Recurrent Checkpoint Inhibitor-Related Pneumonitis Refractory to Corticosteroid Treatment: A Case Report and Literature Review.

Background: Immune checkpoint inhibitors (ICIs) are antibodies that activate the immune system to kill tumor cells and have been widely used in oncology. However, dysregulated immune activation may result in the attack of normal tissues and organs, leading to immune-related adverse events (irAEs). Corticosteroid-refractory irAE pneumonitis severely threatens patient survival and is characterized by a lack of high-level evidence-based management guidelines, highlighting the need for increased scrutiny in this area.

Case presentation: This article presents the diagnosis and treatment of a patient with lung squamous cell carcinoma who developed recurrent corticosteroid-refractory grade 3 checkpoint inhibitor- related pneumonitis (CIP) during treatment with the ICI tislelizumab. The management approach included the use of intravenous immunoglobulin (IVIG) and mycophenolate mofetil (MMF). The case is thoroughly analyzed and discussed, accompanied by a review of relevant literature.

Conclusion: IVIG and MMF showed effectiveness in corticosteroid-refractory CIP, and further investigation is warranted to establish standardized guideline and to optimize therapeutic drug monitoring for immunosuppressive agents.