Echographic Assessment of Extraocular Muscle Response to Teprotumumab

Abstract

Purpose: To evaluate extraocular muscle response to teprotumumab using orbital echography in thyroid eye disease.

Methods: This retrospective study included adult thyroid eye disease patients with pre- and post-teprotumumab orbital echography. Data collected included: age, Hertel measurements, clinical activity score, Gorman diplopia scores, ocular motility, and recti muscle diameters measured by echography. The patient's more proptotic eye before treatment initiation was designated as the study orbit. Ocular motility was assessed by totaling the ductions in all 4 cardinal directions. Orbital echography was obtained pre- and post-treatment to assess response of extraocular muscle diameters.

Results: Six patients with a mean age of 67 years were included. There was a mean improvement in proptosis of 4.3 mm in the study eye with 11/12 orbits showing improvement in globe position ( p < 0.05). All patients had a decrease in clinical activity score with a mean reduction of 2.5. Four patients had an improvement in Gorman diplopia score. Ocular motility in the study orbits improved by a total mean of 26.9° ( p < 0.05). Mean total extraocular muscle diameter was reduced from 27.4 to 23.4 mm ( p < 0.001). On average, superior recti were largest pre- and post-treatment, followed by inferior, medial, then lateral recti. However, inferior recti showed the greatest reduction of 23% ( p < 0.02).

Conclusions: Orbital echography demonstrated extraocular muscle reduction in all patients after teprotumumab, correlating with improved clinical activity score, ocular motility, and proptosis. Orbital echography is a safe and cost-effective imaging alternative to monitor therapeutic response to teprotumumab.