Teprotumumab for Dysthyroid Optic Neuropathy: Early Response to Therapy

[Interdisciplinary Management of Orbital Diseases]

Diagnosis and therapy of orbital diseases is an interdisciplinary challenge, in which i.e. otorhinolaryngologists, ophthalmologists, radiologists, radiation therapists, maxillo-facial surgeons, endocrinologists, and pediatricians are involved. This review article describes frequent diseases which both, otolaryngologists and ophthalmologists are concerned with in interdisciplinary settings. In particular the inflammatory diseases of the orbit including orbital complications, autoimmunological diseases of the orbit including Grave´s orbitopathy, and primary and secondary tumors of the orbit are discussed. Beside describing the clinical characteristics and diagnostic steps the article focusses on the interdisciplinary therapy. The review is completed by the presentation of most important surgical approaches to the orbit, their indications and possible complications. The authors tried to highlight the relevant facts despite the shortness of the text.

Current Therapeutic Approaches for Graves' Orbitopathy - are Targeted Therapies the Future?

Graves' orbitopathy is an autoimmune disease of the orbit that most frequently occurs with Graves' hyperthyroidism. The occurrence of autoantibodies directed against the TSH receptor (TRAb) is of central importance for the diagnosis and pathogenesis. These autoantibodies are mostly stimulating, and induce uncontrolled hyperthyroidism and tissue remodelling in the orbit and more or less pronounced inflammation. Consequently, patients suffer to a variable extent from periocular swelling, exophthalmos, and fibrosis of the eye muscles and thus restrictive motility impairment with double vision. In recent decades, therapeutic approaches have mainly comprised immunosuppressive treatments and antithyroid drug therapy for hyperthyroidism to inhibit thyroid hormone production. With the recognition that TRAb also activates an important growth factor receptor, IGF1R (insulin-like growth factor 1 receptor), biological agents have been developed. Teprotumumab (an inhibitory IGF1R antibody) has already been approved in the USA and the therapeutic effects are enormous, especially with regard to the reduction of exophthalmos. Side effects are to be considered, especially hyperglycaemia and hearing loss. It is not yet clear whether the autoimmune reaction (development of the TRAb/attraction of immunocompetent cells) is also influenced by anti-IGF1R inhibiting agents. Recurrences after therapy show that the inhibition of antibody development must be included in the therapeutic concept, especially in severe cases.

Teprotumumab in thyroid eye disease

Thyroid eye disease (TED) is an inflammatory condition involving the periocular and orbital soft tissues, affecting most commonly patients with hyperthyroid disorders. Traditional treatments used for the active phase of the disease range from conservative lubrication for mild symptoms to systemic immunomodulating drugs for moderate-to-severe symptoms. Teprotumumab (Tepezza) is a monoclonal antibody with an inhibitory effect on insulin-like growth factor 1 and is the first Food and Drug Administration (FDA) approved targeted medical therapy for reducing the inflammatory signs and symptoms associated with TED. Two large multicenter, randomized, double-masked, placebo-controlled trials have confirmed the efficacy and safety of teprotumumab in patients with active, moderate-to-severe TED. Recent reports and publications have also demonstrated the efficacy of teprotumumab in a wider range of patients. In this review, we summarize the clinical features and pathophysiology of TED, disease course, and traditional management methods. We further detail the development of teprotumumab, the founding studies that brought it to its FDA approval, adverse events profile, and ongoing as well as future investigations.

Dysthyroid Optic Neuropathy

PURPOSE

Dysthyroid optic neuropathy (DON) is a sight-threatening complication of thyroid eye disease (TED). This review provides an overview of the epidemiology, pathogenesis, diagnosis, and current therapeutic options for DON.

METHODS

A literature review.

RESULTS

DON occurs in about 5% to 8% of TED patients. Compression of the optic nerve at the apex is the most widely accepted pathogenic mechanism. Excessive stretching of the nerve might play a role in a minority of cases. Increasing age, male gender, smoking, and diabetes mellitus have been identified as risk factors. Diagnosis of DON is based on a combination of ≥2 clinical findings, including decreased visual acuity, decreased color vision, relative afferent pupillary defect, visual field defects, or optic disc edema. Orbital imaging supports the diagnosis by confirming apical crowding or optic nerve stretching. DON should be promptly treated with high-dose intravenous glucocorticoids. Decompression surgery should be performed, but the response is incomplete. Radiotherapy might play a role in the prevention of DON development and may delay or avoid the need for surgery. The advent of new biologic-targeted agents provides an exciting new array of therapeutic options, though more research is needed to clarify the role of these medications in the management of DON.

