Effectiveness of switching between TNF inhibitors in patients with axial spondyloarthritis: is the reason to switch relevant?

Abstract

Background: To investigate whether the reason to discontinue the first TNF inhibitor (TNFi) affects the response to a second TNFi in axial spondyloartrhtis (axSpA).Methods: Patients with axSpA from the Rheumatic Diseases Portuguese Register (ReumaPt), who discontinued their first TNFi and started a second TNFi between June 2008 and May 2018 were included. Response was assessed by the Ankylosing Spondylitis Disease Activity Score (ASDAS) clinically important improvement (ASDAS-CII), major important improvement (ASDAS-MI), low disease activity (ASDAS-LDA) and inactive disease (ASDAS-ID). The reason for discontinuation of the first TNFi was defined, according to ASDAS-CII as: primary failure (no response ≤6 months); secondary failure (response ≤6 months but lost thereafter); adverse events; other. The association between the reason of discontinuation of the first TNFi and response to the second TNFi over time was assessed in multivariable generalized equation (GEE) models.Results: In total, 193 patients were included. The reason of discontinuation of the first TNFi did not influence the response to a second TNFi, according to the ASDAS-CII. However, a difference was found with more stringent outcomes, e.g. there was a higher likelihood to achieve ASDAS-ID with the second TNFi for patients discontinuing the first TNFi due to secondary failure (OR: 7.3 [(95%CI: 1.9; 27.7]), adverse events (OR: 9.1 [2.5; 33.3]), or other reasons (OR: 7.7 [1.6; 37.9]) compared to primary failure.Conclusion: Patients with axSpA with secondary failure to their first TNFi, compared to those with primary failure, have better response to the second TNFi according to stringent outcomes.