Infliximab biosimilar CT-P13 therapy in patients with Takayasu arteritis with low dose of glucocorticoids: a prospective single-arm study

Advanced molecular imaging in large-vessel vasculitis: Adopting FDG-PET into a clinical workflow

The use of fluorodeoxyglucose-positron emission tomography (FDG-PET) imaging to detect vascular inflammation is increasingly common in the clinical management of patients with large-vessel vasculitis (LVV). In this review, the role of FDG-PET imaging to diagnose and monitor vascular disease activity will be detailed. Suggestions on incorporation of FDG-PET imaging into a clinical workflow will be provided with emphasis on patient preparation, image acquisition, and image interpretation. If FDG-PET imaging is obtained, multimodal imaging assessment, whereby FDG-PET imaging and non-invasive angiography are obtained concurrently, and correlation of imaging findings with clinical assessment is generally advisable. Considering the clinical scenario and treatment status of the patient is important when interpreting vascular FDG-PET image findings.

Current Diagnosis and Management of Takayasu Arteritis

Takayasu arteritis (TA or TAK) is a chronic large vessel vasculitis with predilection to affect the aorta and its branches. The new 2022 ACR/EULAR classification criteria for Takayasu arteritis incorporated imaging characteristics as an absolute requirement. ESR and CRP fails in accuracy as disease activity markers. Pentraxin 3 appears to be a relatively superior biomarker, which correlates with ITAS 2010 as per several studies. PET-CT is also increasingly being studied for assessing disease activity with variable results. The management of TAK involves use of steroids with upfront steroid sparing immunosuppressive agents. MMF is one such conventional DMARD/immunosuppressant with good efficacy and better safety profile, as reported in various cohort studies. Tocilizumab is proved to be a rapid remission inducing agent in refractory Takayasu arteritis in observational studies. TNF inhibitors in many uncontrolled studies showed good responses, and there is a need for good RCTs for confirmation. JAK inhibitors have also been used with success in a few reports.

18F-FDG PET/CT in Late Acquisition Identifies Sites of Active Disease in Treated Takayasu Arteritis

OBJECTIVE

Few studies have taken advantage of 18F-fluorodeoxyglucose positron emission tomography associated with computed tomography (18F-FDG PET/CT) to personalize patient evaluation and identify sites of more active disease in Takayasu arteritis (TA)-treated patients. This study aimed to evaluate the utility of 18F-FDG PET/CT in late acquisition in identifying sites of active disease in patients under full treatment for TA.

METHODS

In this cross-sectional study, patients under full treatment underwent whole-body 18F-FDG PET/CT. Sites of increased 18F-FDG uptake were classified by a score of 3 on the visual scale using the liver uptake as reference. A quantitative analysis was also performed by measuring the maximum standardized uptake value (SUV) of the vascular wall of affected arteries. Disease activity using the National Institutes of Health criteria was also evaluated.

RESULTS

Of the 20 patients, there were 18 female and 2 male patients, with a mean age of 43.6 (±11.58) years and a disease duration of 8.3 (±6.25) years. Thirteen participants (65%) were in inflammatory activity according to the criteria proposed by the National Institutes of Health. All patients received immunosuppressive agents, and one of them received immunobiological treatment. The highest SUV value was 6.2 in the aortic arch, and the lowest was 1.0 in the subclavian artery. The mean maximum SUV did not differ between clinically active and inactive patients. In the visual analysis, all participants had at least 1 vascular site with inflammatory activity, with an uptake ≥2 in relation to the liver. The aortic arch was the most frequently involved site.

CONCLUSIONS

This study showed that 18F-FDG PET/CT in late acquisition is an effective imaging method to assess TA activity even in fully treated patients.

Disease-modifying anti-rheumatic drugs for the management of Takayasu arteritis-a systematic review and meta-analysis

The pharmacotherapy of Takayasu arteritis (TAK) with disease-modifying anti-rheumatic drugs (DMARDs) is an evolving area. A systematic review of Scopus, Web of Science, Pubmed Central, clinical trial databases and recent international rheumatology conferences for interventional and observational studies reporting the effectiveness of DMARDs in TAK identified four randomized controlled trials (RCTs, with another longer-term follow-up of one RCT) and 63 observational studies. The identified trials had some concern or high risk of bias. Most observational studies were downgraded on the Newcastle-Ottawa scale due to lack of appropriate comparator groups. Studies used heterogenous outcomes of clinical responses, angiographic stabilization, normalization of inflammatory markers, reduction in vascular uptake on positron emission tomography, reduction in prednisolone doses and relapses. Tocilizumab showed benefit in a RCT compared to placebo in a secondary per-protocol analysis but not the primary intention-to-treat analysis. Abatacept failed to demonstrate benefit compared to placebo for preventing relapses in another RCT. Pooled data from uncontrolled observational studies demonstrated beneficial clinical responses and angiographic stabilization in nearly 80% patients treated with tumour necrosis factor alpha inhibitors, tocilizumab or leflunomide. Certainty of evidence for outcomes from RCTs ranged from moderate to very low and was low to very low for all observational studies. There is a paucity of high-quality evidence to guide the pharmacotherapy of TAK. Future observational studies should attempt to include appropriate comparator arms. Multicentric, adequately powered RCTs assessing both clinical and angiographic responses are necessary in TAK.

