People with thyroid eye disease finally have a nonsurgical option for improving proptosis, thanks to the FDA’s approval of Horizon Therapeutics’ teprotumumab (Tepezza). The monoclonal antibody that inhibits insulin-like growth factor 1 is administered once every 3 weeks for a total of 8 infusions.
The approval was met with excitement by ophthalmologists who have long sought an alternative to steroids, radiation and surgery for managing the condition. Lead investigator Raymond Douglas, MD, PhD, told MedPage Today it was a “watershed moment” for thyroid eye disease.
“Teprotumumab is truly a ’game changer’ as it represents a targeted therapy that has been shown in rigorous trials to improve proptosis and even double vision in a significant number of patients,” said Julian Perry, MD, an oculoplastic surgeon at Cleveland Clinic. Dr. Perry serves on the FDA ophthalmic devices panel but was not involved in this approval. He is hopeful that the drug may spare some patients from the debilitating effects of the disease and invasive surgeries.
The FDA’s decision, which comes more than month ahead of the expected decision date of March 8, was based on strong phase 2 and phase 3 clinical evidence. Both studies, which comprised 170 patients, found that more than 70% of patients treated with teprotumumab had significant improvement in proptosis (≥2 mm), compared with only 10 to 20% of placebo groups. More than twice as many patients in the treatment groups achieved complete resolution of diplopia (53% vs. 25%).
The majority of adverse events during the trials were mild to moderate. The most common reactions include muscle spasm, nausea, hair loss, diarrhea, fatigue, hyperglycemia, hearing loss, dry skin, altered sense of taste and headaches.
Late last year, teprotumumab received unanimous support during an FDA advisory committee meeting, in addition to already having been awarded priority review, orphan drug, fast-track and breakthrough therapy designations.
Horizon plans to continue monitoring the drug’s safety and retreatment rates in a larger postmarketing study. The company expects the drug to hit U.S. markets in the upcoming weeks.