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Objectives: To determine quantitative SI joint MRI lesion cut-offs that optimally define a positive MRI for inflammatory and structural lesions typical of axial SpA (axSpA) and that predict clinical diagnosis., Methods: The Assessment of SpondyloArthritis international Society (ASAS) MRI group assessed MRIs from the ASAS Classification Cohort in two reading exercises where (A) 169 cases and 7 central readers; (B) 107 cases and 8 central readers. We calculated sensitivity/specificity for the number of SI joint quadrants or slices with bone marrow oedema (BME), erosion, fat lesion, where a majority of central readers had high confidence there was a definite active or structural lesion. Cut-offs with ≥95% specificity were analysed for their predictive utility for follow-up rheumatologist diagnosis of axSpA by calculating positive/negative predictive values (PPVs/NPVs) and selecting cut-offs with PPV ≥ 95%., Results: Active or structural lesions typical of axSpA on MRI had PPVs ≥ 95% for clinical diagnosis of axSpA. Cut-offs that best reflected a definite active lesion typical of axSpA were either ≥4 SI joint quadrants with BME at any location or at the same location in ≥3 consecutive slices. For definite structural lesion, the optimal cut-offs were any one of ≥3 SI joint quadrants with erosion or ≥5 with fat lesions, erosion at the same location for ≥2 consecutive slices, fat lesions at the same location for ≥3 consecutive slices, or presence of a deep (i.e. >1 cm depth) fat lesion., Conclusion: We propose cut-offs for definite active and structural lesions typical of axSpA that have high PPVs for a long-term clinical diagnosis of axSpA for application in disease classification and clinical research., (© The Author(s) 2021. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Objectives: The Assessment of SpondyloArthritis international Society (ASAS) MRI working group conducted a multireader exercise on MRI scans from the ASAS classification cohort to assess the spectrum and evolution of lesions in the sacroiliac joint and impact of discrepancies with local readers on numbers of patients classified as axial spondyloarthritis (axSpA)., Methods: Seven readers assessed baseline scans from 278 cases and 8 readers assessed baseline and follow-up scans from 107 cases. Agreement for detection of MRI lesions between central and local readers was assessed descriptively and by the kappa statistic. We calculated the number of patients classified as axSpA by the ASAS criteria after replacing local detection of active lesions by central readers and replacing local reader radiographic sacroiliitis by central reader structural lesions on MRI., Results: Structural lesions, especially erosions, were as frequent as active lesions (≈40%), the majority of patients having both types of lesions. The ASAS definitions for active MRI lesion typical of axSpA and erosion were comparatively discriminatory between axSpA and non-axSpA. Local reader overcall for active MRI lesions was about 30% but this had a minor impact on the number of patients (6.4%) classified as axSpA. Substitution of radiography with MRI structural lesions also had little impact on classification status (1.4%)., Conclusion: Despite substantial discrepancy between central and local readers in interpretation of both types of MRI lesion, this had a minor impact on the numbers of patients classified as axSpA supporting the robustness of the ASAS criteria for differences in assessment of imaging., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: The Assessment of SpondyloArthritis international Society (ASAS) MRI working group (WG) was convened to generate a consensus update on standardised definitions for MRI lesions in the sacroiliac joint (SIJ) of patients with spondyloarthritis (SpA), and to conduct preliminary validation., Methods: The literature pertaining to these MRI lesion definitions was discussed at three meetings of the group. 25 investigators (20 rheumatologists, 5 radiologists) determined which definitions should be retained or required revision, and which required a new definition. Lesion definitions were assessed in a multi-reader validation exercise using 278 MRI scans from the ASAS classification cohort by global assessment (lesion present/absent) and detailed scoring (inflammation and structural). Reliability of detection of lesions was analysed using kappa statistics and the intraclass correlation coefficient (ICC)., Results: No revisions were made to the current ASAS definition of a positive SIJ MRI or definitions for subchondral inflammation and sclerosis. The following definitions were revised: capsulitis, enthesitis, fat lesion and erosion. New definitions were developed for joint space enhancement, joint space fluid, fat metaplasia in an erosion cavity, ankylosis and bone bud. The most frequently detected structural lesion, erosion, was detected almost as reliably as subchondral inflammation (κappa/ICC:0.61/0.54 and 0.60/0.83) . Fat metaplasia in an erosion cavity and ankylosis were also reliably detected despite their low frequency (κappa/ICC:0.50/0.37 and 0.58/0.97)., Conclusion: The ASAS-MRI WG concluded that several definitions required revision and some new definitions were necessary. Multi-reader validation demonstrated substantial reliability for the most frequently detected lesions and comparable reliability between active and structural lesions., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: To compare proton density-weighted short-tau inversion recovery (PD-STIR) and T2-weighted fat-suppressed turbo spin echo (T2-FS) sequences for detecting osteitis lesions of the sacroiliac joints (SIJ) in patients with chronic low back pain (CLBP)., Methods: This prospective study included 110 patients with CLBP and suspected spondyloarthritis and 18 healthy controls. All 128 participants (age range: 19-57 yrs) underwent 3.0 Tesla magnetic resonance imaging (MRI) of the SIJ including PD-STIR and T2-FS. Two readers independently scored PD-STIR and T2-FS images for osteitis in separate sessions. Sum scores and signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were calculated. Images were further analyzed as to whether they fulfilled the Assessment of SpondyloArthritis international Society (ASAS) criterion of a positive MRI (MRI+). Interreader agreement was calculated using intraclass correlation coefficients., Results: Average osteitis sum scores were higher for T2-FS images (mean sum score of 4.10 in T2-FS vs 2.55 in PD-STIR, p = 0.017). Mean SNR was 16.54 for PD-STIR and 37.30 for T2-FS (p = 0.0289). Mean CNR was 4.14 for PD-STIR and 20.20 for T2-FS (p = 0.0212). For both readers, the ASAS MRI+ definition was more often fulfilled by T2-FS than by PD-STIR images, resulting in more patients being classified as having axial spondyloarthritis (axSpA): 68 patients using T2-FS versus 58 patients using PD-STIR. Interreader intraclass correlation coefficients were very good for both PD-STIR (0.91) and T2-FS (0.86)., Conclusion: T2-FS sequences improve image quality and hence the detection of osteitis compared to the PD-STIR sequence. More patients were classified as axSpA based on a positive MRI by T2-FS.

