Efficacy, safety and tolerability of tocilizumab in patients with systemic juvenile idiopathic arthritis

Perspective for Discovery of Small Molecule IL-6 Inhibitors through Study of Structure–Activity Relationships and Molecular Docking

Interleukin-6 (IL-6) is a proinflammatory cytokine that plays a key role in the pathogenesis and physiology of inflammatory and autoimmune diseases, such as coronary heart disease, cancer, Alzheimer's disease, asthma, rheumatoid arthritis, and most recently COVID-19. IL-6 and its signaling pathway are promising targets in the treatment of inflammatory and autoimmune diseases. Although, anti-IL-6 monoclonal antibodies are currently being used in clinics, huge unmet medical needs remain because of the high cost, administration-related toxicity, lack of opportunity for oral dosing, and potential immunogenicity of monoclonal antibody therapy. Furthermore, nonresponse or loss of response to monoclonal antibody therapy has been reported, which increases the importance of optimizing drug therapy with small molecule drugs. This work aims to provide a perspective for the discovery of novel small molecule IL-6 inhibitors by the analysis of the structure-activity relationships and computational studies for protein-protein inhibitors targeting the IL-6/IL-6 receptor/gp130 complex.

Identification of Clinical Response Predictors of Tocilizumab Treatment in Patients with Severe COVID-19 Based on Single-Center Experience

Hyperinflammation in COVID-19 plays a crucial role in pathogenesis and severity; thus, many immunomodulatory agents are applied in its treatment. We aimed to identify good clinical response predictors of tocilizumab (TCZ) treatment in severe COVID-19, among clinical, laboratory, and radiological variables. We conducted a prospective, observational study with 120 patients with severe COVID-19 not improving despite dexamethasone (DEX) treatment. We used parametric and non-parametric statistics, univariate logistic regression, receiver operating characteristic (ROC) curves, and nonlinear factors tertile analysis. In total, 86 (71.7%) patients achieved the primary outcome of a good clinical response to TCZ. We identified forty-nine predictive factors with potential utility in patient selection and treatment monitoring. The strongest included time from symptom onset between 9 and 12 days, less than 70% of estimated radiological lung involvement, and lower activity of lactate dehydrogenase. Additional predictors were associated with respiratory function, vitamin D concentration, comorbidities, and inflammatory/organ damage biomarkers. Adverse events analysis proved the safety of such a regimen. Our study confirmed that using TCZ early in the hyperinflammatory phase, before severe respiratory failure development, is most beneficial. Considering the described predictive factors, employing simple and widely available laboratory, radiological, and clinical tools can optimize patient selection for immunomodulatory treatment with TCZ.

Interleukin-6 cytokine: An overview of the immune regulation, immune dysregulation, and therapeutic approach

Several studies have shown that interleukin 6 (IL-6) is a multifunctional cytokine with both pro-inflammatory and anti-inflammatory activity, depending on the immune response context. Macrophages are among several cells that secrete IL-6, which they express upon activation by antigens, subsequently inducing fever and production of acute-phase proteins from the liver. Moreover, IL-6 induces the final maturation of B cells into memory B cells and plasma cells as well as an adaptive role for short-term energy allocation. Activation of IL-6 receptors results in the intracellular activation of the JAK/STAT pathway with resultant production of inflammatory cytokines. Several mechanisms-controlled IL-6 expression, but aberrant production was shown to be crucial in the pathogenesis of many diseases, which include autoimmune and chronic inflammatory diseases. IL-6 in combination with transforming growth factor β (TGF-β) induced differentiation of naïve T cells to Th17 cells, which is the cornerstone in autoimmune diseases. Recently, IL-6 secretion was shown to form the backbone of hypercytokinemia seen in the Coronavirus disease 2019 (COVID-19)-associated hyperinflammation and multiorgan failure. There are two classes of approved IL-6 inhibitors: anti-IL-6 receptor monoclonal antibodies (e.g., tocilizumab) and anti-IL-6 monoclonal antibodies (i.e., siltuximab). These drugs have been evaluated in patients with rheumatoid arthritis, juvenile idiopathic arthritis, cytokine release syndrome, and COVID-19 who have systemic inflammation. JAK/STAT pathway blockers were also successfully used in dampening IL-6 signal transduction. A better understanding of different mechanisms that modulate IL-6 expression will provide the much-needed solution with excellent safety and efficacy profiles for the treatment of autoimmune and inflammatory diseases in which IL-6 derives their pathogenesis.

Subcutaneous tocilizumab in adults with severe and critical COVID-19: A prospective open-label uncontrolled multicenter trial

Potential therapeutic approaches in coronavirus disease 2019 (COVID-19) comprise antiviral and immunomodulatory agents; however, no immunomodulator drug has been approved. This multicenter, prospective, open-label, uncontrolled study aimed to assess the use of subcutaneous tocilizumab in adult patients with severe and critical COVID-19. Tocilizumab was added to the standard care of therapy at a dose of 324 mg (<100 kg bodyweight) or 486 mg (≥100 kg bodyweight). The study endpoints were all-cause mortality rate, changes in oxygen-support level, oxygen saturation, body temperature, respiratory rate, and laboratory variables during the study, and drug safety. Of 126 patients enrolled, 86 had severe and 40 had critical disease. Most patients were male (63.49%) and aged below 65 (78.57%). By day 14 of the study, 4.65% (4/86) of severe patients and 50.00% (20/40) of critical patients died. By the end, 6.98% (6/86) of severe patients and 60.00% (24/40) of critical patients died.Outcomes concerning three additional endpoints (oral temperature, oxygen saturation, and respiratory rate)were significantly improved as early as three days after tocilizumab administration in both groups of subjects, more considerably in severe patients. Significant improvement in the required level of oxygenation was reported in severe patients seven days after tocilizumab administration. No tocilizumab-related serious adverse event occurred in this study. Subcutaneous tocilizumab might improve some clinical parameters and reduce the risk of death in COVID-19 patients, particularly if used in the early stages of respiratory failure.