CONCLUSIONS

Even with appropriate management, DON can result in irreversible loss of visual function. Prompt diagnosis and management are pivotal and require a multidisciplinary approach. Methylprednisolone infusions still represent first-line therapy, and surgical decompression is performed in cases of treatment failure. Biologics may play a role in the future.

Efficacy of teprotumumab therapy in patients with long-duration thyroid eye disease

PURPOSE OF REVIEW

Teprotumumab, an inhibitor of the insulin-like growth factor 1 receptor (IGF-1R), was approved by the US Food and Drug Administration in January 2020 for the treatment of thyroid eye disease (TED). The clinical trials leading to its approval enrolled patients with recent disease onset and significant inflammatory symptoms and signs. Subsequent real-world teprotumumab use in patients with longer duration of disease also may be effective, and there have been several publications reporting on experience in these patient groups.

RECENT FINDINGS

TED results in disfiguring changes such as ocular proptosis and affects visual function by altering extraocular muscle function, leading to diplopia. Compressive optic neuropathy also may occur, and disease manifestations may persist for years. Teprotumumab treatment in cases of TED in which prior interventions (medical or surgical) had failed, or in treatment-naïve patients whose disease had been stable for years, has been reported to improve both clinical signs and symptoms (proptosis, diplopia) and to reduce the pathologic orbital changes as assessed by orbital imaging.

SUMMARY

Teprotumumab may be an appropriate treatment for TED regardless of disease duration and irrespective of the presence or absence of markers of active inflammation within the orbit.

Dysthyroid optic neuropathy: emerging treatment strategies

PURPOSE

Dysthyroid optic neuropathy (DON) is a rare sight-threatening complication of Graves' disease. First-line treatment for DON consists of high-dose intravenous methylprednisolone (ivMP), followed by immediate orbital decompression (OD) if the response is poor or absent as recommended by the 2021 European Group on Graves' orbitopathy guidelines. The safety and efficacy of the proposed therapy have been proven. However, consensus regarding possible therapeutic options for patients with contraindications to ivMP/OD or resistant form of disease is missing. This paper aims to provide and summarize all available data regarding possible alternative treatment strategies for DON.

METHODS

A comprehensive literature search within an electronic database was performed including data published until December 2022.

RESULTS

Overall, 52 articles describing use of emerging therapeutic strategies for DON were identified. Collected evidence indicates that biologics, including teprotumumab and tocilizumab, may be considered as an important possible treatment option for DON patients. Rituximab should be avoided in DON due to conflicting data and risk of adverse events. Orbital radiotherapy could be beneficial for patients with restricted ocular motility classified as poor surgical candidates.

CONCLUSION

Only a limited number of studies have been dedicated to the therapy of DON, mostly retrospective with a small sample size. Clear criteria regarding diagnosis and resolution of DON do not exist, which restricts comparison of therapeutic outcomes. Randomized clinical trials and comparison studies with long-term follow-ups are necessary to verify the safety and efficacy of each therapeutic option for DON.

The Role of Insulin-like Growth Factor-1 and Its Receptor in the Eye: A Review and Implications for IGF-1R Inhibition

PURPOSE

FDA approval of teprotumumab for thyroid eye disease in January 2020 reinforced interest in the pharmacologic potential of insulin-like growth factor-1 (IGF-1) and its receptor, IGF-1R. Despite recent approval and adaptation for ophthalmic use, IGF-1R inhibitors are not a new therapeutic class. In 1986, Yamashita described aIR3, a monoclonal antibody to IGF-1R (anti-IGF-1R), that inhibited the effect of IGF-1 on growth hormone release. Given the widespread presence of IGF-1R, interrupting this receptor can lead to systemic physiologic effects, some adverse. We aim to review what is known about IGF-1/IGF-1R in the eye and consider the possible local side effects, unintended consequences, and potential uses of this medication class.

