Supplementary Material for: Lethal immune-related pneumonitis after durvalumab therapy for small cell lung cancer: a first case in China

Introduction: Although programmed death ligand 1 (PD-L1) inhibitor plus chemotherapy regimen is a promising strategy for malignant tumors, it can induce significant immune-related adverse events, such as immune-related pneumonitis. Here we report the first case of lethal immune-related pneumonitis in an Asian patient receiving anti-PD-L1 treatment. Case presentation: A 68-year-old man was diagnosed with small cell lung cancer and interstitial pneumonia. After his pulmonary infection was relieved by comprehensive treatment, the patient received first-line treatment with durvalumab plus etoposide and carboplatin. Two weeks after starting durvalumab treatment, the patient had chest pain and shortness of breath. He was diagnosed with immune-induced pneumonia and treated with methylprednisolone, cefoperazone and sulbactam, followed by oxygen and pirfenidone. Oxygen partial pressure decreased to 58 mmHg within next the 4 days and laboratory assessment suggested cytokine storm. The patient underwent two plasma exchanges, one double filtration plasmapheresis and oxygen saturation decreased continuously. The patient died one month after durvalumab treatment. Conclusion: Immune-related pneumonitis induced by PD-L1 inhibitors is rare but life-threatening. Infection should be ruled out before starting immunotherapy.