Molecular and Cellular Mechanisms of Arthritis in Children and Adults: New Perspectives on Applied Photobiomodulation

Juvenile idiopathic arthritis and adult rheumatoid arthritis are two major groups with chronic joint pain and inflammation, extra-articular manifestations, and high risk of comorbidities, which can cause physical and ocular disability, as well as create great socio-economic pressure worldwide. The pathogenesis of arthritis manifested in childhood and adulthood is multifactorial, unclear, and overly complex, in which immunity plays an important role. Although there are more and more biological agents with different mechanisms of action for the treatment of arthritis, the results are not as expected, because there are partial responses or non-responsive patients to these compounds, high therapeutic costs, side effects, and so on; therefore, we must turn our attention to other therapeutic modalities. Updating knowledge on molecular and cellular mechanisms in the comparative pathogenesis of chronic arthritis in both children and adults is necessary in the early and correct approach to treatment. Photobiomodulation (PBM) represents a good option, offering cost-effective advantages over drug therapy, with a quicker, more positive response to treatment and no side effects. The successful management of PBM in arthritis is based on the clinician’s ability to evaluate correctly the inflammatory status of the patient, to seek the optimal solution, to choose the best technology with the best physical parameters, and to select the mode of action to target very precisely the immune system and the molecular signaling pathways at the molecular level with the exact amount of quantum light energy in order to obtain the desired immune modulation and the remission of the disease. Light is a very powerful tool in medicine because it can simultaneously target many cascades of immune system activation in comparison with drugs, so PBM can perform very delicate tasks inside our cells to modulate cellular dysfunctions, helping to initiate self-organization phenomena and finally, healing the disease. Interdisciplinary teams should work diligently to meet these needs by also using single-cell imaging devices for multispectral laser photobiomodulation on immune cells.

Canakinumab for Treatment of Adult-Onset Still's Disease to Achieve Reduction of Arthritic Manifestation (CONSIDER): phase II, randomised, double-blind, placebo-controlled, multicentre, investigator-initiated trial

BACKGROUND

Inhibition of interleukin (IL)-1 represents a promising treatment option in adult-onset Still's disease (AOSD).

OBJECTIVE

To investigate the efficacy and safety of canakinumab in patients with AOSD and active joint involvement by means of a multicentre, double-blind, randomised, placebo-controlled trial.

METHODS

Patients with AOSD and active joint involvement (tender and swollen joint counts of ≥4 each) were treated with canakinumab (4 mg/kg, maximum 300 mg subcutaneous every 4 weeks) or placebo. The primary endpoint was the proportion of patients with a clinically relevant reduction in disease activity at week 12 as determined by the change in disease activity score (ΔDAS28>1.2).

RESULTS

At enrolment, patients had high active disease with a mean DAS28(ESR) of 5.4 in the canakinumab and 5.3 in the placebo group, respectively. In the intention-to-treat analysis, 12 patients (67%) in the canakinumab group and 7 patients (41%) in the placebo group fulfilled the primary outcome criterion (p=0.18). In the per-protocol analysis, significantly higher American College of Rheumatology (ACR) 30% (61% vs 20%, p=0.033), ACR 50% (50% vs 6.7%, p=0.009) and ACR 70% (28% vs 0%, p=0.049) response rates were observed in the canakinumab group compared with the placebo group. Two patients in the canakinumab group experienced a serious adverse event.

CONCLUSION

Although the study was terminated prematurely and the primary endpoint was not achieved, treatment with canakinumab led to an improvement of several outcome measures in AOSD. The overall safety findings were consistent with the known profile of canakinumab. Thus, our data support indication for IL-1 inhibition with canakinumab in AOSD.

The Role of Interleukin-6 Inhibitors in the Treatment of COVID-19 Infections: A Case Series

An outbreak of severe acute respiratory distress syndrome coronavirus 2 (SARS-CoV-2) infection started in December 2019 in China that resulted in a global health emergency. The World Health Organization later named the disease as coronavirus disease 2019 (COVID-19). Currently, there is no effective treatment available and the data are evolving through continuous clinical trials and ongoing research. Severe infections present with hypoxemic respiratory failure from acute respiratory distress syndrome as one of the major complications. We report two cases of COVID-19 patients who initially presented with moderate to severe symptoms. Later, their clinical course worsened despite ongoing treatment with multiple medications such as hydroxychloroquine and azithromycin until they were started on tocilizumab. Within a short period after they were administered tocilizumab, their oxygen saturation improved and other inflammatory markers such as D-dimer levels, lactate dehydrogenase, and ferritin levels decreased. There is an increase in the amount of research citing the role of various cytokines in the pathophysiology of COVID-19. Targeting the inflammatory mediators in the pathogenesis, especially interleukin-6 pathway inhibitors, would improve overall morbidity and mortality, thus decreasing the burden on healthcare systems.