METHODS

A PubMed database search utilizing the keywords "insulin-like growth factor-1, eye, inhibitor, antibody, side effect" was performed to identify publications discussing IGF-1 in the human eye from January 2011 to August 2021. Criteria for acceptance included studies discussing human subjects or human tissue specifically related to the eye.

RESULTS

Out of a total of 230 articles, 47 were organized in 3 subject groups for discussion: thyroid-associated orbitopathy, cornea and the ocular surface, and the retina and neovascularization. Review of the literature demonstrated that IGF-1 affects growth and development of the eye, epithelial proliferation, retinal angiogenesis, inflammation, and is associated with thyroid-associated orbitopathy.

CONCLUSIONS

IGF-1R exists throughout in the human body, including the cornea, retina, and orbit. Research regarding ocular effects of IGF-1/IGF-1R outside thyroid eye disease is limited. Carefully designed studies and clinical assessments of patients undergoing treatment with anti-IGF-1R may identify ocular side effects and foster consideration of the role of anti-IGF-1R in ocular therapeutics. Given the increasing use of anti-IGF-1R antibodies, understanding their ocular effects, side effects, and potential systemic implications for use in disease is critical.

Dysthyroid optic neuropathy: Demographics, risk factors, investigations, and management outcomes

Purpose

To analyze the clinical presentations, risk factors, and management outcomes in patients presenting with dysthyroid optic neuropathy (DON).

Methods

This is a retrospective, single-center study carried out on consecutive patients presenting with DON over a period of 4 years (2013-2016). The VISA classification was used at the first visit and subsequent follow-ups. The diagnosis was based on optic nerve function tests and imaging features. Demographic profiles, clinical features, risk factors, and management outcomes were analyzed.

Results

Thirty-seven eyes of 26 patients diagnosed with DON were included in the study. A significant male preponderance was noted (20, 76.92%). Twenty patients (76.9%, P = 0.011) had hyperthyroidism, and 15 (57.69%, P = 0.02) were smokers. Decreased visual acuity was noted in 28 eyes (75.6%). Abnormal color vision and relative afferent pupillary defects were seen in 24 (64.86%) eyes, and visual field defects were seen in 30 (81.01%) eyes. The visual evoked potential (VEP) showed a reduced amplitude in 30 (96.77%, P = 0.001) of 31 eyes and delayed latency in 20 (64.51%, P = 0.0289) eyes. Twenty-six (70.27%) patients were treated with intravenous methyl prednisolone (IVMP) alone, whereas 11 (29.72%) needed surgical decompression. The overall best-corrected visual acuity improved by 0.2 l logMARunits. There was no statistically significant difference in outcome between medically and surgically treated groups. Four patients developed recurrent DON, and all of them were diabetics.

Conclusion

Male gender, hyperthyroid state, and smoking are risk factors for developing DON. VEP, apical crowding, and optic nerve compression are sensitive indicators for diagnosing DON. Diabetics may have a more defiant course and are prone to develop recurrent DON.

Teprotumumab and the Evolving Therapeutic Landscape in Thyroid Eye Disease

CONTEXT

Thyroid eye disease (TED) is a sight-threatening and debilitating autoimmune condition, with limited therapies available, that often poses diagnostic and therapeutic challenges. In recent years, the treatment landscape has shifted to early intervention with targeted therapy.

METHODS

A PubMed review of the literature was conducted for the period between 1979 and 2021. Search terms included thyroid eye disease, teprotumumab, targeted therapy, Graves disease, Graves ophthalmopathy, dysthyroid optic neuropathy, and related terms in different combinations. Novel biologic therapies for TED have emerged as alternatives to traditional steroid regimens in recent years. New insights into TED pathophysiology have uncovered the role of the insulin-like growth factor 1 receptor (IGF-1R) and led to the development of teprotumumab, an IGF-1R-inhibiting monoclonal antibody.

RESULTS

Randomized clinical trials demonstrating the efficacy of teprotumumab for TED led to Food and Drug Administration approval. Teprotumumab is gradually replacing immunosuppressive agents as first-line therapy in the United States for active moderate-to-severe TED, while emerging reports also show its use in other stages of the disease. Recent data highlight risk factors for adverse events and screening protocols to maximize patient safety. Personalized therapeutic plans developed through effective partnership between endocrinologists and ophthalmologists aim to enhance the safety and outcomes of TED treatments and improve care for this complex disease.

