Successful Rechallenge of Trastuzumab Deruxtecan After Drug-Induced Interstitial Lung Disease in a NSCLC With HER2 Mutation: A Case Report.

Trastuzumab deruxtecan, an antibody-drug conjugate targetingHER2-expressing tumor cells, was found to have promising results in treatment-refractory, metastatic NSCLC harboring HER2 mutations. Nevertheless, drug-induced interstitial lung disease (ILD)/pneumonitis is a concern that limits treatment response in this subset of patients. For grade 2 or more ILD/pneumonitis, permanent discontinuation is warranted with vigorous treatment with high-dose steroid. We report a case of successful rechallenge of trastuzumab deruxtecan after recovery of grade 3 ILD/pneumonitis in treatment-refractory NSCLC harboring ERBB2 Y772-A775dup.