Current and emerging biologics for the treatment of juvenile idiopathic arthritis

INTRODUCTION

The management of a child with juvenile idiopathic arthritis (JIA) requires a combination of pharmacological, physical, and psychosocial therapies in order to induce disease remission, by controlling articular and systemic inflammation. This review aims to provide a comprehensive discussion on the biological therapies currently in use in the treatment of JIA referring to existing recommendations and clinical evidence. We also discuss on the emerging biological drugs actually under consideration.

AREAS COVERED

Recent findings on immunological mechanisms involved in the pathogenesis of the disease allowed us to identify several specific targets for biologic therapies. A systematic literature review was conducted between January 1997 and January 2020 on PubMed including national and international guidelines and recommendations, trials and case-control studies.

EXPERT OPINION

There is now a plethora of therapies that are directed against variable targets, and the physician has to choose the most appropriate available medication in order to achieve early and sustained remission with as few side effects as possible. Research is advancing very fast in order to be more and more specific in suppressing inflammatory pathways without harming natural defenses. Finally, pharmacoeconomic considerations will also be very important to deal with, considering the high cost of most of these molecules.

Tocilizumab for juvenile idiopathic arthritis: a single-center case series

BACKGROUND

Juvenile idiopathic arthritis (JIA) is the commonest chronic rheumatic disease among children. When not treated effectively, JIA can lead to functional disability, due to joint damage, along with long-term morbidities.

OBJECTIVES

To describe the use of tocilizumab therapy for 11 patients with polyarticular JIA (pJIA) and systemic JIA (sJIA) who presented inadequate response or were refractory to disease-modifying anti-rheumatic drugs (DMARDs) and/or other biological therapies; and to evaluate its benefits, safety and tolerability.

DESIGN AND SETTING

Observational retrospective case series at a tertiary-level training and research hospital.

METHODS

We reviewed the medical records of 11 consecutive patients with JIA who received tocilizumab (anti-IL-6) therapy in our pediatric nephrology and rheumatology outpatient clinic. We analyzed their demographic data, clinical and laboratory findings, treatment response and adverse reactions. We determined the efficacy of tocilizumab treatment using the American College of Rheumatology (ACR) pediatric (Pedi) response criteria, including ACR Pedi 30, 50, 70 and 90 scores. We used the Wilcoxon test to compare measurements before and after treatment.

RESULTS

Tocilizumab was given to seven patients with sJIA and four with pJIA (one of the pJIA patients was rheumatoid factor-positive). In most patients, we observed improvement of symptoms, absence of articular and extra-articular inflammation and continued inactive disease. ACR Pedi 30, 50 and 70 scores were achieved by 90.9% of the patients. Five patients showed minor side effects, possibly due to use of tocilizumab.

CONCLUSIONS

Tocilizumab therapy should be considered for treating patients with diagnoses of pJIA or sJIA who are resistant to non-biological DMARDs and/or other biological therapies.

Interleukin-6 inhibition in the management of non-infectious uveitis and beyond

Background

Uveitis consists of a spectrum of inflammatory disorders characterized by ocular inflammation. The underlying pathophysiology consists of a complex interplay of various inflammatory pathways. Interleukin 6 is an important mediator of inflammation in uveitis and constitutes focus of research toward development of newer biological therapies in the management of non-infectious uveitis.

Main body

Pan-blockade of the inflammatory pathways with steroids is generally the first step in the management of acute non-infectious uveitis. However, long-term therapy with steroids is associated with systemic and ocular side effects, thereby necessitating the need for development of steroid sparing agents. IL-6 is a cytokine produced by various immune cells, in response to molecular patterns and affects multiple inflammatory cells. In particular, IL-6 is involved in differentiation of CD-4 cells into Th-17 cells that have been shown to play a significant role in various immune-mediated diseases such as uveitis. This broad-spectrum immunomodulatory activity makes IL-6 an excellent target for immunomodulatory therapy. Tocilizumab was the first IL-6 inhibitor to demonstrate efficacy in humans. It inhibits IL-6 from binding to both membrane-bound and soluble receptor and can be administered via intravenous (IV) and subcutaneous (SC) routes. It has been FDA approved for treatment of rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA). Following the approval in systemic diseases, its efficacy was demonstrated in various uveitis studies including a phase 2 clinical trial (STOP-Uveitis). Overall, tocilizumab has shown a good safety profile with the risk of malignancy consistent with that expected in patients with rheumatoid arthritis. However, tocilizumab therapy has been shown to increase the risk for gastrointestinal perforation and dose-dependent neutropenia. Following the success of tocilizumab, several other agents targeting the IL-6 pathway are in the pipeline. These include sirukumab, siltuximab, olokizumab, clazakizumab, and EBI-031 which target IL-6; Sarilumab and ALX-0061 act on the IL-6 receptor.

Conclusion

Studies have shown that IL-6 inhibitors can be effective in the management of NIU. In addition, the levels of IL-6 are elevated in other ocular vascular diseases such as retinal vein occlusion and diabetic macular edema. The roles of IL-6 inhibition may be broadened in the future to include the management of retinal vascular diseases and non-uveitic macular edema.