CONCLUSION

TED management is shifting to an era of targeted therapy with multidisciplinary care. Teprotumumab has demonstrated superior efficacy to conventional treatments and has transformed our therapeutic and surgical algorithms. Clinical guidelines and additional studies are needed to further guide and refine therapy.

Update on thyroid eye disease: Regional variations in prevalence, diagnosis, and management

Thyroid eye disease (TED) is a rare disease that can lead to decreased quality of life, permanent disfigurement, and vision loss. Clinically, TED presents with exophthalmos, periorbital edema, extraocular muscle dysfunction, and eyelid retraction, and can lead to vision-threatening complications such as exposure to keratopathy and dysthyroid optic neuropathy (DON). Over the last several years, significant advancements have been made in the understanding of its pathophysiology as well as optimal management. Ethnic variations in the prevalence, clinical presentation, and risk of vision-threatening complications of TED are summarized, and risk factors associated with TED are discussed. Additionally, significant advances have been made in the management of TED. The management of TED traditionally included anti-inflammatory medications, orbital radiation therapy, orbital surgical decompression, and biologic therapies. Most recently, targeted therapies such as teprotumumab, an insulin-like growth factor-1 receptor antagonist, have been studied in the context of TED, with promising initial data. In this review, updates in the understanding and management of TED are presented with a focus on the international variations in presentation and management.

Advances in the Treatment of Thyroid Eye Disease Associated Extraocular Muscle Myopathy and Optic Neuropathy

PURPOSE OF REVIEW

To review emerging treatments for thyroid eye disease (TED) associated extraocular muscle myopathy and dysthyroid optic neuropathy (DON).

RECENT FINDINGS

Emerging targeted biologic therapies may alter the disease course in TED. Teprotumumab, a type I insulin-like growth factor receptor inhibitor, is the most recent addition to the treatments available for TED-associated extraocular muscle myopathy causing diplopia. Small studies also suggest a potential therapeutic benefit for DON. Various recent studies have also expanded our knowledge on conventional TED therapies. The therapeutic landscape of TED and its sequelae has evolved in recent years. New targeted therapies have the potential to reduce the extraocular muscle and orbital volume expansion which can lead to diplopia and vision loss from optic nerve compression. Longer term efficacy and durability data is needed to determine the role biologics, such as teprotumumab, should play in the treatment of TED patients compared to the current standard of care.

Effects of teprotumumab on patients with long-standing, active thyroid eye disease

Purpose

Describe five cases of long-standing, active thyroid eye disease that responded to treatment with teprotumumab.

Observations

Five patients with a greater than 9-month-history of thyroid eye disease, including two patients who had previously failed orbital radiotherapy, received eight doses of teprotumumab. All five patients, including those with a history of orbital radiotherapy, achieved a proptosis reduction of at least 2 mm in each eye as well as a Clinical Activity Score reduction of at least 2 points. In addition, all cases of diplopia improved and all but one case of lagophthalmos improved.

Conclusions and Importance

Teprotumumab may be a safe and efficacious therapy for active thyroid eye disease that is of longer duration than previously studied in clinical trials, as well as disease refractory to orbital radiotherapy. In addition to robust improvement in proptosis and Clinical Activity Score, data from this series suggests diplopia and lagophthalmos may also respond to teprotumumab. Further study of teprotumumab is needed, but in the meantime these results may encourage providers to consider teprotumumab for their patients with long-standing or previously treated disease.

A Paradigm Shift in the Management of Thyroid Eye Disease How Teprotumumab Has Changed the Therapeutic Interface

BACKGROUND

Teprotumumab, a monoclonal antibody that blocks the insulin-like growth factor-1 receptor, has recently been approved by the US Food and Drug Administration (FDA) for the treatment of thyroid eye disease (TED). Since its approval, aside from data on the safety and clinical efficacy of teprotumumab from Phase-2 and Phase-3 trials, only a handful of reports have been published regarding its use in the wider population. In this review, we briefly describe the mechanism of action of teprotumumab and review the literature to provide an overview of published clinical experience. This information was used to provide recommendations for patient selection, management of patient expectations, infusion details and site options, tips to optimize the authorization process, and how to monitor and mitigate side effects.