Background: Adalimumab was effective in treating patients with nonradiographic axial spondyloarthritis (nr-axSpA) in the 12-week ABILITY-1 trial. We present long-term efficacy and safety results of adalimumab from the open-label ABILITY-1 extension, including the relationship between clinical and magnetic resonance imaging (MRI) remission and impact of sustained clinical remission on physical function., Methods: Patients received adalimumab 40 mg every other week or placebo for 12 weeks, then open-label adalimumab for up to 144 weeks. Clinical and safety data were collected through 3 years, and MRI data were collected until 2 years. Analyses were performed in the total population and subpopulation with positive MRI and/or elevated C-reactive protein (MRI/CRP-positive) at baseline. Clinical and MRI remission definitions included Ankylosing Spondylitis Disease Activity Score inactive disease (ASDAS ID; score < 1.3) and Spondyloarthritis Research Consortium of Canada (SPARCC) MRI score < 2 for sacroiliac joints (SIJs), spine, or both. Physical function was assessed using the Bath Ankylosing Spondylitis Functional Index., Results: Overall, 185 patients were included in the total population and 142 in the MRI/CRP-positive subpopulation; 65% and 68%, respectively, completed 3 years. Clinical, functional, and MRI improvements were similar and equally sustainable in both populations. At year 3, the percentages of patients in ASDAS ID in the MRI/CRP-positive subpopulation were 30%/33% (nonresponder imputation) and 46%/49% (observed) for those initially receiving adalimumab/placebo. At years 1 and 2, patients in ASDAS ID vs not had significantly greater improvements in SPARCC SIJ scores from baseline (P < 0.001). Among patients with baseline MRI scores ≥ 2 who achieved ASDAS ID at year 2, 44-68% also had MRI remission. Significantly more patients with sustained ASDAS ID through year 2 or 3 vs without achieved normal physical function (100% vs 48%; 100% vs 44%; both P < 0.001). No new safety concerns were observed., Conclusions: In the ABILITY-1 study of nr-axSpA, adalimumab therapy provided sustained clinical and functional improvements through 3 years, as well as suppression of MRI axial inflammation, which was greater in patients who achieved clinical remission. Sustained clinical remission was associated with increased attainment of normal physical function. The safety profile of adalimumab was consistent with prior studies., Trial Registration: ClinicalTrials.gov , NCT00939003 ; registered on July 10, 2009.

Objectives: In patients with active axial spondyloarthritis (axSpA), inflammation in the SIJ or spine on MRI, an elevated CRP level or both are considered useful objective assessments for disease activity and initiation of TNF antagonists. The aim of this post hoc analysis of the randomized, double-blind ABILITY-1 study (NCT00939003) was to assess changes in objective inflammation over time., Methods: Patients with non-radiographic axSpA (nr-axSpA) were randomized to receive adalimumab 40 mg every other week or placebo for 12 weeks in ABILITY-1. MRIs were performed at baseline and week 12; CRP was measured every 4 weeks., Results: Of 94 placebo-treated ABILITY-1 patients, 29 (30.9%) had a normal MRI of the SIJs and spine, 57 (60.6%) had normal CRP and 20 (21.3%) had a normal MRI of the SIJs and spine and a normal CRP at baseline. After 12 weeks of placebo, 9/29 (31.0%) patients subsequently developed inflammation on MRI, 14/57 (24.6%) patients developed elevated CRP and 10/20 (50.0%) patients developed a positive MRI and/or elevated CRP through week 12., Conclusions: Patients who have clinically active disease but who lack objective evidence of inflammation initially may benefit from subsequent retesting for inflammation to guide treatment., (© The Author 2017. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com)

Objectives: To review and update the existing definition of a positive MRI for classification of axial spondyloarthritis (SpA)., Methods: The Assessment in SpondyloArthritis International Society (ASAS) MRI working group conducted a consensus exercise to review the definition of a positive MRI for inclusion in the ASAS classification criteria of axial SpA. Existing definitions and new data relevant to the MRI diagnosis and classification of sacroiliitis and spondylitis in axial SpA, published since the ASAS definition first appeared in print in 2009, were reviewed and discussed. The precise wording of the existing definition was examined in detail and the data and a draft proposal were presented to and voted on by the ASAS membership., Results: The clear presence of bone marrow oedema on MRI in subchondral bone is still considered to be the defining observation that determines the presence of active sacroiliitis. Structural damage lesions seen on MRI may contribute to a decision by the observer that inflammatory lesions are genuinely due to SpA but are not required to meet the definition. The existing definition was clarified adding guidelines and images to assist in the application of the definition., Conclusion: The definition of a positive MRI for classification of axial SpA should continue to primarily depend on the imaging features of 'active sacroiliitis' until more data are available regarding MRI features of structural damage in the sacroiliac joint and MRI features in the spine and their utility when used for classification purposes., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.)

Objective: To investigate the course of active inflammatory and fatty lesions seen on magnetic resonance imaging (MRI) in patients with early axial spondyloarthritis (SpA) treated with the tumor necrosis factor (TNF) inhibitor infliximab added to naproxen as compared to those treated with naproxen alone., Methods: A total of 158 patients with active axial SpA were randomized (2:1) to receive 28 weeks of treatment with either infliximab 5 mg/kg plus naproxen 1,000 mg/day or placebo plus naproxen 1,000 mg/day. MRI of the sacroiliac (SI) joints and of the spine was performed at baseline and week 28. Images were scored for active inflammation and for fatty lesions., Results: After 28 weeks, there was a significant reduction of inflammation in the spine and in the SI joints in both treatment groups, which was, however, more prominent in the infliximab plus naproxen group (mean ± SD spine osteitis change score -2.9 ± 5.1, versus -2.0 ± 4.2 in the placebo plus naproxen group [P < 0.001]; SI joint osteitis change score -4.3 ± 5.2 in the infliximab plus naproxen group versus -3.9 ± 3.7 in the placebo plus naproxen group [P = 0.003]). Similarly, there was a significant increase in the fatty lesion score after 28 weeks in both groups; this change did not, however, differ significantly between groups (spine fatty lesion change score 0.8 ± 1.7 in the infliximab plus naproxen group versus 1.0 ± 1.8 in the placebo plus naproxen group [P = 0.72]; SI joint fatty lesion change score 1.7 ± 2.7 in the infliximab plus naproxen group versus 1.4 ± 2.6 in the placebo plus naproxen group [P = 0.86])., Conclusion: These findings indicate that effective antiinflammatory treatment of axial SpA is associated with an increase in fatty lesion scores, independent of concomitant treatment with or without anti-TNF., (© 2016, American College of Rheumatology.)

