Safety of immune checkpoint inhibitors in non-small-cell lung cancer patients with idiopathic interstitial pneumonia: a matched case–control study

PURPOSE: The immune checkpoint inhibitor nivolumab is commonly used for non-small-cell lung cancer treatment. Immune checkpoint inhibitors cause immune-related adverse events, including interstitial pneumonia. However, there are no studies on the risk factors for interstitial pneumonia exacerbation after immune checkpoint inhibitor administration in patients with a history of different types of interstitial pneumonia. Therefore, we aimed to investigate the risk factors for interstitial pneumonia exacerbation in patients with non-small-cell lung cancer and a history of interstitial pneumonia. We also aimed to explore differences in the risk of interstitial pneumonia exacerbation due to various types of interstitial pneumonia—idiopathic interstitial pneumonia, immune-related pneumonitis, and radiation pneumonitis. METHODS: Eleven patients with a history of interstitial pneumonia exacerbation following the administration of immune checkpoint inhibitor were included in the study. We performed 1:2 matching based on age and sex. Twenty-two patients whose interstitial pneumonia did not worsen after immune checkpoint inhibitor administration belonged to the control group. We calculated odds ratios for each factor in the patients and control subjects. RESULTS: The odds ratio of idiopathic interstitial pneumonia in the case group was 0.15 (95% confidence interval: 0.03–0.89) (p = 0.03). There were no significant differences in other factors, such as smoking history, pulmonary emphysema, and chronic obstructive pulmonary disease. CONCLUSION: The administration of immune checkpoint inhibitors in non-small-cell lung cancer patients with a history of idiopathic interstitial pneumonia might be a viable treatment option and have clinical benefits.