Impact of filgotinib on sacroiliac joint magnetic resonance imaging structural lesions at 12 weeks in patients with active ankylosing spondylitis (TORTUGA trial)

Update of imaging in the assessment of axial spondyloarthritis

This update addresses new developments in imaging of axial spondyloarthritis from the past 5 years. These have focused mostly on enhanced CT and MRI-based technologies that bring greater precision to the assessment of both inflammatory and structural lesions in the sacroiliac joint. An international consensus has recommended a 4-sequence MRI for routine diagnostic evaluation of the sacroiliac joint aimed at depicting the location and extent of inflammation as well as an erosion-sensitive sequence for structural damage. The latter include high resolution thin slice sequences that accentuate the interface between subchondral bone and the overlying cartilage and joint space as well as synthetic CT, a deep learning-based technique that transforms certain MRI sequences into images resembling CT. Algorithms based on deep learning derived from plain radiographic, CT, and MRI datasets are increasingly more accurate at identifying sacroiliitis and individual lesions observed on images of the sacroiliac joints and spine.

Detection of structural lesions of the sacroiliac joints in patients with spondyloarthritis: A comparison of T1-weighted 3D spoiled gradient echo MRI and MRI-based synthetic CT versus T1-weighted turbo spin echo MRI

OBJECTIVES

To investigate the detection of erosion, sclerosis and ankylosis using 1 mm 3D T1-weighted spoiled gradient echo (T1w-GRE) MRI and 1 mm MRI-based synthetic CT (sCT), compared with conventional 4 mm T1w-TSE.

MATERIALS AND METHODS

Prospective, cross-sectional study. Semi-coronal 4 mm T1w-TSE and axial T1w-GRE with 1.6 mm slice thickness and 0.8 mm spacing between overlapping slices were performed. The T1w-GRE images were processed into sCT images using a commercial deep learning algorithm, BoneMRI. Both were reconstructed into 1 mm semi-coronal images. T1w-TSE, T1w-GRE and sCT images were assessed independently by 3 expert and 4 non-expert readers for erosion, sclerosis and ankylosis. Cohen's kappa for inter-reader agreement, exact McNemar test for lesion frequencies and Wilcoxon signed-rank test for confidence in lesion detection were used.

RESULTS

Nineteen patients with axial spondyloarthritis were evaluated. T1w-GRE increased inter-reader agreement for detecting erosion (kappa 0.42 vs 0.21 in non-experts), increased detection of erosion (57 vs 43 of 152 joint quadrants) and sclerosis (26 vs 17 of 152 joint quadrants) among experts, and increased reader confidence for scoring erosion and sclerosis. sCT increased inter-reader agreement for detecting sclerosis (kappa 0.69 vs 0.37 in experts) and ankylosis (0.71 vs 0.52 in non-experts), increased detection of sclerosis (34 vs 17 of 152 joint quadrants) and ankylosis (20 vs 13 of 76 joint halves) among experts, and increased reader confidence for scoring erosion, sclerosis and ankylosis.

CONCLUSION

T1w-GRE and sCT increase sensitivity and reader confidence for the detection of erosion, sclerosis and ankylosis, compared with T1w-TSE.

CLINICAL RELEVANCE STATEMENT

These methods improve the detection of sacroiliac joint structural lesions and might be a useful addition to SIJ MRI protocols both in routine clinical care and as structural outcome measures in clinical trials.

Exploratory analysis of the potential disconnect between objective inflammatory response and clinical response following certolizumab pegol treatment in patients with active axial spondyloarthritis

INTRODUCTION

This post hoc analysis evaluated the relationship between objective measures of inflammation and clinical outcomes following 12 weeks of certolizumab pegol (CZP) treatment in patients with active axial spondyloarthritis (axSpA).

