Commentary: rituximab, adalimumab, etanercept, tocilizumab--are biologics the future for Graves' orbitopathy?

Etanercept as a TNF-alpha inhibitor depresses experimental retinal neovascularization

PURPOSE

The formation of retinal neovascularization (RNV) is the primary pathological process underlying retinopathy of prematurity (ROP). Previous studies have shown that inflammatory factors are related to the formation of RNV. Tumor necrosis factor-α (TNF-α), as an important factor in the inflammatory response, is involved in the regulation of RNV formation. However, the mechanism through which TNF-α inhibition reduces RNV formation is not fully clarified. Therefore, the purpose of this study was to explore the effect of etanercept, an inhibitor of TNF-α, on RNV, and its possible mechanism.

METHODS

In vivo, an oxygen-induced retinopathy (OIR) mouse model was used to determine the effect of etanercept on the formation of RNV by performing immunostaining. The effect of etanercept on tumor necrosis factor receptor-associated factor 2 (TRAF2), pro-angiogenic-related factors, and pro/anti-inflammatory factors in OIR mice was assessed by real-time PCR and Western blotting. In vitro, the effect of etanercept on TNF-α-induced human retinal microvascular endothelial cell tube formation was evaluated by tube formation assays, and the potential mechanism of etanercept was explored by Western blotting.

RESULTS

In vivo, etanercept reduced the area of RNV and decreased the expression of TRAF2 in the OIR mouse model. Etanercept also suppressed the expression of several pro-angiogenic factors and regulated the pro/anti-inflammatory factors. In vitro, etanercept reduced endothelial cell tube formation by inhibiting activation of the NF-κB signaling pathway.

CONCLUSION

Etanercept can regulate pro/anti-inflammatory factors and reduce the expression of pro-angiogenic factors by inhibiting NF-κB phosphorylation, thereby reducing RNV formation.

Immunological Aspects of Graves' Ophthalmopathy

The body's autoimmune process is involved in the development of Graves' disease (GD), which is manifested by an overactive thyroid gland. In some patients, autoreactive inflammatory reactions contribute to the development of symptoms such as thyroid ophthalmopathy, and the subsequent signs and symptoms are derived from the expansion of orbital adipose tissue and edema of extraocular muscles within the orbit. The autoimmune process, production of antibodies against self-antigens such as TSH receptor (TSHR) and IGF-1 receptor (IGF-1R), inflammatory infiltration, and accumulation of glycosaminoglycans (GAG) lead to edematous-infiltrative changes in periocular tissues. As a consequence, edema exophthalmos develops. Orbital fibroblasts seem to play a crucial role in orbital inflammation, tissue expansion, remodeling, and fibrosis because of their proliferative activity as well as their capacity to differentiate into adipocytes and myofibroblasts and production of GAG. In this paper, based on the available medical literature, the immunological mechanism of GO pathogenesis has been summarized. Particular attention was paid to the role of orbital fibroblasts and putative autoantigens. A deeper understanding of the pathomechanism of the disease and the involvement of immunological processes may give rise to the introduction of new, effective, and safe methods of treatment or monitoring of the disease activity.

Molecularly targeted agents in oculoplastic surgery

PURPOSE OF REVIEW

Significant advances have been made in oncology and rheumatology with the introduction of molecularly targeted agents (MTAs). MTAs consist of monoclonal antibodies and small molecule inhibitors. The purpose of this manuscript is to review the recent applications of MTAs to orbital, lacrimal, and eyelid disease.

RECENT FINDINGS

The use of monoclonal antibodies has been described in the treatment of orbital vascular lesions, lymphoma, and squamous cell carcinoma. Inflammatory conditions treated with monoclonal antibodies include thyroid eye disease, IgG4 disease, and granulomatosis with polyangiitis. Immunotherapy with checkpoint inhibitors has also found applications to orbital disease. Use of small molecule inhibitors has been described in the treatment of basal cell carcinoma, squamous cell carcinoma, and Erdheim-Chester disease. There are many orbital, lacrimal, and eyelid side effects of MTAs with which the oculoplastic surgeon should be familiar, including hypertrichosis, edema, and orbital and eyelid inflammation.

SUMMARY

MTAs represent the future of treatment of oncologic and inflammatory conditions. Application of these agents to orbital, lacrimal, and eyelid disease will continue to expand. Elucidating the molecular mechanisms of oculoplastic disorders will facilitate additional potential pathways that could be targeted for therapy.

