Supporting this, an ongoing phase II, open-label, single arm trial aimed at evaluating the efficacy and safety of T-Dxd in Western GC patients progressed with a trastuzumab-containing regimen (DESTINY-Gastric02, NCT04014075) required patients to be re-tested for HER2 positivity before being treated with T-Dxd. The gene discussed is ERBB2; the disease is gastric cancer.