Pembrolizumab-induced pneumonitis

Immune checkpoint inhibitors are promising new therapies for advanced cancers. In particular, antibodies against programmed cell death 1 (PD-1), such as nivolumab and pembrolizumab, increase anti-tumour T cell responses by blocking the interaction between PD-1 on T cells and its ligand PD-L1 on cancer cells [1]. Enhanced T-cell responses resulting from checkpoint inhibition can lead to an unusual spectrum of side effects called immune-related adverse events, which involve numerous organs, particularly the skin, liver, and gastrointestinal and endocrine systems [2–11]. Pneumonitis is a potentially lethal side effect of immune checkpoint inhibition, occurring in 1–5% of patients enrolled in trials [2–11]. However, little is known about the clinical and radiological features of checkpoint inhibitor-induced lung disease. Here, we report three cases of pembrolizumab-induced acute interstitial lung disease (ILD). The medical data of the patients presented below were collected in accordance with French regulations, none of which was opposed to their uses. Three cases of pembrolizumab-induced pneumonitis are described, two being consistent with organising pneumonia