LAUSR

BACKGROUND The prevalence of immune-mediated toxicities from immune checkpoint inhibitors (ICIs) is well described. However, the characteristics and treatment patterns for patients with emergency presentations owing to immune-mediated toxicity are less well known. MATERIALS AND METHODS This study reviews all emergency presentations in patients treated with ICI at a single centre between May 2018 and March 2020. The aims were to describe and quantify patient and treatment characteristics, toxicity type and outcomes. RESULTS 1165 patients were treated with ICI, and there were 597 emergency presentations in 370 patients. Of these, 191/597 (32%) were owing to an immune-mediated toxicity, median age was 64 years, and 127/191 (67%) were men. The most common tumour types were melanoma (53%) and lung cancer (22%), and the most common ICI received was ipilimumab + nivolumab combination immunotherapy (42%), followed by pembrolizumab monotherapy (21%) and nivolumab monotherapy (20%). The median number of cycles received was three (range 1-54), and 75/191 (39%) had previous ≥ grade 2 immune-mediated toxicity. 29% patients required second-line immunosuppression. The median time in the hospital was four days. There was a rising number of emergency presentations reflecting overall increasing use of ICI. CONCLUSIONS Over a quarter of patients treated with ICI had an emergency presentation, and immune-mediated toxicity accounted for 32% of these. A diagnosis of melanoma, treatment with combination immunotherapy and previous ≥ grade 2 immune-mediated toxicity were common in patients with immune-mediated toxicity. These data allow better identification of patients likely to require admission and forward planning for acute oncology services.