In the phase 2 DESTINY-Lung01 trial evaluating T-DXd in HER2-overexpressing NSCLC patients, there was an incidence of 20% for all-grade pneumonitis, with grade 3 or higher events in 6% of patients, including three deaths attributable to drug-related pneumonitis in patients treated with the 6.4 mg/kg dose (cohort 1) [41]. The gene discussed is ERBB2; the disease is pneumonitis.