Clinical and Pathophysiological Characteristics of Patients in Whom Asthma Developed During Treatment with Immune Checkpoint Inhibitors: A Retrospective Single-center Study

Asthma develops as an immune-related adverse event (irAE); however, its clinical and pathophysiological characteristics remain unclear. We retrospectively reviewed five cases of asthma that developed during immune checkpoint inhibitor (ICI) treatment in patients with cancer. In all cases, a significant increase in blood eosinophil count was observed immediately before the onset of asthma symptoms, and serum allergen-specific immunoglobulin E antibodies were positive. ICI treatment could be continued safely, while temporarily suspended in two patients, under asthma treatment. The incidence of asthma was 0.97% (5/514). Early diagnosis and standard treatment enable good asthma control while continuing ICI therapy.