Scintigraphic detection of TNF-driven inflammation by radiolabelled certolizumab pegol in patients with rheumatoid arthritis and spondyloarthritis

Non-TNF biologics and their biosimilars in rheumatoid arthritis

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic inflammatory rheumatic disease that affects both the articular and extra-articular structures, leading to significant joint damage, disability and excess mortality. The treatment algorithm of RA has changed tremendously in the past 1-2 decades because of the emergence of novel biological therapies that target different mechanisms of action in addition to TNFα.

AREAS COVERED

This article summarizes the evidence and safety of the non-TNF biological DMARDs in the treatment of RA, including those that target B cells, T-cell co-stimulation, interleukin (IL)-6 and granulocyte-monocyte colony-stimulating factor (GM-CSF). The targeted synthetic DMARDs such as the Janus kinase inhibitors are not included. The availability of the less costly biosimilars has enabled more patients to receive biological therapy earlier in the course of the disease. The evidence for the non-TNF biosimilar compounds in RA is also reviewed.

EXPERT OPINION

There are unmet needs of developing novel therapeutic agents to enhance the response rate and provide more options for difficult-to-treat RA. These include the newer generation biologic and targeted synthetic DMARDs. A personalized treatment strategy in RA requires evaluation of the cellular, cytokine, genomic and transcriptomic profile that would predict treatment response to biologic or targeted DMARDs of different mechanisms of action.

A Review of Advances in Molecular Imaging of Rheumatoid Arthritis: From In Vitro to Clinic Applications Using Radiolabeled Targeting Vectors with Technetium-99m

Rheumatoid arthritis (RA) is a systemic autoimmune disorder caused by inflammation of cartilaginous diarthrodial joints that destroys joints and cartilage, resulting in synovitis and pannus formation. Timely detection and effective management of RA are pivotal for mitigating inflammatory arthritis consequences, potentially influencing disease progression. Nuclear medicine using radiolabeled targeted vectors presents a promising avenue for RA diagnosis and response to treatment assessment. Radiopharmaceutical such as technetium-99m (99mTc), combined with single photon emission computed tomography (SPECT) combined with CT (SPECT/CT), introduces a more refined diagnostic approach, enhancing accuracy through precise anatomical localization, representing a notable advancement in hybrid molecular imaging for RA evaluation. This comprehensive review discusses existing research, encompassing in vitro, in vivo, and clinical studies to explore the application of 99mTc radiolabeled targeting vectors with SPECT imaging for RA diagnosis. The purpose of this review is to highlight the potential of this strategy to enhance patient outcomes by improving the early detection and management of RA.

Osteoimmunology of Spondyloarthritis

The mechanisms underlying the development of bone damage in the context of spondyloarthritis (SpA) are not completely understood. To date, a considerable amount of evidence indicates that several developmental pathways are crucially involved in osteoimmunology. The present review explores the biological mechanisms underlying the relationship between inflammatory dysregulation, structural progression, and osteoporosis in this diverse family of conditions. We summarize the current knowledge of bone biology and balance and the foundations of bone regulation, including bone morphogenetic protein, the Wnt pathway, and Hedgehog signaling, as well as the role of cytokines in the development of bone damage in SpA. Other areas surveyed include the pathobiology of bone damage and systemic bone loss (osteoporosis) in SpA and the effects of pharmacological treatment on focal bone damage. Lastly, we present data relative to a survey of bone metabolic assessment in SpA from Italian bone specialist rheumatology centers. The results confirm that most of the attention to bone health is given to postmenopausal subjects and that the aspect of metabolic bone health may still be underrepresented. In our opinion, it may be the time for a call to action to increase the interest in and focus on the diagnosis and management of SpA.

A quantitative systems pharmacology model for certolizumab pegol treatment in moderate-to-severe psoriasis

Background

Psoriasis is a chronic immune-mediated inflammatory systemic disease with skin manifestations characterized by erythematous, scaly, itchy and/or painful plaques resulting from hyperproliferation of keratinocytes. Certolizumab pegol [CZP], a PEGylated antigen binding fragment of a humanized monoclonal antibody against TNF-alpha, is approved for the treatment of moderate-to-severe plaque psoriasis. Patients with psoriasis present clinical and molecular variability, affecting response to treatment. Herein, we utilized an in silico approach to model the effects of CZP in a virtual population (vPop) with moderate-to-severe psoriasis. Our proof-of-concept study aims to assess the performance of our model in generating a vPop and defining CZP response variability based on patient profiles.

