A Case Report of Checkpoint Inhibitor Pneumonitis Caused by PD-1 Antibody-Safety and Effectiveness of Pirfenidone

Background and objective Immune checkpoint inhibitor associated pneumonia (CIP) is a serious side effect of immune checkpoint inhibitors. There is a consensus on the treatment of acute phase of CIP, but the treatment of pulmonary interstitial fibrosis after the acute phase is still a clinical problem to be solved. Methods The diagnosis and treatment of a non-small cell lung cancer (NSCLC) patient with immune checkpoint inhibitor associated pneumonia in the Stereotactic Radiotherapy Department of Qingdao Central Hospital were retrospectively analyzed, and literatures were reviewed. Results A 70-year-old male patient was diagnosed with Poorly differentiated squamous cell carcinoma of left lung with mediastinal lymph node metastasis T3N3M0 stage IIIc, EGFR/ALK/ROS1/RAF negative, PD-L1 (22c3) immunohistochemistry negative. After the progression of first-line chemotherapy, the patient was diagnosed as immune checkpoint inhibitor associated pneumonia grade 3 during second-line monotherapy with Nivolumab. After initial high-dose glucocorticoid pulse therapy, the lung computed tomography (CT) imaging and clinical symptoms of the patients were partially relieved, and then pirfenidone (300 mg tid) was given orally for more than 11 months. During the treatment of pirfenidone, the CT imaging and clinical symptoms of the patients were significantly improved, and there were no other adverse reactions except grade 1 nausea. During this period, chemotherapy and Anlotinib was given concurrently with pirfenidone and showed good safety profile. Conclusion This case report is the first report of pirfenidone in the treatment of CIP, which provides a new idea for the clinical practice and research of CIP treatment.