The IL-6 signaling complex is a critical driver, negative prognostic factor, and therapeutic target in diffuse large B-cell lymphoma

Interleukin-6 (IL-6) is a growth factor for normal B cells and plasma cell-derived malignancies. Here, we show that the IL-6 signaling pathway is also active in a subset of diffuse large B-cell lymphoma (DLBCL) patients with particularly poor prognosis. Primary DLBCL cells and DLBCL cell lines expressing IL-6R engraft and form orthotopic lymphomas in humanized mice that ectopically produce human IL-6, and in mice reconstituted with a human immune system. We show that a subset of DLBCL cases have evolved mechanisms that ensure constitutive activation of the IL-6 signaling pathway, i.e., the expression of both chains of the IL-6R, the expression of the cytokine itself, and the mutational inactivation of a negative regulator of IL-6 signaling, SOCS1. IL-6 signaling promotes MYC-driven lymphomagenesis in a genetically engineered model, and treatment with the IL-6R-specific antibody tocilizumab reduces growth of primary DLBCL cells and of DLBCL cell lines in various therapeutic settings. The combined results uncover the IL-6 signaling pathway as a driver and negative prognosticator in aggressive DLBCL that can be targeted with a safe and well-tolerated biologic.

Intravenous dosing of tocilizumab in patients younger than two years of age with systemic juvenile idiopathic arthritis: results from an open-label phase 1 clinical trial

BACKGROUND

The anti-interleukin-6 receptor-alpha antibody tocilizumab was approved for intravenous (IV) injection in the treatment of patients with systemic juvenile idiopathic arthritis (sJIA) aged 2 to 17 years based on results of a randomized controlled phase 3 trial. Tocilizumab treatment in systemic juvenile idiopathic arthritis (sJIA) patients younger than 2 was investigated in this open-label phase 1 trial and compared with data from the previous trial in patients aged 2 to 17 years.

METHODS

Patients younger than 2 received open-label tocilizumab 12 mg/kg IV every 2 weeks (Q2W) during a 12-week main evaluation period and an optional extension period. The primary end point was comparability of pharmacokinetics during the main evaluation period to that of the previous trial (in patients aged 2-17 years), and the secondary end point was safety; pharmacodynamics and efficacy end points were exploratory. Descriptive comparisons for pharmacokinetics, pharmacodynamics, safety, and efficacy were made with sJIA patients aged 2 to 17 years weighing < 30 kg (n = 38) who received tocilizumab 12 mg/kg IV Q2W in the previous trial (control group).

RESULTS

Eleven patients (mean age, 1.3 years) received tocilizumab during the main evaluation period. The primary end point was met: tocilizumab exposures for patients younger than 2 were within the range of the control group (mean [±SD] μg/mL concentration at the end-of-dosing interval [C_min]: 39.8 [±14.3] vs 57.5 [±23.3]; maximum concentration [C_max] postdose: 288 [±40.4] vs 245 [±57.2]). At week 12, pharmacodynamic measures were similar between patients younger than 2 and the control group; mean change from baseline in Juvenile Arthritis Disease Activity Score-71 was - 17.4 in patients younger than 2 and - 28.8 in the control group; rash was reported by 14.3 and 13.5% of patients, respectively. Safety was comparable except for the incidence of serious hypersensitivity reactions (27.3% in patients younger than 2 vs 2.6% in the control group).

CONCLUSIONS

Tocilizumab 12 mg/kg IV Q2W provided pharmacokinetics, pharmacodynamics, and efficacy in sJIA patients younger than 2 comparable to those in patients aged 2 to 17 years. Safety was comparable except for a higher incidence of serious hypersensitivity events in patients younger than 2 years.

CLASSIFICATION

Juvenile idiopathic arthritis.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01455701 . Registered, October 20, 2011, Date of enrollment of first participant: October 26, 2012.

Cytokines in uveitis

PURPOSE OF REVIEW

Increasing evidence supports Th17 cells as key mediators of ocular inflammatory disease. Cytokines that are important for the development and pathologic function of these cells are potential therapeutic targets in patients with immune mediated uveitis. This review provides an overview of these cytokines including recent insights about their roles in ocular inflammation from laboratory and clinical studies.

RECENT FINDINGS

Interleukin (IL)-6, IL-10, IL-17, IL-22, IL-23 and tumour necrosis factor-alpha (TNFα) are cytokines that have been examined for their functional role in uveitis and their relationship to pathologic Th17 cells. Studies in animal models, particularly in experimental autoimmune uveitis (EAU), have been instrumental in studying the role of these cytokines in disease pathogenesis. More recently, studies on aqueous, vitreous and serum from patients with uveitis using flow cytometry and multiplex ELISA bead-based methodologies have provided insights into the contribution of Th17 cells and the related cytokines in ocular inflammatory diseases. The central role of IL-23 in determining the pathologic Th17 fate has made it an effective therapeutic target in systemic diseases such as psoriasis and thereby an attractive potential target for patients with immune-mediated uveitis.

SUMMARY

Th17 cells, and their related cytokines, are important inflammatory mediators in autoimmune uveitis. Animal and human studies continue to provide new information to direct development of new cytokine-targeted therapies for patients with uveitis.

