Teprotumumab is a human monoclonal antibody that blocks the IGF-1 receptor (IGF-1R). Teprotumumab binds to the extracellular α-subunit domain ligand of IGF-1R. Teprotumumab inhibits TSH and IGF-1 action in fibrocytes. Teprotumumab reduces TSH-dependent IL-6 and IL-8 expression and Akt phosphorylation. Teprotumumab can be used in the study of thyroid-associated eye diseases.