Tumor necrosis factor-α (TNFα) inhibitors in the treatment of nonradiographic axial spondyloarthritis: current evidence and place in therapy

Risk of disease flare in spondyloarthritis patients after tapering tumor necrosis factor inhibitors: A meta-analysis and literature review

BACKGROUND

Tumor necrosis factor inhibitors (TNFis) have shown dramatic benefit in patients with spondyloarthritis (SpA). Tapering of TNFi medication may be considered in patients with sustained low disease activity because continued use of TNFis at standard doses may increase the risk of side effects including infections and impose an economic burden. However, the optimal TNFi tapering strategy for SpA patients with inactive disease has not been established. In the present study, we investigated whether tapering TNFi doses is associated with similar risk of disease flare to maintaining SpA patients on TNFis at the standard dosage.

METHODS

The MEDLINE, Embase, and Cochrane databases were systemically searched to retrieve randomized control trials (RCTs) and observational studies published prior to August 2023, that compared disease flare in SpA (including axial SpA [axSpA], psoriatic arthritis [PsA], and SpA with IBD) patients who received standard TNFi doses and those who received a tapered dose of TNFi. Odds ratios (ORs) and 95% confidence intervals (CIs) were directly retrieved or calculated, and meta-analyses were performed. Bias was assessed using funnel plots with Begg and Mazumdar rank correlation / Egger's regression method.

RESULTS

Among 2,237 SpA patients in the 12 studies (9 RCTs and 3 observational studies) retrieved, 1,301 received the standard TNFi dose, while 936 SpA patients underwent TNFi tapering. Of these, 216 (16.6%) standard-dose TNFi and 217 (23.2%) TNF-tapering patients experienced disease flares. The pooled OR for disease flare in TNFi-tapering patients was 1.601 (95% CI 1.276 - 2.008) compared with the standard-dose patients. The funnel plot showed no publication bias.

CONCLUSIONS

The strategy of TNFi tapering was associated with a significantly increased risk of disease flare compared to maintaining SpA patients at the standard TNF dose. Further studies are needed to determine which patients can safely undergo tapering of TNFi and to develop safe tapering strategies.

An update in the pharmacological management of axial spondyloarthritis

INTRODUCTION

Significant progress has been made in the diagnosis and management of axial spondyloarthritis (AxSpA) over recent decades. A greater understanding of the immunopathogenesis of the disease has paved the way for the development of targeted treatments. Their efficacy has been demonstrated in randomized controlled trials, meta-analyses and one head-to-head study of biologic DMARDs. Treatment decisions in AxSpA are currently influenced by patient choice, co-morbidity, clinician familiarity and cost.

AREAS COVERED

We review the clinical trials that underpin the evidence base for treatments in AxSpA. We also cover the meta-analyses and head-to-head data that seek to support clinicians in personalizing treatment decisions. Further, we discuss the recent international guidelines that provide clinicians with treatment pathways and guidance.

EXPERT OPINION

We conclude that treatment decisions in managing both radiographic and non-radiographic AxSpA should be based on shared decision-making with patients, the clinical effectiveness of drug class, co-morbidity and cost. At present, we have limited head-to-head data to prioritize one drug class over another for first-line treatment but can recommend tumor necrosis factor (TNF), interleukin 17 (IL17) and JAK inhibition as being comparable in terms of clinical, structural and patient-reported outcome measures. Further real-world data may guide treatment decision-making in individual patients.

Comparative efficacy and safety of bimekizumab in axial spondyloarthritis: a systematic literature review and network meta-analysis

OBJECTIVES

To compare the efficacy and safety of bimekizumab 160 mg every 4 weeks, a selective inhibitor of IL-17F and IL-17A, with those of biologic/targeted synthetic DMARDs (b/tsDMARDs) in non-radiographic axial SpA (nr-axSpA) and AS.

METHODS

A systematic literature review identified randomized controlled trials until January 2023 for inclusion in Bayesian network meta-analyses (NMAs), including three b/tsDMARDs exposure networks: predominantly-naïve, naïve, and experienced. Outcomes were Assessment of SpondyloArthritis international Society (ASAS)20, ASAS40 and ASAS partial remission (PR) response rates at 12-16 weeks. A safety NMA investigated discontinuations due to any reason and serious adverse events at 12-16 weeks.

RESULTS

The NMA included 36 trials. The predominantly-naïve network provided the most comprehensive results. In the predominantly-naïve nr-axSpA analysis, bimekizumab had significantly higher ASAS20 response rates vs secukinumab 150 mg [with loading dose (LD)/without LD], and comparable response rates vs other active comparators. In the predominantly-naïve AS analysis, bimekizumab had significantly higher ASAS40 response rates vs secukinumab 150 mg (without LD), significantly higher ASAS-PR response rates vs secukinumab 150 mg (with LD) and comparable response rates vs other active comparators. Bimekizumab demonstrated similar safety to that of other b/tsDMARDs.

