Teprotumumab in advanced reactivated thyroid eye disease.

Purpose: To report the case of a patient with reactivated, refractory thyroid eye disease (TED) treated with teprotumumab. Observations: A 51-year-old female with a 16-year history of thyroid eye disease previously treated with orbital decompression and multiple eyelid surgeries presented in a recurrent flare of the disease. The disease recurrence was refractory to intravenous steroid therapy and only partially responsive to oral steroid therapy, and the patient developed dysthyroid optic neuropathy in the right eye with decreased visual acuity and color vision. Clinical activity score was 8/10 and proptosis measurements were 27 mm OD and 26 mm OS. The patient underwent treatment with eight infusions of teprotumumab coinciding with a low taper of oral prednisone and experienced resolution of dysthyroid optic neuropathy, decrease of clinical activity score to 1, and dramatic improvement in proptosis (17 mm OD, 17 mm OS) and extraocular muscle size on imaging. Thirty weeks after completion of teprotumumab and 2 weeks after the second dose of the COVID vaccine, she experienced another flare and subsequently underwent bilateral orbital decompressions. Conclusion: This case report suggests teprotumumab may be used in patients with reactivation of longstanding thyroid eye disease. Reduction of extraocular muscle size and improvement in proptosis suggest teprotumumab may be disease-modifying even in advanced cases.