METHODS

We report the proportion of patients achieving ≥50% and ≥75% improvements in clinical composite outcome measures of disease activity (Axial Spondyloarthritis Disease Activity Score [ASDAS], Bath Ankylosing Spondylitis Disease Activity Index [BASDAI]) and objective measures of inflammation (C reactive protein [CRP], Ankylosing Spondylitis spine MRI score [ASspiMRI-a] Berlin score and Spondyloarthritis Research Consortium of Canada [SPARCC] MRI Sacroiliac Joints [SIJ] score) following 12 weeks of CZP treatment. Data from two independent readers over four MRI reading campaigns were pooled using a mixed model with repeated measures for each variable.

RESULTS

136 patients (radiographic axSpA [r-axSpA]: 76; non-radiographic axSpA [nr-axSpA]: 60) were included. Following CZP treatment, CRP, ASspiMRI-a Berlin score and SPARCC SIJ score were reduced by ≥50% in most patients (CRP: 136/136 [100.0%]; Berlin: 73/136 [53.7%]; SPARCC SIJ: 71/136 [52.2%]), and often by ≥75%. Less than half of patients with r-axSpA and nr-axSpA showed ≥50% reduction in clinical responses (BASDAI: 64/136 [47.1%]; ASDAS: 66/136 [48.5%]). These results were also observed at the individual patient level; ≥50% improvements in MRI/CRP inflammatory measures did not translate into similar improvements in clinical responses for most patients.

CONCLUSION

There is a potential disconnect between objective measures of inflammation and clinical outcome responses in patients with axSpA. The use of only clinical response measures as trial endpoints may underestimate anti-inflammatory treatment effects.

TRIAL REGISTRATION NUMBER

NCT01087762.

Tailoring the treatment of inflammatory rheumatic diseases by a better stratification and characterization of the clinical patient heterogeneity. Findings from a systematic literature review and experts' consensus

Inflammatory rheumatic diseases are different pathologic conditions associated with a deregulated immune response, codified along a spectrum of disorders, with autoinflammatory and autoimmune diseases as two-end phenotypes of this continuum. Despite pathogenic differences, inflammatory rheumatic diseases are commonly managed with a limited number of immunosuppressive drugs, sometimes with partial evidence or transferring physicians' knowledge in different patients. In addition, several randomized clinical trials, enrolling these patients, did not meet the primary pre-established outcomes and these findings could be linked to the underlying molecular diversities along the spectrum of inflammatory rheumatic disorders. In fact, the resulting patient heterogeneity may be driven by differences in underlying molecular pathology also resulting in variable responses to immunosuppressive drugs. Thus, the identification of different clinical subsets may possibly overcome the major obstacles that limit the development more effective therapeutic strategies for these patients with inflammatory rheumatic diseases. This clinical heterogeneity could require a diverse therapeutic management to improve patient outcomes and increase the frequency of clinical remission. Therefore, the importance of better patient stratification and characterization is increasingly pointed out according to the precision medicine principles, also suggesting a new approach for disease treatment. In fact, based on a better proposed patient profiling, clinicians could more appropriately balance the therapeutic management. On these bases, we synthetized and discussed the available literature about the patient profiling in regard to therapy in the context of inflammatory rheumatic diseases, mainly focusing on randomized clinical trials. We provided an overview of the importance of a better stratification and characterization of the clinical heterogeneity of patients with inflammatory rheumatic diseases identifying this point as crucial in improving the management of these patients.

Disease modification in axial spondyloarthritis - still a controversy?

PURPOSE OF REVIEW

This review evaluates recent advancements in disease-modifying therapies for axial spondyloarthritis (axSpA).

RECENT FINDINGS

A recent study could not demonstrate an additional effect of NSAID therapy on golimumab [Tumor Necrosis Factor-α inhibitor (TNFi)] on structural progression; however, this might be due to the fact that the study was underpowered. While DMARDs have shown promise in suppressing inflammation, their impact on structural progression remains uncertain. A well powered trial showed no difference in spinal progression between secukinumab [Interleukin17A inhibitor (IL17Ai)] and adalimumab-biosimilar (TNFi). Preliminary data on Janus kinase inhibitors (JAKi) focus on MRI findings but lack evidence on radiographic spinal progression. While some studies suggest promising outcomes, others reveal limitations and inconclusive findings.

