [42]. The gene discussed is ERBB2; the disease is breast carcinoma.