Tocilizumab - a novel therapy for non-organ-specific autoimmune diseases

Novel therapies for memory cells in autoimmune diseases

Autoimmune diseases are a major cause of morbidity, and their incidence and prevalence continue to rise. Treatments for these diseases are non-specific and result in significant adverse effects. Targeted therapies may help in improving the risk : benefit ratio associated with treatment. Immunological memory is an important feature of the vertebrate immune system that results in the production of cells that are long-lived and able to respond to antigens in a more robust manner. In the setting of autoimmunity this characteristic becomes detrimental due to the ongoing response to a self-antigen(s). These memory cells have been shown to play key roles in various autoimmune diseases such as type 1 diabetes, multiple sclerosis and psoriasis. Memory T cells and B cells can be identified based on various molecules expressed on their surface. Memory T cells can be divided into three main categories - central memory, effector memory and resident memory cells. These subsets have different proliferative potential and cytokine-producing abilities. Utilizing differentially expressed surface molecules or downstream signalling pathway proteins in these cells it is now possible to target memory cells while sparing naive cells. We will discuss the various available options for such a strategy and several potential strategies that may yield successful therapies in the future.

Successful treatment of tumor necrosis factor receptor-associated periodic syndrome (TRAPS) with tocilizumab: A case report

Tumor necrosis factor receptor-associated periodic syndrome (TRAPS) is an autosomal dominant autoinflammatory disease linked to chromosome 12p13 and, more specifically, with mutations within the tumor necrosis factor receptor superfamily, member 1A gene (TNFRSF1A gene). It is characterized by the presence of fever, abdominal pain, myalgia, arthralgia or arthritis, and skin rash. In this report, we describe the case of a patient with tumor necrosis factor receptor-associated periodic syndrome (TRAPS) treated successfully with the anti-interleukin-6 (anti-IL-6) receptor monoclonal antibody tocilizumab, while treatment with anti-TNF α etanercept and infliximab had both failed.

Differential phenotypes of tissue-infiltrating T cells during angiotensin II-induced hypertension in mice

Hypertension remains the leading risk factor for cardiovascular disease (CVD). Experimental hypertension is associated with increased T cell infiltration into blood pressure-controlling organs, such as the aorta and kidney; importantly in absence of T cells of the adaptive immune system, experimental hypertension is significantly blunted. However, the function and phenotype of these T cell infiltrates remains speculative and undefined in the setting of hypertension. The current study compared T cell-derived cytokine and reactive oxygen species (ROS) production from normotensive and hypertensive mice. Splenic, blood, aortic, kidney and brain T cells were isolated from C57BL/6J mice following 14-day vehicle or angiotensin (Ang) II (0.7 mg/kg/day, s.c.) infusion. T cell infiltration was increased in aorta, kidney and brain from hypertensive mice. Cytokine analysis in stimulated T cells indicated an overall Th1 pro-inflammatory phenotype, but a similar proportion (flow cytometry) and quantity (cytometric bead array) of IFN-γ, TNF-α, IL-4 and IL-17 between vehicle- and Ang II- treated groups. Strikingly, elevated T cell-derived production of a chemokine, chemokine C-C motif ligand 2 (CCL2), was observed in aorta (∼6-fold) and kidney in response to Ang II, but not in brain, spleen or blood. Moreover, T cell-derived ROS production in aorta was elevated ∼3 -fold in Ang II-treated mice (n = 7; P<0.05). Ang II-induced hypertension does not affect the overall T cell cytokine profile, but enhanced T cell-derived ROS production and/or leukocyte recruitment due to elevated CCL2, and this effect may be further amplified with increased infiltration of T cells. We have identified a potential hypertension-specific T cell phenotype that may represent a functional contribution of T cells to the development of hypertension, and likely several other associated vascular disorders.

