Considering the limited evidence for the efficacy and safety of T-DXd for the treatment of previously treated HER2-positive advanced gastric cancer patients when this expanded-access study was initiated, this expanded-access study was conducted with most of the same eligibility criteria set in the phase II DG-01 trial regarding bone marrow, renal, hepatic, cardiac function, and performance status [18]. The gene discussed is ERBB2; the disease is gastric cancer.