The safety of T-DXd was evaluated in a pooled analysis of 234 patients with HER2-positive breast cancer who received at least one dose of T-DXd 5.4 mg/kg in the DESTINY-Breast01 (NCT03248492), and in the phase 1 trial DS8201-A-J101 (NCT02564900) [9,10,22]. The gene discussed is ERBB2; the disease is breast cancer.