Teprotumumab

Graves’ Disease is an autoimmune syndrome involving the thyroid, orbital connective tissues, and some regions of the skin. One manifestation of Graves’ Disease is thyroid-associated ophthalmopathy, or thyroid eye disease, which is characterized by orbital inflammation, tissue remodeling, and fibrosis. As the disease progresses, patients may develop proptosis, strabismus, corneal ulceration, and optic neuropathy. It has been demonstrated that insulin-like growth factor-1 receptors (IGF-1R) are overexpressed by orbital fibroblasts in patients with thyroid eye disease, in addition to being overexpressed on T-cells and B-cells in these patients. It was found that Graves’ Disease IgG molecules could mimic the principal ligand of IGF-1R, insulin-like growth factor-1 (IGF-1), and their binding of IGF-1R induces the expression of chemokines that play roles in tissue remodeling and inflammation. For these reasons, IGF-1R was sought after as a potential therapeutic target for the treatment of thyroid eye disease.

Teprotumumab is a fully human IgG1 monoclonal antibody directed against IGF-1R. It binds to and induces internalization and degradation of these receptors, thus preventing their downstream effects and alleviating symptoms of thyroid eye disease.