SUMMARY

Recent studies explore the effectiveness of NSAIDs, biological disease-modifying antirheumatic drugs like TNFi and IL-17i, as well as JAK inhibitors in axSpA. Conflicting evidence surrounds these therapies' ability to impede structural progression, with challenges in study design and interpretation. Moreover, changes in demographics and treatment methods underscore the importance of examining trends over time when assessing disease outcomes. Ultimately, ongoing research could benefit from new imaging tools when evaluating therapeutic strategies for modifying disease progression in axSpA.

MRI-based synthetic CT: a new method for structural damage assessment in the spine in patients with axial spondyloarthritis - a comparison with low-dose CT and radiography

OBJECTIVE

To investigate the ability of MRI-based synthetic CT (sCT), low-dose CT (ldCT) and radiography to detect spinal new bone formation (NBF) in patients with axial spondyloarthritis (axSpA).

METHODS

Radiography of lumbar and cervical spine, ldCT and sCT of the entire spine were performed in 17 patients with axSpA. sCT was reconstructed using the BoneMRI application (V.1.6, MRIGuidance BV, Utrecht, NL), a quantitative three-dimensional MRI-technique based on a dual-echo gradient sequence and a machine learning processing pipeline that can generate CT-like MR images. Images were anonymised and scored by four readers blinded to other imaging/clinical information, applying the Canada-Denmark NBF assessment system.

RESULTS

Mean scores of NBF lesions for the four readers were 188/209/37 for ldCT/sCT/radiography. Most NBF findings were at anterior vertebral corners with means 163 on ldCT, 166 on sCT and 35 on radiography. With ldCT of the entire spine as reference standard, the sensitivity to detect NBF was 0.67/0.13 for sCT/radiography; both with specificities >0.95. For levels that were assessable on radiography (C2-T1 and T12-S1), the sensitivity was 0.61/0.48 for sCT/radiography, specificities >0.90. For facet joints, the sensitivity was 0.46/0.03 for sCT/radiography, specificities >0.94. The mean inter-reader agreements (kappa) for all locations were 0.68/0.58/0.56 for ldCT/sCT/radiography, best for anterior corners.

CONCLUSION

With ldCT as reference standard, MRI-based sCT of the spine showed very high specificity and a sensitivity much higher than radiography, despite limited reader training. sCT could become highly valuable for detecting/monitoring structural spine damage in axSpA, not the least in clinical trials.

Erosions on T1-Weighted Magnetic Resonance Imaging Versus Radiography of Sacroiliac Joints in Recent-Onset Axial Spondyloarthritis: 2-Year Data (EMBARK Trial and DESIR Cohort)

OBJECTIVE

(1) To compare the capacity to detect sacroiliac joint (SIJ) erosions and baseline-to-week 104 change in erosions between magnetic resonance imaging (MRI) and radiographs in recent-onset axial spondyloarthritis (axSpA); and (2) to compare treatment-discriminatory capacities of MRI and radiographic scores for erosion detection in patients receiving etanercept in the Effect of Etanercept on Symptoms and Objective Inflammation in Nonradiographic axSpA (EMBARK) trial vs controls in the DESIR (Devenir des Spondylarthropathies Indifférenciées Récentes) cohort.

METHODS

Anonymized SIJ MRI and radiographs were assessed at patient and joint surface levels. Three readers evaluated MRI; 3 different readers evaluated radiographs. Final scores for comparison of radiographs and MRI for detection of erosions were assigned based on agreement of ≥ 2 of 3 readers' assessments.