Objective: To evaluate the efficacy and safety of etanercept (ETN) after 48 weeks in patients with early active non-radiographic axial spondyloarthritis (nr-axSpA)., Methods: Patients meeting Assessment of SpondyloArthritis international Society (ASAS) classification criteria for axSpA, but not modified New York radiographic criteria, received double-blind ETN 50 mg/week or placebo (PBO) for 12 weeks, then open-label ETN (ETN/ETN or PBO/ETN). Clinical, health, productivity, MRI and safety outcomes were assessed and the 48-week data are presented here., Results: 208/225 patients (92%) entered the open-label phase at week 12 (ETN, n=102; PBO, n=106). The percentage of patients achieving ASAS40 increased from 33% to 52% between weeks 12 and 48 for ETN/ETN and from 15% to 53% for PBO/ETN (within-group p value <0.001 for both). For ETN/ETN and PBO/ETN, the EuroQol 5 Dimensions utility score improved by 0.14 and 0.08, respectively, between baseline and week 12 and by 0.23 and 0.22 between baseline and week 48. Between weeks 12 and 48, MRI Spondyloarthritis Research Consortium of Canada sacroiliac joint (SIJ) scores decreased by -1.1 for ETN/ETN and by -3.0 for PBO/ETN, p<0.001 for both. Decreases in MRI SIJ inflammation and C-reactive protein correlated with several clinical outcomes at weeks 12 and 48., Conclusions: Patients with early active nr-axSpA demonstrated improvement from week 12 in clinical, health, productivity and MRI outcomes that was sustained to 48 weeks., Trial Registration Number: NCT01258738., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

Objective: To compare clinical examination versus whole-body magnetic resonance imaging (WB-MRI) of enthesitis in patients with early axial spondyloarthritis during 3 years of continuous etanercept (ETN) treatment., Methods: Forty-one patients underwent clinical and WB-MRI examinations for enthesitis at baseline and after 2 and 3 years of treatment. Twenty-one sites were assessed in 4 anatomic regions - anterior chest wall, pelvis, knee, and foot., Results: Clinical examination at baseline detected enthesitis in 57% of the patients (85 lesions, mean 2.1 lesions, SD 2.9), most of them in the pelvis (42 lesions in 17 patients) and anterior chest wall (19 lesions in 10 patients). The proportion of patients with clinically detected enthesitis decreased to 19% at Year 2 (mean 0.5, SD 1.5) and 14% at Year 3 (mean 0.7, SD 1.8). WB-MRI detected enthesitis at baseline in 21% of patients (22 lesions, mean 0.5 lesions, SD 1.1), also most frequently in the pelvis (12 lesions) and anterior chest wall (7 lesions). MRI-positive enthesitis decreased to 13% at Year 2 (mean 0.2 lesions, SD 0.5) and 14% at Year 3 (mean 0.2 lesions, SD 0.5). There was positive correlation of clinical and MRI findings at baseline at the anterior chest wall (p = 0.001) and the pelvis (p = 0.0001). No correlation was found at the knee and foot at baseline and for all regions at followup., Conclusion: Both clinical examination and WB-MRI show a decrease in enthesitis after 2 and 3 years of ETN treatment, but correlation was limited to the pelvis and anterior chest wall at baseline.

Objective: To assess the relationship between active inflammation and development of chronic lesions in the spine and sacroiliac (SI)-joints on MRI in early axial spondyloarthritis (SpA) during treatment with etanercept., Methods: Here, we analyzed the 41 patients of the ESTHER trial, who were treated with etanercept over 3 continuous years and of whom MRIs were available for baseline, year 2, and year 3. MRIs were scored for active inflammation (STIR sequences) and chronic changes (T1 sequence) such as fatty lesions, erosions, and ankylosis in the SI joints and spinal vertebral units (VUs)., Results: The mean fatty lesion scores increased between baseline and year 2 both in the spine (1.13 at baseline vs. 1.40 at year 2, p = 0.0254) and in the SI joints (4.76 at baseline vs. 5.46 at year 2, p = 0.27), but we found no further increase of the fatty lesion score between years 2 and 3. New fatty lesions at years 2 and 3 developed nearly exclusively in SI joint quadrants and VUs in which active MRI inflammation was present at baseline. Fatty lesions disappeared only in 3 SI joint quadrants and in none of VUs at years 2 and 3. Erosion and ankylosis scores remained unchanged., Conclusion: Our data indicate a relationship between the presence of active MRI inflammation and the new development of fatty lesions. Furthermore, there was no increase of fatty lesions during continuous treatment of axial SpA patients with etanercept after successful suppression of active inflammation. Whether this is predictive of stopping radiographic progression needs to be further investigated., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Objective: Assessment of structural damage of sacroiliac joints (SIJ) in patients with axial spondyloarthritides (axSpA) has been discussed as a useful outcome measure in clinical trials. The aim of our study was to evaluate different magnetic resonance imaging (MRI) scoring methods and pulse sequences with a focus on fatty lesions and bony erosions., Methods: Seventy-five patients with the diagnosis of axSpA underwent MRI at 3 timepoints as part of the ESTHER trial, which compared 2 groups of patients treated with etanercept or sulfasalazine. Two MRI sequences [unenhanced T1-weighted (T1w) turbo spin-echo (TSE) and unenhanced T1w opposed-phase gradient-echo sequences (opGRE)] and 2 different scoring systems (simple and comprehensive Berlin method) were used for the evaluation of fatty lesions and erosions of the SIJ. Differences between techniques and methods were evaluated by intraclass correlation coefficients (ICC) and standardized response means (SRM)., Results: Applying the simple Berlin method, mean fatty lesion scores for etanercept-treated patients were 4.59 and 5.19 at baseline and Week 48, respectively, while the comprehensive Berlin method revealed mean fatty lesion scores of 6.59 and 7.64, respectively. Corresponding SRM were 0.59 and 0.86 for simple and comprehensive methods, respectively, while ICC dropped from 0.76-0.77 to 0.59-0.62. Scoring of erosions on T1w opGRE images resulted in a higher interreader agreement (ICC of 0.65) compared to T1w TSE sequences (ICC of 0.18)., Conclusion: Better characterization of fatty lesion changes within 1 year was achieved by the comprehensive Berlin scoring method; however, more reader variation has to be taken into account. The delineation of erosions is markedly improved when using T1w opGRE pulse sequences.