Advances in treatment of active, moderate-to-severe Graves' ophthalmopathy

Graves' ophthalmopathy is defined as autoimmune inflammation of extraocular muscles and orbital fat or connective tissue, usually in patients with Graves' disease. About one in 20 patients with Graves' hyperthyroidism has moderate-to-severe Graves' ophthalmopathy. Corticosteroids have been the mainstay of treatment, but new evidence about immune mechanisms has provided a basis to explore other drug classes. Intravenous methylprednisolone pulses are more effective and better tolerated than oral prednisone in the treatment of active, moderate-to-severe Graves' ophthalmopathy. Rituximab has also been suggested as a possible replacement for intravenous corticosteroids. Two randomised controlled trials of rituximab reached seemingly contradictory conclusions-rituximab was not better with respect to the primary outcome (clinical activity score) than placebo in one trial (which, however, was confounded by rather long Graves' ophthalmopathy duration), but was slightly better than intravenous methylprednisolone pulses in the other (disease flare-ups occurred only in the latter group). On the basis of evidence published so far, rituximab cannot replace intravenous methylprednisolone pulses, but could have a role in corticosteroid-resistant cases. Open-label studies of tumour-necrosis-factor-α blockade had limited efficacy, but other studies showed that interleukin-6 receptor antibodies were effective. Results of randomised controlled trials investigating the efficacy of the IGF-1 receptor antibody teprotumumab and the interleukin-6 receptor antibody tocilizumab are expected shortly. Approaches that target the causal mechanism of Graves' ophthalmopathy (antibodies or antagonists that block thyroid-stimulating-hormone receptors) also look promising.

Orbital inflammation: Corticosteroids first

Orbital inflammation is common, and may affect all ages and both genders. By combining a thorough history and physical examination, targeted ancillary laboratory testing and imaging, a presumptive diagnosis can often be made. Nearly all orbital inflammatory pathology can be empirically treated with corticosteroids, thus obviating the need for histopathologic diagnosis prior to initiation of therapy. In addition, corticosteroids may be effective in treating concurrent systemic disease. Unless orbital inflammation responds atypically or incompletely, patients can be spared biopsy.

Graves' Ophthalmopathy: VISA versus EUGOGO Classification, Assessment, and Management

Graves' ophthalmopathy (GO) is an autoimmune inflammatory disorder associated with thyroid disease which affects ocular and orbital tissues. GO follows a biphasic course in which an initial active phase of progression is followed by a subsequent partial regression and a static inactive phase. Although the majority of GO patients have a mild, self-limiting, and nonprogressive ocular involvement, about 3–7% of GO patients exhibit a severe sight-threatening form of the disease due to corneal exposure or compressive optic neuropathy. An appropriate assessment of both severity and activity of the disease warrants an adequate treatment. The VISA (vision, inflammation, strabismus, and appearance), and the European Group of Graves' Orbitopathy (EUGOGO) classifications are the two widely used grading systems conceived to assess the activity and severity of GO and guide the therapeutic decision making. A critical analysis of classification, assessment, and management systems is reported. A simplified “GO activity assessment checklist” for routine clinical practice is proposed. Current treatments are reviewed and management guidelines according to the severity and activity of the disease are provided. New treatment modalities such as specific monoclonal antibodies, TSH-R antagonists, and other immunomodulatory agents show a promising outcome for GO patients.

Extrathyroidal manifestations of Graves' disease: a 2014 update

INTRODUCTION

Graves' orbitopathy (GO), thyroid dermopathy (also called pretibial myxedema) and acropachy are the extrathyroidal manifestations of Graves' disease. They occur in 25, 1.5, and 0.3 % of Graves' patients, respectively. Thus, GO is the main and most common extrathyroidal manifestation. Dermopathy is usually present if the patient is also affected with GO. The very rare acropachy occurs only in patients who also have dermopathy. GO and dermopathy have an autoimmune origin and are probably triggered by autoimmunity to the TSH receptor and, likely, the IGF-1 receptor. Both GO and dermopathy may be mild to severe.

MANAGEMENT

Mild GO usually does not require any treatment except for local measures and preventive actions (especially refraining from smoking). Currently, moderate-to-severe and active GO is best treated by systemic glucocorticoids, but response to treatment is not optimal in many instances, and retreatments and use of other modalities (glucocorticoids, orbital radiotherapy, cyclosporine) and, in the end, rehabilitative surgery are often needed. Dermopathy is usually managed by local glucocorticoid treatment. No specific treatment is available for acropachy.

PERSPECTIVES

Novel treatments are presently being investigated for GO, and particular attention is paid to the use of rituximab. It is unknown whether novel treatments for GO might be useful for the other extrathyroidal manifestations. Future novel therapies shown to be beneficial for GO in randomized studies may be empirically used for dermopathy and acropachy.