Methods

We built a quantitative systems pharmacology (QSP) model of a clinical trial-like vPop with moderate-to-severe psoriasis treated with two dosing schemes of CZP (200 mg and 400 mg, both every two weeks for 16 weeks, starting with a loading dose of CZP 400 mg at weeks 0, 2, and 4). We applied different modelling approaches: (i) an algorithm to generate vPop according to reference population values and comorbidity frequencies in real-world populations; (ii) physiologically based pharmacokinetic (PBPK) models of CZP dosing schemes in each virtual patient; and (iii) systems biology-based models of the mechanism of action (MoA) of the drug.

Results

The combination of our different modelling approaches yielded a vPop distribution and a PBPK model that aligned with existing literature. Our systems biology and QSP models reproduced known biological and clinical activity, presenting outcomes correlating with clinical efficacy measures. We identified distinct clusters of virtual patients based on their psoriasis-related protein predicted activity when treated with CZP, which could help unravel differences in drug efficacy in diverse subpopulations. Moreover, our models revealed clusters of MoA solutions irrespective of the dosing regimen employed.

Conclusion

Our study provided patient specific QSP models that reproduced clinical and molecular efficacy features, supporting the use of computational methods as modelling strategy to explore drug response variability. This might shed light on the differences in drug efficacy in diverse subpopulations, especially useful in complex diseases such as psoriasis, through the generation of mechanistically based hypotheses.

Use of Imaging in Axial Spondyloarthritis for Diagnosis and Assessment of Disease Remission in the Year 2022

Medical imaging remains the cornerstone of diagnostics and follow-up of axial spondyloarthritis (axSpA) patients. With the lack of specific biomarkers allowing monitoring of disease activity and progression, clinicians refer to imaging modalities for accurate evaluation of the axSpA burden. Technological advances and increasing availability of modern imaging techniques such as MRI have enabled faster diagnosis of the disease, hence dramatically changed the diagnostic delay and improved the prognosis and functional outcomes for axSpA patients.Active sacroiliitis as visualized by MRI has been widely accepted as a diagnostic tool, and definitions of inflammatory and structural lesions within the axial skeleton have been developed. Recently, it has been acknowledged that bone marrow edema, suggestive of sacroiliitis, is a common finding among non-SpA patients, and could be attributed to mechanical loading or accumulate with age in healthy individuals. Therefore, it is crucial to distinguish between true pathological and concealing imaging findings, not only for diagnostic but also for disease remission purposes. New imaging modalities, aimed for in vivo visualization of specific molecular processes, could be employed to cross-validate findings from techniques used in daily clinical practice. This review critically evaluates the use of different imaging modalities for diagnosis and assessment of disease remission in axSpA in the year 2022.

A glance into the future of diagnosis and treatment of spondyloarthritis

The last two decades have seen major developments in the field of spondyloarthritis (SpA), but there are still important unmet needs to address. In the future, we envisage important advances in the diagnosis and treatment of SpA. In the diagnosis of SpA, the use of online and social media tools will increase awareness of the disease and facilitate the referral of patients to rheumatology clinics. In addition, more specific diagnostic tests will be available, especially advanced imaging methods and new biomarkers. This will allow most patients to be diagnosed at an early stage of the disease. In the treatment of SpA, an increasing number of novel treatment targets can be expected, most of which will be directed against intracellular enzymes. We hope to see more strategy trials shaping treatment pathways in SpA and accommodating principals of precision medicine. Approved treatment options will be available for both axial and peripheral SpA. We also hope to intervene not only at the inflammation level but also at the level of underlying immunological processes that might be associated with a higher probability of long-standing remission if not a cure. Finally, artificial intelligence techniques will allow for the analysis of large-scale data to answer relevant research questions for the diagnosis and management of patients with SpA.

Systematic Review: Targeted Molecular Imaging of Angiogenesis and Its Mediators in Rheumatoid Arthritis

Extensive angiogenesis is a characteristic feature in the synovial tissue of rheumatoid arthritis (RA) from a very early stage of the disease onward and constitutes a crucial event for the development of the proliferative synovium. This process is markedly intensified in patients with prolonged disease duration, high disease activity, disease severity, and significant inflammatory cell infiltration. Angiogenesis is therefore an interesting target for the development of new therapeutic approaches as well as disease monitoring strategies in RA. To this end, nuclear imaging modalities represent valuable non-invasive tools that can selectively target molecular markers of angiogenesis and accurately and quantitatively track molecular changes in multiple joints simultaneously. This systematic review summarizes the imaging markers used for single photon emission computed tomography (SPECT) and/or positron emission tomography (PET) approaches, targeting pathways and mediators involved in synovial neo-angiogenesis in RA.

