Resolution of immune checkpoint inhibitors-induced inflammatory arthritis while maintaining active treatment with checkpoint inhibitors and after its discontinuation: An observational study

INTRODUCTION: Immune checkpoint inhibitors-induced inflammatory arthritis (ICI-IA) affects about 5% of ICI recipients. We aimed (1) to characterize the resolution of ICI-IA during ICI treatment and after ICI discontinuation and (2) to assess how ICI-IA influences ICI management across time. METHODS: All ICI-treated patients referred to rheumatology at Bordeaux University Hospital were identified and patients with ICI-IA with a follow-up of≥6months after ICI-IA onset were included. Resolution of ICI-IA was defined by discontinuation of ICI-IA medications without recurrence of ICI-IA symptoms. RESULTS: Resolution of ICI-IA occurred in 13 of 80 patients (16%) while maintaining active ICI treatment, mainly in patients with polymyalgia rheumatica (PMR)-like clinical presentation (P=0.03). Synovitis was more frequent in those whose ICI-IA persisted throughout ICI treatment. In patients with persistent ICI-IA throughout ICI treatment, 34 (50%) and 47 (70%) resolved at 6- and 12-months post-ICI discontinuation, respectively. Reason for terminating ICI was more frequently cancer stable or in remission in those who still had active ICI-IA at 6- and 12-months post-ICI discontinuation. Both progression-free survival and overall survival were longer in the groups with active ICI-IA at 6- and 12-months after ICI discontinuation. DISCUSSION: In this cohort, ICI was safely continued in most patients experiencing ICI-IA. About one sixth of ICI-IA resolved despite maintaining active ICI treatment and allowing ICI-IA treatment discontinuation without recurrence of symptoms, mainly in those with PMR-like presentation. Larger studies are needed to determine predicting factors of resolving ICI-IA to minimize exposure to immunosuppressive treatment.