Article Text
Abstract
Objective To assess the effectiveness of switching to a second tumour necrosis factor inhibitor (TNFi) in patients with ankylosing spondylitis (AS).
Methods Data were extracted from an ongoing longitudinal observational multicentre study in Norway. This study included anti-TNF naïve patients with AS starting treatment with a TNFi as well as treatment with a second TNFi in these same patients. Effectiveness data and 2-year drug survival were compared between switchers and non-switchers and within switchers (first and second TNFi).
Results 514 anti-TNF naïve patients with AS were included; 77 patients switched to a second TNFi while 437 patients did not switch. The percentages of non-switchers using etanercept, infliximab or adalimumab were 53%, 32% and 15%, and the percentages of first and second TNFi in the switchers were 42%, 53% and 5% and 40%, 23% and 36%, respectively. The reason for switching was insufficient response (IR) in 30, adverse events (AEs) in 44 and not reported in 3 patients. Baseline disease activity was similar between the groups. Three-month BASDAI 50 and ASAS 40 responses were achieved by 49% and 38% of non-switchers, by 25% and 30% of switchers after the first TNFi and by 28% and 31% after the second TNFi. The 3-month disease activity level was higher for switchers on the second TNFi than for non-switchers. Drug withdrawal rate was higher during the second TNFi among switchers than for non-switchers (p=0.001). No difference was found in the effectiveness of the second TNFi between switchers due to IR and AE.
Conclusion This study confirms that switching to a second TNFi can be effective in AS and can be as useful as in rheumatoid arthritis, although overall effectiveness seems to be somewhat lower than in non-switchers.
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Footnotes
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Funding The work was supported by Eastern Norway Regional Health Authority. The Norwegian disease-modifying antirheumatic drug study has received unrestricted grant support from Abbott, Amgen, Wyeth, Aventis, MSD, Schering-Plough/Centocor, BristolMyers Squibb, Roche and the Norwegian Directorate for Health and Social Affairs.
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Ethics approval This study was conducted with the approval of the regional ethics committee and by the Data Inspectorate. Patients gave written informed consent before participation.
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Competing interests The NOR-DMARD register is financially supported by pharmaceutical companies but the sponsors are not involved in the analyses and presentation of data. Most of the authors have received speaker and/or consultancy honoraria from companies marketing biological DMARDs. Johannes WJ Bijlsma was the handling editor for this manuscript.
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Provenance and peer review Not commissioned; externally peer reviewed.