Teprotumumab in thyroid eye disease: wonder drug or great divider?

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

This was a study of all patients followed for active thyroid eye disease at the Cole Eye Institute, Cleveland Clinic, treated with teprotumumab between May 2020 and May 2021. Patients with less than 6 months follow-up after completion of infusions were excluded. The primary outcome measure was reactivation, defined as a regression in proptosis (increase of ≥2 mm in either eye and to within ≤2 mm of pre-treatment level and Clinical Activity Score [CAS] worsening of 2 points or greater). Secondary outcome was diplopia response.

RESULTS

A total of 21 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 to 4 mm). Of the 17 initial responders, there were 8 reactivations (47%) and 2 isolated proptosis regressions (12%); Overall, 7 of 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 to >.99).

CONCLUSIONS

At most, 33% of patients demonstrate continued response 2 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.

Efficacy and Safety of Teprotumumab in Patients With Thyroid Eye Disease of Long Duration and Low Disease Activity

CONTEXT

Early inflammatory thyroid eye disease (TED) can lead to symptomatic chronic disease, including disabling proptosis. Teprotumumab, an insulin-like growth factor-1 receptor (IGF-1R) inhibitor, previously demonstrated efficacy in acute, high-inflammation TED trials.

OBJECTIVE

We present data from the first placebo-controlled trial with teprotumumab in chronic/low disease activity TED.

METHODS

This randomized double-masked, placebo-controlled trial, conducted at 11 US centers, enrolled adult participants with TED duration of 2 to 10 years, Clinical Activity Score (CAS) ≤ 1 or no additional inflammation or progression in proptosis/diplopia for ≥1 year, proptosis ≥3 mm from before TED and/or from normal, euthyroid/mildly hypo/hyperthyroid, no prior teprotumumab, and no steroids within 3 weeks of baseline. Patients received (2:1) intravenous teprotumumab or placebo once every 3 weeks (total 8 infusions). The primary endpoint was proptosis (mm) improvement at Week 24. Adverse events (AEs) were assessed.

RESULTS

A total of 62 (42 teprotumumab and 20 placebo) patients were randomized. At Week 24, least squares mean (SE) proptosis improvement was greater with teprotumumab (-2.41 [0.228]) than with placebo (-0.92 [0.323]), difference -1.48 (95% CI -2.28, -0.69; P = .0004). Proportions of patients with AEs were similar between groups. Hyperglycemia was reported in 6 (15%) vs 2 (10%) and hearing impairment in 9 (22%) vs 2 (10%) with teprotumumab and placebo, respectively. AEs led to discontinuation in 1 teprotumumab (left ear conductive hearing loss with congenital anomaly) and 1 placebo patient (infusion-related). There were no deaths.

CONCLUSION

Teprotumumab significantly improved proptosis vs placebo in longstanding/low inflammation TED, demonstrating efficacy regardless of disease duration/activity. The safety profile was comparable to that previously reported.