Objective Diplopia Outcomes for Patients Treated With Teprotumumab for Thyroid Eye Disease

Abstract

Background: Thyroid eye disease (TED) is a condition caused by inflammatory damage to the periocular tissue that often leads to double vision. Teprotumumab is an insulin-like growth factor 1 receptor antibody that was FDA approved for the management of TED in 2020, although much is yet to be elucidated regarding its effects on diplopia outcomes among patients with TED. Diplopia is a significant and life-altering effect of TED. Previous studies have reported the effect of teprotumumab on double vision subjectively using the Gorman diplopia score. However, there is a gap in the literature addressing the effect of teprotumumab treatment on objective ocular alignment measures. The purpose of our study was to address this gap. Methods: We performed a retrospective review of patients who were diagnosed with TED, presented with diplopia, and treated with teprotumumab in a single-center academic ophthalmology practice. The primary outcome was change in ocular alignment in primary gaze position at 6 months (completion of teprotumumab treatment). Secondary outcomes included change in ocular alignment in other gaze positions, proptosis, eyelid position, and clinical activity score (CAS) at 6 months compared with baseline. To determine what factors may predict ocular alignment response to teprotumumab, we analyzed baseline characteristics among 3 groups, divided based on whether ocular alignment was worsened, stable, or improved at 6 months. Results: Seventeen patients met inclusion criteria, 3 (18%) worsened, 10 (59%) were stable, and 4 (24%) improved. CAS (P = 0.02) was significantly different among the groups and was higher in those who worsened and those who improved compared with those who remained stable. Right gaze horizontal prism deviation (P = 0.01) and left gaze horizontal prism deviation (P = 0.03) were significantly different among the groups, with a greater degree of left gaze horizontal prism deviation in the worse group than the stable group (P = 0.04). Conclusions: Our study demonstrated that most patients remained stable after teprotumumab treatment regarding ocular alignment in primary gaze and the number of patients who improved was slightly higher than the number of patients who worsened after teprotumumab treatment. There are some baseline measures, such as CAS and right and left gaze horizontal prism deviation that can help better predict how a patient will respond to teprotumumab treatment. Our results can better inform physicians of how to counsel patients with TED when considering teprotumumab therapy.