Bimekizumab rescue therapy in a patient with relapsing polychondritis-associated aortitis.

Relapsing polychondritis (RP) is a rare inflammatory disease characterised by recurrent inflammation of cartilaginous structures, especially of the ears, nose and respiratory tract, with a broad spectrum of systemic features. Furthermore, cardiovascular involvement is a rare but potentially life-threatening complication. We report the case of a 28-year-old woman with RP and refractory disease activity complicated by an aortic aneurysm, severe aortic regurgitation and embolic strokes. Positron emission tomography/computed tomography (PET/CT) imaging confirmed large vessel vasculitis of the aorta. Despite multiple immunosuppressive therapies, including glucocorticoids, methotrexate, cyclophosphamide and biologics targeting tumour necrosis factor-alpha (TNF-α), interleukin (IL)-1 and IL-6, high disease activity persisted. Rescue therapy with bimekizumab, a dual inhibitor of IL-17A and IL-17F, was associated with the normalisation of inflammation markers, PET/CT features and sustained clinical remission. To the best of our knowledge, this is the first report of successful treatment of RP-associated aortitis with bimekizumab, highlighting the potential role of IL-17A and IL17F in RP pathogenesis. These findings provide a foundation for further exploration of IL-17 inhibition in RP-associated vasculitis.