A Prospective Observational Study on the Efficacy and Safety of Infliximab-Biosimilar (CT-P13) in Patients With Takayasu Arteritis (TAKASIM)

Objectives: Infliximab (IFX) is widely used in patients with refractory Takayasu arteritis (TAK). Recently, the IFX-biosimilar CT-P13 has been introduced for the treatment of inflammatory diseases. The aim of this study was to assess the efficacy and safety of CT-P13 in patients with refractory TAK.

Methods: In this prospective, open-label, single-center trial, TAK patients either already on treatment with IFX-originator (switch group) or never treated with IFX (naïve group) received CT-P13 for 52 weeks. The primary outcomes of the study were: (i) number of patients with active disease at month 6; (ii) incidence of treatment-emergent adverse events at month 12. Disease activity was assessed at month 6 and month 12 by clinical evaluation (ITAS-2020, ITAS-ESR, and ITAS-CRP scores) and imaging assessment [magnetic resonance angiography (MRA) and (18F)-FDG-PET].

Results: 23 patients were recruited (21 switch, 2 naïve). At baseline, 7 patients (32%) were classified as active. At month 6, one patient voluntarily dropped out and 7 patients were still active (30%), including one patient started on a different bDMARD at month 2 due to poor disease control. Mean daily dose of prednisone equivalent was significantly lower than baseline (4.2 ± 1.9 mg vs. 4.8 ± 2.1 mg, p = 0.009). At month 12, another patient was excluded because of pregnancy desire. Five patients were classified as active (24%), including two patients started on a different bDMARD at month 2 and month 6. Mean daily dose of prednisone equivalent was significantly lower than baseline (3.3 ± 2.6, p = 0.034). No patient experienced side effects during CT-P13 infusion. Overall, one patient experienced grade 1 adverse event and 9 patients experienced grade 2 adverse events. In no case hospitalization was required. CT-P13 retention rate was 90.9% at month 6 and 90.4% at month 12.

Conclusion: In this study, the use of IFX-biosimilar CT-P13 in patients with refractory TAK showed satisfying efficacy and safety profile.

Effectiveness and safety of infliximab dose escalation in patients with refractory Takayasu arteritis: A real-life experience from a monocentric cohort

OBJECTIVES

To evaluate effectiveness and safety of infliximab dose escalation in Takayasu arteritis (TAK) patients. To identify factors associated with refractoriness to standard-dose infliximab.

METHODS

Medical records of infliximab-treated TAK patients from a large single-centre observational cohort were reviewed. Infliximab therapy duration, concomitant therapies, and reasons for dose escalation and therapy suspension were evaluated. Occurrence of adverse events was recorded. A comparison between patients who maintained infliximab standard-dose and those who needed dose-escalation was performed. Factors associated with refractoriness to standard dose were analysed.

RESULTS

Forty-one patients were included. Starting infliximab dose was 5 mg/kg 6-weekly and 28 patients (68%) needed dose escalation. Persistence/recurrence of clinical symptoms was the most frequent reason for escalation. Median therapy duration was 39 (IQR, 26-61) months in the standard-dose group and 68 (38-87) months in the intensified-dose group. In the intensified-dose-group, infliximab was suspended in eight patients (29%) after a median of 38 (31-71) months, due to loss of response (n = 7) or patient's request (n = 1). Patients in the intensified-dose group had a higher number of relapses (3.4 vs 0.8 events/patient) and received a higher cumulative steroid dose (1.7 [1.6-2.3] vs 1.3 [1-1.6] g/month of prednisone). Three patients from the intensified-dose group had serious infections; one patient from the standard-dose group developed paradoxical psoriasis. At univariate analysis, age at diagnosis and age at infliximab start were associated with infliximab escalation.

CONCLUSION

In TAK, dose escalation is safe and allows to optimise infliximab durability in refractory patients. Younger patients seem to be more refractory to standard dosages.

Value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography in the evaluation of pulmonary artery activity in patients with Takayasu's arteritis

AIMS

To explore the value of 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in the detection of active pulmonary artery (PA) lesions in patients with Takayasu's arteritis (TA).