Interleukin-6 blockade in ocular inflammatory diseases

Interleukin-6 (IL-6) is a key cytokine featuring redundancy and pleiotropic activity. It plays a central role in host defence against environmental stress such as infection and injury. Dysregulated, persistent interleukin (IL)-6 production has been implicated in the development of various autoimmune, chronic inflammatory diseases and even cancers. Significant elevation of IL-6 has been found in ocular fluids derived from refractory/chronic uveitis patients. In experimental autoimmune uveitis models with IL-6 knock-out mice, IL-6 has shown to be essential for inducing inflammation. IL-6 blockade can suppress acute T helper type 17 (Th17) responses via its differentiation and, importantly, can ameliorate chronic inflammation. Tocilizumab, a recombinant humanized anti-IL-6 receptor antibody, has been shown to be effective in several autoimmune diseases, including uveitis. Herein, we discuss the basic biology of IL-6 and its role in development of autoimmune conditions, focusing particularly on non-infectious uveitis. It also provides an overview of efficacy and safety of tocilizumab therapy for ocular inflammatory diseases.

Ingested (oral) tocilizumab inhibits EAE

BACKGROUND

Blocking the activity of IL-6 can inhibit autoimmune diseases such as rheumatoid arthritis and Crohn's disease.

OBJECTIVE

We examined whether an antibody against IL-6, tocilizumab (TCZ) (Actemra®), used clinically in rheumatoid arthritis (RA) would have similar anti-inflammatory effects in EAE after oral administration.

DESIGN/METHOD

B6 mice were immunized with MOG peptide 35-55 and gavaged with control saline or TCZ during ongoing disease. Splenocytes, CD4(+) T cells or macrophages/monocyte lineage cells (CD11b(+)) from control fed or TCZ fed mice were adoptively transferred into active MOG peptide 35-55 immunized recipient mice during ongoing disease. Actively fed and recipient mice were examined for disease inhibition, inflammation, and cytokine responses.

RESULTS

Ingested (oral) TCZ inhibited ongoing disease and decreased inflammation. Adoptively transferred cells from TCZ fed donors protected against actively induced disease and decreased inflammation. There was a decrease in IL-6 in actively treated spleen, decrease in TNF-α, Th1-like cytokine IL-12 and increase in Th2-like cytokine IL-10 in active fed and adoptively treated recipients.

CONCLUSIONS

Ingested (orally administered) TCZ can inhibit disease, CNS inflammation, decrease pro-inflammatory Th1-like cytokines and increase Th2-like anti-inflammatory cytokines.

[Sustained response with tocilizumab in a case of refractory relapsing polychondritis]

INTRODUCTION

Relapsing polychondritis (RP) is a rare inflammatory disease characterized by diffuse cartilage involvement, especially those of the respiratory tract, leading to potentially life threatening complications. Corticosteroids remain the first-line empirical therapy. Immunosuppressive drugs such as azathioprine, cyclophosphamide and tumor necrosis factor blockers (anti-TNFα) are commonly used as second-line therapy with varying degrees of success.

CASE REPORT

We report a 40-year-old man with severe RP for whom conventional therapy and immunosuppressive treatments were ineffective. Prolonged clinical remission was obtained after introduction of the anti-interleukin-6 receptor antibody (tocilizumab), which was perfectly tolerated and allowed to taper steroids and methotrexate to a very low dosage.

CONCLUSION

Our patient is the fifth published one documenting the efficacy of tocilizumab in severe refractory RP, which strengthens the use of anti-IL-6 in that indication.

