Teprotumumab

What it isIGF-1 receptor monoclonal antibody (TEPEZZA, 2020) — the first drug approved for thyroid eye disease, indicated regardless of disease activity or duration; 10 mg/kg IV, then 20 mg/kg every three weeks for seven more infusions, eight in all over 21 weeks.

Why this oneOrbital fibroblasts in thyroid eye disease over-express IGF-1R alongside the TSH receptor; blocking IGF-1R signaling reduces the inflammation and tissue expansion behind the proptosis, so the eyes recede rather than merely stop worsening.

What limits itHearing impairment including hearing loss — which can persist — plus hyperglycemia, exacerbation of inflammatory bowel disease, and infusion reactions; contraindicated in pregnancy. Half-life about 20 days.