The Effect of Teprotumumab on Thyroid Eye Disease and Thyroid Dysfunction

Thyroid eye disease (TED), also known as Graves' orbitopathy or thyroid-associated ophthalmopathy is a rare debilitating autoimmune condition in which immune cells attack the eye muscles and connective tissues within the eye socket, leading to proptosis, pain, diplopia, periorbital and orbital erythema and edema, exposure keratopathy and lagophthalmos, decreased vision, and compressive optic neuropathy. It has an incidence of 1.9 cases per 10,000 population per year. Approximately 25% of patients with autoimmune thyroid disease develop TED within 18 months of diagnosis. Severe optic neuropathy will affect 10% of patients with TED, leading to irreversible vision loss.

The natural history of TED involves an initial active phase, during which the autoimmune process causes the above mentioned morbidity, followed by a quiescent phase. The active period usually lasts 2-3 years and requires monitoring until the disease is quiescent. Until now, treatment during the active period focuses on preserving sight and providing treatment for double vision. Emergent orbital decompression or radiation treatment is reserved for compressive optic neuropathy. Alternative therapies, such as glucocorticoids, have little effect on proptosis and can have dose-limiting side effects. When the active phase "burns" out, the treatment for thyroid eye disease involves rehabilitative surgeries for orbital decompression, followed by strabismus surgery, followed by eyelid recession surgery; altogether, this may involve multiple surgeries which don't reverse the damage of the ocular and orbital tissues.

Tepezza®, or teprotumumab, is a fully human monoclonal insulin-like growth factor-1 receptor (IGF-1R) inhibitor antibody which blocks the inflammatory/autoimmune pathophysiology that underlies thyroid eye disease. It is the first FDA-approved medication for the treatment of adults with thyroid eye disease, reversing inflammatory changes of proptosis and diplopia. In clinical trials, 83% of patients receiving teprotumumab demonstrated a greater than 2 mm reduction in proptosis compared to 10% of participants who received placebo (between-group difference, 73% points; 95% CI = 59-88; P<0.001). Teprotumumab had a quick improvement on each outcome, which was evident at the first postbaseline evaluation at week 6, and the results improved during the 24-week treatment period. This therapy could potentially replace surgery for many patients, including those with more advanced disease.

The investigators propose a retrospective observational chart review of a cohort of adults with active TED without compressive optic neuropathy necessitating urgent orbital decompression or radiation who are undergoing treatment with Tepezza®. Inclusion criteria are patients with a clinical diagnosis of autoimmune thyroid disease and moderate-severe TED with clinical activity including symptoms of proptosis, diplopia, orbital pain, lid/orbital edema, or lid/orbital erythema, and with circulating thyroid stimulating or anti-thyroid auto-antibodies present within the last 18 months from the initiation of treatment. Exclusion criteria include patients with a history of compressive optic neuropathy necessitating urgent orbital decompression or external beam radiation, patients with a history of uncontrolled diabetes, uncontrolled inflammatory bowel disease, patients under 18 years old, and patients who are pregnant or trying to become pregnant.

The primary outcome is CAS score improvement and TSI level.