Objective: We investigated the performance of magnetic resonance imaging (MRI) compared to conventional radiographs for detection of chronic structural changes in the sacroiliac joints (SIJ) in patients with axial spondyloarthritis (SpA)., Methods: We included 112 patients with definite axial SpA (68 with ankylosing spondylitis and 44 with nonradiographic axial SpA), for whom radiographs and MRI scans of the SIJ performed at the same time were available. Radiographs and MRI of the SIJ were scored for subchondral sclerosis (score 0-2), erosions (score 0-3), and joint space changes (score 0-5) in each SIJ. Readers provided an overall impression of the extent of damage according to the scoring system of the modified New York criteria., Results: In total, 224 SIJ from 112 patients were available for analysis. There was rather low agreement between MRI and radiographs concerning definite erosions of SIJ (κ = 0.11), moderate agreement for definite subchondral sclerosis (κ = 0.46) and definite joint space abnormalities (κ = 0.41), and almost perfect agreement for joint ankylosis (κ = 0.85). MRI demonstrated a good overall performance in detection of definite "chronic" sacroiliitis, with a sensitivity of 84% and a specificity of 61%. For sacroiliitis fulfilling the modified New York criteria, MRI had a sensitivity of 81% and a specificity of 64% using radiographs as the reference method., Conclusion: MRI demonstrated good overall performance for detection of chronic structural changes in the SIJ as compared to radiographs.

Objective: The aim of this study was to define characteristic MRI findings in the spine of patients with axial spondyloarthritis (SpA) and provide a definition of a positive spinal MRI for inflammation and structural changes., Methods: Technical details of spinal MRI and the description of spinal lesions of both inflammation and structural changes were discussed in consecutive meetings of 10 experts of the Assessment in SpondyloArthritis international Society (ASAS). The discussions aimed at a broad consensus on definitions of 'a positive spinal MRI' for both types of lesions and were backed up by a systematic literature search., Results: A total of six different types of lesions were described for inflammation--anterior/posterior spondylitis, spondylodiscitis, arthritis of costovertebral joints, arthritis of zygoapophyseal joints and enthesitis of spinal ligaments--and another four for structural changes--fatty deposition, erosions, syndesmophytes and ankylosis. In the literature review, four relevant papers were identified. Anterior/posterior spondylitis and fat depositions at vertebral edges were considered as the most typical findings in SpA. Based on expert consensus and taking the literature review into consideration, a positive spinal MRI for inflammation was defined as the presence of anterior/posterior spondylitis in ≥3 sites. Evidence of fatty deposition at several vertebral corners was found to be suggestive of axial SpA, especially in younger adults. ASAS members (n=56) approved these definitions by voting in January 2010., Conclusions: This consensus statement gives clear descriptions of disease-related spinal lesions and of definitions of a positive spinal MRI for inflammatory lesions (spondylitis) and structural changes (fat deposition). These definitions can be used to describe findings of spinal MRI in patients with SpA in daily practice and clinical studies.

Ankylosing spondylitis is the prototypical spondyloarthritis. Early diagnosis has gained clinical importance with the advent of new therapeutic options such as TNF-alpha inhibitors, which can dramatically improve clinical outcome when initiated early. Whole-body MRI can contribute important diagnostic information for detecting early forms of spondyloarthritis because it enables evaluation of all important joints that may be involved in the disease process as a one-stop shop modality. MRI allows much more accurate diagnostic evaluation of the thoracic spine, which is affected in the majority of patients. This article provides an overview of the use of whole-body magnetic resonance imaging (MRI) in the spondyloarthritides. The recommendations given reflect the most recent scientific data and expert opinions. The focus of this review is on MRI findings at both the axial and the appendicular skeleton and the technical feasibility of whole-body MRI in the clinical setting.

Background: A 32-year-old white man presented with features of inflammatory back pain, including awakening at night and morning stiffness. He had acute back pain 4 years earlier as a result of a herniated lumbar disc., Investigations: The orthopedic consultation included tests for neurologic deficits; a Lasègue test; a finger-to-floor distance test; X-rays of the lumbar spine; and MRI of the lumbar spine. The rheumatologic consultation included recordal of clinical history and family history; physical examination, including a Schober's test, lateral spine flexion, chest expansion, cervical rotation, and tragus-to-wall distance; blood tests, including genotyping for human leukocyte antigen B27 positivity, and measurements of C-reactive protein level and erythrocyte sedimentation rate; MRI of the sacroiliac joints with use of short tau inversion recovery sequences; and measurement of the Bath Ankylosing Spondylitis Disease Activity Index and the Bath Ankylosing Spondylitis Functional Index., Diagnosis: Axial undifferentiated spondyloarthritis., Management: NSAIDs and physiotherapy.

Ankylosing spondylitis (AS) is a chronic inflammatory disease which affects primarily the sacroiliac joints and the spine. In patients with active disease, magnetic resonance imaging (MRI) of the spine shows areas of bone marrow edema, the histopathological equivalent of which is unknown. In this study we correlate inflammation in the spine of patients with AS as revealed by histological examination with bone marrow edema as detected by MRI. We have compared the histopathological findings of zygapophyseal joints from 8 patients with AS (age: 30 to 64, disease duration 7 to 33 years) undergoing spinal surgery with findings in MRI. For histopathological analysis, we quantified infiltrates of CD3+, CD4+ and CD8+ T cells as well as CD20+ B cells immunohistochemically. Bone marrow edema was evaluated in hematoxylin and eosin stained sections and quantified as the percentage of the bone marrow area involved. All patients with AS showed interstitial mononuclear cell infiltrates and various degrees of bone marrow edema (range from 10% to 60%) in histopathological analysis. However, in only three of eight patients histopathological inflammation and edema in the zygapophyseal joints correlated with bone marrow edema in zygapophyseal joints of the lumbar spine as detected by MRI. Interestingly, two of these patients showed the highest histological score for bone marrow edema (60%). This first study correlating histopathological changes in the spine of patients with AS with findings in MRI scans suggests that a substantial degree of bone marrow inflammation and edema is necessary to be detected by MRI.