CONCLUSION

Across ASAS outcomes, bimekizumab was comparable with most b/tsDMARDs, including ixekizumab, TNF inhibitors and upadacitinib, and achieved higher response rates vs secukinumab for some ASAS outcomes in predominantly b/tsDMARD-naïve nr-axSpA and AS patients at 12-16 weeks. In a pooled axSpA network, bimekizumab demonstrated comparable safety vs other b/tsDMARDs.

Bimekizumab treatment in patients with active axial spondyloarthritis: 52-week efficacy and safety from the randomised parallel phase 3 BE MOBILE 1 and BE MOBILE 2 studies

OBJECTIVES

Bimekizumab (BKZ), a monoclonal IgG1 antibody that selectively inhibits interleukin (IL)-17F in addition to IL-17A, has demonstrated superior efficacy versus placebo in patients with non-radiographic (nr-) and radiographic (r-) axial spondyloarthritis (axSpA) at Week 16. Here, the objective is to report the efficacy and safety of BKZ at Week 52.

METHODS

BE MOBILE 1 (nr-axSpA; NCT03928704) and BE MOBILE 2 (r-axSpA; NCT03928743) comprised a 16-week, double-blind, placebo-controlled period, then a 36-week maintenance period. From Week 16, all patients received subcutaneous BKZ 160 mg every 4 weeks.

RESULTS

Improvements versus placebo in Assessment of SpondyloArthritis International Society ≥40% response (primary endpoint), Ankylosing Spondylitis Disease Activity Score, high-sensitivity C-reactive protein levels and MRI inflammation of the sacroiliac joints/spine at Week 16 were sustained to Week 52 in BKZ-randomised patients. At Week 52, responses of patients switching from placebo to BKZ at Week 16 were comparable to BKZ-randomised patients. At Week 52, ≥1 treatment-emergent adverse events (TEAEs) were reported in 183 (75.0%) and 249 (75.5%) patients with nr-axSpA and r-axSpA, respectively. Serious TEAEs occurred in 9 (3.7%) patients with nr-axSpA and 20 (6.1%) patients with r-axSpA. Oral candidiasis was the most frequent fungal infection (nr-axSpA: 18 (7.4%); r-axSpA: 20 (6.1%)). Uveitis occurred in three (1.2%) and seven (2.1%) patients with nr-axSpA and r-axSpA, and inflammatory bowel disease in two (0.8%) and three (0.9%).

CONCLUSIONS

At Week 52, dual inhibition of IL-17A and IL-17F with BKZ resulted in sustained efficacy across the axSpA spectrum; the safety profile was consistent with the known safety of BKZ.

TRIAL REGISTRATION NUMBER

NCT03928704; NCT03928743.

When MRI would be useful in patients without evidence of sacroiliitis on radiographs?

We aimed to identify when magnetic resonance imaging (MRI) would be useful to diagnose patients with suspected axial spondyloarthropathy (AxSpA) without evidence of sacroiliitis on radiographs. We retrospectively reviewed electronic medical records of patients who underwent pelvis MRI after radiographs at the rheumatology clinic in a single tertiary center in Korea. Patients underwent imaging from January 2020 to July 2022. We collected data including complete blood count, erythrocyte sedimentation rate, C-reactive protein (CRP), human leukocyte antigen (HLA)-B27, history of acute anterior uveitis (AAU), peripheral arthritis, dactylitis, inflammatory bowel disease (IBD), enthesopathy, and psoriasis. A total of 105 patients who showed no evidence of sacroiliitis on radiographs were included. The median age of patients was 41.0 years, and 44.8% were male. Of them, 34 showed sacroiliitis on MRI (group 1), and 71 showed no evidence of sacroiliitis even on MRI (group 2). Known AxSpA-related clinical features including AAU, peripheral arthritis, dactylitis, IBD, enthesopathy, and psoriasis were not different between the two groups. HLA-B27 positivity (79.4% vs. 40.0%, p < 0.001), median white blood cell count (7700 vs. 6300, p = 0.007), mean platelet count (307.7 ± 69.7 vs. 265.3 ± 68.9 × 103/µL, p = 0.005), and median CRP level (0.38 vs. 0.10, p = 0.001) showed significant differences between the two groups. In a multivariate analysis, HLA-B27 positivity and platelet count were significantly associated with sacroiliitis on MRI. In our cohort, sacroiliitis was observed on MRI in one-third of patients without radiographic evidence. MRI could be recommended to evaluate sacroiliitis in patients with positive HLA-B27 and a high platelet count.

