The DESTINY-Lung01 phase 2 multicentre trial enrolled a total of 49 HER2-overexpressing NSCLC patients in cohort 1 (6.4 mg/kg of T-DXd) and reported 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 lung disease [41]. Here, ERBB2 is linked to pneumonitis.