Objectives To compare MRI and conventional radiography of SI joints for detection of structural lesions typical for axial spondyloarthritis (axSpA). Methods Adult patients from the Assessment of SpondyloArthritis international Society (ASAS) cohort with symptoms suggestive of axSpA and both SI joint MRI and radiographs available for central reading were included. Radiographs were evaluated by three readers according to the modified New York (mNY) criteria grading system. The presence of structural damage on radiographs was defined as fulfilment of the radiographic mNY criterion and, additionally, a lower threshold for sacroiliitis of at least grade 2 unilaterally. MRI scans were assessed for the presence of structural changes indicative of axSpA by seven readers. Diagnostic performance [sensitivity, specificity, positive and negative predictive values (PPV and NPV) and positive and negative likelihood ratios (LR+ and LR−)] of MRI and radiographs (vs rheumatologist's diagnosis of axSpA) were calculated. Results Overall, 183 patients were included and 135 (73.7%) were diagnosed with axSpA. Structural lesions indicative of axSpA on MRI had sensitivity 38.5%, specificity 91.7%, PPV 92.9%, NPV 34.6%, LR+ 4.62 and LR− 0.67. Sacroiliitis according to the mNY criteria had sensitivity 54.8%, specificity 70.8%, PPV 84.1%, NPV 35.8%, LR+ 1.88 and LR− 0.64. Radiographic sacroiliitis of at least grade 2 unilaterally had sensitivity 65.2%, specificity 50.0%, PPV 78.6%, NPV 33.8%, LR+ 1.30 and LR− 0.69. Conclusion Structural lesions of the SI joint detected by MRI demonstrated better diagnostic performance and better interreader reliability compared with conventional radiography. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the efficacy and safety of upadacitinib, a Janus kinase inhibitor, in patients with active ankylosing spondylitis (AS) with an inadequate response (IR) to biological disease-modifying antirheumatic drugs (bDMARDs).Methods: Adults with active AS who met modified New York criteria and had an IR to one or two bDMARDs (tumour necrosis factor or interleukin-17 inhibitors) were randomised 1:1 to oral upadacitinib 15 mg once daily or placebo. The primary endpoint was Assessment of SpondyloArthritis international Society 40 (ASAS40) response at week 14. Sequentially tested secondary endpoints included Ankylosing Spondylitis Disease Activity score, Spondyloarthritis Research Consortium of Canada MRI spine inflammation score, total back pain, nocturnal back pain, Bath Ankylosing Spondylitis Functional Index, Bath Ankylosing Spondylitis Metrology Index and Maastricht Ankylosing Spondylitis Enthesitis Score. Results are reported from the 14-week double-blind treatment period.Results: A total of 420 patients with active AS were randomised (upadacitinib 15 mg, n=211; placebo, n=209). Significantly more patients achieved the primary endpoint of ASAS40 at week 14 with upadacitinib vs placebo (45% vs 18%; p<0.0001). Statistically significant improvements were observed with upadacitinib vs placebo for all multiplicity-controlled secondary endpoints (p<0.0001). Adverse events were reported for 41% of upadacitinib-treated and 37% of placebo-treated patients through week 14. No events of malignancy, major adverse cardiovascular events, venous thromboembolism or deaths were reported with upadacitinib.Conclusion: Upadacitinib 15 mg was significantly more effective than placebo over 14 weeks of treatment in bDMARD-IR patients with active AS. No new safety risks were identified with upadacitinib.Trial Registration Number: NCT04169373. [ABSTRACT FROM AUTHOR]

Objectives Osteitis condensans ilii (OCI) has become an important differential diagnosis for axial spondyloarthritis (axSpA). The objective of this matched case–control study was to investigate demographic, clinical, laboratory and MRI characteristics of OCI as compared with axial spondyloarthritis (axSpA). Methods A total of 60 patients diagnosed with OCI were included in the final analysis. From 27 of these patients, MRIs of the sacroiliac joints were available. OCI patients were matched with a 1:1 ratio by back pain duration to patients with definite axSpA in order to compare clinical, laboratory and MRI characteristics. Results The OCI patients were nearly all females (96.7 vs 46.7%), had a significantly lower prevalence of inflammatory back pain (39.5 vs 88.9%), a significantly lower percentage of HLA-B27 positives (35.2 vs 80.0%) and a lower prevalence of the majority of other SpA features as compared with axSpA patients. Interestingly, there was no difference in the prevalence of osteitis in the sacroiliac joints (92.6 vs 85.2% in OCI and axSpA, respectively, P  = 0.44), but there was a difference in the prevalence of erosions (7.4 vs 66.7%, respectively, P  = 0.0001). In addition, in OCI nearly all lesions were localized in the anterior part of the sacroiliac joints while in axSpA lesions were localized predominantly in the middle part of the joint (for osteitis: 96 vs 4% in OCI and 28.6 vs 71.4% in axSpA; P  = 0.0002 for the inter-group difference). Conclusion Clinical and imaging features of OCI compared with axSpA are described that should help in differential diagnosis. [ABSTRACT FROM AUTHOR]

The authors discuss their research on the radiographic sacroiliitis progression in patients with axial spondyloarthritis (axSpA) who were included in the Assessment of SpA International Society cohort. Topics mentioned include the use of the modified New York criteria in scoring the pelvic radiographs of patients, the procedure of calculating the sacroiliitis sum score, and the parameters associated with the radiographic axSpA classification including male sex and HLA-B27 positivity.

