AB0657 Discontinuation of Anti-TNF Therapy in Patients with Axial Spondyloarthritis in Clinical Practice: Prevalence and Causes

Abstract

BackgroundThe majority of patients with axial spondyloarthritis (SpA) response to anti-TNF therapy. However, discontinuation of this therapy due to different reasons is still a relevant problem. Currently, there is not enough data to know exactly which is the prevalence and causes of interruption of anti-TNF therapies in clinical practice.ObjectivesFirst, to evaluate the frequency and causes of discontinuating adalimumab or infliximab as the first anti-TNF in patients with axial SpA in clinical practice. Second, to investigate the influence of anti-drug antibodies (ADA) on these causes.MethodsA total of 326 patients with axial SpA who had received adalimumab (34%) or infliximab (66%) as a first anti-TNF therapy were included in this retrospective, observational study performed in a tertiary hospital. Disease activity (BASDAI, ASDAS, CRP and ESR) was measured before starting anti-TNF therapy, after 6 months and when interrupting the therapy to assess properly whether the reason for discontinuation was primary or secondary failure. Serum drug levels and/or ADA were measured at 6 months visit and at the end of anti-TNF treatment.ResultsA total of 99 (30.4%) patients discontinued treatment. Mean (SD) under anti-TNF therapy until discontinuation was 2.5 (2.9) years. Characteristics of these patients when initiating anti-TNF therapy are shown in Table 1. The reason to interrupt treatment was: primary failure in 22.2%, secondary failure in 36.4%, side effects 32.3%), and other reasons in 9.1%. Serum drug levels and ADA were available in 83 patients. In most patients with ADA positive (14/17), the reason for discontinuation was secondary failure. Out of those patients who discontinued due to secondary failure, 38.9% had ADA positive.ConclusionsIn our cohort of patients with axial SpA treated with adalimumab/infliximab, 30% of patients discontinued anti-TNF therapy. The main reason to discontinue treatment was secondary failure, which was related to the presence of ADA in almost 40% of patients.Disclosure of InterestE. Moral Grant/research support from: Funded by an unrestricted medical grant from Pfizer, C. Plasencia: None declared, V. Navarro-Compán: None declared, D. Pascual Salcedo: None declared, T. Jurado: None declared, C. Tornero: None declared, A. Pierens: None declared, M. B. Paredes: None declared, P. Bogas: None declared, I. Monjo: None declared, E. Martin Mola: None declared, A. Balsa: None declared

Have Therapeutics Enhanced Our Knowledge of Axial Spondyloarthritis?

“…Given the above, it is unsurprising that TNFis are effective for axSpA. However, the response is not ubiquitous, and over a third of patients experience non-response (NR) to their first TNFi [ 51 , 52 ]. Possible explanations include non-compliance with treatment, individual differences in drug metabolism, pharmacodynamics and pharmacokinetics or the development of anti-drug antibodies [ 53 , 54 ].…”

Treatment Failure in Axial Spondyloarthritis: Insights for a Standardized Definition

“…A new therapeutic class for the treatment of axial SpA, Janus kinase inhibitors (JAKi), has also been approved. Unfortunately, response rates to bDMARDs are far from optimal, and many patients (about 40%) experience treatment failure [9]. Subsequent management is challenging, and the practicing clinician should carefully consider the moment and the reason for discontinuing the first bDMARD to decide the next therapeutic step [10].…”