Jinyu Yu,1,2,* Xuanjun Liu,3,4,* Xingjiao Ma,4,5 Li Liang,1,2 Yan’e Liu,1,2 Wencheng Yin,1,2 Qian Li,1,2 Baoshan Cao,1,2 Wei Liu4 

1Department of Medical Oncology and Radiation Sickness, Peking University Third Hospital, Beijing, 100191, People’s Republic of China; 2Cancer Center, Peking University Third Hospital, Beijing, 100191, People’s Republic of China; 3Department of Pharmacy, Guangxi Academy of Medical Sciences and the People’s Hospital of Guangxi Zhuang Autonomous Region, Nanning, Guangxi, 530021, People’s Republic of China; 4Department of Pharmacy, Peking University Third Hospital, Beijing, 100191, People’s Republic of China; 5Department of Pharmacy, Peking University International Hospital, Beijing, 102206, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Baoshan Cao, Email caobaoshan0711@aliyun.com Wei Liu, Email liuwei0023@bjmu.edu.cn

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.

Keywords: immune checkpoint inhibitors, corticosteroid-refractory, pneumonitis, mycophenolate mofetil