T-DXd had an ORR of 55% in advanced HER2-mutant NSCLC with a median PFS of 8.2 months (95% CI, 6.0–11.9 months) and a median OS of 17.8 months (95% CI, 13.8–22.1 months). The gene discussed is ERBB2; the disease is non-small cell lung carcinoma.