METHODS AND RESULTS

Consecutive TA patients with PA involvement were prospectively recruited. Clinical activity was assessed according to the National Institutes of Health (NIH) criteria. CT pulmonary angiography (CTPA) or magnetic resonance pulmonary angiography was performed for evaluation of vascular structural characteristics, and mural thickening was considered as radiologically active. A vascular segment with 18F-FDG uptake ≥ liver was considered as PET-active. A total of 38 18F-FDG PET/CT scans were performed in 29 patients. In terms of disease activity, the sensitivity of 18F-FDG PET/CT did not significantly differ from radiological imaging (71.4% vs. 92.9%, P = 0.250), but 18F-FDG PET/CT had higher specificity (91.7% vs. 37.5%, P = 0.001) and accuracy (84.2% vs. 57.9%, P = 0.022). Although the majority of PET-active PA segments (54.9%) showed mural thickening, 14 PA segments with normal structure were also PET-active. 18F-FDG activity did not significantly differ between the PA and aorta in clinically active patients. In addition, 18F-FDG activity of the PA was positively correlated with inflammatory markers. Changes in 18F-FDG activity in PA during follow-up reflected therapeutic effects.

CONCLUSION

18F-FDG PET/CT can effectively evaluate PA activity in TA patients, and its diagnostic performance is superior to radiological imaging. The 18F-FDG activity of PA shows a good correlation with clinical disease status and inflammatory markers and can be used to monitor therapeutic effects.

Diagnostic value of [18F]FDG-PET/CT for treatment monitoring in large vessel vasculitis: a systematic review and meta-analysis

PURPOSE

Monitoring disease activity in patients with large vessel vasculitis (LVV) can be challenging. [18F]FDG-PET/CT is increasingly used to evaluate treatment response in LVV. In this systematic review and meta-analysis, we aimed to summarize the current evidence on the value of [18F]FDG-PET/CT for treatment monitoring in LVV.

METHODS

PubMed/MEDLINE and the Cochrane library database were searched from inception through October 21, 2020. Studies containing patients with LVV (i.e. giant cell arteritis, Takayasu arteritis and isolated aortitis) that received treatment and underwent [18F]FDG-PET/CT were included. Screening, full-text review and data extraction were performed by 2 investigators. The risk of bias was examined with the QUADAS-2 tool. Meta-analysis of proportions and diagnostic test accuracy was performed by a random-effects model and bivariate model, respectively.

RESULTS

Twenty-one studies were included in the systematic review, of which 8 studies were eligible for meta-analysis. Arterial [18F]FDG uptake decreased upon clinical remission in longitudinal studies. High heterogeneity (I² statistic 94%) precluded meta-analysis of the proportion of patients in which the scan normalized during clinical remission. Meta-analysis of cross-sectional studies indicated that [18F]FDG-PET/CT may detect relapsing/refractory disease with a sensitivity of 77% (95%CI 57-90%) and specificity of 71% (95%CI 47-87%). Substantial heterogeneity was observed among the cross-sectional studies. Both variation in clinical aspects and imaging procedures contributed to the heterogeneity.

CONCLUSION

Treatment of LVV leads to reduction of arterial [18F]FDG uptake during clinical remission. [18F]FDG-PET/CT has moderate diagnostic accuracy for detecting active LVV. [18F]FDG-PET/CT may aid treatment monitoring in LVV, but its findings should be interpreted in the context of the clinical suspicion of disease activity. This study underlines the relevance of published procedural recommendations for the use of [18F]FDG-PET/CT in LVV.

Vasculitis therapy refines vasculitis mechanistic classification

The primary vasculitides constitute a heterogeneous group of immune mediated diseases of incompletely understood pathogenesis currently classified by the size of blood vessels affected (Chapel Hill classification). In recent years, several drugs with well-characterized immunological targets have been tested in clinical trials in large vessel vasculitis and small vessel vasculitis. Such trials provide "reverse translational" or bedside to bench information about underlying pathogenic mechanisms. Therefore, the aim of this systematic literature review was to examine the evidence base for a more refined mechanistic immunological classification of vasculitis. A total of 40 studies (20 randomized controlled trials (RCTs), 16 prospective studies, 1 retrospective cohort study and 3 case series) were included for full qualitative assessment. RCTs concerning biologic therapy for large vessel vasculitis mainly supports interleukin 6 receptor inhibition (tocilizumab). RCTs concerning biologic therapy for granulomatosis with polyangiitis and microscopic polyangiitis mainly support anti-CD20 treatment (rituximab) and complement inhibition with a small molecule C5a receptor antagonist (avacopan) is an emerging treatment option. The biologic treatment of eosinophilic granulomatosis with polyangiitis is centered around interleukin 5 inhibition (mepolizumab). Studies on tumor necrosis factor alpha inhibition (adalimumab, infliximab, and etanercept) showed negative results in giant cell arteritis but some effect in Takayasu arteritis. Taken together, clinical studies with cytokine and cell specific drugs are dissecting the heterogeneous immunopathogenic mechanisms of vasculitis and support a mechanistic immunological classification. Especially, cytokine antagonism is pointing towards immunological distinctions between eosinophilic granulomatosis with polyangiitis and granulomatosis with polyangiitis/microscopic polyangiitis and differences between giant cell arteritis and Takayasu arteritis.