RESULTS

At baseline, discordance in erosion detection between imaging methods was more frequent for MRI erosions in the absence of radiographic erosions (48/224 [21.4%] patients) than for radiographic erosions in the absence of MRI erosions (14/224 [6.3%] patients; P < 0.001). After 104 weeks, a decrease in erosions was observed on MRI but not radiographs in 49/221 (22.2%) patients, and on radiographs but not MRI in 6/221 (2.7%) patients (P < 0.001). In the treatment-discriminant capacity analysis, the largest standardized differences between etanercept and control cohorts at week 104 were changes in Spondyloarthritis Research Consortium of Canada MRI erosion discrete score, changes in erosion average score, and meeting the modified New York criteria on radiographs, with unadjusted/adjusted Hedges G effect sizes of 0.40/0.50, 0.40/0.56, and 0.40/0.43, respectively.

CONCLUSION

In recent-onset axSpA, SIJ erosions and erosion change were observed more frequently on MRI than radiography. The significance of interval improvement of MRI erosions warrants further research. [ClinicalTrials.gov: NCT01258738, NCT01648907].

Validation of SPARCC MRI-RETIC e-tools for increasing scoring proficiency of MRI sacroiliac joint lesions in axial spondyloarthritis

BACKGROUND

The Spondyloarthritis Research Consortium of Canada (SPARCC) developers have created web-based calibration modules for the SPARCC MRI sacroiliac joint (SIJ) scoring methods. We aimed to test the impact of applying these e-modules on the feasibility and reliability of these methods.

METHODS

The SPARCC-SIJ RETIC e-modules contain cases with baseline and follow-up scans and an online scoring interface. Visual real-time feedback regarding concordance/discordance of scoring with expert readers is provided by a colour-coding scheme. Reliability is assessed in real time by intraclass correlation coefficient (ICC), cases being scored until ICC targets are attained. Participating readers (n=17) from the EuroSpA Imaging project were randomised to one of two reader calibration strategies that each comprised three stages. Baseline and follow-up scans from 25 cases were scored after each stage was completed. Reliability was compared with a SPARCC developer, and the System Usability Scale (SUS) assessed feasibility.

RESULTS

The reliability of readers for scoring bone marrow oedema was high after the first stage of calibration, and only minor improvement was noted following the use of the inflammation module. Greater enhancement of reader reliability was evident after the use of the structural module and was most consistently evident for the scoring of erosion (ICC status/change: stage 1 (0.42/0.20) to stage 3 (0.50/0.38)) and backfill (ICC status/change: stage 1 (0.51/0.19) to stage 3 (0.69/0.41)). The feasibility of both e-modules was evident by high SUS scores.

CONCLUSION

The SPARCC-SIJ RETIC e-modules are feasible, effective knowledge transfer tools, and their use is recommended before using the SPARCC methods for clinical research and tria.

Current Pharmacological Therapies for the Management of Spondyloarthritis: Special Considerations in Older Patients

Spondylarthritis (SpA) is generally observed in young male patients but can be diagnosed in older patients. These cases correspond to late-onset SpA (LoSpA) with two main clinical presentations, axial and peripheral SpA. Another increasingly common situation is that of older patients who have had SpA for many years. The therapeutic management of LoSpA is quite smilar to the management of patients with an early-onset disease, combining both non-pharmacological and pharmacological treatments. The treatments that can be used in LoSpA include non-steroidal anti-inflammatory drugs (NSAIDs) and biological agents targeting TNFα or IL-17A. Janus kinase inhibitors (JAKi) were recently introduced on the market for SpA. TNF inhibitors and IL-17inhibitors are very effective drugs in early-onset SpA. The effectiveness and safety of targeted therapies have not been specifically evaluated in LoSpA or older patients, and thus caution is required for these patients with comorbidities and/or polymedication. According to indirect data, biological agents seem to be less effective in LoSpA compared with early-onset disease. In parallel, a careful evaluation for the risk of infection, malignancy and cardiovascular events is recommended before initiating these drugs in this age category. JAKi may be used in LoSpA, but only in selected patients according to recent recommendations from the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA). When considering that the prevalence of such situations is expected to increase as ageing progresses, it is certainly time to consider this patient category as a distinct subgroup within the spectrum of SpA. Specific studies evaluating targeted agents in this age category are thus desirable.

