Reactivation After Teprotumumab Treatment for Active Thyroid Eye Disease

Purpose To determine the recurrence and reactivation rates after teprotumumab therapy for active thyroid eye disease. Design Retrospective consecutive case series. Methods Setting: Institutional, Study Population: All patients followed for active thyroid eye disease at the Cole Eye Institute treated with teprotumumab between May 2020 and May 2021. Patients with under 6-months follow-up after completion of infusions were excluded., Outcome Measures: Primary outcome measure was reactivation, defined as a regression in proptosis (increase of ≥2mm in either eye and to within ≤ 2mm of pre-treatment level) and CAS (worsening of 2 points or greater). Secondary outcome was diplopia response. Results Twenty-one patients were included in the study. The average long-term improvement in proptosis in the eye with more proptosis after teprotumumab was 1.57mm (range, -3-4 mm). Of the 17/21 of initial responders, there were 8 reactivations (47%) and 2 isolated proptosis regressions (12%); Overall, 7/21 patients (33%) responded throughout the study period. Average time to regression was 12.25 months (range, 2-22.5 months). There was no statistically significant change in diplopia at final visit in any subgroup (p=0.68->0.99). Conclusions At most, 33% of patients demonstrate continued response two years after teprotumumab treatment. The proptosis and CAS regression occurs in the setting of disease reactivation in 80% of regressions. Teprotumumab treatment appears to offer minimal long term improvement in diplopia.