Thyroid eye disease, also known as Graves’ orbitopathy or thyroid-associated ophthalmopathy, is a rare, autoimmune condition in which immune cells attack the thyroid gland which responds by secreting an excess amount of thyroid hormone. Thyroid eye disease cause eye pain, double vision, light sensitivity or difficulty in closing the eye.
Patients with severe disease often require multiple surgical procedures including orbital decompression, strabismus correction, eyelid repair and cosmetic procedures. The remodeling of the orbit and upper face results in diverse presentations which include dry eyes, increased lacrimation, local irritation, and eyelid retraction in mild cases, but it can also manifest as pronounced proptosis, diplopia, and optic nerve compression, with potential vision loss in more severe disease.
Immunomodulatory agents reduce inflammation in active disease but have limited effects on the long-term sequel of thyroid eye disease, such as disfigurement and disability from proptosis and diplopia, which impair quality of life.
Current medical therapies, which primarily consist of glucocorticoids and orbital radiotherapy minimally affect proptosis and can cause dose-limiting adverse reactions. In many patients, the condition does not improve, and in some patients it progresses to dysthyroid optic neuropathy. The Inhibition of insulin-like growth factor I receptor (IGF-IR) is a new therapeutic strategy to reduce the underlying autoimmune pathogenesis of ophthalmopathy.
FDA approved teprotumuma (Tepezza), the first drug for the treatment of adults with thyroid eye disease. It is administered to patients once every 3 weeks for a total of 8 infusions.
Teprotumumab, an insulin-like growth factor I receptor inhibitor, is a fully human monoclonal antibody developed to address a substantial unmet need for patients with thyroid eye disease. The drug blocks the inflamation that underlies thyroid eye disease.
The approval of Teprotumumab (Tepezza) was based on the results of 2 studies of 170 patients with active thyroid eye disease who were randomized to either receive the drug or a placebo. Patients who were administered teprotumumab, 71% in the first study and 83% in second study, demonstrated greater reduction in proptosis compared with 20% and 10% of subjects, respectively, who received placebo, according to the FDA.
The approval marks an important breakthrough for the treatment of thyroid eye disease. Currently, there are very limited treatment options for this debilitating disease. This type of treatment has the potential to change the course of the disease, potentially sparing patients from needing multiple invasive surgeries by providing an alternative, nonsurgical treatment option.
The thyroid eye disease is a rare disease that impacts a small percentage of the population, and for a variety of reasons, treatments for rare diseases are often unavailable. This approval represents important progress in the approval of effective treatments for rare diseases, such as thyroid eye disease.
The most common adverse effects observed in patients treated with teprotumumab are fatigue, alopecia, hyperglycemia, muscle spasm, nausea, diarrhea, hearing loss, dry skin, altered sense of taste and headache. Teprotumumab should be avoided in pregnant women.