New monoclonal antibody for thyroid eye disease
David B Granet MD
FACS FAAP FAAO
The introduction and FDA approval of the monoclonal antibody teprotumumab (Tepezza, Horizon Therapeutics) heralds a new era in the treatment of thyroid eye disease, said David B Granet, MD FACS FAAP FAAO, Shiley Eye Center, University of California, San Diego, US.
“We used to say that in the future thyroid eye disease will be stopped with medication and not the scalpel. The future has arrived,” Dr Granet told the 2020 WSPOS Virtual Meeting.
The human monoclonal antibody was approved for use in the United States in January 2020. It binds to the insulin-like growth factor 1 receptor (IGF-1R) and by doing so also inhibits thyroid-stimulating hormone (TSH). In this way it inhibits the inflammatory cascade thereby reducing oedema and glycosaminoglycan production. It is administered intravenously at a dosage of 20mg/kg in eight cyles over 24 weeks, Dr Granet noted.
The FDA approved teprotumumab based on two randomised controlled studies showing a greater than 2.0mm reduction in proptosis in 71% and 83% of patients receiving the monoclonal antibody, compared to 20% and 10% of control patients. Dr Granet presented two case studies, one with active disease and the other with chronic disease, whose eyes in both cases returned to their normal state after completing eight cycles of treatment.
“This is a game changer; however, there are side-effects and of course we have to pay attention to the teratogenicity of this in someone who might be pregnant. There may be relapses as well and it is expensive,” Dr Granet added.