Immune Checkpoint Inhibitor-related Adverse Events in Publicly Accessible United States Malpractice Records: A Systematic Legal Database Review, 2015 to 2026

Objectives: By 2023, an estimated 56.7% of US patients with advanced or metastatic cancer were eligible for immune checkpoint inhibitor (ICI) therapy. Grade 3 to 4 immune-related adverse events (irAEs) occur in ∼14% to 21% of patients depending on regimen, yet publicly accessible malpractice records involving ICI administration or irAE management have not been systematically described. Methods: We searched Lexis+ and Westlaw Advantage for publicly accessible US malpractice records filed from January 1, 2015, through March 31, 2026. Sources included jury verdicts and settlement databases, federal and state dockets, and briefs, pleadings, and motions databases. Cases were included only when ICI administration, indication selection, toxicity counseling, toxicity recognition, toxicity monitoring, or irAE management was causally central to the alleged negligence. Results: Among 38 legal matters identified after cross-platform deduplication, 4 met eligibility criteria. These matters reflected 4 pleaded negligence theories: inappropriate ICI indication, toxicity counseling and informed-consent failure, irAE mismanagement, and treatment-related multiorgan toxicity. Publicly visible irAE-centered malpractice records were rare relative to the clinical burden, but the data do not support a national litigation incidence estimate. Conclusions: Publicly accessible irAE-centered malpractice records appear rare. As ICI use expands, litigation risk may increasingly focus on indication documentation, individualized toxicity counseling, and structured monitoring.