POS0765 REALITY OF TOCILIZUMAB DISCONTINUATION IN PATIENTS WITH GIANT CELL ARTERITIS: A ROUTINE CARE STUDY IN FOUR FRENCH HOSPITALS

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Background: Tocilizumab (TCZ), a biotherapy targeting IL-6, is approved for giant cell arteritis (GCA) as a cortisone-sparing strategy. Despite its success and efficiency in ACG, a lot of questions remain, especially concerning prescription duration and treatment discontinuation methods. Several studies have reported a high risk of relapse, around 50% after stopping TCZ, and the semiology of relapses and their predictive factors are poorly described. Finally, data on the use of TCZ in current practice are lacking. Objectives: This study aimed to examine the evolutionary profiles of patients with GCA treated with TCZ for one year or more, i.e. those for whom the question of biotherapy discontinuation could arise, with a particular attention on the relapse rate. The aim was also to describe the semiology and the predictive factors of relapses, and to assess cortisone sparing and long-term tolerance of TCZ in routine care. Methods: We carried out a retrospective, multi-centre study in 4 departments of internal medicine in the hospitals of Grenoble, Voiron, Chambéry and Annecy. The study involved patients who received a first initiation of TCZ at diagnosis or during follow-up of their disease between January 2013 and October 2022. Data were obtained from the Electronic Patients Records and the diagnosis of ACG had to meet the ACR/EULAR 1990/2022 criteria. Relapse-free survival curves were estimated using the Kaplan-Meier method and factors associated with relapse were identified using a Fischer exact test for qualitative variables and a non-parametric Wilcoxon-Mann-Whitney test for quantitative variables. Results: A total of 60 patients were enrolled, with a median TCZ treatment duration of 33 months (20-55.5). Of the 60 patients, 43 patients (71.7%) benefited from a decision to discontinue the biotherapy after a median treatment duration of 18 months (12.5-25.5). The decision was applied progressively in 74% of cases and scheduled in 83% of cases. 26 patients (60.5%) were successfully weaned off TCZ after a median treatment duration of 26 months (17.7-47.5), representing 43.3% of all patients included. However, the half of the patients (53.8%) experienced a relapse following the discontinuation of the biotherapy, with a median relapse-free survival of eight months. Only one patient experiencing a severe relapse with reversible visual blurring. Main symptoms of relapse were general, head and joint symptoms. After a relapse, the TCZ was reintroduced in 85.7% of cases. Overall, by the end of the study, only 20% of the patients had successfully achieved prolonged relapse-free withdrawal from TCZ. We did not identify any predictive factor for relapse, except for a tendency to relapse in women ( p =0.07) and in patients who were not weaned off corticosteroids when the decision to discontinue TCZ was made ( p =0.06). In terms of cortisone sparing, weaning was achieved in 70% of patients. However, 38% had to resume corticosteroid therapy after a relapse. In terms of TCZ safety, the half of the patient experienced an infectious adverse event, including two serious respiratory infections and one complicated diverticulitis. The other common side effects, such as cytopenias and lipid and hepatic abnormalities, were also seen and did not affect treatment continuation. Conclusion: These results highlight the difficulties of TCZ discontinuation in real-world practice, with less than 50% of patients weaned during the study and a high and rapid risk of relapse despite prolonged treatment. However, only one patient experienced a severe relapse. REFERENCES: [1] Matza MA, Dagincourt N, Mohan SV, Pavlov A, Han J, Stone JH, et al. Outcomes during and after long-term tocilizumab treatment in patients with giant cell arteritis. RMD Open. 1 avr 2023;9(2):e002923. [2] Peyrac G, Lomba Goncalves N, Kante A, Cacoub P, Sacre K, Saadoun D, et al. Traitement par tocilizumab en vie reéelle au cours de l'arteérite à cellules geéantes, eétude Toci-NEWTON. Rev Meédecine Interne. 1 juin 2024;45:A65‐6. [3] Samec MJ, Rakholiya J, Langenfeld H, Crowson CS, Abril A, Wang B, et al. Relapse Risk and Safety of Long-Term Tocilizumab Use Among Patients With Giant Cell Arteritis: A Single-Enterprise Cohort Study. J Rheumatol. oct 2023;50(10):1310‐7. [4] Nielsen MK, Nielsen AW, Donskov AO, Hansen IT, Nielsen BD, Mørk C, et al. Taper versus discontinuation of tocilizumab in patients with giant cell arteritis: Real-world experience from a tertiary center. Semin Arthritis Rheum. oct 2024;68:152508. Acknowledgements: Thanks to all the members of the internal medicine departments of Grenoble, Voiron, Chambéry and Annecy, and the rheumatology department of Grenoble, for their help and support in this work. Disclosure of Interests: None declared . © The Authors 2025. This abstract is an open access article published in Annals of Rheumatic Diseases under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Neither EULAR nor the publisher make any representation as to the accuracy of the content. The authors are solely responsible for the content in their abstract including accuracy of the facts, statements, results, conclusion, citing resources etc.

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