Recent progress in treatments of rheumatoid arthritis: an overview of developments in biologics and small molecules, and remaining unmet needs

Through treatment with biological DMARDs (bDMARDs) or targeted synthetic (tsDMARDs) such as Janus kinase (JAK) inhibitors in addition to MTX, clinical remission has become a realistic therapeutic goal for the majority of patients with RA, and sustained remission facilitates prevention of joint damage and physical dysfunction. Long-term safety and sustained inhibition of structural changes and physical dysfunction by bDMARDs have been reported. The development of next-generation bDMARDs and expansion of their indications to various autoimmune diseases are expected. Five JAK inhibitors show comparable efficacy to bDMARDs, and the latest ones are effective for overcoming difficult-to-treat RA regardless of prior medications. Patients treated with JAK inhibitors should be adequately screened and monitored for infection, cardiovascular disorders, thrombosis, malignancies and so on. Advances in therapeutic strategies, including the differential use of therapeutic drugs and de-escalation of treatment after remission induction, are prioritized.

Pathogenesis of Axial Spondyloarthritis - Sources and Current State of Knowledge

Scientific breakthroughs have culminated in the development of the spondyloarthritis (SpA) concept as a family of rheumatic diseases, distinct from rheumatoid arthritis. The demonstration of inflammatory lesions in the sacroiliac joints and spine of patients with axial symptoms of SpA who lacked radiographic features of ankylosing spondylitis (AS) helped refine the SpA concept. Axial SpA includes patients with AS and patients with axial symptoms previously categorized as undifferentiated SpA. This review examines the sources of knowledge that inform axial SpA pathogenesis, highlighting current limitations, and a basic working model of axial SpA pathogenesis.

Serum TNFα levels at 24 h after certolizumab pegol predict effectiveness at week 12 in patients with rheumatoid arthritis from TSUBAME study

Objective

To estimate the relationship between serum TNFα, IL-6, and serum CZP levels and the clinical response to CZP in RA patients in the TSUBAME study.

Methods

One hundred patients with RA who received CZP were enrolled and multiple clinical parameters, serum TNFα, IL-6, and CZP levels, were assessed at 0, 24, and 48 h and 12 weeks after first administration of CZP.

Results

The CZP therapy significantly improved the DAS28(ESR) at 12 weeks. Serum TNFα and IL-6 levels significantly decreased from baseline at 24 h after the first administration of CZP. Serum TNFα levels at baseline were not related to clinical parameters at baseline and improvement in DAS28(ESR) at week 12 of the CZP therapy. However, serum levels of CZP at 24 h were strongly and negatively correlated with TNFα levels at 24 h, which were negatively correlated with improved rate in DAS28(ESR) at week 12. Only serum levels of TNFα, but not IL-6, at 24 h had a negative correlation with achievement of DAS28(ESR)<2.6 at week 12 by the multivariate analysis (odds ratio 0.01, 95% confidence interval 0.04e−2–0.22, p < 0.01). A receiver operating characteristic analysis was conducted to estimate the achievement of DAS28(ESR)<2.6 at week 12 after the CZP therapy and cut-off value of 0.76 pg/ml for serum levels of TNFα at 24 h was yielded (area under the curve=0.75). DAS28(ESR)<2.6 was achieved at week 12 significantly more patients with lower serum TNF levels (≦0.76 pg/ml) at 24 h than those with higher TNF levels.

Conclusions

CZP was highly effective in RA patients who had low serum TNFα levels at 24 h after the initial administration of CZP. Therefore, we propose that serum TNFα levels at 24 h could serve as a biomarker predicting effectiveness to CZP at week 12 in patients with RA.

Trial registration

Clinical trial registration number: UMIN ID:000022831

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-021-02547-2.

99mTc-antitumor necrosis factor-alpha scintigraphy for the detection of inflammatory activity in rheumatoid arthritis

OBJECTIVE

Tumor necrosis factor-alpha (TNF-α) is an important inflammatory cytokine. 99mTc-anti-TNF-α antibody scintigraphy has proven to be a viable alternative to MRI in specific cases. The objective of this study was to evaluate the performance of scintigraphy with 99mTc-anti-TNF-α in the identification of inflammatory foci in individuals diagnosed with rheumatoid arthritis using MRI as the gold standard.

METHODS

This cross-sectional, descriptive and analytical-qualitative clinical study compared the performance of 99mTc-anti-TNF-α scintigraphy with that of MRI with intravenous administration of gadolinium (used as the gold standard) and a clinical examination (Disease Activity Score 28) in 220 joints of 20 patients with a diagnosis of rheumatoid arthritis and one healthy control.

