ERBB2 and breast cancer: Based on breast cancer findings [54], the efficacy of T-DXd in HER2 low tumours was explored in the DESTINY-Gastric01 trial (cohort 1 included 19 patients with a central confirmed IHC 2+/ISH–negative HER2 status and cohort 2 included 21 patients with IHC 1+ status) [55].