Tepezza is a biologic drug that is the first and only FDA-approved medication used to treat thyroid eye disease (TED). 

Behind your eyes there are tissues with cells that have receptors on their surface that act like light switches. When you have TED your body’s immune system attacks this tissue which causes molecules known as auto antibodies to turn these switches on.  

This leads to swelling to the muscle and fat. This in turn causes eye pain, redness around the eyes, and swollen eyelids. The swollen muscle and fat tissue behind the eye can make eyes bulge and cause double vision.  

Tepezza is designed to bind to the switch and block it from staying on. The two main mediators in TED are thyroid stimulating hormone receptor (TSHR) and insulin growth like factor 1 receptor (IGFR-1).   

In TED autoantibodies activate the IGFR-1R and TSHR signaling complex which stimulate orbital fibroblasts. Orbital fibroblasts are thought to be the cause of the severe inflammation and expansion of muscle and fat behind the eye. Tepezza blocks the IGFR 1R.