Immune checkpoint inhibitor associated vasculitis and polymyalgia rheumatica: a case series and systematic review

Background: Immune checkpoint inhibitors (ICIs) have been associated with immune-related adverse events (irAEs), including ICI associated vasculitis (ICI-vasculitis) and ICI associated PMR (ICI-polymyalgia rheumatica (PMR)-like syndromes). We sought to describe the characteristics of ICI-vasculitis and ICI-PMR in individuals treated with ICIs through a systematic review and local case series. Methods: We searched MEDLINE and Embase from inception to July 2023 for cases of ICI-vasculitis and ICI-PMR in ICI-treated individuals. Our series included cases obtained from clinicians at the Universities of Toronto, McMaster, and Western in Ontario, Canada. Results: One hundred and forty-four patients were identified: 130 from the systematic review in 76 articles and 14 from our case series. This included 73 patients with ICI-vasculitis (14 large vessel, 7 ANCA-associated, 52 other) and 71 with ICI-PMR. Ninety-five per cent of patients were treated with glucocorticoids and 17% received disease-modifying antirheumatic drugs (DMARDs). Among 4 individuals with vasculitis who continued the ICI, two remitted. Of five who paused and restarted ICIs, one experienced a recurrence. Among four individuals with vasculitis who continued ICIs, two remitted. All 11 ICI-PMR cases that continued ICIs remitted; among 3 patients who paused and restarted two did not relapse and one had a relapse that improved with an increase in their dose of prednisone. Conclusion: ICI-vasculitis and ICI-PMR are underrecognized complications of ICIs. Glucocorticoids are effective for ICI-vasculitis and ICI-PMR. It is unclear if ICIs can be safely continued or restarted after remission of ICI-vasculitis or ICI-PMR. Limited data suggests ICIs may be resumed in individuals with non-severe ICI-vasculitis or ICI-PMR.