Structural disease modification in axial spondyloarthritis

"Disease modification" in axial spondyloarthritis (axSpA) seeks to not only alleviate clinical symptoms but also alter the disease's natural course by impeding new bone formation. Recent years have witnessed the effectiveness of treatments, including biologics and nonsteroidal anti-inflammatory drugs, in managing axSpA symptoms. Emerging evidence points toward their potential impact on slowing structural disease progression. This comprehensive review centers on the pivotal role of inhibiting new bone formation in axSpA disease modification. It delves into the significance of imaging techniques for assessing disease progression and explores the disease-modifying properties of available axSpA treatments, encompassing NSAIDs, TNF inhibitors, IL-17 inhibitors, and JAK inhibitors. This article offers valuable insights into the evolving landscape of disease modification strategies in axial spondyloarthritis, highlighting the multifaceted approaches used to attain these objectives.

Advances in pharmacotherapies for axial spondyloarthritis

INTRODUCTION

Axial spondyloarthritis (axSpA) refers to an inflammatory rheumatic disease that mainly affects the axial skeleton and leads to progressive radiographic changes of the sacroiliac joints and spine. axSpA is currently subdivided into the radiographic (r-axSpA) and non-radiographic (nr-axSpA) form. Both forms are associated with musculoskeletal pain, restriction of spinal mobility, specific extra-musculoskeletal manifestations, and overall, altered quality of life. The therapeutic management of axSpA is currently well standardized.

AREAS COVERED

We reviewed available literature (by using PubMed search) on non-pharmacological and pharmacological treatment options that may be used in axSpA, including r-axSpA and nr-axSpA, as well as the role of non-steroidal anti-inflammatory drugs (NSAIDs), biological agents including TNFalpha (TNFi) and IL-17 (IL-17i) inhibitors. New treatment options such as Janus kinase inhibitors are also reviewed.

EXPERT OPINION

NSAIDs remain the mainstay of initial therapy, and subsequently, biological agents (TNFi and IL-17i) may be envisaged. Four TNFi are licensed for the treatment of both r-axSpA and nr-axSpA, while IL-17i are approved in each indication. The choice between a TNFi and an IL-17i is mainly guided by the presence of extra-articular manifestations. JAKi were more recently introduced for the treatment of r-axSpA, but their use is restricted to specific patients with a safe cardiovascular profile.

Efficacy and safety of Janus kinase inhibitors in axial spondyloarthritis

Skin manifestations are common in axial spondyloarthritis (axSpA) and may precede axial involvement. Multidisciplinary management of patients with spondyloarthritis (SpA) is essential. Combined dermatology-rheumatology clinics are established for early recognition of the disease, comorbidities and a comprehensive treatment approach. Treatment options for axSpA are limited because conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) and glucocorticoids are ineffective for axial symptoms. Janus kinase inhibitors (JAKi) are targeted synthetic disease-modifying antirheumatic drugs (tsDMARDs) that decrease transduction signalling to the nucleus, resulting in a reduced inflammatory response. Currently, tofacitinib and upadacitinib are approved for treating axSpA in patients with inadequate response to TNF inhibitors (TNFi). Upadacitinib has shown efficacy in non-radiographic axSpA (nr-axSpA), suggesting that JAKi are efficacious across the spectrum of axSpA. The availability of JAKi has opened more options for patients with active axSpA based on the efficacy data and the ease of administration.

JAK Inhibitors for the Treatment of Axial Spondyloarthritis

Axial spondyloarthritis (axSpA) is a chronic disease characterized by inflammation and new bone formation that causes pain and results in functional impairment and long-term disability. Biologic agents targeting TNFα or IL-17 have been the mainstay of treatment for patients with axSpA and an inadequate response to nonsteroidal anti-inflammatory drugs. However, a proportion of axSpA patients do not respond adequately to those drugs either, creating the need to target alternative disease pathways. Janus kinase (JAK) inhibitors (JAKis) are a group of targeted synthetic disease-modifying anti-rheumatic drugs that block the intracellular signalling pathway of several proinflammatory cytokines. Given their efficacy in the management of rheumatoid arthritis and that JAKs mediate the signalling of cytokines involved in the pathogenesis of axSpA as well, JAKis have been successfully tested in a number of clinical trials in axSpA, which has led to the approval of two compounds, tofacitinib and upadacitinib for the treatment of the disease. Data from new clinical trials, long-term extensions of completed trials, and real-life observational studies that continuously emerge will shape the efficacy and safety profile and ultimately the place of JAKis in the treatment of AxSpA.