EVIDENCE ACQUISITION

A systemic review of the literature was performed regarding teprotumumab, focusing on its mechanisms of action and published reports on its use on patients with TED. A review of Embase, Medline (PubMed), Web of Science, and Google Scholar was conducted.

RESULTS

Clinical experience following the approval of teprotumumab has confirmed its efficacy in reducing inflammation and proptosis in patients with acute TED (<2 years). The reduction in proptosis occurs due to a reduction in orbital fat and muscle volume. Furthermore, there is evidence for its use in patients with compressive optic neuropathy. There are also reports that show its efficacy in reducing proptosis, inflammation, and diplopia in patients with chronic TED (>2 years). Teprotumumab was associated with side effects, such as muscle spasm, hearing loss, and hyperglycemia. To date, 2 case reports have shown a possible association with flares of inflammatory bowel disease.

CONCLUSIONS

Teprotumumab is a powerful therapeutic option for the treatment of TED. Clinical experience following FDA approval has demonstrated efficacy in treating patients with acute and chronic TED. It is the only therapeutic option that has been shown to reduce orbital soft tissue expansion in TED. However, it is expensive, and sometimes, obtaining insurance authorization can be time consuming and difficult. Further work will reveal its full side effect profile and help to establish its role in the armamentarium used to treat TED.

2021 update on thyroid-associated ophthalmopathy

PURPOSE

Our understanding of thyroid-associated ophthalmopathy (TAO, A.K.A Graves' orbitopathy, thyroid eye disease) has advanced substantially, since one of us (TJS) wrote the 2010 update on TAO, appearing in this journal.

METHODS

PubMed was searched for relevant articles.

RESULTS

Recent insights have resulted from important studies conducted by many different laboratory groups around the World. A clearer understanding of autoimmune diseases in general and TAO specifically emerged from the use of improved research methodologies. Several key concepts have matured over the past decade. Among them, those arising from the refinement of mouse models of TAO, early stage investigation into restoring immune tolerance in Graves' disease, and a hard-won acknowledgement that the insulin-like growth factor-I receptor (IGF-IR) might play a critical role in the development of TAO, stand out as important. The therapeutic inhibition of IGF-IR has blossomed into an effective and safe medical treatment. Teprotumumab, a β-arrestin biased agonist monoclonal antibody inhibitor of IGF-IR has been studied in two multicenter, double-masked, placebo-controlled clinical trials demonstrated both effectiveness and a promising safety profile in moderate-to-severe, active TAO. Those studies led to the approval by the US FDA of teprotumumab, currently marketed as Tepezza for TAO. We have also learned far more about the putative role that CD34⁺ fibrocytes and their derivatives, CD34⁺ orbital fibroblasts, play in TAO.

CONCLUSION

The past decade has been filled with substantial scientific advances that should provide the necessary springboard for continually accelerating discovery over the next 10 years and beyond.

Efficacy and Safety of Teprotumumab in Thyroid Eye Disease

Thyroid eye disease (TED; also known as thyroid-associated ophthalmopathy) is an autoimmune condition with disabling and disfiguring consequences. Teprotumumab is the first and only medication approved by the United States Food and Drug Administration for the treatment of TED. We review the efficacy and safety of teprotumumab in TED, highlighting results from the 2 randomized, double-masked, placebo-controlled trials. Post-approval case reports of teprotumumab use in patients with compressive optic neuropathy (CON) and inactive TED were similarly favorable to those from the trials. The preliminarily results of teprotumumab for CON and inactive TED should be investigated in formal clinical trials. Teprotumumab should be avoided in pregnancy. Evidence also suggests that teprotumumab may exacerbate pre-existing inflammatory bowel disease, worsen hyperglycemia, and be associated with hearing impairment. Patients at risk for these adverse events need to be closely monitored with baseline and periodic assessments.

Infusion Center Guidelines for Teprotumumab Infusions: Informed Consent, Safety, and Management of Side Effects

Teprotumumab was the first and only medication approved by the US Food and Drug Administration for the treatment of thyroid eye disease in January 2020. Thyroid eye disease is a complex autoimmune inflammatory disease that can be sight-threatening, debilitating, and disfiguring to affected patients. Although biologic therapies are a preferred treatment option for many complex immunologic and oncologic conditions, their use in ophthalmology and endocrinology may be more novel. The goals of this article are to introduce this new therapeutic option; discuss its mechanism of action, indications for use, administration protocol, infusion precautions, and informed consent; and review common side effects and management.

