Immune checkpoint inhibitor-related pneumonitis(CIP)is a relatively common immune-related adverse event.The current treatment for CIP mainly relies on glucocorticoids,with 70％～80％of patients being controlled by conventional glucocorticoid therapy.However,steroid-unresponsive CIP is often se-vere and can be life-threatening.There is no standard treatment protocol for steroid-unresponsive CIP,highlighting a significant unmet clinical need.This paper reviews the diagnosis,treatment progress,and exploratory research of steroid-unresponsive CIP to provide evidence-based guidelines and directions for clinical and translational research.

Immune checkpoint inhibitor-related pneumonitis(CIP)is a relatively common immune-related adverse event.The current treatment for CIP mainly relies on glucocorticoids,with 70％～80％of patients being controlled by conventional glucocorticoid therapy.However,steroid-unresponsive CIP is often se-vere and can be life-threatening.There is no standard treatment protocol for steroid-unresponsive CIP,highlighting a significant unmet clinical need.This paper reviews the diagnosis,treatment progress,and exploratory research of steroid-unresponsive CIP to provide evidence-based guidelines and directions for clinical and translational research.

A 56-year-old male patient with nasopharyngeal carcinoma had progressed disease after receiving radiotherapy, chemotherapy, and targeted therapy, etc. Then he received chemotherapy combined with immunotherapy (capecitabine and sintilimab). Before receiving the 3rd immunotherapy, no abnormality was found in the relevant examination in the patient. On the 3rd day of treatment, he developed cough, shortness of breath, and other symptoms, and chest CT imaging indicated inflammatory lesion of both lungs. The results of sputum culture, sputum smear examination, G test, GM test, and autoantibody examination were all negative. Infectious pneumonia and interstitial pneumonia with autoimmune features were excluded. The common respiratory adverse reaction to capecitabine was pharyngeal discomfort, and no large-scale pneumonia caused by capecitabine was reported. Therefore, it was considered to be immune-associated pneumonitis cause by sintilimab. Treatments such as intravenous injection of methylprednisolone, IV infusion of cefoperazone sodium and sulbactam sodium and moxifloxacin were given and the patient′s condition was improved. After that, methylprednisolone dose was gradually reduced, and then changed to oral prednisone. On the 10th day of oral prednisone, the symptom of shortness of breath worsened. Chest CT imaging indicated that the pneumonitis was more severe than before. Intravenous methylprednisolone was re-given but the condition was not improved.

A 56-year-old male patient with nasopharyngeal carcinoma had progressed disease after receiving radiotherapy, chemotherapy, and targeted therapy, etc. Then he received chemotherapy combined with immunotherapy (capecitabine and sintilimab). Before receiving the 3rd immunotherapy, no abnormality was found in the relevant examination in the patient. On the 3rd day of treatment, he developed cough, shortness of breath, and other symptoms, and chest CT imaging indicated inflammatory lesion of both lungs. The results of sputum culture, sputum smear examination, G test, GM test, and autoantibody examination were all negative. Infectious pneumonia and interstitial pneumonia with autoimmune features were excluded. The common respiratory adverse reaction to capecitabine was pharyngeal discomfort, and no large-scale pneumonia caused by capecitabine was reported. Therefore, it was considered to be immune-associated pneumonitis cause by sintilimab. Treatments such as intravenous injection of methylprednisolone, IV infusion of cefoperazone sodium and sulbactam sodium and moxifloxacin were given and the patient′s condition was improved. After that, methylprednisolone dose was gradually reduced, and then changed to oral prednisone. On the 10th day of oral prednisone, the symptom of shortness of breath worsened. Chest CT imaging indicated that the pneumonitis was more severe than before. Intravenous methylprednisolone was re-given but the condition was not improved.