Tocilizumab - a disease-modulating treatment for thyroid associated ophthalmopathy?

Purpose: To analyze Tocilizumab (TCZ, an interleukin 6 inhibitor) as a second-line treatment for thyroid-associated ophthalmopathy (TAO).

Methods: In this retrospective observational study, the charts of patients with moderately severe to severe TAO who received intravenous Tocilizumab as a second-line treatment 2020-2023 were reviewed.

Results: Twenty-three patients were enrolled in the study. At the follow-up visit 24 weeks after the initiation of treatment, 14 out of 22 patients (63.6%, one missing data) had a reduction of proptosis of 2 mm or more. The mean proptosis decreased from 21.07 (±3.23) to 19.18 (±2.52) mm in the right eye (RE) and from 20.61 (±3.12) to 19.95 (±2.81) mm in the left eye (LE). Twenty patients (87%) also showed a reduction of the clinical activity score (CAS) of at least two points with a mean decrease from 5.22 (±1.53) pre-treatment to 2.09 (±1.38) post-treatment points. The median patient total follow-up time after treatment was ten (range 6-26) months. The comparisons reached strong significance between pre-treatment and 24 weeks, as well as pre-treatment and final visit assessments for both proptosis and clinical activity scores. Serum TRAb levels also dropped significantly, and only two patients needed re-treatment with TCZ. Improvement of diplopia did not reach statistical significance.

Conclusions: Intravenous Tocilizumab as a second-line treatment for TAO led to a significant improvement of proptosis and CAS at 24 weeks follow-up, with a sustained effect over time.