Checkpoint Inhibitor Pneumonitis - a Tertiary Centres Experience

Introduction: Immune checkpoint inhibitors (ICIs) have transformed outcomes in several cancers including melanoma. Patients on ICIs are at risk of immune related adverse events (ir-AEs). Checkpoint inhibitor Pneumonitis (CIP) is an uncommon but potentially life-threatening ir-AE. Little evidence exists to guide management. We present our experience managing CIP in a tertiary interstitial lung disease (ILD) service. Methods: We retrospectively reviewed electronic case notes and imaging of consecutive patients diagnosed with CIP between July 2020 to December 2022. Results: The most common CT appearances were diffuse ground glass opacification followed by organising pneumonia. 7 patients (27%) had new radiological changes consistent with CIP but were asymptomatic. Pre-existing ILD was present in 8 patients (31%) and 14 patients (53%) had a history of previous irAEs. Combination ICIs were used in 7 patients (27%). Mycophenolate mofetil was used as a steroid sparer in 23% of patients. There were 4 ICI toxicity related deaths (15%). Conclusion: CIP can manifest later than previously described and commonly occurs alongside other irAEs. Treatment often involves a prolonged steroid course. More studies are needed to evaluate the role of steroid sparing agents.