Early efficacy of teprotumumab for the treatment of dysthyroid optic neuropathy: A multicenter study

Purpose

To study post-interventional findings in patients with dysthyroid optic neuropathy (DON) treated with teprotumumab.

Observations

In this multicenter observational Case series, patients with DON were treated with teprotumumab, an insulin-like growth factor I receptor inhibitor (10 mg/kg for the first infusion then 20 mg/kg for subsequent infusions, every three weeks for a total 8 infusions). This study included patients with acute and chronic thyroid eye disease (TED) with DON who had failed conventional therapies and were not candidates for surgical decompression. Data collected included best corrected visual acuity (BCVA), color vision, RAPD when present, and orbital CT or MRI. Proptosis, clinical activity score (CAS), Gorman diplopia score (GDS), and Humphrey visual fields (HVF) were also evaluated.

Ten patients (6 women, 4 men) with an average age 64 years old were included in this study. Mean follow up after completion of infusions was 15 weeks. Baseline visual acuity (VA) impairment ranged from hand motion (HM) to 20/25 in affected eyes. All patients had pre-treatment orbital CT or MRI that confirmed orbital apex compression. Seventy percent of patients had objective improvement in DON after 2 infusions of teprotumumab measured as significant improvement in visual acuity, resolution of RAPD, or both. After completion of treatment, affected eyes had a mean BCVA improvement of 0.87 logMAR (p=0.0207), proptosis reduction of 4.7 mm (p<0.00001), CAS improvement of 5.25 points (p<0.00001), and GDS improvement of 0.75 points (p=0.160). All 6 patients who presented with an RAPD had resolution or improvement of RAPD. All 7 patients who presented with color vision deficits had normalization or improvement of color vision.

Conclusions and Importance

Teprotumumab infusions resulted in medical decompression and objective resolution or improvement of dysthyroid optic neuropathy. Most patients had rapid improvement of visual acuity and reversal of RAPD. Post-infusion imaging demonstrated reduction in extraocular muscle size that correlated with improvement in visual dysfunction. However, patients who presented with longstanding severe visual loss had limited improvement. There was no recurrence of DON after completion of teprotumumab in our cohort.

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Teprotumumab is effective for the treatment of dysthyroid optic neuropathy.

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Most patients demonstrated rapid objective improvement after 2 infusions.

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Visual acuity improved and relative afferent pupillary defect resolved after treatment.

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Orbital imaging showed improvement of orbital apex crowding after treatment.

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Patients with longstanding severe vision loss had limited improvement in visual acuity.

Teprotumumab: Interpreting the Clinical Trials in the Context of Thyroid Eye Disease Pathogenesis and Current Therapies

Teprotumumab, a monoclonal antibody targeted against the insulin-like growth factor 1 (IGF-1) receptor, was recently approved by the United States Food and Drug Administration for the treatment of thyroid eye disease (TED). Phase 1 studies of teprotumumab for the treatment of malignancies demonstrated an acceptable safety profile but limited effectiveness. Basic research implicating the IGF-1 receptor on the CD-34+ orbital fibrocyte in the pathogenesis of TED renewed interest in the drug. Two multicenter, randomized, double-masked, clinical trials (phase 2 and 3) evaluated the efficacy of 8 infusions of teprotumumab every 3 weeks versus placebo in 170 patients with recent-onset active TED, as defined by a clinical activity score (CAS) of at least 4. Teprotumumab was superior to placebo for the primary efficacy end points in both studies: overall responder rate as defined by a reduction of 2 or more CAS points and a reduction of 2 mm or more in proptosis (69% vs. 20%; P < 0.001; phase 2 study) and proptosis responder rate as defined by a reduction of 2 mm or more in proptosis (83% vs. 10%; P < 0.001; phase 3 study). In both studies, treatment with teprotumumab compared with placebo achieved a significant mean reduction of proptosis (-3.0 mm vs. -0.3 mm, phase 2 study; -3.32 mm vs. -0.53 mm, phase 3 study) and CAS (-4.0 vs. -2.5, phase 2 study; -3.7 vs. -2.0, phase 3 study). Teprotumumab also resulted in a greater proportion of patients with a final CAS of 0 or 1, higher diplopia responder rate, and a larger improvement in the Graves' Ophthalmopathy Quality of Life overall score. More than half of patients (62%, phase 2 trial; 56%, phase 3 trial) who were primary end point responders maintained this response at 51 weeks after the last dose of therapy. The most common adverse events reported with teprotumumab included muscle spasms (25%), nausea (17%), alopecia (13%), diarrhea (13%), fatigue (10%), hearing impairment (10%), and hyperglycemia (8%). Teprotumumab is contraindicated for those with inflammatory bowel disease and who are pregnant. Although the current dosing regimen has proven effective for TED, dose-ranging studies including variable concentrations, infusion frequencies, and durations of teprotumumab therapy in the setting of TED have not been performed.