RESULTS

The concordance of scintigraphy with MRI in individuals with a diagnosis of rheumatoid arthritis was 79%. The accuracy, sensitivity and specificity of scintigraphy for distinguishing between inflammatory and noninflammatory sites were 92, 89, and 93%, respectively. No adverse reactions to the examinations were reported.

CONCLUSIONS

Scintigraphy with 99mTc-anti-TNF-α was well-tolerated and had a good ability to distinguish between inflammatory and noninflammatory lesions in patients with rheumatoid arthritis.

Pathophysiology, assessment and treatment of psoriatic dactylitis

Dactylitis is diffuse swelling of the digits that is usually related to an underlying inflammatory or infiltrative disorder. Psoriatic arthritis (PsA) is the most common severe disease thought to cause dactylitis. Our understanding of the pathogenesis of PsA-related dactylitis comes from experimental animal models of PsA-like disease, as well as advances in imaging and other clinical studies. Clinical trials in PsA have increasingly included dactylitis as an important secondary outcome measure. These studies indicate that cytokines drive multi-locus microanatomical pan-digital pathology. Given the importance of pro-inflammatory cytokines, the pathogenesis of dactylitis is best understood as an initial aberrant innate immune response to biomechanical stress or injury, with subsequent adaptive immune mechanisms amplifying the dactylitis inflammatory response. Regarding the treatment of dactylitis, no studies have been conducted using dactylitis as the primary outcome measure, and the current knowledge comes from analysis of dactylitis as a secondary outcome measure.

Imaging Techniques: Options for the Diagnosis and Monitoring of Treatment of Enthesitis in Psoriatic Arthritis

Psoriatic arthritis (PsA) affects up to 30% of patients with psoriasis and may include musculoskeletal manifestations such as enthesitis. Enthesitis is associated with joint damage, and early detection and treatment are essential to management of the disease. Traditionally assessed by clinical examination and conventional radiography, entheseal inflammation can now be more accurately assessed earlier in the disease using techniques such as ultrasound, magnetic resonance imaging, computed tomography, and molecular imaging. However, there is little consensus on the optimum definition for diagnosing enthesitis in PsA or on the ideal scoring system for measuring response to treatment. This review aims to summarize the benefits and limitations of different imaging modalities in the assessment of enthesitis. It also proposes that adoption of standardized definitions and validation of scoring systems and imaging techniques in clinical trials will allow the efficacy of new treatment options to be assessed more accurately.

Immuno-Imaging to Predict Treatment Response in Infection, Inflammation and Oncology

Background: Molecular nuclear medicine plays a pivotal role for diagnosis in a preclinical phase, in genetically susceptible patients, for radio-guided surgery, for disease relapse evaluation, and for therapy decision-making and follow-up. This is possible thanks to the development of new radiopharmaceuticals to target specific biomarkers of infection, inflammation and tumour immunology. Methods: In this review, we describe the use of specific radiopharmaceuticals for infectious and inflammatory diseases with the aim of fast and accurate diagnosis and treatment follow-up. Furthermore, we focus on specific oncological indications with an emphasis on tumour immunology and visualizing the tumour environment. Results: Molecular nuclear medicine imaging techniques get a foothold in the diagnosis of a variety of infectious and inflammatory diseases, such as bacterial and fungal infections, rheumatoid arthritis, and large vessel vasculitis, but also for treatment response in cancer immunotherapy. Conclusion: Several specific radiopharmaceuticals can be used to improve diagnosis and staging, but also for therapy decision-making and follow-up in infectious, inflammatory and oncological diseases where immune cells are involved. The identification of these cell subpopulations by nuclear medicine techniques would provide personalized medicine for these patients, avoiding side effects and improving therapeutic approaches.

Properties of Fluorescent Far-Red Anti-TNF Nanobodies

Upregulation of the expression of tumor necrosis factor (TNF-α, TNF) has a significant role in the development of autoimmune diseases. The fluorescent antibodies binding TNF may be used for personalized therapy of TNF-dependent diseases as a tool to predict the response to anti-TNF treatment. We generated recombinant fluorescent proteins consisting of the anti-TNF module based on the variable heavy chain (VHH) of camelid antibodies fused with the far-red fluorescent protein Katushka (Kat). Two types of anti-TNF VHH were developed: one (BTN-Kat) that was bound both human or mouse TNF, but did not neutralize their activity, and a second (ITN-Kat) that was binding and neutralizing human TNF. BTN-Kat does not interfere with TNF biological functions and can be used for whole-body imaging. ITN-Kat can be evaluated in humanized mice or in cells isolated from humanized mice. It is able to block human TNF (hTNF) activities both in vitro and in vivo and may be considered as a prototype of a theranostic agent for autoimmune diseases.

