OA15 Real-world experience with avacopan in anti-neutrophil cytoplasmic autoantibody-associated vasculitis: first experiences in Northern Ireland

Abstract Background/Aims Avacopan is an oral C5a receptor inhibitor approved by NICE in 2022 as adjuvant therapy for treatment of severe anti-neutrophil cytoplasmic antibody-associated vasculitis to suppress disease activity and reduce rate of glucocorticoid related toxicity. Our objective was to describe real-world experience of avacopan to learn more about its role and standardise clinical practice across Northern Ireland. Methods We conducted a retrospective multi-centre cohort study including patients with newly diagnosed and relapsed anti-neutrophil cytoplasmic antibody-associated vasculitis who received avacopan between March 2023 and July 2025. All data was extracted from electronic medical records. Results This study included 40 patients across 5 tertiary centres in Northern Ireland. 22 tested positive for PR3, 17 MPO and 1 PR3/MPO. Their mean weight was 81.6 kg. Four patients required admission to intensive care and 5 required haemodialysis on a renal unit. The duration of steroid taper ranged from 2 weeks to 13 months (SD = 3.32). 61.29% (n = 19) stopped steroids within 3 months or less. Avacopan was continued uninterrupted in 24 patients for 12 months or since their last follow up. 17 stopped treatment prior to 52 weeks due to adverse events. Common reasons for discontinuation included transaminititis (n = 7) and nausea (n = 4). Infection was reported in 14 patients leading to avacopan being withdrawn in 1 patient. Inpatient admission for IV anti-biotics was required in 3 cases. Clinical remission at week 26 and week 52 were achieved in 28 out of 32 patients and 21 out of 24 patients retrospectively. Relapse occurred in 27.5% (n = 11) of patients. Conclusion Our data demonstrates the potentially life-threatening manifestations of anti-neutrophil cytoplasmic antibody-associated vasculitis. It also reflects challenges related to glucocorticoid toxicity such as obesity. Therefore, developing the role of steroid sparing agents by describing their use in clinical practice is necessary. We found the addition of avacopan supports the management in relation to withdrawal of steroids. Furthermore, it is safe in terms of infection, with the majority of cases being treated with oral anti-biotics or managed conservatively. Discontinuation rates are high, the most common reason being secondary to transaminitis, however, avacopan was successfully restarted in all patients when temporarily held because of abnormal liver function tests. This suggests it is safe to re-introduce once blood tests have normalised. Knowledge of this will help standardise clinical use of avacopan. Disclosure C. Lavery: None.