Objective: To evaluate radiographic progression in the sacroiliac (SI) joints and to identify its predictors during long‐term treatment (up to 6 years) with the tumor necrosis factor (TNF) inhibitor etanercept in patients with early axial spondyloarthritis (SpA). Methods: Patients with early axial SpA who were treated with etanercept for up to 6 years in the Etanercept versus Sulfasalazine in Early Axial Spondyloarthritis (ESTHER) trial were selected based on the availability of radiographs of the SI joints. Two readers who were blinded with regard to clinical data scored the radiographs according to the modified New York criteria (range 0–4 per SI joint). A sacroiliitis sum score (total range 0–8) was calculated as the mean of the scores of the 2 readers. Active and chronic inflammatory changes in the SI joints on magnetic resonance imaging (MRI) performed at baseline, year 2, and year 4 were assessed according to the Berlin MRI scoring system. Results: Of the 76 patients originally included in the study, 42 had radiographs of the SI joints available at baseline and at least 1 follow‐up time point (year 2, 4, or 6). The mean ± SD change in the sacroiliitis sum score was 0.13 ± 0.73, −0.27 ± 0.76, and −0.09 ± 0.68, in the time intervals baseline to year 2, year 2 to year 4, and year 4 to year 6, respectively. In the longitudinal mixed model analysis, elevated C‐reactive protein level (β = 0.58 [95% confidence interval 0.24, 0.91]) and MRI SI joint osteitis score (β = 0.06 [95% confidence interval 0.03, 0.10]) were independently associated with progression of the sacroiliitis sum score. Conclusion: Our findings indicate that long‐term anti‐TNF therapy decelerates the progression of structural damage in the SI joints. Elevated CRP level and presence of osteitis on MRI were independently associated with radiographic sacroiliitis progression. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the long-term clinical and imaging efficacy of etanercept in patients with early, active nonradiographic axial spondyloarthritis (SpA).Methods: Adult patients who satisfied the Assessment of SpondyloArthritis international Society (ASAS) classification criteria for axial SpA (but not the modified New York radiographic criteria), with symptom duration >3 months to <5 years, and who were unresponsive to ≥2 nonsteroidal antirheumatic drugs (NSAIDs) received double-blind etanercept 50 mg/week or placebo for 12 weeks, followed by open-label etanercept 50 mg/week to week 104. Clinical, magnetic resonance imaging (MRI; Spondyloarthritis Research Consortium of Canada [SPARCC] scores), and safety outcomes at 104 weeks were analyzed.Results: Of 215 randomized patients (etanercept: n = 106; placebo: n = 109), 205 entered the study (etanercept/etanercept: n = 100; placebo/etanercept: n = 105) and 169 completed the open-label period (etanercept/etanercept: n = 83; placebo/etanercept: n = 86). At week 104, 61 of 81 (75%), 49 of 81 (61%), 48 of 80 (60%), and 57 of 81 (70%) patients who received etanercept throughout the trial achieved ASAS20, ASAS40, Ankylosing Spondylitis Disease Activity Score (ASDAS) inactive disease, and Bath Ankylosing Spondylitis Disease Activity Index criteria for 50% improvement (BASDAI 50) scores, respectively (observed). From baseline to week 104, continued improvements in clinical outcomes (ASDAS-C-reactive protein: -1.5 and -1.7; BASDAI: -3.3 and -3.8 [last observation carried forward]), and SPARCC MRI scores (sacroiliac joint: -6.0 and -3.4; spinal: -2.1 and -0.8 [observed]) were seen in patients receiving etanercept/etanercept and placebo/etanercept. During the study, 8% in the etanercept/etanercept group and 7% in the placebo/etanercept group had serious adverse events; no new safety signals were seen.Conclusion: Patients with early, active nonradiographic axial SpA and an inadequate response to at least 2 NSAIDs demonstrated improvement in clinical and imaging outcomes that were sustained through 104 weeks of etanercept treatment. [ABSTRACT FROM AUTHOR]

Non-steroidal anti-inflammatory drugs (NSAIDs) are the first-line treatment for patients with symptomatic axial spondyloarthritis (SpA), who seem to respond best if treated early in the course of disease. The effect of NSAIDs on radiographic disease progression is less clear. Conventional disease-modifying antirheumatic drugs (DMARDs) are not recommended in the treatment of axial SpA, either alone or in combination with TNF blockers. Patients with nonradiographic axial SpA (nr-axSpA) seem to respond as well to TNF blockers as do patients with radiographic axial SpA (ankylosing spondylitis (AS)). However, patients with nr-axSpA should, in addition to a high severity of symptoms, also have objective signs of inflammation, detectable by MRI or by C-reactive protein testing, to be treated with TNF blockers. Whether early TNF-blocker treatment can retard new bone formation needs clarification. In clinical trials, anti-IL-17 agents and TNF blockers showed similar efficacy in patients with AS. The potential of IL-23 blockade for treatment of axial SpA needs to be further investigated. Treatment options for peripheral SpA have been much less thoroughly investigated than those for axial SpA. However, some data indicate that TNF blockers are effective for treating peripheral arthritis, enthesitis and dactylitis, the typical manifestations of peripheral SpA. [ABSTRACT FROM AUTHOR]

Introduction: A 28-week study suggested efficacy of the anti-interleukin-17A monoclonal antibody secukinumab in active ankylosing spondylitis (AS). MRI-assessed inflammation was reduced at weeks 6, 28.Objective: To analyse the longer-term effects of secukinumab on MRI inflammatory and non-inflammatory spinal lesions in relation to its clinical efficacy in subjects with active AS.Methods: Spinal MRI results (baseline, week 94) for 13 subjects with AS initially treated with secukinumab 2×10 mg/kg intravenously (n=10) or placebo (n=3) and receiving a secukinumab maintenance dose of 3 mg/kg IV every 4 weeks up to week 94 were evaluated by the Berlin score; inflammatory/non-inflammatory (fatty) changes were assessed at vertebral edges (VEs). Results were compared with clinical outcomes.Results: Most of the 13 subjects assessed at week 94 had sustained clinical responses: 8 (62%) achieved Assessment of SpondyloArthritis international Society 20% (ASAS20), including 6 (46%) achieving ASAS40 responses, corresponding to 75% and 83% reductions in the Berlin score, respectively. In the 10 subjects treated with secukinumab throughout the study period, 79/91 (87%) inflammatory VEs at baseline resolved by week 94; new fatty lesions occurred in 39/796 (4.9%) of VEs; 87/124 (70%) VEs with fatty lesions at baseline remained unchanged; 30% were no longer visible.Conclusions: In this pilot study, secukinumab treatment up to 2 years yielded sustained clinical improvement accompanied by regression of spinal inflammation. The impact of secukinumab on the development of fatty changes and bone formation in AS will be assessed in larger trials.Trial Registration Number: This study is registered with ClinicalTrials.gov, number NCT00809159. [ABSTRACT FROM AUTHOR]

