Teprotumumab for the Treatment of Recalcitrant Thyroid Eye Disease
Authors: Men Clara J. , Amarikwa Linus , Pham Brandon , Sears Connie , Clauss Kevin , Lee Bradford W. , Lee Wendy W. , Pasol Joshua , Ugradar Shoaib , Shinder Roman , Cockerham Kimberly , Wester Sara , Douglas Raymond , Kossler Andrea L. 
Published: November 2023

Purpose:
Teprotumumab, an insulin-like growth factor 1 receptor monoclonal antibody, is FDA-approved to treat thyroid eye disease (TED). The initial clinical trials excluded patients with previous orbital irradiation, surgery, glucocorticoid use (cumulative dose >1 gm), or prior biologic treatment. Information on the use of teprotumumab for patients who failed prior therapy is limited. Our purpose is to characterize the efficacy of teprotumumab for the treatment of recalcitrant TED.

Methods:
This is a multicenter retrospective study of all patients treated with teprotumumab for moderate-to-severe TED after failing conventional therapy with corticosteroids, orbital radiation, surgical decompression, biologics, or other steroid-sparing medications. Treatment failure was defined as an incomplete response to or reactivation after previous treatment. Only patients who received at least 4 infusions of teprotumumab were included in the analysis. Primary outcome measures comprised proptosis response (≥2 mm reduction in the study eye without a similar increase in the other eye), clinical activity score (CAS) response (≥2-point reduction in CAS), and diplopia response (≥1 point improvement in Gorman diplopia score in patients with baseline diplopia) following treatment. Adverse events and risk factors for recalcitrant disease were also evaluated.

Results:
Sixty-six patients were included in this study, 46 females and 20 males. Average age was 59.3 years (range 29–93). The mean duration of disease from TED diagnosis to first infusion was 57.8 months. The proptosis, CAS, and diplopia responses in this recalcitrant patient population were 85.9%, 93.8%, and 69.1%, respectively. Patients experienced a mean reduction in proptosis of 3.1 ± 2.4 mm and a mean improvement in CAS of 3.8 ± 1.6. Patients who underwent prior decompression surgery experienced a statistically significant decrease in diplopia response (46.7% vs. 77.5%, p = 0.014) and proptosis response (75.0% vs. 90.9%, p = 0.045) when compared with nondecompression patients. Additionally, there were no significant differences in proptosis, CAS, and diplopia responses between patients with acute (defined as disease duration <1 year) versus chronic (disease duration ≥1 year) TED. While most adverse events were mild to moderate, 4 patients reported serious adverse events related to persistent hearing loss.

Conclusions:
Patients with recalcitrant TED demonstrated a significant improvement after teprotumumab in each of the primary study outcomes. The degree of proptosis reduction, diplopia response, and CAS improvement in the recalcitrant group were similar to those of treatment-naïve patients from the pivotal clinical trials. Patients with a prior history of orbital decompression, however, demonstrated poor improvement in diplopia and less reduction in proptosis than surgery naïve patients. These results indicate that teprotumumab is a treatment option for the treatment of patients with TED recalcitrant to prior medical therapies.