Clinical and MRI outcomes of teprotumumab in Japanese thyroid eye disease.

OBJECTIVE

To evaluate and compare the clinical and magnetic resonance imaging (MRI)-based radiologic outcomes of teprotumumab treatment between patients with active thyroid eye disease (TED) with and without dysthyroid optic neuropathy (DON).

DESIGN

Retrospective multicentre study.

PARTICIPANTS

Patients with active moderate-to-severe or sight-threatening TED who completed teprotumumab treatment and a 3-month follow-up after treatment completion.

METHODS

Patients were classified according to the presence or absence of DON. Clinical evaluation included clinical activity score, visual acuity, Hertel exophthalmometric values, and thyroid-stimulating antibody activity. MRI-based quantitative analyses included measurements of extraocular muscle (EOM) volume on T1-weighted images and signal intensity ratio on short tau inversion recovery MRI.

RESULTS

Thirty-one patients were included, comprising 24 patients without DON and 7 patients with DON. After teprotumumab treatment, significant improvements or reductions were observed in visual acuity, clinical activity score, Hertel exophthalmometric values, thyroid-stimulating antibody activity, EOM volume, and signal intensity ratio in all rectus muscles (all P < 0.05). Follow-up MRI showed complete resolution of high-signal inflammatory lesions in all patients. Patients with DON demonstrated significantly greater EOM volume reduction compared with patients without DON (P < 0.050). Adverse events occurred in 77.4% of patients, most commonly otologic symptoms and muscle cramps, although no patient required permanent treatment discontinuation.

CONCLUSIONS

Teprotumumab demonstrated significant clinical and radiologic efficacy in patients with active TED, including those with DON. MRI revealed marked reductions in orbital inflammation and EOM enlargement after treatment, supporting the value of MRI as an objective tool for assessing disease activity and treatment response.