Objective To investigate changes in magnetic resonance imaging (MRI)-assessed inflammation and structural lesions in the sacroiliac (SI) joints during treatment with adalimumab versus placebo. Methods In a 48-week double-blind, placebo-controlled trial, 52 patients with spondyloarthritis were randomized to receive subcutaneous injections of either adalimumab 40 mg (n = 25) or placebo (n = 27) every other week for 12 weeks. Patients in the adalimumab group continued to receive and patients in the placebo group were switched to adalimumab 40 mg every other week for an additional 12 weeks. MRI of the SI joints was performed at weeks 0, 12, 24, and 48, and the images were assessed independently in a blinded manner using the modified Berlin and the Spondyloarthritis Research Consortium of Canada (SPARCC) MRI scores for inflammation and structural lesions of the SI joints. Results At baseline, 56% of the adalimumab group and ∼72% of the placebo group had an MRI-assessed inflammation score of ≥1. Among the patients with inflammation at baseline, the mean percent reductions in MRI scores for inflammation from week 0 to 12 were greater in the adalimumab group compared with the placebo group (Berlin method, −62% versus −5%; SPARCC method, −58% versus −12% [both P < 0.04]). Furthermore, the mean SPARCC erosion score decreased (−0.6) and the SPARCC backfill score increased (+0.8) in the adalimumab group from week 0 to week 12. From week 12 to week 24, larger absolute reductions in the Berlin/SPARCC inflammation scores and the SPARCC erosion score and larger increases in the Berlin/SPARCC fatty lesion scores were seen in the placebo group compared with the adalimumab group. In univariate regression analyses (analysis of covariance) and multivariate stepwise regression analyses, treatment with adalimumab was independently associated with regression of the SPARCC erosion score from week 0 to 12 but not with changes in the other types of MRI lesions. Conclusion Significant changes in the Berlin and SPARCC MRI-assessed inflammation scores and in the SPARCC MRI-assessed erosion scores occurred within 12 weeks after initiation of adalimumab. Tumor necrosis factor inhibitor treatment was associated with resolution of erosions and the development of backfill. [ABSTRACT FROM AUTHOR]

Objective. To investigate the clinical course of disease over 2 years in patients with nonradiographic axial spondylarthritis (SpA) and patients with ankylosing spondylitis (AS). Methods. The study group comprised 303 patients with axial SpA (158 patients with AS and a symptom duration of ≤10 years and 145 patients with nonradiographic axial SpA and a symptom duration of ≥5 years) who did not receive tumor necrosis factor (TNF) blockers during 2 years of followup. Results. The Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) did not differ between patients with nonradiographic axial SpA and those with AS at any time point during followup. The Bath Ankylosing Spondylitis Functional Index was significantly higher in patients with AS at baseline only, but spinal mobility was generally better in patients with nonradiographic SpA compared with those with AS. At all time points, C-reactive protein (CRP) levels were significantly higher in patients with AS compared with patients with nonradiographic axial SpA. Accordingly, the Ankylosing Spondylitis Disease Activity Score (ASDAS) was significantly higher in the patients with AS at 2 of 4 time points. When patients with a BASDAI score of 4 plus an elevated CRP level at baseline were analyzed over time, there were no significant differences in the proportions of patients with nonradiographic axial SpA and those with AS who reached low disease activity status at 2 time points during 2 years of followup when a clinical definition of low disease activity was used (38% and 35%, respectively, achieved a BASDAI score of ≥4, and 13% and 15%, respectively, achieved a score of ≥2). When definitions that included the CRP level were used, however, a greater percentage of patients with nonradiographic axial SpA achieved low disease activity (25% of patients with nonradiographic axial SpA and 10% of patients with AS achieved a BASDAI score of <4 and a normal CRP level, and 13% of patients with nonradiographic axial SpA and 3% of those with AS achieved ASDAS-defined low disease activity). Conclusion. Patients with nonradiographic axial SpA and those with AS who were not treated with TNF blockers demonstrated a similar clinical disease course over 2 years. Patients with nonradiographic axial SpA achieved a status of low disease activity more frequently than those with AS if outcome parameters that included the CRP level were used. [ABSTRACT FROM AUTHOR]

Objective. The aim of this study was to assess the degree of fluctuation of osteitis on MRI during long-term treatment with etanercept (ETN) in patients with early axial SpA (axSpA) with active inflammation (osteitis) on whole-body MRI in the spine and/or the SI joints at baseline.Methods. We analysed MRI data from 328 SI joint quadrants and 943 spine vertebral units (VUs) in terms of osteitis in the pooled data set of 41 patients who were treated with ETN for 3 consecutive years. Scoring was performed by two blinded radiologists at baseline, year 2 and year 3.Results. Through years 2 and 3, osteitis on MRI resolved completely in 56 of 144 (38.9%) SI joint quadrants and in 20 of 40 (50%) VUs affected at baseline, while persistent osteitis was found in 24 of 144 (16.7%) SI joint quadrants and in 8 of 40 (20.0%) spine VUs. The development of new osteitis in sites that were free of osteitis at baseline only occurred in 2 of 131 (1.5%) SI joint quadrants and in 3 of 862 (0.4%) spine VUs in both year 2 and year 3.Conclusion. There was a consistently small amount of osteitis on MRI in patients with early axSpA compared with baseline values, and only a very low rate of new-onset osteitis was found during 3 years of continuous treatment with ETN.Trial registration: www.clinicaltrials.gov, NCT00844142. [ABSTRACT FROM PUBLISHER]