Thyroid Eye Disease: Navigating the New Treatment Landscape

Thyroid eye disease (TED) is a complex inflammatory disease that can have a long clinical course with sight-threatening and debilitating ocular sequelae. Until recently, there were limited therapeutic options available. In the last decade we have gained a deeper understanding of the underlying pathophysiology, which has led to the development of novel effective targeted therapies. This article discusses the challenges encountered in the clinical evaluation and treatment of TED patients, with the goal to empower endocrinologists and ophthalmologists to work together to provide effective multidisciplinary care. We will review recommendations of past clinical guidelines around evaluation and management of TED patients, discuss the randomized controlled trials of new biologic therapies, and explore how to navigate the emerging therapeutic landscape.

Teprotumumab for the treatment of mild compressive optic neuropathy in thyroid eye disease: A report of two cases

Purpose

To report two cases of thyroid eye disease (TED) associated compressive optic neuropathy (CON) that resolved after treatment with teprotumumab.

Observation

Two patients presented with active TED resulting in mild CON with the typical corresponding visual field (VF) defects. Both patients were initiated on intravenous (IV) corticosteroid therapy but despite treatment had persistent VF defects. Both patients were then treated with teprotumumab and demonstrated marked clinical improvement and complete resolution of TED-CON VF defects early in their infusion course.

Conclusions and importance

These cases suggest that teprotumumab can be a rapid and effective treatment for TED-CON, and raises the question of whether it may be superior to IV corticosteroid therapy.

Lessons Learned from Targeting IGF-I Receptor in Thyroid-Associated Ophthalmopathy

Complex immunological mechanisms underlie the pathogenesis of thyroid-associated ophthalmopathy (TAO). Historical models of Graves’ disease and TAO have focused almost entirely on autoimmune reactivity directed against the thyrotropin receptor (TSHR). The insulin-like growth factor-I receptor (IGF-IR) has been proposed as a second participating antigen in TAO by virtue of its interactions with IGFs and anti-IGF-IR antibodies generated in Graves’ disease. Furthermore, the IGF-IR forms with TSHR a physical and functional complex which is involved in signaling downstream from both receptors. Inhibition of IGF-IR activity results in attenuation of signaling initiated at either receptor. Based on the aggregate of findings implicating IGF-IR in TAO, the receptor has become an attractive therapeutic target. Recently, teprotumumab, a human monoclonal antibody IGF-IR inhibitor was evaluated in two clinical trials of patients with moderate to severe, active TAO. Those studies revealed that teprotumumab was safe and highly effective in reducing disease activity and severity. Targeting IGF-IR with specific biologic agents may result in a paradigm shift in the therapy of TAO.

Bilateral dysthyroid compressive optic neuropathy responsive to teprotumumab

Thyroid eye disease is an auto-immune mediated orbitopathy which can cause dysthyroid compressive optic neuropathy. Traditional management of active thyroid eye disease includes temporizing high-dose steroids, orbital radiation and surgical decompression, which each possess significant limitations and/or side effects. Teprotumumab is an IGF-IR inhibitor recently FDA-approved for active thyroid eye disease. The authors report reversal of bilateral dysthyroid compressive optic neuropathy managed medically utilizing teprotumumab.