Is Takayasu arteritis the result of a Mycobacterium tuberculosis infection? The use of TNF inhibitors may be the proof-of-concept to demonstrate that this association is epiphenomenal

Although the association between Takayasu arteritis (TA) and latent or active Mycobacterium tuberculosis infection has been suggested for a long time, studies conducted in recent years are challenging this notion. Until recently, the possibility of a pathogenic relationship between TA and tuberculosis (TB) was considered a medical curiosity, but the advent of tumor necrosis factor (TNF) inhibitors as therapy for recalcitrant TA cases, as well as the widespread use of Bacille Calmette-Guérin (BCG) for vaccination purposes, has relocated this association as a top priority issue. In an attempt to define whether both diseases are pathogenically linked or if their association is only epiphenomenal in nature, we conduct a thorough literature search on the development of TB in patients with TA receiving TNF inhibitors. From a total of 13 studies that included 214 patients, the occurrence of TB was observed only in two individuals exposed to infliximab. This frequency of 0.93% is similar to that encountered in patients with other rheumatic diseases exposed to TNF inhibitors. Finally, we propose a novel pathogenic model that could reconcile the epidemiological, clinical, and immunological evidence that links TA and TB, while providing rationality for the use of TNF inhibitors in patients with TA.

Clinical Factors Associated with Time-Specific Distribution of 18F-Fluorodeoxyglucose in Large-Vessel Vasculitis

¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) can detect vascular inflammation in large-vessel vasculitis (LVV). Clinical factors that influence distribution of FDG into the arterial wall and other tissues have not been characterized in LVV. Understanding these factors will inform analytic strategies to quantify vascular PET activity. Patients with LVV (n = 69) underwent 141 paired FDG-PET imaging studies at one and two hours per a delayed image acquisition protocol. Arterial uptake was quantified as standardized uptake values (SUV_Max). SUV_Mean values were obtained for background tissues (blood pool, liver, spleen). Target-to-background ratios (TBRs) were calculated for each background tissue. Mixed model multivariable linear regression was used to identify time-dependent associations between FDG uptake and selected clinical features. Clinical factors associated with FDG distribution differed in a tissue- and time-dependent manner. Age, body mass index, and C-reactive protein were significantly associated with arterial FDG uptake at both time points. Clearance factors (e.g. glomerular filtration rate) were significantly associated with FDG uptake in background tissues at one hour but were weakly or not associated at two hours. TBRs using liver or blood pool at two hours were most strongly associated with vasculitis-related factors. These findings inform standardization of FDG-PET protocols and analytic approaches in LVV.

Effect of Treatment on Imaging, Clinical, and Serologic Assessments of Disease Activity in Large-vessel Vasculitis

OBJECTIVE

Disease activity in large-vessel vasculitis (LVV) is traditionally assessed by clinical and serological variables rather than vascular imaging. This study determined the effect of treatment on 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) vascular activity in relation to clinical- and serologic-based assessments.

METHODS

Patients with giant cell arteritis (GCA) or Takayasu arteritis (TA) were prospectively evaluated at 6-month intervals in an observational cohort. Treatment changes were made at least 3 months before the followup visit and categorized as increased, decreased, or unchanged. Imaging (FDG-PET qualitative analysis), clinical, and serologic (erythrocyte sedimentation rate, C-reactive protein) assessments were determined at each visit and compared over interval visits.

RESULTS

Serial assessments were performed in 52 patients with LVV (GCA = 31; TA = 21) over 156 visits. Increased, decreased, or unchanged therapy was recorded for 36-, 23-, and 32-visit intervals, respectively. When treatment was increased, there was significant reduction in disease activity by imaging, clinical, and inflammatory markers (p ≤ 0.01 for each). When treatment was unchanged, all 3 assessments of disease activity remained similarly unchanged over 6-month intervals. When treatment was reduced, PET activity significantly worsened (p = 0.02) but clinical and serologic activity did not significantly change. Treatment of GCA with tocilizumab and of TA with tumor necrosis factor inhibitors resulted in significant improvement in imaging and clinical assessments of disease activity, but only rarely did the assessments both become normal.

CONCLUSION

In addition to clinical and serologic assessments, vascular imaging has potential to monitor disease activity in LVV and should be tested as an outcome measure in randomized clinical trials.