Two-year imaging outcomes from a phase 3 randomized trial of secukinumab in patients with non-radiographic axial spondyloarthritis

BACKGROUND

Radiographic progression and course of inflammation over 2 years in patients with non-radiographic axial spondyloarthritis (nr-axSpA) from the phase 3, randomized, PREVENT study are reported here.

METHODS

In the PREVENT study, adult patients fulfilling the Assessment of SpondyloArthritis International Society classification criteria for nr-axSpA with elevated CRP and/or MRI inflammation received secukinumab 150 mg or placebo. All patients received open-label secukinumab from week 52 onward. Sacroiliac (SI) joint and spinal radiographs were scored using the modified New York (mNY) grading (total sacroiliitis score; range, 0-8) and modified Stoke Ankylosing Spondylitis Spine Score (mSASSS; range, 0-72), respectively. SI joint bone marrow edema (BME) was assessed using the Berlin Active Inflammatory Lesions Scoring (0-24) and spinal MRI using the Berlin modification of the AS spine MRI (ASspiMRI) scoring (0-69).

RESULTS

Overall, 78.9% (438/555) of patients completed week 104 of the study. Over 2 years, minimal changes were observed in total radiographic SI joint scores (mean [SD] change, - 0.04 [0.49] and 0.04 [0.36]) and mSASSS scores (0.04 [0.47] and 0.07 [0.36]) in the secukinumab and placebo-secukinumab groups. Most of the patients showed no structural progression (increase ≤ smallest detectable change) in SI joint score (87.7% and 85.6%) and mSASSS score (97.5% and 97.1%) in the secukinumab and placebo-secukinumab groups. Only 3.3% (n = 7) and 2.9% (n = 3) of patients in the secukinumab and placebo-secukinumab groups, respectively, who were mNY-negative at baseline were scored as mNY-positive at week 104. Overall, 1.7% and 3.4% of patients with no syndesmophytes at baseline in the secukinumab and placebo-secukinumab group, respectively, developed ≥ 1 new syndesmophyte over 2 years. Reduction in SI joint BME observed at week 16 with secukinumab (mean [SD], - 1.23 [2.81] vs - 0.37 [1.90] with placebo) was sustained through week 104 (- 1.73 [3.49]). Spinal inflammation on MRI was low at baseline (mean score, 0.82 and 1.07 in the secukinumab and placebo groups, respectively) and remained low (mean score, 0.56 at week 104).

CONCLUSION

Structural damage was low at baseline and most patients showed no radiographic progression in SI joints and spine over 2 years in the secukinumab and placebo-secukinumab groups. Secukinumab reduced SI joint inflammation, which was sustained over 2 years.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02696031.

Can radiomics replace the SPARCC scoring system in evaluating bone marrow edema of sacroiliac joints in patients with axial spondyloarthritis?

OBJECTIVES

To develop an objective and efficient method based on radiomics to evaluate bone marrow edema (BMO) of sacroiliac joints (SIJs) by magnetic resonance imaging (MRI) in patients with axial spondyloarthritis (axSpA) and to compare with the Spondyloarthritis Research Consortium of Canada (SPARCC) scoring system.

METHODS

From September 2013 to March 2022, patients with axSpA who underwent 3.0T SIJ-MRI were included and were randomly divided into training and validation cohorts at a ratio of 7:3. The optimal radiomics features selected from the SIJ-MRI in the training cohort were included to generate the radiomics model. The performance of the model was evaluated by ROC analysis and decision curve analysis (DCA). Rad scores were calculated using the radiomics model. The responsiveness was compared for Rad scores and SPARCC scores. We also assessed the correlation between the Rad score and SPARCC score.