Objective To assess the efficacy of etanercept in the treatment of early active nonsteroidal antiinflammatory drug (NSAID)-refractory nonradiographic axial spondyloarthritis (SpA). Methods The study population consisted of patients who met the Assessment of SpondyloArthritis international Society (ASAS) classification criteria for axial SpA but not the modified New York radiographic criteria for ankylosing spondylitis (as assessed by a radiologist at the central trial site), had a symptom duration of >3 months but <5 years, had a score of ≥4 on the Bath Ankylosing Spondylitis Disease Activity Index, and had been treated unsuccessfully with ≥2 NSAIDs. Patients were randomized to receive etanercept 50 mg/week or placebo and continued background NSAID treatment for 12 weeks (double-blind study); during the subsequent open-label period, all patients received etanercept 50 mg/week. The primary study end point was meeting the ASAS criteria for 40% improvement (ASAS40) at week 12. Magnetic resonance imaging (MRI) of the sacroiliac joints and spine was performed at baseline and week 12. Results One hundred six patients were randomized to the etanercept group and 109 to the placebo group. Of the 215 patients, the mean ± SD age at baseline was 32.0 ± 7.8 years, 154 (72%) were HLA-B27 positive, and 174 (81%) had MRI-confirmed sacroiliitis. At 12 weeks, the proportion of patients with improvement according to the ASAS40 was significantly higher in the etanercept group than in the placebo group (34 of 105 [32%] versus 17 of 108 [16%]; P = 0.006). Patients who received etanercept exhibited a greater reduction in MRI-based scores for sacroiliac joint inflammation (−46.9% versus −10.9%; P < 0.001) and spinal inflammation (−45.4% versus −33.4%; P = 0.04) compared with placebo-treated patients at week 12. Post hoc analyses suggested a possible association between higher baseline C-reactive protein levels or MRI sacroiliac joint inflammation scores and higher rates of ASAS40 response to etanercept. At week 24, patients in the placebo group who had switched to etanercept at 12 weeks exhibited improvement similar to that observed in patients who had received etanercept for 24 weeks. Conclusion In patients with nonradiographic axial SpA, etanercept treatment was associated with rapid, significant improvement in symptomatic disease activity, function, and systemic and skeletal inflammation over 12 weeks; clinical/functional improvement was sustained over 24 weeks. [ABSTRACT FROM AUTHOR]

Objective To evaluate the presence of spinal inflammation with and without sacroiliac (SI) joint inflammation on magnetic resonance imaging (MRI) in patients with active nonradiographic axial spondyloarthritis (SpA), and to compare the disease characteristics of these subgroups. Methods ABILITY-1 is a multicenter, randomized, controlled trial of adalimumab versus placebo in patients with nonradiographic axial SpA classified using the Assessment of SpondyloArthritis international Society axial SpA criteria. Baseline MRIs were centrally scored independently by 2 readers using the Spondyloarthritis Research Consortium of Canada (SPARCC) method for the SI joints and the SPARCC 6-discovertebral unit method for the spine. Positive evidence of inflammation on MRI was defined as a SPARCC score of ≥2 for either the SI joints or the spine. Results Among patients with baseline SPARCC scores, 40% had an SI joint score of ≥2 and 52% had a spine score of ≥2. Forty-nine percent of patients with baseline SI joint scores of <2, and 58% of those with baseline SI joint scores of ≥2, had a spine score of ≥2. Comparison of baseline disease characteristics by baseline SI joint and spine scores showed that a greater proportion of patients in the subgroup with a baseline SPARCC score of ≥2 for both SI joints and spine were male, and patients with spine and SI joint scores of <2 were younger and had shorter symptom duration. SPARCC spine scores correlated with baseline symptom duration, and SI joint scores correlated negatively with the baseline Bath Ankylosing Spondylitis Disease Activity Index, but neither correlated with the baseline Ankylosing Spondylitis Disease Activity Score, total back pain, the patient's global assessment of disease activity, the Bath Ankylosing Spondylitis Functional Index, morning stiffness, nocturnal pain, or C-reactive protein level. Conclusion Assessment by experienced readers showed that spinal inflammation on MRI might be observed in half of patients with nonradiographic axial SpA without SI joint inflammation. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article related to nonradiographic axial spondyloarthritis that was published in the previous in the previous issue of the periodical.

Background: The JAK pathway is a potential therapeutic target in ankylosing spondylitis. This study assessed the efficacy and safety of upadacitinib, a selective JAK1 inhibitor, in patients with ankylosing spondylitis.Methods: This multicentre, randomised, double-blind, placebo-controlled, two-period, parallel-group, phase 2/3 study, SELECT-AXIS 1, enrolled adults in 62 sites in 20 countries. Eligible patients had active ankylosing spondylitis, fulfilled modified New York criteria, were previously untreated with biological disease-modifying antirheumatic drugs, and had inadequate response to at least two or intolerance or contraindication to non-steroidal anti-inflammatory drugs. Patients were randomly assigned 1:1 using interactive response technology to take oral upadacitinib 15 mg once daily or oral placebo for the 14-week period 1; only period 1 data are reported here. The primary endpoint was the composite outcome measure of the Assessment of SpondyloArthritis international Society 40 response at week 14. Analyses were done in the full analysis set of patients who were randomly assigned and received at least one dose of study drug. This study is registered with ClinicalTrials.gov, NCT03178487.Findings: Between Nov 30, 2017, and Oct 15, 2018, 187 patients were randomly assigned to upadacitinib 15 mg (93 patients) or to placebo (94 patients), and 178 (95%) patients (89 in the upadacitinib group and 89 in the placebo group) completed period 1 on study drug (by the completion date of Jan 21, 2019). Significantly more patients had an Assessment of SpondyloArthritis international Society 40 response in the upadacitinib group versus in the placebo group at week 14 (48 [52%] of 93 patients vs 24 [26%] of 94 patients; p=0·0003; treatment difference 26% [95% CI 13-40]). Adverse events were reported in 58 (62%) of 93 patients in the upadacitinib group versus 52 (55%) of 94 in the placebo group. The most common adverse event in the upadacitinib group was increased creatine phosphokinase (eight [9%] of 93 patients in the upadacitinib group vs two [2%] of 94 patients with placebo). No serious infections, herpes zoster, malignancy, venous thromboembolic events, or deaths were reported; one serious adverse event was reported in each group.Interpretation: Upadacitinib 15 mg was efficacious and well tolerated in patients with active ankylosing spondylitis who had an inadequate response or contraindication to non-steroidal anti-inflammatory drugs. These data support the further investigation of upadacitinib for the treatment of axial spondyloarthritis.Funding: AbbVie. [ABSTRACT FROM AUTHOR]