The Role of Imaging in Diagnosing Axial Spondyloarthritis

Imaging has a central role in the diagnosis, management, and follow-up of patients with axial spondyloarthritis (axSpA). For the early diagnosis of axSpA, magnetic resonance imaging is of utmost relevance. While no novel imaging techniques were developed during the past decade, improvements to the existing modalities have been introduced. This report provides an overview of the applications and limitations of the existing imaging modalities.

New SPECT and PET Radiopharmaceuticals for Imaging Inflammatory Diseases: A Meta-analysis of the Last 10 Years

Modern molecular nuclear medicine is rapidly developing in the field of imaging of chronic inflammatory diseases, and many new radiopharmaceuticals have been recently described and tested in animals and man. These can detect early pathophysiological changes before the development of anatomical changes and, often, before clinical onset of symptoms. This field includes new radiopharmaceuticals for SPECT and PET use to define new strategies for imaging immune cells as well as tissue modifications induced by the inflammatory process. In this review, we present the results of a meta-analysis based on radiopharmaceuticals (for SPECT or PET) that are not commercially available and that have been used, at least once, in humans in the last 10 years.

99mTc-labelled S-HYNIC certolizumab pegol in rheumatoid arthritis and spondyloarthritis patients: a biodistribution and dosimetry study

BACKGROUND

Biologicals directed against tumour necrosis factor (TNF) have proven their efficacy in the treatment of spondyloarthritis and rheumatoid arthritis. We present a radiolabelling method for certolizumab pegol (CZP), a commercially available humanized Fab'-fragment directed against TNF. A biodistribution and dosimetry study was conducted. Tc-S-HYNIC CZP was synthesized. The in vitro TNF neutralizing activity was tested by exposing L929s-cells to various concentrations 99mTc-S-HYNIC CZP and measuring TNF-induced cytotoxicity. For biodistribution and dosimetry, WB images and blood and urine sampling were performed up to 24 h pi. Cumulative activities were estimated using mono-exponential fitting, and organ doses were estimated using OLINDA/EXM. The effective dose was calculated using the International Commission on Radiological Protection 103 recommendations. The uptake of the tracer in the peripheral joints was assessed visually and semiquantitatively.

RESULTS

In vitro tests showed blocking of TNF cytotoxicity by the 99mTc-S-HYNIC CZP formulation comparable to the effect obtained with the unlabelled CZP with or without the HYNIC linker. We analysed eight patients with rheumatoid arthritis or spondyloarthritis. The highest mean absorbed organ doses were recorded for kidneys, spleen, and liver: 56 (SD 7), 34 (SD 6), and 33 (SD 7) μGy/MBq. The effective dose was 6.1 (SD 0.9) mSv for a mean injected activity of 690 (SD 35) MBq. The urinary excretion was 15.1% (SD 8.1) of the IA at 22.5 h. Blood analysis yielded a distribution half-life of 1.2 h (SD 1.5) and an elimination half-life of 26.9 h (SD 2.7). Visual analysis of the scans revealed marked tracer accumulation in the clinically affected peripheral joints. In addition, there was a statistically significant higher uptake of the tracer in the swollen joints (median uptake ratio compared to background of 3.3 in rheumatoid arthritis and 2.4 in peripheral spondyloarthritis) compared to clinically negative joints (respectively 1.3 and 1.6).

CONCLUSIONS

We present a radiolabelling technique for CZP, a Fab'-fragment directed against TNF and currently used as a therapeutic agent in rheumatology. An effective dose of 6.1 mSv (SD 0.9) was estimated. We confirmed the uptake of this new radiopharmaceutical in clinically affected peripheral joints.

Radionuclide Methods in the Diagnosis of Sacroiliitis in Patients with Spondyloarthritis: An Update

Sacroiliitis, inflammation of the sacroiliac joint (SIJ), is the hallmark of ankylosing spondylitis and spondyloarthritis (SpA) in general. The arsenal of recommended diagnostic modalities for imaging of the SIJ is scanty and, in practice, includes only conventional X-rays and magnetic resonance imaging (MRI). This review suggests that bone scintigraphy, particularly single-photon emission computed tomography (SPECT) with calculation of indices, or SPECT in combination with low-dose computed tomography (CT) can be a sensitive and specific tool for the diagnosis of sacroiliitis and can be used as part of the individualized approach to the diagnosis of axial SpA. In addition, [¹⁸F]fluoride positron emission tomography (PET)/CT imaging and immunoscintigraphy, using labeled monoclonal anti-cytokine antibodies, are promising methods of current scientific interest in this field.