IL-6 blockade in systemic juvenile idiopathic arthritis - achievement of inactive disease and remission (data from the German AID-registry)

BACKGROUND

Systemic juvenile idiopathic arthritis (sJIA) is a complex disease with an autoinflammatory component of unknown etiology related to the innate immune system. A major role in the pathogenesis has been ascribed to proinflammatory cytokines like interleukin-6 (IL-6), and effective drugs inhibiting their signaling are being developed. This study evaluates sJIA patients treated with the IL-6 inhibitor tocilizumab (TCZ) concerning clinical response rate, disease course and adverse effects in a real-life clinical setting.

METHODS

In 2009 a clinical and research consortium was established, including an online registry for autoinflammatory diseases (AID) ( https://aid-register.de ). Data for this retrospective TCZ study were documented by 13 centers.

RESULTS

From 7/2009 to 4/2014, 200 patients with sJIA were recorded in the AID-registry. Out of these, 46 (19 m, 27 f, age 1-18 years) received therapy with TCZ. Long term treatment (median 23 months) has been documented in 24/46 patients who were evaluated according to Wallace criteria (active disease 6/24, inactive disease 5/24, remission 13/24 cases). Under observation co-medication were used in 40/46 cases. Adverse events were reported in 11/46 patients. The clinical response rate (no clinical manifestation, no increased inflammation parameters) within the first 12 weeks of treatment was calculated to be 35%.

CONCLUSION

Out of 200 sJIA children reported in the German AID-registry, 46 were treated with TCZ, showing a clinical response rate of 35% during the first 12 weeks, and inactive disease and/or remission under medication in 75% after one year. Adverse events were seen in 24% and severe adverse events in 4%.

TRIAL REGISTRATION

The AID-Registry is funded by the BMBF (01GM08104, 01GM1112D, 01GM1512D).

IL-1 Inhibition in Systemic Juvenile Idiopathic Arthritis

Systemic juvenile idiopathic arthritis (sJIA) is the form of childhood arthritis whose treatment is most challenging. The demonstration of the prominent involvement of interleukin (IL)-1 in disease pathogenesis has provided the rationale for the treatment with biologic medications that antagonize this cytokine. The three IL-1 blockers that have been tested so far (anakinra, canakinumab, and rilonacept) have all been proven effective and safe, although only canakinumab is currently approved for use in sJIA. The studies on IL-1 inhibition in sJIA published in the past few years suggest that children with fewer affected joints, higher neutrophil count, younger age at disease onset, shorter disease duration, or, possibly, higher ferritin level may respond better to anti-IL-1 treatment. In addition, it has been postulated that use of IL-1 blockade as first-line therapy may take advantage of a "window of opportunity," in which disease pathophysiology can be altered to prevent the occurrence of chronic arthritis. In this review, we analyze the published literature on IL-1 inhibitors in sJIA and discuss the rationale underlying the use of these medications, the results of therapeutic studies, and the controversial issues.

Juvenile Idiopathic Arthritis: Diagnosis and Treatment

Juvenile idiopathic arthritis is a broad term that describes a clinically heterogeneous group of arthritides of unknown cause, which begin before 16 years of age. This term encompasses several disease categories, each of which has distinct presentation, clinical manifestations, and, presumably, genetic background and etiopathogenesis. Although none of the available drugs has curative potential, prognosis has greatly improved as a result of substantial progresses in disease management. The most important new development has been the introduction of the biologic medications, which constitute a valuable treatment option for patients who are resistant to conventional antirheumatic agents. Further insights into the disease pathogenesis and treatment will be provided by the continuous advances in understanding of the mechanisms related to the immune response and inflammatory process, and by the development of new drugs that are capable of selectively inhibiting single molecules or pathways.

Tocilizumab's effect on cognitive deficits induced by intracerebroventricular administration of streptozotocin in Alzheimer's model

Neuroinflammation plays pivotal roles in the pathogenesis of Alzheimer's disease (AD). IL-6 is pleiotropic cytokine which plays significant pathological role in inflammatory diseases and causes prolonged inflammation. Additionally, IL-6 activates microglia cells and enhances the accumulation of amyloid-β peptides. Moreover, IL-6 signal transduction is mediated by membrane-bound and soluble IL-6 receptors. Tocilizumab which is a humanized anti-human IL-6 receptor (IL-6R) monoclonal antibody binds to both of these receptors and inhibits IL-6 signaling by this route. The objective was to investigate tocilizumab's potential effects in the treatment of AD. Male Sprague-Dawley rats were divided into three groups: sham (control), streptozotocin (STZ), and tocilizumab-STZ. We used a single dose of intracerebroventricular (ICV) tocilizumab, beginning 1 h prior to injection of STZ for 3 weeks. The rats in STZ and tocilizumab-STZ groups were given ICV-STZ (3 mg/kg). Behavioral parameters were evaluated on days 17-20 and the rats were sacrificed on day-21 to examine histopathological changes. STZ injection caused significant decrease in the mean escape latency in passive avoidance and also declined the performance improvement in Morris water maze tests. Tocilizumab-STZ group significantly improved learning and spatial memory functions by increasing RLT in the passive avoidance and by shortening escape latency in reaching the platform in the Morris water maze. Histopathological changes were examined using hematoxylin and eosin and immunohistochemical (IHC) stainings. IHC analysis revealed that while protein expressions of amyloid-ß (3.5 ± 0.2) and IL-6 (2.9 ± 0.4) showed intense immune-positivity in STZ group, amyloid-ß (1.3 ± 0.1) and IL-6 (1.5 ± 0.2) immunoreactivities were substantially decreased in tocilizumab treatment group. We conclude that tocilizumab treatment attenuated significantly STZ-induced cognitive impairment and histopathological changes. Further studies would be desirable to investigate clinically relevant protective effects of tocilizumab in AD.