Insulin-Like Growth Factor Pathway and the Thyroid

The insulin-like growth factor (IGF) pathway comprises two activating ligands (IGF-I and IGF-II), two cell-surface receptors (IGF-IR and IGF-IIR), six IGF binding proteins (IGFBP) and nine IGFBP related proteins. IGF-I and the IGF-IR share substantial structural and functional similarities to those of insulin and its receptor. IGF-I plays important regulatory roles in the development, growth, and function of many human tissues. Its pathway intersects with those mediating the actions of many cytokines, growth factors and hormones. Among these, IGFs impact the thyroid and the hormones that it generates. Further, thyroid hormones and thyrotropin (TSH) can influence the biological effects of growth hormone and IGF-I on target tissues. The consequences of this two-way interplay can be far-reaching on many metabolic and immunologic processes. Specifically, IGF-I supports normal function, volume and hormone synthesis of the thyroid gland. Some of these effects are mediated through enhancement of sensitivity to the actions of TSH while others may be independent of pituitary function. IGF-I also participates in pathological conditions of the thyroid, including benign enlargement and tumorigenesis, such as those occurring in acromegaly. With regard to Graves' disease (GD) and the periocular process frequently associated with it, namely thyroid-associated ophthalmopathy (TAO), IGF-IR has been found overexpressed in orbital connective tissues, T and B cells in GD and TAO. Autoantibodies of the IgG class are generated in patients with GD that bind to IGF-IR and initiate the signaling from the TSHR/IGF-IR physical and functional protein complex. Further, inhibition of IGF-IR with monoclonal antibody inhibitors can attenuate signaling from either TSHR or IGF-IR. Based on those findings, the development of teprotumumab, a β-arrestin biased agonist as a therapeutic has resulted in the first medication approved by the US FDA for the treatment of TAO. Teprotumumab is now in wide clinical use in North America.

Updates on the understanding and management of thyroid eye disease

Thyroid eye disease (TED) is a complex disease associated with myriad clinical presentations, including facial disfigurement, vision loss, and decreased quality of life. Traditionally, steroid therapy and/or radiation therapy were commonly used in the treatment of active TED. While these therapies can help reduce inflammation, they often do not have a sustainable, significant long-term effect on disease outcomes, including proptosis and diplopia. Recent advances in our understanding of the pathophysiology of TED have shifted the focus of treatment toward targeted biologic therapies. Biologics have the advantage of precise immune modulation, which can have better safety profiles and greater efficacy compared to traditional approaches. For instance, the insulin-like growth factor-1 receptor (IGF-1R) has been found to be upregulated in TED patients and to colocalize with the thyroid-stimulating hormone receptor (TSHR), forming a signaling complex. Teprotumumab is an antibody targeted against IGF-1R. By inhibiting the IGF-1R/TSHR signaling pathway, teprotumumab may reduce the production of proinflammatory cytokines, hyaluronan secretion, and orbital fibroblast activation in patients with TED. Due to promising phase II and III clinical trial results, teprotumumab has become the first biologic US Food and Drug Administration (FDA)-approved for the treatment of TED. In addition, there are currently ongoing studies looking at the use of antibodies targeting the neonatal Fc receptor (FcRn) in various autoimmune diseases, including TED. FcRn functions to transport immunoglobulin G (IgG) and prevent their lysosomal degradation. By blocking the recycling of IgG, this approach may dampen the body's immune response, in particular the pathogenic IgG implicated in some autoimmune diseases. Advances in our understanding of the pathophysiology of TED, therefore, are leading to more targeted therapeutic options, and we are entering an exciting new phase in the management of TED. This review will cover recent insights into the understanding of TED pathophysiology and novel treatment options as well as ongoing studies of new potential treatment options for TED.

Teprotumumab as a Novel Therapy for Thyroid-Associated Ophthalmopathy

Thyroid-associated ophthalmopathy (TAO) has remained a vexing and poorly managed autoimmune component of Graves' disease where the tissues surrounding the eye and in the upper face become inflamed and undergo remodeling. This leads to substantial facial disfigurement while in its most severe forms, TAO can threaten eye sight. In this brief paper, I review some of the background investigation that has led to development of teprotumumab as the first and only US FDA approved medical therapy for TAO. This novel treatment was predicated on recognition that the insulin-like growth factor I receptor plays an important role in the pathogenesis of TAO. It is possible that a similar involvement of that receptor in other autoimmune disease may lead to additional indications for this and alternative insulin-like growth factor I receptor-inhibiting strategies.