Targeting interleukin-6 in rheumatoid arthritis

Interleukin (IL)-6 is a potent pro-inflammatory agent that plays a crucial role in the pathogenesis of systemic inflammatory disease. Targeting this pathway in rheumatoid arthritis (RA) seems an attractive option as IL-6 is important for both joint destruction and systemic manifestations. Currently, tocilizumab, which binds the IL-6 receptor, is licensed for treatment in active, moderate to severe disease in RA and systemic juvenile idiopathic arthritis (JIA). Several other promising IL-6 blocking agents as well as a subcutaneous form of tocilizumab are currently undergoing phase III clinical trials. The aim of this article is to provide an up-to-date analysis of clinical efficacy and tolerability data concerning the use of IL-6 inhibitors. Data from clinical trials demonstrated that clinical efficacy for tocilizumab, which included improvement in physical function and halting radiographic progression, were comparable to other biologics licensed for use in RA. Patients who should gain most are RA patients with systemic features such as high inflammatory markers and anaemia. Perhaps, the strongest selling point lies in its effectiveness as a monotherapy. This is particularly useful in those who are not tolerating combination treatment with methotrexate. Tocilizumab is one of a few biologics that have been shown to be superior to methotrexate in head-to-head studies. The safety profile of tocilizumab also is comparable to other currently available biologics. There is a small but significant increase in adverse events including infections in patients treated with tocilizumab compared to placebo, particularly in patients who are elderly and those with multiple comorbidities. Elevated lipid profiles are frequent but have not been associated with major cardiovascular events. IL-6 blockade is a major advancement in the treatment of RA as it targets a unique molecule. Over the next few years, evidence will be available on the long-term cardiovascular safety and efficacy of subcutaneous IL-6 blocking agents.

Tocilizumab: a novel humanized anti-interleukin 6 (IL-6) receptor antibody for the treatment of patients with non-RA systemic, inflammatory rheumatic diseases

Tocilizumab is a highly effective therapeutic agent for the treatment of rheumatoid arthritis and systemic juvenile idiopathic arthritis. Furthermore, a large amount of case study data reveals that tocilizumab can be an effective therapy for not only rheumatoid arthritis but also for other mostly rare inflammatory rheumatic diseases. By blocking the interleukin-6 pathway tocilizumab can be a useful therapeutic alternative when conventional treatment fails. It is successful in treating diseases such as the adult-onset Still's disease, amyloidosis, giant cell arteritis, multiple myeloma, polymyalgia rheumatica, relapsing polychondritis, remitting seronegative symmetrical synovitis with pitting edema-syndrome, systemic lupus erythematosus, systemic sclerosis, and Takayasu arteritis. Studies underway are now recruiting patients to acquire further data on treating patients with non-rheumatic arthritis, inflammatory diseases. This review focuses on tocilizumab as a promising agent for treating rare and orphan diseases in rheumatology for which no satisfactory treatment is yet available.

Current and future treatments for Behçet's uveitis: road to remission

Behçet's disease (BD) is a multisystem inflammatory disorder of uncertain origin, although it remains defined within the spectrum of systemic immune-mediated vasculitic disorders and also represents a spectrum of putative autoimmune disease. Major symptoms include oral aphthous ulcers, genital ulcerations, skin lesions, and ocular lesions. Despite afflicting many systems, ocular complications of BD are some of the more devastating for the patient and their quality of life. Eye involvement, which affects 60-80 % of BD patients, is characterized in its more severe form by posterior or panuveitis including occlusive retinal vasculitis. While pathogenesis of BD remains complex, association with Class I MHC (HLA-B*51) predisposing to inflammation with engagement of the innate-immune system (neutrophils, NK cells), and perpetuated by the adaptive T cell responses against infectious- and/or auto-antigens. Despite the choice of conventional immunosuppressive therapies available, only recently with the advent of biologic therapy has visual prognosis and outcomes been substantially and favorably altered. For example, both interferon-α (IFN-α) and tumour necrosis factor (TNF)-α antagonists deliver promising results and for the first time improve prognosis. With IFN-α therapy, durable remissions of uveitis can be achieved and lead to drug-free remission. Similarly, anti-TNF therapy with infliximab is reported to be rapidly effective in inducing and maintaining remission. Most recently, rising evidence reports on the use of adalimumab, etanercept, and golimumab, while use of anti-interleukin (IL)-1 agents (anakinra, canakinumab, gevokizumab), IL-6 blockers (tocilizumab), and rituximab (depleting anti-CD20 antibody) is also increasing. The aim of this review is to provide evidence for the role of conventional therapies combined with evidence for advantages and disadvantages of biologic therapies in the treatment of ocular BD. Although randomized controlled trials remain sparse, evidence remains strong and enticing that biologic agents are invaluable for the treatment of sight-threatening Behçet's uveitis and makes it an exciting time for Behçet's specialists worldwide.