Adult-onset Still's disease: current challenges and future prospects

Adult-onset Still’s disease (AOSD) – a multi-systemic inflammatory condition characterized by high fevers, polyarthritis, an evanescent rash, and pharyngitis – has been a challenging condition to diagnose expediently and treat effectively. Questions remain regarding the underlying pathophysiology and etiology of AOSD. Pathognomonic diagnostic tests and reliable biomarkers remain undiscovered. Over the past decade, important progress has been made. Diagnostic criteria employing glycosylated ferritin have improved specificity. More important, novel biologic therapies have offered important clues to AOSD’s underlying pathophysiology. Cytokine-specific biologic therapies have been instrumental in providing more effective treatment for disease refractory to conventional treatment. While IL-1 therapy has demonstrated efficacy in refractory disease, novel therapies targeting IL-6 and IL-18 show great promise and are currently under investigation.

Mitochondrial and oxidative stress genes are differentially expressed in neutrophils of sJIA patients treated with tocilizumab: a pilot microarray study

BACKGROUND

Various pathways involved in the pathogenesis of sJIA have been identified through gene expression profiling in peripheral blood mononuclear cells (PBMC), but not in neutrophils. Since neutrophils are important in tissue damage during inflammation, and are elevated as part of the acute phase response, we hypothesised that neutrophil pathways could also be important in the pathogenesis of sJIA. We therefore studied the gene profile in both PBMC and neutrophils of sJIA patients treated with tocilizumab.

METHODS

We studied the transcriptomes of peripheral blood mononuclear cells (PBMC) and neutrophils from eight paired samples obtained from 4 sJIA patients taken before and after treatment, selected on the basis that they achieved ACR90 responses within 12 weeks of therapy initiation with tocilizumab. RNA was extracted and gene expression profiling was performed using Affymetrix GeneChip Human Genome U133 Plus 2.0 microarray platform. A longitudinal analysis using paired t-test (p < 0.05 and FC ≥ 1.5) was applied to identify differentially expressed genes (DEGs) between the two time points followed by ingenuity pathway analysis. Gene Set Enrichment Analysis (GSEA) and quantitative real-time PCR were then performed to verify the microarray results.

RESULTS

Gene ontology analysis in neutrophils revealed that response to tocilizumab significantly altered genes regulating mitochondrial dysfunction and oxidative stress (p = 4.6E-05). This was independently verified with GSEA, by identifying a set of oxidative genes whose expression correlated with response to tocilizumab. In PBMC, treatment of sJIA with tocilizumab appeared to affect genes in Oncostatin M signalling and B cell pathways.

CONCLUSIONS

For the first time we demonstrate that neutrophils from sJIA patients responding to tocilizumab showed significantly different changes in gene expression. These data could highlight the importance of mitochondrial genes that modulate oxidative stress in the pathogenesis of sJIA.

Effective use of tocilizumab for the treatment of steroid-refractory gastrointestinal acute graft versus host disease in a child with very high levels of serum interleukin-6

Steroid-refractory acute graft versus host disease (SR-aGVHD) is associated with poor prognosis. A three year old male with severe sickle cell disease (SCD) received a 7/8 HLA-matched unrelated bone marrow transplant. He developed grade III acute graft versus host disease (aGVHD) of the gut, which was refractory to methylprednisolone and five other treatment regimens. Due to very high serum Interleukin-6 (IL-6) levels, he received salvage therapy with tocilizumab with resolution of aGVHD. It may be reasonable to further prospectively study routine monitoring of IL-6 levels and the use of tocilizumab in such patients. Pediatr Blood Cancer 2015;62:362-363. © 2014 Wiley Periodicals, Inc.

[Tocilizumab: experience in a French rheumatological pediatric center]

Tocilizumab (TCZ) is an anti-interleukin-6-receptor antibody. The blockade of IL-6 is used as a strategy for the treatment of systemic juvenile idiopathic arthritis (S-JIA) and multicentric Castleman disease (MCD). In this study, we describe the tolerability profile of tocilizumab in eight children followed in a pediatric rheumatology department. Six patients were treated for S-JIA and two for a MCD. They received doses of TCZ between 8 and 12mg/kg of body weight depending on their disease. Infusions were received every 2-4 weeks. The mean duration of treatment was 32.9 months (14 months to 4.5 years). Clinical adverse events were all mild or moderate. No cases of macrophage activation syndrome and no anaphylactic reactions were reported. TCZ was never stopped for a clinical adverse event. Neutropenia was the most common biological adverse event, sometimes requiring dose adjustments. Thrombopenia, lymphopenia, and increased liver enzymes were reported as well, but treatment was not modified. All these biological adverse events were not complicated by any clinical manifestation. In conclusion, TCZ had a good tolerability profile in these eight patients with partial or total efficacy. Despite this advantageous profile, TCZ should be closely monitored because of the potential severity of adverse events. Moreover, long-term safety has still not been assessed.

