Rheumatic Syndromes Associated With Immune Checkpoint Inhibitors: A Single-Center Cohort of Sixty-One Patients

Objective: To describe the prevalence, clinical presentation, and management of rheumatic immune-related adverse effects (Rh-irAEs) from immune checkpoint inhibitor (ICI) therapy. Methods: From a database of all patients who received any ICI at the Mayo Clinic Rochester, Minnesota campus between January 1, 2011 and March 1, 2018, we retrospectively identified those with Rh-irAEs, using diagnostic codes, search terms, and manual chart review. Results: Of the 1,293 patients who received any ICI, Rh-irAEs were clinically diagnosed in 43. Eighteen patients with Rh-irAEs who received ICI therapy elsewhere were also analyzed. Clinical syndromes included inflammatory arthritis (n = 34 [prevalence 2%]), myopathy (n = 10), and other rheumatic syndromes (n = 17). Inflammatory arthritis was most commonly polyarticular, and glucocorticoid treatment was required in 26 patients (76%). The mean ± SD duration of treatment was 18 ± 18 weeks. Five patients (15%) also received disease-modifying antirheumatic drugs, and ICI therapy had to be discontinued in 3 patients (9%). Myopathy was treated with glucocorticoids in all cases (mean ± SD treatment duration 15 ± 17 weeks) and led to 2 deaths and permanent ICI discontinuation in 9 patients (90%). Other syndromes included connective tissue diseases, vasculitis, polymyalgia rheumatica–like syndrome, and flare of preexisting rheumatic disease. Most (71%) were treated with immunosuppression, with 12% requiring ICI discontinuation. Conclusion: This study represents the largest cohort of patients with Rh-irAEs reported to date. Most patients received long courses of immunosuppressive treatment, although discontinuation of ICI therapy was required in only a minority.