Teprotumumab Effective for Dysthyroid Optic Neuropathy

Teprotumumab continues to demonstrate clinical effectiveness, as shown in a new case report by researchers from Medical College of Georgia at Augusta University. The unique case is one of the first involving a patient with dysthyroid optic neuropathy (DON) to receive primary treatment with this recently approved medication.¹ Michael Lopez presented their results at the 2021 North American Neuro-Ophthalmology Society Annual Meeting.

The case reviewed a 61-years-old male patient who presented with a 4-month history of visual loss and recent onset of hyperthyroidism.¹ In an initial examination, his visual acuity was considerably impacted — counting fingers at 4 feet with the right eye, and 20/50 in the left. Relative afferent pupillary defect (RAPD) was also detected OD. Humphrey visual field analyzer demonstrated multiple scotomas and arcuate defects, especially prevalent in the right eye. Exophthalmos for the patient measured 25 mm OD and 27 mm OS. He could not identify any of the figures in color plates with the right eye, and 7 out of 15 with the left.

Prednisone was prescribed immediately, and teprotumumab therapy began 13 days from his initial visit. He received 2 infusions prior to his 1-month follow-up. “The patient showed rapid improvement in visual acuity, visual field loss, color vision, and reduction in exophthalmos,” the study shows.¹

At 1 month, proptosis improved between 3 mm and 4 mm, and RAPD in the right eye was no longer an issue. The patient’s visual acuity increased to 20/50+1 right and 20/30 left, and he was able to identify all of the figures in color plates with either eye. The patient was then tapered off prednisone in month 2.

By 4 months, he had received 5 teprotumumab infusions. Images of the patient’s orbital region displayed reduced extraocular muscle inflammation and less apical crowding. Best corrected visual acuity reached an essentially normal level at 20/25 OD and 20/20 OS. Exophthalmos decreased to 18 mm right and 21 mm left — lid retraction was lessened, as well. Humphrey visual field analyzer showed substantial improvement in central scotoma OD, and overall improvement in both eyes with diminished arcuate defects.

Teprotumumab is an insulin-like growth factor 1 receptor (IGF-IR) blocker, and is administered by intravenous infusions about 3 weeks apart, with the typical course of 8 doses.² Tepezza, from Horizon Therapeutics Ireland DAC, was approved by the U.S. Food and Drug Administration (FDA) in January 2020, according to an FDA press release.²

The IV infusions, together with corticosteroids proved effective as therapy in this case. “Teprotumumab may be a novel, effective first-line therapy for DON and other forms of thyroid eye disease,” the study says.¹

References

1. Lopez MJ, Thomas C, Thomas DA. Teprotumumab Treats Sight-Threatening Thyroid Eye Disease. Presented at: North American Neuro-Ophthalmology Society Annual Meeting; February 20-23, 2021; Poster 2.
2. Pluchino K. FDA approves first treatment for thyroid eye disease. US Food and Drug Administration. January 21, 2021. Accessed March 12, 2021.