IL-6 in inflammation, immunity, and disease

Interleukin 6 (IL-6), promptly and transiently produced in response to infections and tissue injuries, contributes to host defense through the stimulation of acute phase responses, hematopoiesis, and immune reactions. Although its expression is strictly controlled by transcriptional and posttranscriptional mechanisms, dysregulated continual synthesis of IL-6 plays a pathological effect on chronic inflammation and autoimmunity. For this reason, tocilizumab, a humanized anti-IL-6 receptor antibody was developed. Various clinical trials have since shown the exceptional efficacy of tocilizumab, which resulted in its approval for the treatment of rheumatoid arthritis and juvenile idiopathic arthritis. Moreover, tocilizumab is expected to be effective for other intractable immune-mediated diseases. In this context, the mechanism for the continual synthesis of IL-6 needs to be elucidated to facilitate the development of more specific therapeutic approaches and analysis of the pathogenesis of specific diseases.

Pathogenesis of systemic inflammatory diseases in childhood: "Lessons from clinical trials of anti-cytokine monoclonal antibodies for Kawasaki disease, systemic onset juvenile idiopathic arthritis, and cryopyrin-associated periodic fever syndrome"

Inflammation has often been considered to be a nonspecific response and to play a bridging role in the activation of adaptive immunity. However, it is now accepted that inflammation is the product of an independent innate immune system closely linked to the adaptive immune system. The key mediators of inflammation are inflammatory cytokines, as determined by multiple lines of evidence both in vitro and in vivo. Due to the crucial role of inflammatory cytokines in the pathogenesis of autoimmune disorders, anti-cytokine treatment has been developed as a therapy for rheumatoid arthritis, juvenile idiopathic arthritis (JIA), and inflammatory bowel diseases. We recently completed several clinical trials of anti-cytokine treatment for children with systemic inflammatory diseases: anti-IL-6 receptor monoclonal antibody (tocilizumab) for children with two subtypes of JIA (poly-JIA and systemic JIA), anti-TNF-α monoclonal antibody (infliximab) for children with Kawasaki disease, and anti-IL-1-β monoclonal antibody (canakinumab) for children with cryopyrin-associated periodic syndrome. This review summarizes the basis of inflammation in terms of innate immunity and adaptive immunity in these systemic inflammatory diseases, clinical efficacy, and tolerability of these biologic agents, and attempts to determine the roles of individual inflammatory cytokines in disease pathogenesis.

A new era for the treatment of inflammatory autoimmune diseases by interleukin-6 blockade strategy

Interleukin-6 (IL-6) is a cytokine with redundant and pleiotropic activities, and its synthesis is tightly regulated by transcriptional and posttranscriptional mechanisms. When infections and tissue injuries occur, IL-6 synthesis is promptly induced and provides an emergent signal that contributes to host defense through the stimulation of acute-phase responses, immune reactions, and hematopoiesis. After the environmental stress is removed from the host, the production of IL-6 is terminated. However, dysregulated continual synthesis of IL-6 is involved in the development of chronic inflammatory autoimmune diseases. For this reason, tocilizumab, a humanized anti-IL-6 receptor antibody, was developed. Worldwide clinical trials have demonstrated the outstanding efficacy of tocilizumab in rheumatoid arthritis, systemic juvenile idiopathic arthritis, and Castleman's disease; thus, a new era has come for the treatment of these diseases, which were previously considered intractable. Moreover, favorable results from off-label use of tocilizumab strongly suggest that it will be widely applicable for various refractory inflammatory autoimmune diseases. In this context, the mechanism for the continual synthesis of IL-6 needs to be elucidated in order to investigate the pathogenesis of specific diseases and to facilitate the development of more specific therapeutic strategies.

Life-threatening complications of adult-onset Still's disease

Adult-onset Still's Disease (AOSD) since its description in 1971 has proven to be a very complex and challenging disease entity. This rare auto-inflammatory disease is classically described by the "Still's triad" of fever, rash, and arthritis, although the atypical cases frequently outnumber the typical ones. The exact pathogenesis and etiologic factors responsible for the clinical features remain largely obscure, despite recent suggestive cytokine biology findings. Diagnosis is made on clinical grounds, following the exclusion of mimickers of infectious, autoimmune or neoplastic etiology, with the additional consideration of non-specific laboratory abnormalities such as peripheral leukocytosis and elevation of serum ferritin and other acute phase reactants. The disease manifestations are protean and can include diverse complications, affecting multiple organ systems. Moreover, the severity of the organ involvement can vary considerably, representing a wide spectrum from the self-limited to severe. The mainstay of therapy has evolved from the traditional use of corticosteroids and oral immunosupressants to the newer targeted treatments with biologic agents. The scope of this review is to alert the clinician to the existence of life-threatening AOSD complications, namely the macrophage activation syndrome, disseminated intravascular coagulopathy, thrombotic thrombocytopenic purpura, diffuse alveolar hemorrhage, and pulmonary arterial hypertension. Such knowledge may lead in earlier recognition, prompt treatment, and, ideally, improved patient outcomes.

