Intensive care admissions for severe immune-related adverse events associated with immune checkpoint inhibitor therapy: a 10-year cohort study

OBJECTIVE: This study aimed to assess the prevalence of immune-related adverse events (irAEs) among patients admitted to the intensive care unit (ICU) while receiving immune checkpoint inhibitor (ICI) therapy, and to describe their clinical characteristics, management, and outcomes. METHODS: We retrospectively included all patients admitted to the Lille University Hospital ICU for ICI-related irAEs between January 2015 and May 2024. Overall survival was estimated using the Kaplan Meier method, and factors associated with ICU mortality were analyzed using Cox proportional hazards regression. RESULTS: Among 244 ICI-treated patients admitted to the ICU, 55 (23%) presented an irAE. The most frequent irAEs were myositis/myocarditis (29%) and pneumonitis (22%). Median time from first ICI infusion to irAE onset was 63 days [IQR 21-144]. Corticosteroids were initiated in 84% of cases, corresponding to 98% of treated patients; 39% were corticosteroid-refractory and 48% received additional immunosuppressive therapy. Half of the patients received vasopressors and 31% required mechanical ventilation. ICU mortality was 33%, mostly attributable to refractory irAEs. Corticosteroid refractoriness and mechanical ventilation were independently associated with ICU mortality (HR 12.32, 95% CI 3.26-46.52, p < 0.001; and HR 3.59, 95% CI 1.15-11.24, p = 0.028, respectively). CONCLUSION: This large ICU cohort of life-threatening irAEs reports high morbidity and mortality, particularly in patients with myositis, myocarditis, and pneumonitis. Corticosteroid refractoriness and mechanical ventilation were independently associated with ICU mortality. Early recognition, rapid escalation of care, and aggressive management may improve outcomes.