RESULTS

A total of 558 patients were finally included. The radiomics model showed favorable discrimination of a SPARCC score <2 or ≥2 both in the training (AUC, 0.90; 95% CI: 0.87-0.93) and validation cohorts (AUC, 0.90; 95% CI, 0.86-0.95). DCA confirmed that the model was clinically useful. Rad score showed higher responsiveness to treatment-related change than SPARCC score. Furthermore, a significant correlation was noted between the Rad score and SPARCC score when scoring the status of BMO (r_s=0.80, P < 0.001), and a strong correlation was noted when scoring the change in BMO (r=0.70, P < 0.001).

CONCLUSION

The study proposed a radiomics model to accurately quantify the BMO of SIJs in patients with axSpA, providing an alternative to the SPARCC scoring system. Key Points • The Rad score is an index with high validity for the objective and quantitative evaluation of bone marrow edema (BMO) of the sacroiliac joints in axial spondyloarthritis. • The Rad score is a promising tool to monitor the change of BMO upon treatment.

Janus Kinase Inhibitors: A New Tool for the Treatment of Axial Spondyloarthritis

Axial spondyloarthritis (axSpA) is a chronic inflammatory disease involving the spine, peripheral joints, and entheses. This condition causes stiffness, pain, and significant limitation of movement. In recent years, several effective therapies have become available based on the use of biologics that selectively block cytokines involved in the pathogenesis of the disease, such as tumor necrosis factor-α (TNFα), interleukin (IL)-17, and IL-23. However, a significant number of patients show an inadequate response to treatment. Over 10 years ago, small synthetic molecules capable of blocking the activity of Janus kinases (JAK) were introduced in the therapy of rheumatoid arthritis. Subsequently, their indication extended to the treatment of other inflammatory rheumatic diseases. The purpose of this review is to discuss the efficacy and safety of these molecules in axSpA therapy.

Novel therapies in axial spondyloarthritis

Over the past two decades, advancements in understanding the pathogenesis of axial spondyloarthritis have led to discoveries of new therapeutic targets, particularly the interleukin-17, tumor necrosis factor axis, and Janus kinase-signal transducer and activator of transcription pathway. While many of the available agents have proven to be efficacious and safe for the treatment of axial spondyloarthritis, a remarkable percentage of patients either fail or cannot tolerate these medications. This has prompted researchers to look for new targets that would maximize efficacy and minimize toxicity. In this article, we review novel agents that were recently approved, in trials, and possible future targets or mechanisms. We also discuss their role as it pertains to the prevention of radiographic progression and the management of extra-musculoskeletal manifestations.

Significance of structural changes in the axial skeleton in patients with axial spondyloarthritis: how important are lesions in the sacroiliac joint?

Inflammatory back pain (IBP) is a characteristic clinical symptom of patients with axial spondyloarthritis (axSpA) that is caused by inflammation in the axial skeleton. In early disease stages the sacroiliac joints (SIJ) are most often affected, the spine usually at later stages. In many but clearly not all cases of axSpA new bone formation in form of syndesmophytes and ankylosis occur in the further course of the disease. Function and mobility may be impaired by both, inflammation and structural changes. In clinical trials outcome parameters most often used refer to pain, disease activity, function, mobility and global health but many researchers are also interested in radiographic progression in the axial skeleton of patients with axSpA. This viewpoint discusses the relevance of structural changes in the SIJ in comparison to the spine and in relation to functional outcomes and mobility.