Tocilizumab in pediatric rheumatology: the clinical experience

During the last two decades, clinical use of novel biological therapy has led to increased mechanistic understanding of complex rheumatological diseases. Conversely, basic and translational studies have led to development of new and varied therapeutic agents. These new medications which "target" specific steps in one or more immune pathways have the potential to control disease symptoms, improve quality of life and long-term prognosis, and perhaps in some, restore immunological tolerance. Use of these agents in clinical trials, combined with post-marketing surveillance, has revealed both the benefits and the undesirable side-effects of biological disease-modifying anti-rheumatic drugs (DMARDs). In this review we focus on the use of tocilizumab, a monoclonal antibody directed against the IL6 receptor (IL6R), which potently inhibits IL-6/IL6R signaling.

Tocilizumab: a review of its use in the treatment of juvenile idiopathic arthritis

Tocilizumab (RoActemra(®); Actemra(®)) is a recombinant humanized monoclonal antibody that acts as an interleukin-6 receptor antagonist. Both in the US and EU, tocilizumab has been approved for the treatment of two subtypes of juvenile idiopathic arthritis (JIA), namely systemic JIA (sJIA) and polyarticular JIA (pJIA), in patients aged ≥2 years. These approvals are based on favorable results from two randomized, double-blind, placebo-controlled, multinational, phase III trials in which patients aged 2-17 years with active sJIA (TENDER) or pJIA (CHERISH) received an intravenous dose of tocilizumab based on bodyweight every 2 or 4 weeks, respectively. Tocilizumab met the primary endpoint in both of these ongoing, multi-part studies. That is, in TENDER, significantly more tocilizumab recipients than placebo recipients achieved a JIA American College of Rheumatology (ACR) 30 response plus absence of fever, as assessed at the end of a 12-week double-blind treatment period, while in CHERISH, significantly fewer tocilizumab recipients than placebo recipients experienced a JIA ACR 30 flare during a 24-week double-blind withdrawal period (all patients had previously received open-label tocilizumab in a 16-week lead-in phase). Tocilizumab was generally well tolerated in the TENDER trial. Infections (e.g. upper respiratory tract infection and pharyngitis or nasopharyngitis) accounted for just over one-third of all reported adverse events in this trial; tocilizumab-treated patients appeared to have an approximately 11 % risk of a serious infection per year of treatment. Clinical laboratory abnormalities included neutropenia and elevated aminotransferase levels. The tolerability profile of tocilizumab in CHERISH was generally consistent with that of the drug in TENDER.

Advances in understanding the pathogenesis of HLH

Haemophagocytic lymphohistiocytosis (HLH) is a hyperinflammatory disorder resulting from immune dysfunction reflecting either primary immune deficiency or acquired failure of normal immune homeostasis. Familial HLH includes autosomal recessive and X-linked disorders characterized by uncontrolled activation of T cells and macrophages and overproduction of inflammatory cytokines, secondary to defects in genes encoding proteins involved in granule-dependent cytolytic pathways. In older children and adults, HLH is associated more often with infections, malignancies, autoimmune diseases, and acquired immune deficiencies. HLH, macrophage activation syndrome, sepsis, and systemic inflammatory response syndrome are different clinical entities that probably represent a common immunopathological state, termed cytokine storm. These conditions may be clinically indistinguishable; all include massive inflammatory response, elevated serum cytokine levels, multi-organ involvement, haemophagocytic macrophages, and often death. Tissues of haematopoietic and lymphoid function are directly involved; other organs are secondarily damaged by circulating cytokines and chemokines. Haemophagocytic disorders are now increasingly diagnosed in the context of severe inflammatory reactions to viruses, malignancies and systemic connective tissue diseases. Many of these cases may reflect underlying genetic predispositions to HLH. The detection of gene defects has contributed considerably to our understanding of HLH, but the mechanisms leading to acquired HLH have yet to be fully determined.

Tocilizumab: An Updated Review of Its Use in the Treatment of Rheumatoid Arthritis and Its Application for Other Immune-Mediated Diseases

Interleukin-6 (IL-6), produced by a variety of cells, is a typical cytokine featuring redundancy and pleiotropic activity. IL-6 is promptly and transiently synthesized in response to infections or injuries, and participates in host defense by inducing immune responses, hematopoiesis, and acute-phase reactions. However, since its abnormal persistent production of mostly unknown etiology plays an important pathological role in the development of various immune-mediated diseases, a humanized anti-IL-6 receptor monoclonal antibody, tocilizumab, was developed and is now used as an innovative biologic for rheumatoid arthritis in more than 90 countries. Several factors strongly suggest that a IL-6 blockade strategy may have a broad application for the treatment of various immune-mediated diseases. These factors include favorable results of pilot or case studies with off-label use of tocilizumab, pathological analyses of the contribution of IL-6 to the development of immune-mediated diseases, and the potential capability of tocilizumab to both repair an imbalance of effector T cell subsets and to suppress pathologic autoantibody production. However, clinical trials to evaluate the efficacy and safety of tocilizumab for these diseases are essential. Furthermore, clarification of the cell source of IL-6 production and of the mechanisms through which dysregulated continuous IL-6 synthesis is induced constitutes an important issue for future studies into the pathogenesis of diseases.