P168 Real-world experience of IL-17 inhibitors in ankylosing spondylitis and psoriatic arthritis, including intra-class drug switching

Abstract

Background/Aims Intra-class switching between Interleukin-17 inhibitors (IL-17i) has been studied in psoriasis, but not in inflammatory arthritis. We aim to retrospectively evaluate the use of IL-17i in our single-centre cohort of patients with axial spondyloarthropathy (axSpA) and psoriatic arthritis (PsA). Outcomes of interest included drug survival, reason for treatment discontinuation and efficacy of intra-class IL17i switching. Methods Patients commenced on IL-17i (secukinumab and ixekizumab) for axSpA or PsA in the rheumatology service at Guys & St Thomas Hospitals NHS Foundation Trust were identified. Patient demographics, comorbidities, duration of IL-17i use, and reasons for treatment cessation was collected. Kaplan-Meier and log-rank analyses were used to compare drug survival between diagnosis, drug, and line of therapy. Ethical approval was not sought as this study was untaken as part of an audit evaluation. Results 300 patients (211 PsA and 89 axSpA) initiated an IL-17i between 2007 and 2023. Patient characteristics are shown in Table 1. There was no difference between 24-month IL-17i survival in patients with axSpA versus PsA (p value 0.99) or first-line secukinumab versus ixekizumab (p value: 0.55). 49 patients switched to a second anti-IL17 drug. There was no difference between 24-month IL-17i survival in patients receiving their first versus second anti-IL-17 drug (p value 0.86). 22 patients discontinued IL-17i due to adverse events (AEs). Common AEs included eczema (n = 9), infections (n = 5) and inflammatory bowel disease (n = 4). Although fungal infections are a well-documented side-effect of IL-17i, this was not a reason for IL-17i discontinuation in our cohort. Conclusion In our cohort, IL-17i treatments in axSpA and PSA, showed similar persistence to previous studies of TNFi therapy, with an average 2-year drug survival of 60%. IL-17i were well-tolerated with 22 patients stopping treatment due to AEs. We show equivalent 24-month survival in axSpA and PsA patients with first- and second-line IL-17i, supporting the efficacy of IL17i intra-class switching. The strengths of our study include a large sample size and benefits of a single centre cohort, reducing variability in clinical practice and prescribing behaviours. Study limitations include lack of available outcome measures and exclusion of patients prescribed IL-17i through a different speciality. Disclosure S. Lee: None. K. Biddle: None. C. Lee: None. F. Humby: Consultancies; Pfizer, Roche, UCB, Genentech and Novartis. Grants/research support; Pfizer. B. Kirkham: Consultancies; Abbvie, BMS, Eli Lilly, Galapagos, Janssen, Novartis, Pfizer and UCB. Grants/research support; Novartis and Eli Lilly.