Axial involvement in psoriatic arthritis

Among the variety of clinical manifestations of psoriatic arthritis (PsA) – including peripheral arthritis, dactylitis, enthesitis, and axial disease – spondylitis is the least studied. There is no generally accepted definition of axial PsA (axPsA), nor is there any common terminology or diagnostic criteria for it. In the rheumatology community, there is also no consensus regarding radiological and MRI assessment of axial involvement in PsA patients, while disease activity indexes and the therapeutic tactics are borrowed from those used in treating axial spondyloarthritis (axSpA) and ankylosing spondylitis (AS). However, despite a range of similarities in immunopathogenetic mechanisms of axPsA and axSpA, there are also certain differences that may affect the treatment response in these patients. The aim of this review is the analysis of data on axial disease in PsA. The article discusses the genetic features, clinical presentations, imaging techniques, differential diagnostics and treatment options of axPsA.

Non-radiographic versus radiographic axSpA: what's in a name?

Axial spondyloarthritis is a heterogeneous inflammatory condition with variable clinical presentations and outcomes. The complexity of its diagnosis and absence of biomarkers hamper the development of diagnostic criteria with the risk of misuse of the available classification criteria in clinical practice and its consequences. Axial spondyloarthritis should be regarded as a continuum in which some patients, but not all, will have a more severe phenotype characterized by progression into new bone formation and joint fusion. Growing understanding of the factors that might drive disease progression and treatment response will allow for better characterization of treatment options and outcome for each affected individual. The aim of this review is to update the current evidence of what is axial spondyloarthritis and to highlight the need to focus on the concept rather than its classification.

Biologic therapy and spinal radiographic progression in patients with axial spondyloarthritis: A structured literature review

We aimed to perform a structured literature review of spinal radiographic progression, as assessed by the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS), in patients with ankylosing spondylitis (AS) or nonradiographic axial spondyloarthritis (nr-axSpA) treated with biologic therapy. Searches were limited to English language manuscripts published in the 11 years prior to 9 July 2019. Randomized controlled trials, open-label extensions (OLEs) and observational studies reporting mSASSS progression in patients with AS or nr-axSpA treated with biologics were eligible for inclusion. Bias was assessed using the methodological index for nonrandomized studies (MINORS) tool. Among the 322 studies identified in the literature search, 23 (11 OLEs and 12 cohort studies) met the eligibility criteria and were selected for inclusion. Most studies reported mSASSS progression in patients with AS receiving tumor necrosis factor inhibitor (TNFi) treatment. One study reported mSASSS progression in patients with AS treated with secukinumab, an interleukin-17A inhibitor. The mean (range) MINORS score was 11.3 (7-15) for the 15 noncomparative studies and 15 (12-22) for the 8 comparative studies. Although results of the individual studies were variable, mSASSS progression in patients with AS was generally minimal and slow with long-term TNFi therapy. Moreover, odds ratios for the likelihood of mSASSS progression with/without TNFi favoured TNFi therapy in several of the cohort studies. The rate of mSASSS progression following continuous secukinumab treatment was low and remained stable over 4 years. Of two studies reporting progression in patients with nr-axSpA treated with TNFis, one showed no mSASSS progression; however, the lack of control limited comparative conclusions.

Radiographic progression in non-radiographic axial spondyloarthritis

INTRODUCTION

Non-radiographic axial spondyloarthritis (nr-axSpA) represents a subtype of axial spondyloarthritis (axSpA) with no significant structural damage in sacroiliac joints and spine. In addition, patients with nr-axSpA demonstrate a substantial burden of illness, and a considerable share of them might progress to radiographic axSpA (r-axSpA) over time. The amount and quality of published data allows crude estimation of progression rate and factors related to a higher risk of progression. Areas covered: This review discusses the available data reporting the rates and predictors of radiographic progression in the sacroiliac joints and in the spine in patients with nr-axSpA as well as predisposing factors for such a progression. Expert commentary: Most of the studies report about 10-40% of patients with nr-axSpA to progress to r-axSpA over a period of 2-10 years. Multiple risk factors for the radiographic sacroiliitis progression are outlined and explored. There are not enough data to presume that any treatment modality may influence progression from nr-axSpA to r-axSpA, with TNFi showing some promising results. Radiographic progression in the spine is in general low in nr-axSpA; thus, long-term studies are required to investigate the natural course of the progression and possible treatment effects.