Management of Axial Spondyloarthritis - Insights into Upadacitinib

Although the pathogenesis of spondyloarthritis (SpA) has still not been elucidated our options to treat SpA have definitely improved in the last decades. There are two main types of SpA: (i) axial spondyloarthritis (axSpA), also covering the classical ankylosing spondylitis (AS) which is largely equivalent to radiographic (r)-axSpA but different from non-radiographic (nr)-axSpA, and (ii) peripheral SpA (pSpA) also covering psoriatic arthritis (PsA) as the main subtype. The subtype nr-axSpA has historically developed because the approval of drugs for AS did not cover forms without structural changes in the sacroiliac joints which is mandatory in the 1984 New York criteria. The definitions for axSpA are based on the 2009 Assessments in AxSpA International Society (ASAS) classification criteria. Several biologic disease modifying anti-rheumatic drugs (bDMARDs) such as the tumor necrosis factor alpha inhibitors (TNFi) and the interleukin-17-inhibitors (IL-17i) are approved mostly for the whole spectrum of SpA including axSpA and PsA but L-17i does not work in inflammatory bowel disease (IBD). Targeted synthetic (ts) DMARDs cover mainly the janus kinase (JAK)-inhibitors which have recently been developed to inhibit inflammation in several rheumatic and other immune mediated diseases such as IBD. Indeed, the physiologic mechanism of JAK-mediated signal transduction has been recognized as an important target because the inhibition of its actions was shown to successfully work as a therapeutic mechanism. There are now 4 small molecule JAK inhibitors (JAKi) that currently play a role in rheumatology with variable selectivity for the four different JAK isoforms: tofacitinib, baricitinib, upadacitinib and filgotinib. In this review, we summarize current clinical trial data and evaluate the use of the JAK1 selective inhibitor upadacitinib in the treatment of axSpA, including nr-axSpA and r-axSpA. Even though the efficacy and safety of upadacitinib over shorter periods of time has been convincing to date, long-term trials are needed to fully establish its performance and also evaluate the safety at higher doses, and its use in PsA.

The Use of Janus Kinase Inhibitors in Axial Spondyloarthritis: Current Insights

Current pharmacological treatments of axial spondyloarthritis (axSpA) are limited to non-steroidal anti-inflammatory drugs (NSAIDs) and biological agents, including TNFα inhibitors and IL-17 inhibitors. Despite the availability of these agents, many patients either fail to respond adequately, lose their initial therapeutic response over time, or develop undesirable side effects, thus highlighting the need for new treatment options. Janus kinase (JAK) and signal transducers and activators of transcription (STAT) are a group of intracellular kinases that play a role in the signaling pathway induced by cytokines and certain growth factors associated with the inflammatory process of axSpA. There are several lines of evidence implicating the JAK–STAT pathway in the pathophysiological process of axSpA, including genetic data, the use of certain JAK in the intracellular signal of specific cytokines involved in axSpA (IL-23, IL-22, and IL-6), and data from experimental models of SpA. This provides a rationale for the assessment of JAK inhibitors (JAKi) in clinical trials with patients with axSpA. In this review, we examine the role of JAK–STAT signaling in the pathogenesis of axSpA and summarize the results from recent clinical trials of JAKi (tofacitinib, upadacitinib, and filgotinib) in patients with axSpA.

Significance of structural changes in the sacroiliac joints of patients with axial spondyloarthritis detected by MRI related to patients symptoms and functioning

Axial spondyloarthritis (axSpA) is a chronic inflammatory rheumatic disease that manifests primarily in the axial skeleton, initially mostly in the sacroiliac joints (SIJ), usually later spreading to the spine. The disease is characterised by inflammation and new bone formation which are mainly assessed by conventional radiography (CR) and magnetic resonance imaging (MRI). Tumour necrosis factor inhibitors (TNFi) and interleukin-17 antagonists have been shown to be efficacious and efficient in patients with axSpA. This treatment seems to also inhibit structural damage, for example, retard radiographic progression. Indeed, a reduction of new bone formation in the spine, as assessed by CR, has been reported to occur after at least 2 years of therapy with TNFi. Recently, a reduction of erosions and ankylosis in the SIJ has also been observed in axSpA patients treated with etanercept and filgotinib. In this narrative review, we discuss the limited significance of such findings.