ABSTRACT Trastuzumab deruxtecan (T‐DXd) is a HER2‐targeted antibody–drug conjugate with proven efficacy in metastatic breast cancer, but interstitial lung disease (ILD) and drug‐induced pneumonitis are potentially life‐threatening toxicities. We retrospectively reviewed three patients with HER2‐positive metastatic breast cancer treated with T‐DXd at a tertiary hospital in Saudi Arabia who subsequently developed pneumonitis. Pneumonitis developed after 2–9 cycles of T‐DXd, presenting with cough, dyspnea, and ground‐glass opacities. All patients received corticosteroids and required permanent discontinuation. Early recognition and multidisciplinary management of T‐DXd‐induced pneumonitis are essential. Clinicians should monitor respiratory symptoms and apply timely corticosteroid therapy.
Alhuthali et al. (Sun,) studied this question.