LAUSR

Immunosuppression in Takayasu arteritis (TA) reduces the risk of arterial disease progression. However, long-term use of glucocorticoids (GC) and other agents carries risk, particularly as patients age. GC tapering practice can vary and there are no guidelines on the safety of treatment cessation due to a lack of data. This study describes the cessation of treatment in a large single-centre cohort and evaluates the baseline, clinical and treatment parameters associated with successful treatment stop. The Imperial College Takayasu Arteritis Cohort (UK) was reviewed retrospectively; 158 patients, median follow-up 8.4 [5-13.6] years. Patients with data available within 1 year of audit (31/03/2021) were analysed. Treatment was defined as > 6 months of GC, csDMARD or biologic medication and cessation as stopping treatment for >1 year. Cessation safety was assessed by serial angiography (whole aorta MRI or CT) and NIH disease activity scoring. Baseline demographic, clinical and treatment parameters as well as initial treatment responses were compared for cessation and non-cessation cases. Data are median [IQR], comparisons are non-parametric for continuous variables. Of 129 (82%) cases requiring treatment, 107 (83%) remained in care. 29 (27.1%) cases of cessation were identified, time off-treatment was 3.6 [2.5-8.2] years. For 25 (86%) cessation cases, treatment withdrawal was due to sustained quiescence. Infection, non-adherence and tolerance accelerated cessation in 4 cases. Long-term inactivity was confirmed by disease activity scoring in all cases and by angiography where available (23 cases). No instances of treatment restart were observed. Baseline demographic and disease severity parameters were similar in cessation and non-cessation patients (Table). Cessation cases had lower GC doses after 2 years of treatment and a trend towards lower disease activity, suggesting better responses. Relatedly, biologic administration (reserved for refractory disease) was markedly lower in the cessation group. Finally, cessation cases had earlier treatment start years, were older at audit and had an increased proportion of Numano Type V classification. In TA, complete treatment cessation is feasible and safe in a proportion of cases. Initial treatment response, treatment duration and Numano type V arterial involvement are potential predictors of successful treatment cessation and may aid future stratification strategies after validation. Disclosure R.T. Maughan: None. A. Porter: None. C. Dahanayake: None. C. Ianonne: None. R. Alapat: None. C. Pericleous: None. T.A. Youngstein: None. J. Mason: None.