Teprotumumab Shows Potential As First Line Therapy for Dysthyroid Optic Neuropathy

Teprotumumab has potential to be used as monotherapy for the treatment of dysthyroid optic neuropathy (DON), according to data presented at the American Society of Ophthalmic Plastic & Reconstructive Surgery 2021 Annual Meeting, held November 11-12 in New Orleans. 

Dysthyroid optic neuropathy (DON), a complication of thyroid eye disease (TED), that occurs in 5% to 9% of patients, is the result of an expansion of orbital fat or muscles, or both. If left untreated this complication can result in permanent vision loss. Traditional modes of treatment include orbital decompression, systemic glucocorticoids, and radiotherapy, according to the report. Recently, teprotumumab, a human monoclonal antibody targeting the insulin-like growth factor I receptor has been approved by the FDA for the treatment of thyroid eye disease and data suggests use of this therapy leads to a decrease in extraocular muscle size as measured by radiography and has proven to be particularly useful in patients with DON who have not responded to conventional treatments. This study reported on early experiences using teprotumumab as the first-line therapy for treating patients with DON.

This study was performed as a retrospective single-center interventional case series. TED patients included in the study were treated with teprotumumab infusions of 10 mg/kg for the first infusion, followed by 20 mg/kg for subsequent infusions every 3 weeks for a total of 8 infusions. Baseline and post-treatment data gathered included Snellen best-corrected visual acuity (BCVA), pupil exam, color vision, dilated exam, and automated Humphrey visual fields (HVF) after the 2nd, 4th, 6th, and 8th infusions were completed. 

All patients assessed showed improvements in BCVA and HVF in addition to normalization of color vision and relative afferent pupillary defect with teprotumumab treatment. After the second infusion, all patients showed significant improvement in all variables tested. In all cases, clinical improvement remained stable or continued for the full follow-up period. Additionally, no patients required subsequent surgical decompression, steroids, or radiotherapy. With a mean follow-up of 5.5 months, no patients had a recurrence of symptoms. Only 1 mild adverse event was noted, related to muscle cramps, in a single patient. 

Overall, researchers concluded that teprotumumab led to significant improvement in resolving DON in patients with TED and while larger prospective studies are needed, preliminary data indicates teprotumumab is extremely promising. 

Reference

Artymowicz A, Shinder R. Teprotumumab as monotherapy for dysthyroid optic neuropathy. Poster presented at: American Society of Ophthalmic Plastic & Reconstructive Surgery 2021 Annual Meeting; November 12-15, 2021; New Orleans, LA.

This article originally appeared on Ophthalmology Advisor