Background/Purpose: Axial spondyloarthritis (AxSpA) is a chronic inflammatory disease characterized by inflammatory back pain, morning stiffness, and reduced functional capacity. Approved therapies for AxSpA include IL-17, Janus kinase, and TNF (TNFi) inhibitors. An inadequate response to a first line TNFi may result in switching to a second TNFi; the efficacy of this remains unclear. This study assessed disease activity and persistency of therapy (up to 2 years) among patients (pts) with AxSpA who cycle to a second TNFi after discontinuing a first line TNFi.

Methods: This study included pts with AxSpA, as determined by a treating rheumatologist, enrolled in the CorEvitas Psoriatic Arthritis/Spondyloarthritis Registry between May 2013–January 2022 who had discontinued a 1^st line TNFi and initiated a 2^nd line TNFi. Pts included in disease activity analyses had a 6-month follow-up visit; those included in persistency analyses had any follow-up up to 24-months after 2^nd line TNFi initiation. Ankylosing Spondylitis Disease Activity Score (ASDAS) and BASDAI were collected at baseline and 6-months. Baseline pt characteristics were summarized descriptively. At 6-months, proportions of pts achieving ASDAS low disease activity (LDA; ASDAS < 2.1), minimal clinically important difference (MCID; ≥1.1-point decrease), and major improvement (MI; ≥2-point decrease); BASDAI MCID (≥1.4-point reduction) and improvement ≥50%; and MCID in patient-reported outcomes were calculated. For persistency analysis, Kaplan-Meier survival estimates were used to calculate the proportion of pts with persistent (ie, continued) 2^nd line TNFi use over 24 months.

Results: The disease activity analyses included 86 pts with an average age (± standard deviation) of 52.0 ± 13.2 years and a mean of 8.7 ± 10.3 years since AxSpA diagnosis (Table 1). On average, pts spent 16.1 ± 18.9 months on a first line TNFi before discontinuation, with lack of efficacy cited as the most common reason for discontinuation. At baseline, 42% of pts had high (≥2.1) and 24% very high ( >3.5 ) disease activity as measured by ASDAS. The mean BASDAI score was 4.6 ± 2.5, indicating poorly controlled disease. Seventy-seven percent were receiving TNFi monotherapy, with 23% currently receiving NSAIDs. After 6 months of therapy with a 2^nd line TNFi, 15% achieved ASDAS-LDA and 7% achieved MCID in ASDAS (Table 2); no pts achieved MI. Thirty-six percent of pts achieved MCID in BASDAI, yet only 8% had a ≥50% improvement. Less than half of patients achieved MCID in patient-reported pain (44%), fatigue (36%), morning stiffness (40%), and overall work improvement (25%). Of the 120 pts in the persistency analysis, 21% remained on the 2^nd line TNFi through 24-months (Figure).

Conclusion: These data demonstrate that cycling to a second line TNFi provides limited benefits to pts with AxSpA who discontinued a first line TNFi. Few pts showed clinically meaningful improvement in disease severity after 6 months and less than a quarter of pts remained on therapy after 2 years. While these data were limited by small sample size, they do highlight the high burden and unmet needs for pts with AxSpA that do not respond to a first line TNFi.

ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-impact-of-cycling-among-tumor-necrosis-factor-inhibitors-on-disease-control-in-patients-with-axial-spondyloarthritis-a-study-from-the-corevitas-psa-spa-registry/