Preliminary evidence shows that T-DXd has clinical activity in an exploratory cohort of patients with low HER2 (IHC 2+/ISH− or IHC 1+) G/GEJ adenocarcinoma who did not receive anti-HER2 treatment in the DESTINY-Gastric01 trial [53]. This evidence concerns the gene ERBB2 and gastroesophageal junction adenocarcinoma.